As 1715 Selection Use Maint of Respiratory Protective Device

AS/NZS 1715:1994

Australian/New Zealand Standard

Accessed by Clough Engineering on 05 Sep 2001

Selection, use and maintenance of respiratory protective devices

AS/NZS 1715:1994 This Joint Australian/New Zealand Standard was prepared by Joint Technical Committee SF/10, Industrial Respiratory Protection. It was approved on behalf of the Council of Standards Australia on 17 March 1994 and on behalf of the Council of Standards New Zealand on 27 April 1994. It was published on 16 May 1994.

The following interests are represented on Committee SF/10:


Australian Assembly of Fire Authorities Australian Institute of Petroleum Composites Institute of Australia Confederation of Australian Industry County Fire Authority, Australia Department of Defence, Australia Department of Labour, Victoria Department of Minerals and Energy, N.S.W. Electricity Supply Association of Australia Gas Fuel Corporation, Victoria Metal Trades Industry Association, Australia Safety Institute of Australia Water Board, Sydney—Illawarra—Blue Mountains WorkCover Authority of N.S.W.

Review of Standards. To keep abreast of progress in industry, Joint Australian/New Zealand Standards are subject to periodic review and are kept up to date by the issue of amendments or new editions as necessary. It is important therefore that Standards users ensure that they are in possession of the latest edition, and any amendments thereto. Full details of all Joint Standards and related publications will be found in the Standards Australia and Standards New Zealand Catalogue of Publications; this information is supplemented each month by the magazines ‘The Australian Standard’ and ‘Standards New Zealand’, which subscribing members receive, and which give details of new publications, new editions and amendments, and of withdrawn Standards. Suggestions for improvements to Joint Standards, addressed to the head office of either Standards Australia or Standards New Zealand, are welcomed. Notification of any inaccuracy or ambiguity found in a Joint Australian/New Zealand Standard should be made without delay in order that the matter may be investigated and appropriate action taken.

AS/NZS 1715:1994

Australian/New Zealand Standard Selection, use and maintenance of respiratory protective devices

For history before 1994 see Preface.


Jointl y revised and designated as Joint Standard AS/NZS 1715:1994.

PUBLISHED JOINTLY BY: STANDARDS AUSTRALIA 1 The Crescent, Homebush NSW 2140 Australia STANDARDS NEW ZEALAND Level 10, Radio New Zealand House, 155 The Terrace, Wellington 6001 New Zealand ISBN 0 7262 8878 0

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PREFACE This Standard was prepared by the Joint Australia/New Zealand Standards Committee SF/10 on Industrial Respiratory Protection to supersede AS 1715— 1991. This Standard is issued as a Joint Standard under the terms of the Active Cooperative Agreement between Standards Australia and Standards New Zealand. This Standard was revised in 1994 with the objective of taking account of the changes to AS/NZS 1716:1994, Respiratory protective devices, and problems of interpretations that have arisen since AS 1715 was last published in 1991. As most readers will not need to refer to the performance and testing specification AS/NZS 1716:1994, the listings of definitions and referenced Standards have been expanded to include several new definitions and Standards to aid the reader’s understanding of the text. The list of regulatory authorities has been revised. Throughout the text, examples of types of chemicals or other technical concepts have been expanded. Additional warnings about the possible misuse of respirators have also been included. Qualitative facial fit testing has been retained as being a suitable means of monitoring a respirator program. It has been the aim of the Committee to further explain that the provision of a respirator is only part of ensuring an overall system of respiratory protection for all employees. The history of the Standards which have been revised and amalgamated to form this Standard is as follows: In Australia, AS CZ11 was first published in 1960 and revised in 1968. This Standard was revised and redesignated AS 1715 in 1975, with a second edition in 1982 and a third edition in 1991. In New Zealand the Standard was first published in 1961 in part as NZS 1586, being an endorsement of BS 2091:1954 with amendments. NZS 1586 was superseded in part by NZS 2267 in 1969. NZS 2267 was replaced in part by NZS/AS 1715-1991 (harmonized) in 1992. Requirements for the performance and testing of respiratory protective devices are not covered in this Standard but are specified in AS/NZS 1716:1994.


Additional relevant Standards which may assist with the selection, care and use of respiratory devices have been specified under the heading of Related Documents (Clause 1.4). The terms ‘normative’ and ‘informative’ have been used in this Standard to define the application of the appendix to which they apply. A ‘normative’ appendix is an integral part of a Standard, whereas an ‘informative’ appendix is only for information and guidance.

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CONTENTS Page SECTION 1 SCOPE AND GENERAL 1.1 SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 GENERAL PRINCIPLES . . . . . . . . . . . . . . . . 1.3 REFERENCED DOCUMENTS . . . . . . . . . . . . 1.4 RELATED DOCUMENTS . . . . . . . . . . . . . . . 1.5 DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . .

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SECTION 2 ENTRY OF SUBSTANCES INTO THE BODY 2.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 INHALATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 ABSORPTION . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 INGESTION . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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SECTION 3 OXYGEN-DEFICIENT ATMOSPHERES 3.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3.2 ATMOSPHERIC COMPOSITION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3.3 SYMPTOMS OF OXYGEN DEFICIENCY . . . . . . . . . . . . . . . . . . . . . . . . . 17


SECTION 4 HAZARD RECOGNITION, EVALUATION AND CONTROL 4.1 RECOGNITION OF HAZARDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.2 HAZARD EVALUATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.3 HAZARD CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 SECTION 5 TYPES OF RESPIRATOR 5.1 METHOD OF PROVIDING PERSONAL RESPIRATORY PROTECTION . . 5.2 TYPES OF RESPIRATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3 AIR-PURIFYING RESPIRATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4 SUPPLIED AIR RESPIRATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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SECTION 6 SELECTION OF RESPIRATORS 6.1 FACTORS IN SELECTION . . . . . . . . . . . . . . . . . . . . 6.2 SELECTION FACTORS—CONTAMINANT-RELATED 6.3 SELECTION FACTORS—TASK-RELATED . . . . . . . . 6.4 SELECTION FACTORS—OPERATOR-RELATED . . . .

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SECTION 7 THE RESPIRATORY PROTECTION PROGRAM 7.1 MANAGEMENT RESPONSIBILITY . . . . . . . . . . . . . . . . . . 7.2 COMPLIANCE OF EQUIPMENT . . . . . . . . . . . . . . . . . . . . 7.3 MEDICAL SCREENING . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4 ISSUE OF RESPIRATORS . . . . . . . . . . . . . . . . . . . . . . . . . 7.5 FACIAL FIT TESTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6 CLEANING AND MAINTENANCE . . . . . . . . . . . . . . . . . . 7.7 INSPECTION FOR DEFECTS . . . . . . . . . . . . . . . . . . . . . . 7.8 INSPECTION AND MAINTENANCE CONSIDERATIONS . 7.9 SAFE WORKING PRACTICES . . . . . . . . . . . . . . . . . . . . .

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Page 7.10 REPLACEMENT OF FILTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 7.11 ENSURING THE CONTINUED EFFECTIVENESS OF THE RESPIRATOR PROGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 7.12 TRAINING IN RESPIRATORY PROTECTION USAGE . . . . . . . . . . . . . . . 51 SECTION 8 SPECIFIC MAINTENANCE REQUIREMENTS 8.1 SERVICING FACEPIECES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 8.2 SERVICING EXHALATION VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 8.3 SERVICING OTHER COMPONENT PARTS . . . . . . . . . . . . . . . . . . . . . . . 52 APPENDICES A REQUIREMENTS FOR AIR QUALITY (COMPRESSORS OR CYLINDERS) FOR SUPPLIED AIR RESPIRATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 B ADVISORY AUTHORITIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 C RESPIRATOR SELECTION EXAMPLES . . . . . . . . . . . . . . . . . . . . . . . . . 57 D TYPICAL RESPIRATOR FIT TESTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 E FACIAL SEAL OF RESPIRATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 F EMPLOYEE TRAINING PROGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 G TYPICAL METHOD OF MEASURING VALVE LEAKAGE . . . . . . . . . . . . 71 H COMPRESSED BREATHING AIR FILTRATION SYSTEMS . . . . . . . . . . . 73 I TYPICAL METHOD OF MEASURING INHALATION AND EXHALATION RESISTANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 J CHECKPOINTS FOR RESPIRATOR PROGRAM ADMINISTRATION AND OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77


INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

 Copyright

STANDARDS AUSTRALIA/ STANDARDS NEW ZEALAND

Users of Standards are reminded that copyright subsists in all Standards Australia and Standards New Zealand publications and software. Except where the Copyright Act allows and except where provided for below no publications or software produced by Standards Australia or Standards New Zealand may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing from Standards Australia or Standards New Zealand. Permission may be conditional on an appropriate royalty payment. Australian requests for permission and information on commercial software royalties should be directed to the head office of Standards Australia. New Zealand requests should be directed to Standards New Zealand. Up to 10 percent of the technical content pages of a Standard may be copied for use exclusively in-house by purchasers of the Standard without payment of a royalty or advice to Standards Australia or Standards New Zealand. Inclusion of copyright material in computer software programs is also permitted without royalty payment provided such programs are used exclusively in-house by the creators of the programs. Care should be taken to ensure that material used is from the current edition of the Standard and that it is updated whenever the Standard is amended or revised. The number and date of the Standard should therefore be clearly identified. The use of material in print form or in computer software programs to be used commercially, with or without payment, or in commercial contracts is subject to the payment of a royalty. This policy may be varied by Standards Australia or Standards New Zealand at any time.

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STANDARDS AUSTRALIA / STANDARDS NEW ZEALAND Australian/New Zealand Standard Selection, use and maintenance of respiratory protective devices S E C T I O N

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S C O P E

A N D

G E N E R A L

1.1 SCOPE This Standard sets out the principles of respiratory protection and makes recommendations for the selection, use and maintenance of personal respiratory protective devices (respirators) for the protection of the body against atmospheres deficient in oxygen or against harmful substances which could enter the body through the respiratory system, or both. Harmful substances may be in the form of dusts, mists, fumes, smokes, gases and vapours, or combinations of these substances. This Standard does not deal with the special problems connected with diving and underwater breathing (see AS 2299), the use of respirators in aircraft, or the use of life support respirators for medical or resuscitation purposes. Design, manufacturing and type approval test requirements for respiratory protective devices are not covered in this Standard, but are specified in AS/NZS 1716. 1.2 GENERAL PRINCIPLES The following principles should be observed in the protection of the body against the effects of harmful substances: (a) No person should be exposed without suitable protection to an atmosphere that is or may be injurious to health. There are substances which are irritant to or which can be absorbed through the skin. Where an atmosphere containing such substances is to be entered, respiratory protection alone is not sufficient and appropriate protective equipment and clothing should be used. (b) Where the workplace atmosphere is or may become contaminated, a regular system of testing by a properly trained and responsible person using suitable equipment should be undertaken.


(c) Every effort should be made to prevent the release of harmful substances into the working environment. This may be achieved through the design of buildings, plant and equipment; or by work procedures and controls (e.g. extraction systems) to obviate the need for respirators. (d) If efforts to prevent or control the hazard at the source are unsuccessful, suitable respirators should be provided and used. (e) In emergencies where contaminants may be released into the atmosphere, suitable respirators should be provided and worn. 1.3 REFERENCED DOCUMENTS The following documents are referred to in this Standard: AS 1020

The control of undesirable static electricity

1210

Unfired Pressure Vessels (known as the SAA Unfired Pressure Vessels Code)

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AS 1319

Safety signs for the occupational environment

1345

Identification of the contents of piping, conduits and ducts

2030

2030.1

The approval, filling, inspection, testing and maintenance of cylinders for the storage and transport of compressed gases (known as the SAA Gas Cylinders Code) Part 1: Cylinders for compressed gases other than acetylene

2299

Occupational diving

2337 2337.1

Gas cylinder test stations Part 1: General requirements, inspections and tests — Gas cylinders

2380 2380.2 2380.7

Electrical equipment for techniques Flame proof enclosure d Intrinsic safety i

2865

Safe working in a confined space

2985

Workplace atmospheres—Method for sampling and gravimetric determination of respirable dust

3765 3765.1 3765.2

Clothing for protection against hazardous chemicals Part 1: Protection against general or specific chemicals Part 2: Limited protection against specific chemicals

SAA MP69

Explosion-protected electrical equipment —Certification scheme — Policy

AS/NZS 1716

Respiratory protective devices

explosive

atmospheres— Explosion-protection

ISO TR 7708 Air quality — Particle size fraction definitions for health-related sampling NOHSC* Exposure standards for atmospheric environment (first published May 1990)

contaminants

in

the

occupational

1.4 RELATED DOCUMENTS The following documents are specified as references to assist with the selection, care and use of respiratory devices:


AS 1470

Health and safety at work—Principles and practices

2986

Workplace atmospheres—Organic vapours—Sampling techniques

3640

Workplace atmospheres—Method for sampling and gravimetric determination of inspirable dust

1.5 1.5.1

by solid adsorption

DEFINITIONS For the purpose of this Standard, the definitions below apply. Acute—health effects of rapid onset.

1.5.2 Air-hose respirator—a device, used with a facepiece or headcovering, through which respirable air from a source remote from the workplace is made available to the wearer through an air hose at near atmospheric pressure.

*National Occupational Health and Safety Commission COPYRIGHT

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1.5.3 Air-line respirator—a device through which air, at greater than atmospheric pressure, from a source of compressed air capable of providing breathing air of the quality defined in Appendix A, is supplied to the wearer by means of an air-line. 1.5.4

Air-purifying respirator—a device which filters contaminants from inhaled air.

1.5.5 Atmospheric contaminant—any substance, either gaseous or particulate, which is not a constituent of the normal atmosphere or which is present in a concentration greater than that found in the normal atmosphere. 1.5.6

Breathing air — see respirable air.

1.5.7

Chronic—health effects which may have a slow onset and are long lasting.

1.5.8 Combination filter respirator—a device combining the filtration capabilities of gas and particulate filters. The filters may be a single unit (integral) or consist of separate filters in series to form one unit (combination). 1.5.9 Demand valve—a device for the controlled release of air or oxygen actuated by a reduction in pressure created by the action of inhalation. The regulation may be such that the pressure inside the facepiece is maintained above atmospheric pressure (positive pressure type) or falls to below atmospheric pressure (negative pressure type) during the inhalation phase. 1.5.10 Disposable respirator—a device for which maintenance is not intended and which is designed to be discarded after excessive resistance, sorbent exhaustion, physical damage or end of service-life renders it unsuitable for use. 1.5.11 Dust—solid particles suspended in the air as a result of the disintegration of matter. Dust may be generated by mechanical means. 1.5.12 Escape type respirator—a device for emergency escape from a respiratory hazard. 1.5.13 Facial fit check—a quick check to ensure that the respirator is fitting each time it is donned, e.g. positive and negative pressure fit checks. 1.5.14 Facial fit test—a validated method of matching a specific respirator to an individual. 1.5.15 Filter—a component of air-purifying respirators through which inhaled air passes and which removes particulates or certain gases or both. Filters may form part of the construction of the facepiece, may be attached to the facepiece or may be carried separately and connected to the facepiece by a breathing hose.


1.5.16 Filtration type escape respirator—a device incorporating filters which removes certain particulates and gases or vapours from the air inhaled by the wearer for a limited time during escape from a respiratory hazard. 1.5.17 Full facepiece—a close fitting device to cover the eyes, nose and mouth and be secured in position by suitable means. 1.5.18 Fume—particles forming an airborne suspension. Fuming is usually caused by the heating of a solid to such an extent that it vaporizes and then condenses into small particles in the surrounding air. Fume may be termed a thermally generated particulate. NOTE: Within the context of this Standard the term fume does not include vapours, gases or a combination of these.

1.5.19 Gas—a substance which is airlike. It is neither solid nor liquid at room temperature. The term gas in this Standard also includes vapours. 1.5.20 Gas filter—a filter designed to remove certain substances in gaseous or vapour form from the inhaled air.

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1.5.21 Gas filter respirator—a device consisting of a half facepiece, full facepiece or head covering or mouthpiece with a filter which removes certain gases or vapours from the air to be inhaled by the wearer for a limited time. It may also incorporate a filter to remove particulates. 1.5.22 Half facepiece—a close fitting device to cover the nose, mouth and chin and be secured in position by suitable means. 1.5.23 Head covering—a hood, blouse or helmet covering all or most of the head and extending where appropriate to the shoulders or waist. It may include sleeves and is secured in position by suitable means. 1.5.24 Hose-mask respirator —a respirator, used with a full facepiece through which respirable air from a source remote from the workplace is available to the wearer through an air hose at atmospheric or near atmospheric pressure. 1.5.25 Immediately dangerous to life and health (IDLH)—exposure to an atmosphere that poses an immediate adverse effect on health or the ability to escape. 1.5.26 Informative—describes material which does not form an integral part of the Standard but provides additional information and, for reasons of convenience, is placed after the body of the Standard. NOTE: An informative appendix does not contain conditions that are mandatory.

1.5.27 Inspirable fraction—those airborne particles which are taken through the nose or mouth during breathing and which have been so defined by the International Standards Organization in ISO/TR 7708. 1.5.28

Local effects—reactions by parts of the body in contact with a contaminant.

1.5.29

Mechanically generated particulates—see dust and mist.

1.5.30 Mist—airborne droplets. The droplets may carry substances in solution or particles in suspension. Mists are usually formed by the condensation of vapour but may be produced by the atomization of a liquid (see dust). 1.5.31 Mouthpiece—a device, designed to be held in the mouth, through which all breathing air passes. Normally used in conjunction with a nose clip. 1.5.32 Natural breathing—the normal breathing action of the wearer draws air into the facepiece through filters or wide bore tube. The pressure inside the respirator is at or near atmospheric pressure. 1.5.33 Normative—describes material which is an integral part of the body of the Standard and, for reasons of convenience, is placed after the body of the Standard.


NOTE: All requirements set out in a normative appendix must be met for compliance with this Standard.

1.5.34 Nose clip—a device designed to occlude the nostrils to prevent air inhalation. Normally used in conjunction with a mouthpiece. 1.5.35 Occupational hygiene — the application of scientific methods and principles, and the appropriate technological and managerial measures to the overall assessment of working conditions. NOTE: This includes the anticipation, recognition, evaluation, and control of the occurrence of any substance, physical or biological agencies at or related to the workplace which would otherwise adversely affect the health, comfort or efficiency of the workforce, or the well-being of their families and community.

1.5.36

Occupational hygienist —a practitioner of occupational hygiene.

1.5.37 Oxygen-deficient atmosphere—an atmosphere which does not contain enough oxygen to fully support the body’s metabolic processes. It is generally acknowledged that an atmospheric concentration below 18% by volume is deficient in oxygen. COPYRIGHT

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1.5.38 Oxygen generating respirator—a device which generates oxygen by means of a chemical reaction for use by a wearer in a contaminated atmosphere or one lacking in oxygen. 1.5.39 Particulates—a generic term used in this Standard to refer to particulate aerosols such as dusts, mists, smoke, and fumes. NOTE: As the word ‘particulate’ is defined as an adjective (not a noun) in the dictionary, the definition used in this Standard describes the common usage of the word in industry.

1.5.40 Particulate filter—a filter designed to remove solid or liquid aerosols or both from the inhaled air. 1.5.41 Particulate filter respirator—a device consisting of a half facepiece, full facepiece or head covering with particulate filter or filters which remove finely divided solids or liquid matter from the air to be inhaled by the wearer. The filter medium may be replaceable or be an integral part of the construction. 1.5.42 Powered air-purifying respirator—a device incorporating a half facepiece, full facepiece or head covering which provides the wearer with air filtered through a powered filtering unit, comprising a filter or filters, and an electrically operated blower unit. This respirator is referred to as a PAPR. 1.5.43 Protection factor—a measure of the degree of protection afforded by the respirator, defined as the ratio of the concentration of contaminant outside the respirator to that inside the respirator. 1.5.44 Qualitative fit test—a facial fit test giving pass/fail results and relying on the subject’s response to a test agent. 1.5.45 Quantitative fit test—a facial fit test giving numerical results and not relying on the subject’s response to a test agent. 1.5.46 Regulatory authority—a minister of the Crown, a government department, or commission, or a statutory or public authority having power to issue regulations, orders, or other instructions having the force of law in respect of any subject covered by this Standard. NOTE: A listing of Australian regulatory, advisory and other authorities is given in Appendix B.

1.5.47 Required minimum protection factor—the protection factor required to reduce exposure to an accepted level. It is expressed as a ratio of the measured ambient airborne concentration of a contaminant to an acceptable exposure level or standard.


1.5.48 Respirable air — air of quality intended to be suitable for human respiration (see Appendix A). 1.5.49 Respirable dust fraction—the definition of ‘respirable’ particles is that adopted by the British Medical Research Council (BMRC) and the recommendation of the Pneumoconiosis Conference held in Johannesburg in 1959. This definition has been adopted by Worksafe Australia and is described in AS 2985. 1.5.50 Respirator—a personal respiratory protective device which is designed to prevent the inhalation of contaminated air. 1.5.51 Self-contained breathing apparatus (SCBA)—a portable respirator which supplies oxygen, air or other respirable gas from a source carried by the user. 1.5.52 Single use low-boiling point filter — a category of filter intended to be used solely against low boiling point organic compounds during a single eight-hour shift, where the total logged period of use does not exceed the minimum specified absorption time of the filter. It is intended that the filter be discarded after such a period of use. 1.5.53

Shall—indicates that a statement is mandatory. COPYRIGHT

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Should—indicates a recommendation.

1.5.55 Smoke—particles of low vapour pressure suspended in the air. Smoke is made up from the solid and liquid products of combustion. Smoke particles settle slowly under gravity. NOTE: Normally, the combustion process producing smoke also produces gases.

1.5.56

Sorbent—filter medium which captures gases by chemical or physical means.

1.5.57 Supplied-air respirator—a source of respirable air, independent of the work environment, which is conveyed to the person through an air line, air hose or by the person carrying apparatus which provides the air. 1.5.58 Supplied-oxygen respirator—a device whereby oxygen is supplied from a source of liquid or compressed oxygen carried by the wearer. 1.5.59 Systemic effect—reactions of the body to absorbed contaminants remote from the point of entry. 1.5.60

Thermally generated particulates — see fume and smoke.

1.5.61 Toxicity —a substance’s potential to poison. All substances are toxic, their impact depending on how much is required to be harmful (dose), e.g. beryllium is highly toxic and fresh water is relatively non-toxic. 1.5.62 Vapour—the gaseous form of a substance which is a solid or liquid at room temperature.


1.5.63 Work sets—self-contained breathing apparatus designed for general entry to or working in an area with airborne contaminants or oxygen deficiency.

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S E C T I O N

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E N T R Y O F S U B S T A NC E S T H E B O D Y

AS/NZS 1715:1994

I N T O

2.1 GENERAL In many working environments, employees are exposed to a variety of substances which may be in the form of a gas, vapour, dust, mist, fume or smoke. Not all substances that are present in the working environment have been tested for their toxicological effects; however, all substances are capable of causing harm if exposure is sufficiently high. For airborne substances with defined properties and known toxic effects, reference shall be made to the National Occupational Health and Safety Commission document, Exposure Standards for Atmospheric Contaminants in the Occupational Environment, to ensure the safety of employees. A substance may exert a harmful effect if it comes into contact with a susceptible site in or on the body. The basic routes of entry into the body of gaseous substances are inhalation, skin absorption and ingestion. Other entry routes include skin abrasions, skin penetration and deep wounds. NOTE: Tobacco smoke is known to enhance the toxicological effects of some gases and many particulates.

2.2

INHALATION

2.2.1 General Inhalation is by far the most common route by which substances gain entry to the body. The main anatomical features of the respiratory system are shown in Figure 2.1. Air inhaled through the nose and mouth is warmed and moistened. The large airways, or bronchii, are protected by a thick layer of mucus which is moved to the throat by millions of hair-like projections called cilia. The small airways or bronchioles have attached to them three to six clusters of extremely small sacs called alveoli. There are approximately 300 million alveoli in the lungs, providing a very large surface area. The air in the alveoli is separated from blood capillaries by a thin membrane (0.2 µm), which allows almost instantaneous transfer of gases to and from the bloodstream. 2.2.2 Inhalation of gaseous contaminants These contaminants occur as individual molecules similar to those in the air we breathe and so can gain easy access to the bloodstream. Gases are classified according to their effect on the body as follows:


(a)

Irritants—may be gases which are readily water soluble and cause irritation of the nose and upper respiratory tract, for example ammonia (NH3 ) and hydrogen chloride (HCl). Alternatively, irritant gases which are relatively water insoluble, e.g. nitrogen dioxide (NO 2), will reach deeper into the lungs where irritation and absorption into the bloodstream will occur. Upper respiratory tract irritants generally have good warning properties—they are immediately noticed and the worker will usually leave the area promptly. Lower respiratory tract irritants, however, are difficult to perceive initially. Often the exposed worker is unaware of their presence, as symptoms may not become apparent until hours later.

(b)

Asphyxiants —gases which act by interfering with the supply or use of oxygen by the body. They may be simple asphyxiants which act by diluting the available oxygen, e.g. nitrogen (N 2). Alternatively, they may be chemical asphyxiants which, even in low concentration, will be absorbed by the blood in preference to oxygen, e.g. carbon monoxide (CO) and hydrogen cyanide (HCN).

(c)

Systemic poisons—gases which, once absorbed into the blood, target specific organs or body systems, e.g. carbon tetrachloride (CCl4 ) which causes liver damage. COPYRIGHT

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(e)

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Anaesthetics —gases which result in the partial or complete loss of sensation. Their effects are similar to alcohol as such gases depress the central nervous system, initially causing mild intoxication with dizziness and loss of coordination. Continued exposure causes unconsciousness and may lead to respiratory paralysis and death. Examples include many common organic solvents, e.g. methyl ethyl ketone, trichloroethylene. Sensitizing agents—exposure to these gases, at even extremely low concentrations, may cause severe allergic reactions in some previously exposed individuals, e.g. toluene 2-4 di-isocyanate (TDI). Once an individual has become sensitized, the process is seldom reversible.

FIGURE 2.1

THE HUMAN RESPIRATORY SYSTEM

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2.2.3 Inhalation of particulates Particulates are much larger than individual molecules and their inhalation and damage causing properties depend on such characteristics as size, shape and density, as well as physical and chemical characteristics. The potential hazard depends on the size as well as the mass concentration because of the effects of particle size on deposition in the respiratory tract. 2.2.4 Particle size There is a particle size range generally taken to be 0.2—10.0 µm which is of particular importance when providing respiratory protection (see Figure 2.2). Large particulates are not usually able to enter the lung. However, large particles of inspirable size (up to 100 µm) may be associated with systemic poisoning or sensitization, e.g. lead dust, animal protein. Very small particulates are inhaled and exhaled and may not be retained anywhere in the lungs. Particulates in the respirable range can penetrate deep into the lungs and remain there (see Figure 2.2). The definition of ‘respirable’ dust is that adopted by the British Medical Research Council and the recommendation of the Pneumoconiosis Conference held in Johannesburg in 1959. This definition has been adopted by Worksafe Australia and is detailed in AS 2985. The respirable fraction is defined by a sampling efficiency curve which depends on the settling velocity of the particle which passes through the points indicated in Table 2.1. This curve is often known as the ‘Johannesburg Curve’. There are practical sampling devices which collect dust in accordance with this definition. Effectively these devices collect 100% of particles 1 micron or less, 50% of 5 micron particles and no particles that are 7 microns or larger. All sizes refer to equivalent aerodynamic diameters. TABLE 2.1 RESPIRABLE MASS FRACTION Particle equivalent aerodynamic diameter µm 0 1 2 3 4 5 6 7

Respirability % 100 98 92 82 68 50 28 0


As with gases, particulates within the respirable size range may be classified according to their effect on the body, as follows: (a)

Nuisance particulates —inert particulates which, when inhaled, produce no tissue changes but may cause discomfort or minor irritation, e.g. titanium oxide (TiO2). Large quantities, however, may overwhelm the lung protection mechanisms and, in the long term, produce injury by blocking the bronchioles.

(b)

Lung-damaging dusts—particulates which reduce lung capacity by causing physical changes in the lung structure. Such particulates may act by giving rise to scar tissue which is not capable of gas exchange. Examples of lung-damaging dusts are silica and asbestos particulates.

(c)

Irritant particulates —chemically active particulates which irritate, inflame and ulcerate the respiratory tract. Irritant particulates cause immediate discomfort. Examples are acid or alkaline mists.

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(d)

Fever producing particulates —particulates which produce chills followed by intense fever or influenza-like symptoms. Such effects may be delayed for several hours after exposure. An example is the fumes evolved by welding of zinc and copper which give rise to ‘metal fume fever’.

(e)

Systemic poisons—as with some gases, certain substances, e.g. cadmium compounds, in soluble particulate form may, by dissolution, enter the bloodstream and target specific organs or systems.

(f)

Sensitizing agents—particulates which even in extremely low concentrations may cause severe allergic reactions in some previously exposed persons, e.g. mould, platinum.

FIGURE 2.2

2.3

SIZE RANGE OF COMMON PARTICULATES

ABSORPTION

2.3.1 Skin absorption The intact skin normally acts as an effective barrier both against entry into the body of, and epidermal reaction to, many substances. However, some substances, liquids, vapours and gases, may enter through the intact skin, e.g. heptachlor, styrene, tetraethyl lead, xylene, while others enter only through abraded skin, e.g. methomyl. These types of absorption may make a significant contribution to overall exposure.

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2.3.2 Eye absorption The effects of exposure of the eye to substances can vary from minor irritation of the eye to total loss of vision, depending on the substance and extent of exposure. Some substances which do not cause irritation following contact with the eye can be absorbed into the body in sufficient amounts to cause systemic poisoning, e.g. hydrogen cyanide, sodium cyanide and some pesticides, e.g. dichlorvos, mevinphos.


2.4 INGESTION Ingestion is the process by which substances enter the body through the mouth (by swallowing). Depending on its physical and chemical properties, an ingested substance may exert its effect on the tissue of the digestive tract or may be absorbed and enter the bloodstream. A toxic substance may be ingested while eating, drinking or smoking in contaminated areas or by transfer to the mouth with contaminated hands. Inhaled particles which have been deposited on the mucus in the respiratory tract will be ingested if the mucus is swallowed.

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S E C T I O N

3 O X Y G E N - D E F I C I E N T A T M O S P H E R E S

3.1 GENERAL Particular attention should be paid to entry to or work in oxygen-deficient atmospheres (ODA). Such atmospheres may occur in confined spaces, or by chemical reaction or displacement. These conditions generally exist in areas with limited ventilation, e.g. tanks, vats, reaction vessels, wells, tunnels, pipes, conduits, access holes, silage pits and deep earthen trenches. Safe procedures for working in confined spaces are not covered in this Standard. These are specified in AS 2865. WARNING: THERE ARE FOUR BASIC MECHANISMS BY WHICH OXYGEN-DEFICIENT ATMOSPHERES, OR THEIR EQUIVALENT, MAY OCCUR. THESE ARE: (1)

ASCENDING TO ALTITUDE.

(2)

CHEMICAL REACTION WITH SOLID PRODUCTS, E.G. FORMATION OF RUST OR OTHER CORROSION PRODUCTS.

(3)

CHEMICAL REACTION WITH GASEOUS PRODUCTS, E.G. RESPIRATION, FIRE.

(4)

DISPLACEMENT (DILUTION) VAPOUR.

BY

SOME OTHER

GAS

THE

OR

OF THESE, ONLY THE FIRST TWO MAY RESULT IN AN OXYGEN DEFICIENCY WITHOUT THE INTRODUCTION OF, OR AN INCREASE IN CONCENTRATION OF, SOME OTHER GAS OR VAPOUR. IN THE LATTER TWO CASES A SIGNIFICANT OXYGEN DEFICIENCY WILL USUALLY BE CAUSED WITH THE SIMULTANEOUS PRODUCTION OF A TOXIC CONCENTRATION OF SUCH GAS OR VAPOUR.

3.2 ATMOSPHERIC COMPOSITION Earth’s atmosphere has an essentially fixed composition of the gases shown in Table 3.1. TABLE 3.1 TYPICAL COMPOSITION OF EARTH’S ATMOSPHERE (DRY STATE CONDITION)


Gas Nitrogen Oxygen Carbon dioxide Other gases

% composition by volume 78.09 20.95 0.04 0.92

Other gases present in small amounts include neon, helium, and krypton. Water vapour, an important constituent of the normal atmosphere, may be present up to 5% of the total volume. Although no one definition (value) of an oxygen-deficient atmosphere has been universally accepted, it is generally acknowledged that the human body can adapt to oxygen concentrations down to 18% at sea level without any noticeable adverse effects. Where a definition is required however, local legislation should be followed. Appendix B provides a listing of authorities who can assist in matters of local legislation.

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3.3 SYMPTOMS OF OXYGEN DEFICIENCY The symptoms of oxygen deficiency depend on the oxygen concentration present. Table 3.2 indicates common symptoms evident at various oxygen concentrations. At high altitudes, although the oxygen percent by volume remains constant, the amount of oxygen available for breathing is reduced owing to the lower pressure. This may produce effects similar to those of oxygen deficiency. TABLE 3.2 SYMPTOMS OF OXYGEN DEFICIENCY Oxygen volume % at sea level

Symptoms

21-18

No noticeable effect

18-14

Increased breathing volume Accelerated heartbeat Impaired attention and thinking Impaired coordination

14-10

Very faulty judgement Very poor muscular coordination Muscular exertion causes rapid fatigue and may cause permanent heart damage Intermittent respiration

10-6

Nausea Vomiting Inability to perform vigorous movement, or loss of all movement Unconsciousness, followed by death

Less than 6

Spasmodic breathing Convulsive movements Death in minutes


It is difficult for the exposed person to appreciate the effect of oxygen deficiency. Gradual depression of the central nervous system affects powers of discrimination, logic and hearing and, when combined with attendant muscular weaknesses and lack of coordination, may lead to death in minutes.

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S E C T I O N 4 H AZ A R D R E C O G N I T I O N, E V A LU A T I O N A N D C O N T R O L 4.1

RECOGNITION OF HAZARDS

4.1.1 General the following:

The recognition of hazardous situations requires detailed knowledge of

(a)

Work processes.

(b)

Materials present, their physical form and properties.

(c)

Intermediates or products formed.

(d)

Control measures used to minimize the release of airborne substances into the workplace atmosphere.

(e)

Degree of exposure.

Knowledge of the processes, the substances used and their products will enable identification of possible sources of airborne contaminants. Information can be gained by observing the process in operation. For example, some processes produce dusts which may readily be seen. However, others may produce dusts of microscopic size which may be invisible but which are respirable—the absence of visible dust does not mean that the atmosphere is free of particles of respirable size. Information can also be gained by asking questions of process operators and supervisors, studying process flow sheets and identifying the composition of raw materials used. Material safety data sheets should be obtained from manufacturers for all substances used and similar information should be compiled for all products and by-products of process operations. 4.1.2 Classification of inhalation hazards For the purpose of this Standard, respirators are designed to give protection against one or more of the following: (a)

Deficiency of oxygen.

(b)

Contaminants in particulate form.

(c)

Contaminants in gaseous form.

Respirators which are designed to give protection against all three types of atmospheric hazard should be used where the type or extent of atmospheric hazard is unknown.


CAUTION: RESPIRATORS USED TO PROTECT AGAINST PARTICULATE OR GASE OUS C ONTAMINANT S MAY NOT NE CE SS AR IL Y PR OVIDE PROTECTION AGAINST OXYGEN DEFICIENCY.

4.2

HAZARD EVALUATION

4.2.1 General Measurements of the concentration of airborne contaminants or depletion of oxygen in the workplace atmosphere can be used to establish the existence of a hazard by reference to current occupational exposure limits (see Clause 2.1). Evaluation of a person’s exposure may involve both personal and biological monitoring as follows: (a)

Personal monitoring The exposure a person receives is estimated by measuring the concentration of an airborne substance in the person’s breathing zone (air near the nose and mouth) and the duration of exposure.

(b)

Environmental monitoring Measuring air contaminants in the working environment can give an indirect estimate of a person’s exposure and indicate the existence of a potential hazard.

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Biological monitoring The measurement of levels of chemical substances or their metabolites, or other biochemical indicators in the appropriate biological medium of the body (for example in urine, blood or exhaled air). Such monitoring can, in some circumstances, detect unexpected exposure of a person who was not suspected of being in contact with the particular chemical substance. It can also be used to indicate the effectiveness of worker protection programs.

4.2.2 Exposure standards The National Occupational Health and Safety Commission (see Clause 2.1) publishes standards of exposure to airborne concentrations of individual substances which, according to current knowledge, should neither impair the health of, nor cause undue discomfort to, most persons. These or other standards may be included in state legislation or codes of practice. Individuals vary in their susceptibility to a given contaminant and exposure of some persons to contaminant concentrations at or even well below the exposure standard may result in discomfort, aggravation of a pre-existing condition or development of an occupational illness. The adverse effect of exposure to one contaminant may be increased or enhanced if the person is exposed to another. For example, the effects of asbestos are exacerbated by tobacco smoke. The best hygiene practice is to minimize any potential risk by keeping concentrations of all airborne contaminants as low as is reasonably practicable regardless of whether they are known to present a health hazard and irrespective of their assigned exposure standard.


4.3 HAZARD CONTROL The recognition and evaluation steps will identify the process that exposes a person to a hazard and evaluate the exposure which that person receives. Three basic principles are involved in controlling employee exposure: (a)

Substitution Occupational health risks from airborne contaminants generated by a certain process might be reduced or eliminated by the substitution or modification of a process with less hazardous materials, process equipment or by using a less hazardous process. For example, the risks of inhaling toxic dusts might be reduced by modifying dust-producing processes to allow the application of water or other suitable wetting agents at the source of the dust.

(b)

Isolation A potential health risk will be reduced or eliminated by isolating those operations likely to produce airborne contaminants from the immediate workplace. Isolation may be achieved by—

(c)

(i)

installation of a physical barrier between the hazardous operation and the operator;

(ii)

locating the operator further away from the process; or

(iii)

using a time delay so that the operator does not need to be in attendance while the process is in operation.

Ventilation The control of the occupational environment by the use of airflow according to proved engineering principles may be used to dilute the workplace atmosphere or to remove the contaminants at their source (local exhaust). Both methods may be combined with heating or cooling, or the recycling of air in the workplace.

Wherever possible, engineering controls following the above principles should be adopted to minimize the need for personal protective equipment. These controls are preferred because they do not depend on worker cooperation, proper fitting and appropriate training in the use of respirators. Although it should be emphasized that any procedure which relies on personal protective equipment as the primary control device is less than the ideal solution, there will always be situations in industry where hazardous contaminant control principles cannot be fully applied. For such situations, and for secondary, back-up protection, careful consideration should be given to the correct choice of respirators. COPYRIGHT

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5

T Y P E S

O F

R E S P I R A T O R

5.1 METHOD OF PROVIDING PERSONAL RESPIRATORY PROTECTION There are two ways of providing personal respiratory protection against atmospheric contaminants: (a)

Purifying the air that a person breathes The inhaled air is drawn through a filter that removes the harmful substances. The nature of the filter depends upon the composition and physical state of the contaminating agent. Such devices do not provide protection in an oxygen-deficient atmosphere, or give protection against all contaminants, e.g. there are some gases and vapours which cannot be removed by any available filter.

(b)

Supplying the person with respirable air Providing a source of respirable air which is independent of the working environment, conveying respirable air to the person through an air line, air hose, or by the person carrying apparatus which provides the air.

5.2 TYPES OF RESPIRATOR The classification of the major types of respirator described in this Section is set out in Figure 5.1. 5.3

AIR-PURIFYING RESPIRATORS

5.3.1 General There are two main types of air-purifying respirator; particulate respirators which filter out thermally and mechanically generated particulates, and gas respirators which only filter out certain gases and vapours. In addition, filter combinations are used where both hazard types exist.


The mode of air delivery may be either one or a combination of the following: (a)

Non-powered Air is drawn through the filter or filters by wearer inhalation. The respirator may consist of a half facepiece with one or more replaceable filters, a filtering (disposable type) half facepiece, a full facepiece or head covering with one or more replaceable filters, or a mouthpiece and nose clip, with integral filter.

(b)

Powered The contaminated air is drawn through a filter by means of a fan and delivered to the space enclosed by the head covering, generally under positive pressure. This respirator may be a half facepiece, full facepiece or head covering with one or more replaceable filters and an electrically operated blower unit. A lowflow warning device may be fitted to indicate a reduced air supply.

5.3.2 Particulate filters There are three classes of particulate filter suitable for filtering finely divided solid or liquid particles, or both, from the inhaled air. These are classified, in accordance with the tests in AS/NZS 1716, as follows: (a)

Class P1—intended for use against mechanically generated particulates, e.g. silica, asbestos.

(b)

Class P2—intended for use against both mechanically and thermally generated particulates, e.g. metal fumes.

(c)

Class P3—intended for use against all particulates including highly toxic materials, e.g. beryllium.

For non-powered respirators, Class P3 respirator classification can only be assigned where a Class P3 filter is combined with a full facepiece to ensure that the effectiveness of the facial seal is more compatible with that of the filter. Non-powered particulate respirators with Class P1 and Class P2 filters usually, but not exclusively, incorporate a half facepiece. COPYRIGHT


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NOTE: This diagram excludes auxiliary protection systems (see Clause 5.4.7). FIGURE 5.1

MAJOR TYPES OF RESPIRATORS

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Powered particulate respirators may have any facepiece or head covering regardless of filter class. Where filters are designed for use in a PAPR, it is a requirement of AS/NZS 1716 that they be marked with the prefix ‘PAPR’ in conjunction with the filter description, e.g. PAPR P2. NOTE: Manufacturers making a statement of compliance with this Australian Standard on a product, packaging, or promotional material related to that product are advised to ensure that such compliance is capable of being verified.

5.3.3

Gas filters

5.3.3.1 General The gas filter removes certain gases from the inhaled air. The filter has a limited useful life which varies with the volume of sorbent and the conditions under which it is used. Gas filters are affected by such factors as the concentration of the contaminant in the atmosphere, the humidity, and the breathing rate of the wearer. 5.3.3.2

Types

The basic types of gas filter are as follows:

Type A—for use against certain organic gases and vapours, as specified by the manufacturer. Type B—for use against certain inorganic gases and acid gases, as specified by the manufacturer (excluding carbon monoxide). Type E—for use against sulfur dioxide and other inorganic gases and acid gases as specified by the manufacturer (excluding carbon monoxide). Type G—for use against low vapour pressure chemicals, as specified by the manufacturer (vapour pressure less than 1.3 Pa [0.01 mm Hg] at 25°C), e.g. many agricultural chemicals. Type K—for use against ammonia and ammonia derivatives as specified by the manufacturer. Type MB—for use against methyl bromide. Type AX—for use against certain groups of low boiling point organic compounds as specified by the manufacturer (boiling point less than 65°C). Type Hg—for use against mercury vapour. Type NO—for use against oxides of nitrogen.


Specific chemical type—for use against one or more specific chemicals not falling into any of the above type descriptions. The filter is identified by the name of that chemical. Additional particulate filtration may be provided. 5.3.3.3 Gas filter classification The class designation relates to the total amount (capacity) of gas which can be collected by the filter, and is not an indication of the filter efficiency. Each gas filter may be available in one of four classes which are arranged in order of increasing capacity. The higher the number, the longer the filter will last for a given concentration of gas where other factors remain constant. These classes are— Class AUS—low capacity filters with a shorter life than Class 1; Class 1—low absorption capacity filters; Class 2—medium absorption capacity filters; and Class 3—high absorption capacity filters.

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NOTES: 1

Filters may be required to comply with additional performance requirements if specified by a regulatory authority.

2

Some filters may provide protection against more than one gas.

3

Class AUS and Class 1 filters were previously designated as cartridges and Class 3 filters as canisters.

4

See Table 6.4 for selection criteria.

Because of possible differences in sorbents used for each class, the physical dimensions of Class 2 or Class 3 gas filters need not be greater than the corresponding filter of lower class or classes. Generally, however, a higher class number denotes a filter of greater mass and volume as well as greater absorptive capacity. The mass and bulk dictates the choice of facepiece type and harness configuration, as required by AS/NZS 1716. Filters are connected as follows: (a)

A filter of mass up to 300 g is connected directly to either a half or full facepiece or it may be body mounted.

(b)

A filter of mass between 300 and 500 g may only be connected directly to a full facepiece or it may be body mounted.

(c)

A filter of more than 500 g may only be body mounted.

The mass limitations are intended to minimize respirator instability and discomfort and apply to both powered and non-powered air-purifying respirators. Non-powered half facepiece respirators either with replaceable filters or of the disposable type generally are used with or already incorporate Class AUS, Class 1 or Class 2 gas filters. Non-powered full facepiece respirators with replaceable gas filters are usually used with Class 2 or Class 3 to last longer or for higher concentrations. Powered respirators with PAPR Class 1 or Class 2 gas filters may be used with any facepiece or head covering. CAUTION: ONLY PAPR LABELLED FILTERS, SPECIFIED BY THE MANUFACTURER FOR USE IN A PARTICULAR MODEL OF POWERED RESPIRATOR, SHALL BE USED IN THAT POWERED RESPIRATOR.


5.3.4 Combination particulate and gas filters may have the following configurations:

Combination particulate and gas filters

(a)

Filter combinations The respirator has a gas filter (as described in Clause 5.3.3) with a separate particulate filter of Class P1, P2 or P3 (as described in Clause 5.3.2) attached to it on the inlet side.

(b)

Integral combined filters The respirator has a composite filter which, in addition to providing protection against low concentrations of certain gases or vapours, has an integrated particulate filter of Class P1, P2 or P3.

An external pre-filter may be added to either filter type to remove coarse particulates and so extend the life of the main filter. NOTE: AS/NZS 1716 does not specify performance requirements for these coarse external pre-filters.

Where gas and particulate filters are separate component parts, they must be placed in sequence so that the incoming air passes through the particulate filter first. 5.3.5

Filter self-rescue respirators

5.3.5.1 General Some forms of filter respirator are designed solely for escape purposes. There are three types as follows: (a)

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(b)

Smoke mask.

(c)

Filter self-rescuer (industrial).

5.3.5.2 Filter self-rescuer (mines) The carbon monoxide self-rescue device is a respirator for emergency use by underground miners. In the event of an explosion or fire, this equipment provides protection against particulates such as dust or smoke, and low concentrations of carbon monoxide and other gases as specified by the manufacturer, and enables the wearer to withdraw to a safe atmosphere. 5.3.5.3 Smoke mask The smoke mask is a respirator intended to be used only for a short time, e.g. escape from fires. It is not intended as a substitute or replacement for SCBA apparatus or for routine use by workers. This respirator provides protection against particulates, such as dust or smoke, and low concentrations of carbon monoxide. Additional protection is provided against other gases commonly encountered in building fires. The smoke mask may be built into a simple hood made of impervious flame-retardant material. 5.3.5.4 Filter self-rescuer (industrial) The filter self-rescuer (industrial) is designed for use when escaping from chemical hazards that may occur in either industrial or laboratory incidents. The respirator includes an appropriate gas filter and, depending on the nature of the likely hazard, may also include a particulate filter (see also Clauses 5.4.6.4 and 5.4.7.2.) 5.4

SUPPLIED AIR RESPIRATORS

5.4.1 General Supplied air respirators deliver breathing air or oxygen to the wearer from an independent source.


5.4.2

Supplied air

There are three major categories of supplied air respirator:

(a)

Air-hose respirators—the air supplied in this type of respirator is not pressurized, i.e. it is at or near atmospheric pressure. The mode of air delivery may be one of those listed in Clauses 5.4.3(a) and 5.4.3(b)(ii).

(b)

Air-line respirators—the air supplied to this type of respirator is pressurized, i.e. it is greater than atmospheric pressure. The mode of air delivery may be (b), (c) or (d), as described in Clause 5.4.3. Air-line respirators could utilize a compressor or large compressed gas cylinders. The air should be of the quality defined in Appendix A.

(c)

Self-contained breathing apparatus —the air supplied to this type of respirator is pressurized, i.e. it is greater than atmospheric pressure. The mode of air delivery may be (b), (c) or (d), as described in Clause 5.4.3. This apparatus uses cylinders of compressed air strapped to the user’s body.

NOTE: An air-line respirator may be used in conjunction with an SCBA to guard against airline failure.

5.4.3 Mode of air delivery to the respirator one or a combination of the following options:

The air supply for these respirators is

(a)

Natural breathing The pressure inside the full facepiece is near atmospheric. The normal breathing action of the wearer draws the air into the close-fitting facepiece. A wide bore air hose is used. These respirators are normally termed hosemasks. They may also incorporate a manually-operated blower. When this type of respiratory protection is used, it is essential that the air-hose inlet be positioned securely in an uncontaminated area.

(b)

Continuous flow The volume of air supplied is more than that required by the wearer. The pressure inside the facepiece or head covering is greater than that of the immediate environment. The pressure is controlled mainly by the degree of restriction to the escaping air, e.g. facial fit, outlet valve resistance, the presence of COPYRIGHT

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a neck bib and shoulder cape or integral jacket or suit. The source of air may be either— (i)

through a compressed air line and reduced to near atmospheric pressure by the use of a regulator or control valve; or

(ii)

through an air hose connected to a low pressure electrically-operated blower. When this type of respiratory protection is used, it is essential that the air intake be positioned securely in uncontaminated air before entering any contaminated area.

NOTE: Some self-contained breathing apparatus units of the escape type incorporate continuous flow.

(c)

Negative pressure demand The pressure inside the facepiece is less than that of the immediate environment during inhalation, causing the demand valve to open, supplying air to the wearer. The demand valve shuts off completely during exhalation. This type of system is used with a close-fitting facepiece.

(d)

Positive pressure demand The pressure within the facepiece remains greater than the immediate environment during use. The demand valve opens to supply air to the wearer when the positive pressure inside the facepiece decreases to a preset minimum. This type of system is used with a close-fitting facepiece.

Both types of demand system may receive air either from a compressed air line or from a self-contained source. An air-hose respirator cannot be fitted with a demand valve. 5.4.4

Respirators supplied through an air hose

5.4.4.1

General

Two types of respirator may be supplied through an air hose:

(a)

Natural breathing type.

(b)

Electrically-operated blower type.

5.4.4.2 Air-hose respirator—natural breathing type (‘hosemask’) The hosemask comprises a full facepiece fitted with a valve system and a breathing tube connecting the facepiece to a relatively wide bore air hose. Air at atmospheric pressure is drawn through the air hose by the normal breathing action of the wearer, or supplied by a manuallyoperated blower.


The inlet end of the air hose is anchored in a safe location away from contamination. The breathing resistance of the air hose limits its length. A longer air hose may be used if the air is supplied under slight pressure by means of a manually-operated pump, blower or bellows. 5.4.4.3 Air-hose respirator—electrically-operated blower type Respirators in this group may have a half facepiece, full facepiece or head covering. The air is supplied continuously by an electrically-operated blower. No control valve is fitted. This type of equipment shall not be used in immediately dangerous to life and health (IDLH) atmospheres unless an auxiliary protection system is used (see Clause 5.4.7). This allows for possible electrical failure. 5.4.5 Respirators supplied through an air line Respirators which are supplied from a compressed air source through a relatively small bore air line, may have a full facepiece, half facepiece or head covering. Air-line respirators shall not be used in IDLH atmospheres unless an auxiliary protection system is used (see Clause 5.4.7). This allows for possible interruption of the air supply. 5.4.6 Self-contained breathing apparatus 5.4.6.1 General This class of respirator permits the wearer to move without being restricted by a hose or air line, in atmospheres which are contaminated to any degree or which are deficient in oxygen or both. COPYRIGHT


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The types of self-contained breathing apparatus (SCBA) from which the wearer obtains a supply of respirable air are as follows: (a) Compressed air—open-circuit type. (b) Compressed oxygen—closed-circuit type. (c) Compressed air—open-circuit escape type. (d) Liquid oxygen—closed-circuit type. (e) Oxygen generating—closed-circuit type. 5.4.6.2 Compressed air—open-circuit type Compressed air is carried in one or more cylinders and is released through a pressure demand valve and breathing tube to a facepiece or head covering from which exhaled air passes through a non-return valve to the atmosphere. The nominal effective life of such apparatus exceeds 15 min. 5.4.6.3 Compressed oxygen—closed-circuit type The exhaled air passes from the facepiece or mouthpiece through a breathing tube into a purifier containing chemicals which absorb the exhaled carbon dioxide, and oxygen is metered into the breathing circuit from a cylinder of compressed oxygen. The oxygen and purified gases mix and are inhaled by the wearer from a breathing bag and any excess gas is released through a relief valve. 5.4.6.4 Compressed air—open-circuit escape type Compressed air is carried in one or more cylinders and is released through a pressure demand or constant flow valve and breathing tube to a full facepiece or hood from which exhaled air passes through a non-return valve to the atmosphere. The nominal effective life of such apparatus is less than 15 min. 5.4.6.5 Liquid oxygen—closed-circuit type This equipment is similar to the compressed oxygen type, except that the oxygen is supplied by evaporation of liquid oxygen contained in a tank or cylinder carried by the wearer. 5.4.6.6 Oxygen generating—closed-circuit type This equipment is similar to the compressed oxygen type except that the oxygen is supplied from a container of chemical which releases oxygen by reaction with water vapour and carbon dioxide in the exhaled air. 5.4.7 Auxiliary protection systems 5.4.7.1 General Where routine work is to be undertaken in an atmosphere which is harmful, an auxiliary protection system should be carried for movement within the work area or to facilitate escape. This system should provide a short-term back-up to the main, air-hose or air-line respirator. There are two types of auxiliary protection system: (a) Self-contained breathing apparatus—escape type. (b) Filter type. 5.4.7.2 SCBA type In this auxiliary protection system, the SCBA which may be of the escape type is attached to the wearer’s air-line system. It is designed to provide adequate protection for a short period, thereby allowing the wearer to retreat from the contaminated atmosphere should the air-line system fail. 5.4.7.3 Filter type This may be either a particulate and gas filter or a gas filter attached to a supplied air system as an escape device. It is designed to provide, for short periods, adequate protection from the contaminants for which it is specifically designed. CAUTION: THIS FILTER TYPE IS OXYGEN-DEFICIENT ATMOSPHERES.

5.4.8 Low flow warning devices warn of reduced air supply.

NOT

SUITABLE

FOR

USE

IN

These may be fitted on compressed air systems to

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S E C T I O N

6

S EL E C TI ON

AS/NZS 1715:1994

O F

R E S P I R A T O R S

6.1 FACTORS IN SELECTION Many points need to be considered when selecting a suitable respirator for a particular situation. It is important to ensure that only respiratory protective devices complying with AS/NZS 1716 be used and, where there is any doubt, expert occupational hygiene advice, such as can be obtained from State Departments of Health or other authorities (see Appendix B), should be sought.


To protect effectively, a respirator must be worn whenever the person is exposed to the contaminant.

FIGURE 6.1

FLOW CHART FOR RESPIRATOR SELECTION

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The selection of respiratory protective devices will be influenced by the following factors: (a) Contaminant. (b) Task. (c) Operator. Selection guides based on identified and quantified contaminants are given in Tables 6.1 to 6.6. Figure 6.1 is a work-through flow chart to determine which table to use for a given situation. Tables 6.1 to 6.6 select respirators for specific contaminants based on the level of protection required. Further explanation of the recommendations is given in the rest of this Section and should be read in conjunction with these tables. It is emphasized again that where there is doubt about the correct selection, expert advice should be sought from persons experienced in respiratory protection. This Standard provides guidance on selection of adequate protection. The information should not be viewed as minimum protection requirements. Over-specifying is warned against as generally this will result in increased body burden without any improvement in protection, e.g. for mechanically generated particulates such as silica dust and chrysotile, a P1 respirator will provide adequate protection. Recommendation of a P2 respirator will provide little or no improvement in filtration of these dusts but may have a higher breathing resistance and therefore may force the wearer to work harder for no additional protection. To ensure adequate protection is achieved at all times, it is essential that a full respiratory protection program is conducted using the guidelines provided in Section 7. 6.2 SELECTION FACTORS—CONTAMINANT-RELATED 6.2.1 General The following contaminant-related factors should be considered as part of the respirator selection process: (a) The nature, toxicity, physical form and concentration of the contaminant, whether particulate, gas or vapour, or a combination of these. (b) Whether failure of the device can result in a situation which is immediately dangerous to life or health. (c) The need to wear other personal protective equipment e.g. eye or skin protection to protect against irritants. (d) The adequacy of the warning given by the contaminant. (e) The possibility of the contaminated atmosphere being flammable. 6.2.2 Nature, toxicity, physical form and concentration of the contaminant 6.2.2.1 General Before selecting a respirator, the physical characteristics of the contaminant or combination of contaminants needs to be known, i.e. whether it is a particulate, a gas or a combination of them, and such conditions as the boiling point and vapour pressure. Where the type or extent of atmospheric contamination (gaseous or particulate) remains unknown and a safe level of oxygen cannot be assured, then devices which are designed to give protection against all three types of hazard should be used. 6.2.2.2 Protection factors and exposure standards A major factor when selecting a respirator is to determine the reduction in exposure which a particular respirator type can be expected to provide. This reduction, termed ‘protection factor’, is defined as the ratio between the concentration of a contaminant outside the respirator to the concentration inside the respirator, i.e. breathed by the wearer. The ‘protection factor’ can also be expressed by the following equations: Protection factor

Ambient airborne concentration Concentration inhaled inside respirator COPYRIGHT

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Required minimum protection factor

AS/NZS 1715:1994

Ambient airborne concentration Acceptable exposure level/standard

The required minimum protection factor for any given situation is that factor necessary to reduce the exposure of the wearer to below an accepted level or exposure standard or to minimize the potential exposure. A choice based upon the desired protection may be made by referring to Tables 6.1 to 6.5. A respirator may be selected which will ensure that the exposure level is reduced below the accepted level. In practice, the maximum contamination level of the ambient atmosphere for which a given respirator or class of respirator is approved may be set by a regulatory authority. 6.2.2.3 Concentration of contaminant In estimating the required minimum protection factor, some evaluation of the likely range of contaminant concentration in the atmosphere should be made. (Advice should be sought from occupational hygienists on the type of equipment, method of measurement and interpretation of test results.) The assessed levels of contaminants, taking into account peak levels, can then be used to determine the required protection both on a routine basis and for emergencies.

TABLE 6.1 SELECTION CONSIDERATIONS CONTAMINANT: MECHANICALLY GENERATED PARTICULATES Required minimum protection factor Up to 10

Suitable respirator • • •

P1, P2 or P3 (see Clause 6.2.3.5) filter half facepiece—replaceable filter or disposable facepiece Half facepiece air-line respirator—negative pressure demand PAPR — P1 filter with any head covering or facepiece

Up to 50

• • • •

P2 filter in full facepiece PAPR-P2 filter in PAPR with any head covering or full facepiece PAPR-P3 filter in PAPR with any head covering Half facepiece with continuous flow air line or air hose

Up to 100

• •

P3 filter in full facepiece Full facepiece air-line respirator—negative pressure demand

100+

• • •

PAPR-P3 filter in PAPR with full facepiece or head covering and blouse Head covering air-hose or air-line respirator—continuous flow Full facepiece air-line respirator—positive pressure demand or continuous flow modes Full facepiece air hose—continuous flow


•

CAUTION: WHERE EXPOSURE TO THE CONTAMINANT COULD BE IMMEDIATELY DANGEROUS TO LIFE OR HEALTH, SEE TABLES 6.5 AND 6.6. NOTES: 1 The required minimum protection factor is explained in Clause 6.2.2. 2 Respirators listed as suitable for the higher protection factors are also suitable for lower protection factors. 3 These tables do not cover all considerations for all applications of respiratory protective devices and should be read in conjunction with Section 6. 4 Where the process also liberates toxic gases, see Table 6.5. 5 See Appendix C for a respirator selection example.

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Examples of processes which would result in the mechanical generation of particles: Grinding, blasting, sanding, mixing powders, chipping, spraying. Examples of mechanically generated particulates: Silica dust, coal dust, asbestos fibres, lead dust, sodium hydroxide mist. TABLE 6.2 SELECTION CONSIDERATIONS CONTAMINANT: THERMALLY GENERATED PARTICULATES Required minimum protection factor Up to 10

Suitable respirator • •

P2, or P3 (see Clause 6.2.3.5) filter half facepiece—replaceable filter or disposable facepiece Half facepiece air-line respirator—negative pressure demand

Up to 50

• • • •

P2 filter in full facepiece PAPR-P2 filter in PAPR with any head covering or full facepiece PAPR-P3 filter in PAPR with any head covering or full facepiece Half facepiece with continuous flow air line or air hose

Up to 100

• •

P3 filter in full facepiece Full facepiece air-line respirator—negative pressure demand

100+

• • •

PAPR-P3 filter in PAPR with full facepiece or head covering and blouse Head covering air-hose or air-line respirator—continuous flow Full facepiece air-line respirator—positive pressure demand or continuous flow modes

CAUTION: WHERE EXPOSURE TO THE CONTAMINANT COULD BE IMMEDIATELY DANGEROUS TO LIFE OR HEALTH, SEE TABLES 6.5 AND 6.6. NOTES: 1 The required minimum protection factor is explained in Clause 6.2.2. 2 Respirators listed as suitable for the higher protection factors are also suitable for lower protection factors. 3 Where the process also releases toxic gases, see Table 6.5.

Examples of processes which result in the thermal generation of particles: Smelting, welding, brazing, heating.


Examples of thermally generated particles: Lead fume, zinc oxide fume, chromium fume, manganese fume, welding fume.

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TABLE 6.3 SELECTION CONSIDERATIONS CONTAMINANT: GASES AND VAPOURS Required minimum protection factor Up to 10

Maximum gas/vapour concentration present in air p.p.m. (by volume) 1 000

Suitable respirator • • •

Class AUS, 1, 2 or 3 filter with half facepiece—replaceable filter or disposable facepiece Class PAPR-AU S, PAPR-1 or PAPR-2 filters in PAPR with any head covering or facepiece Half facepiece air-line respirator—negative pressure demand

Up to 50

1 000

•

Class AUS or Class 1 filter with full facepiece

Up to 50

5 000

•

Half facepiece air-line respirator—continuous flow

Up to 100

5 000

• •

Class 2 filter with full facepiece Class PAPR-2 filters, filters with full facepiece PAPR

Up to 100

10 000

• •

Class 3 filter with full facepiece Full facepiece air-line respirator—negative pressure demand SCBA negative pressure demand

• 100+

• •

Full facepiece, head covering or air-supplied suit with air-line respirator—positive pressure demand or continuous-flow SCBA positive pressure demand

CAUTION: WHERE EXPOSURE TO THE CONTAMINANT COULD BE IMMEDIATELY DANGEROUS TO LIFE OR HEALTH, SEE TABLES 6.5 AND 6.6. NOTES: 1 The required minimum protection factor is explained in Clause 6.2.2. 2 Respirators listed as suitable for the higher protection factors are also suitable for lower protection factors. 3 Eye protection may be required.


4 See Appendix C for a respirator selection example.

Filter class refers to the capacity of the filter. Table 6.3 considers class (capacity) only and must be read in conjunction with Table 6.4 when selecting a gas filter. Both required minimum protection factor and maximum gas/vapour concentration present in air should not exceed those listed, e.g. where the exposure standard is 200 p.p.m. (by volume) and the workplace concentration is 1200 p.p.m. (by volume), the required minimum protection factor is 6 (1200/200). However, the ambient concentration is greater than 1000 p.p.m. (by volume), so the appropriate respirator is chosen from the section of the Table commencing, ‘required minimum protection factor up to 50’. This is because a Class 1 filter would have insufficient capacity to be of practical use in such an ambient contaminant concentration.

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TABLE 6.4 SELECTION CONSIDERATIONS FILTER TYPES FOR GASES AND VAPOURS Filter type

Descriptive name

Examples of contaminants/uses

A

Organic vapours

Solvents (with boiling point above 65°C)

B Aus or B1

Acid gases

Chlorine/sterilization of water; chemical manufacture; hydrogen chloride/chlorinated organic chemical manufacture; steel pickling

B2

Acid gas and hydrogen cyanide (HC N)

Plastics manufacture; gold ore refining

B3

Acid gas and hydrogen cyanide (HC N)

HC N fumigation

E

Sulfur dioxide (SO2)

SO 2/casting of metals; bleach manufacture; manufacture of sulfuric acid; fertilizer manufacture; metal cleaning; petroleum refining

G

Agriculture chemicals

Low vapour pressure (below 1.3 Pa at 25°C) pesticide spraying, mixing, manufacture

K

Am monia (NH 3)

NH 3/refrigeration; manufacture of fertilizers, explosives, plastics; low boiling point amines/chemical manufacture

Hg

Mercury

Metallic mercury/chemical industry; inorganic-mercury compounds

NO

Oxides of nitrogen

Oxides of nitrogen

MB

Methyl bromide

Fumigation

AX

Low boiling point organic compounds (below 65°C)

As specified by the manufacturer, e.g. dimethyl ether, vinyl chloride

Specific chemical type

Specific chemical name

For use against specific chemicals not falling in the above type descriptions as specified by the manufacturer, e.g. hydrogen fluoride

NO TE: See Appendix C for a respirator selection example.

Table 6.4 lists some examples of compounds for which the different types of filter should be suitable.


As sorbents vary from one manufacturer to the next, it should be ensured that the filter type selected is appropriate for all contaminants present. When in doubt, check with the manufacturer.

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AS/NZS 1715:1994

TABLE 6.5 SELECTION CONSIDERATIONS RESPIRATORS FOR COMBINED PARTICULATES AND GASES Hazard

Respirator

General particulates, gases or vapours listed in Tables 6.1, 6.2, 6.3 or 6.4

1 Integral gas and particulate filter 2 Gas filter with particulate filter attachment 3 Supplied-air respirator

Escape from smoke— no oxygen deficiency

Smoke-mask respirator

Escape from smoke and carbon monoxide (in an underground fire, explosion)

Filter self-rescuer (mines)

Escape from gases (industrial)

Filter self-rescuer (industrial) Class 2 or 3 gas filters

TABLE 6.6 SELECTION CONSIDERATIONS RESPIRATORS FOR OXYGEN DEFICIENCY OR ATMOSPHERE OF HIGH OR UNKNOWN CONCENTRATIONS OF CONTAMINANTS Expected use

Equipment

Remarks

Escape, easy access

SCBA , escape type (hood) duration: 5 to 8 min, according to type approval

Access to respirable atmosphere achievable at walking (6.5 km/h) pace within the nominal effective life of the apparatus of choice

Escape

SCBA , escape type (full facepiece) duration: 5 to 15 min, according to type approval Oxygen generating set duration: 30 to 90 min, according to type approval

Duration of set limited to 5 to 15 min, (SCB A escape type) and 30 to 90 min (oxygen-generating type). No work or rescue usage

Work, routine

Air-hose (hosemask) natural breathing type Air-line or air-hose with auxiliary protection

Limited mobility and distance to source of respirable air

Work, including rescue use

Compressed air SCB A duration: >15 min, according to type approval Oxygen SCBA Air line with SCB A

Limited duration Specialist training essential Limited mobility and distance to source of respirable air


NO TE: Where work is conducted in confined spaces, refer to AS 2865. Appendix B of this Standard provides a listing of regulatory and other authorities who can assist with local regulations.

6.2.3

Protection against particulates

6.2.3.1 General In most circumstances adequate respiratory protection against non-volatile particulates can be obtained by the use of a particulate respirator. The degree of protection is governed by the type of filter and facepiece and the effectiveness of the individual’s facial seal (see Appendices D and E). CAUTION: DEVICES ARE AVAILABLE, MANUFACTURED FROM MATERIALS SUCH AS SYNTHETIC FIBRE, COTTON FIBRE, OR PLASTIC FOAM PADS, WHICH DO NOT COMPLY WITH THE REQUIREMENTS OF AS/NZS 1716. THESE GENERALLY HAVE AN INADEQUATE PARTICULATE FILTERING ABILITY AND WILL REMOVE ONLY COARSE PARTICLES FROM THE INHALED AIR. THEIR USE SHOULD BE ACTIVELY DISCOURAGED, AS THEY OFFER NO EFFECTIVE PROTECTION AGAINST AIRBORNE CONTAMINANTS. IN SOME STATES, LABELS INDICATING THE LIMITED USE OF THESE DEVICES ARE REQUIRED BY REGULATORY AUTHORITIES.

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6.2.3.2 Classification of filters Particulate (i.e. dust, mist, smoke and fume) filters are classified according to their ability to filter a test cloud of particles having a size distribution as defined in AS/NZS 1716. NOTES: 1

The test particles have an average size which is very much finer than that of particulates usually found in industry.

2

Respirator users are advised that an additional gas filter or filters will be required where the process responsible for generating particulates also liberates toxic gases.

6.2.3.3 Class P1 filters Respirators with P1 filters are commonly used against mechanically-generated particulates of the size most often encountered in industry, e.g. silica and chrysotile. Three types of Class P1 respirator are generally available, i.e. powered type, replaceable filter type and disposable type. 6.2.3.4 Class P2 filters Respirators with P2 filters are used for protection against mechanically or thermally generated particulates or both, e.g. metal fumes. Three types of Class P2 respirator are generally available, i.e. powered type, replaceable filter type and disposable type. 6.2.3.5 Class P3 filters For P3 filter classification, a full facepiece is required. These are used for protection against highly toxic or highly irritant particulates, such as beryllium. Two types of class P3 respirator are generally available, e.g. powered type and replaceable filter type. 6.2.3.6 Use of air-hose or air-line respirators Where the particulate concentration causes rapid clogging of the filter or the occupation is a routine one and does not require great mobility, the use of an air-hose or an air-line respirator may be more suitable. An air-line or air-hose respirator, used in conjunction with self-contained breathing apparatus of the escape type, is suitable for long-term use in potentially dangerous or unknown situations where an air supply failure would cause loss of protection. 6.2.4

Protection against toxic gases

6.2.4.1 General Protection air-purifying respirator or by governed by the type of filter facial seal (see Appendices D

against toxic gases may be obtained by the use of an a supplied air device. The degree of protection provided is used in the respirator and the effectiveness of the individual and E).


6.2.4.2 Gas filter respirator The different types of filters are specified in Clause 5.3.3, Tables 6.3 and 6.4, and AS/NZS 1716. The classes are distinguished by their gas absorptive capacity and, in general, by their size and mass. Class AUS and Class 1, the lowest capacity filters, are generally combined with a half facepiece, the limiting factor of which is the adequacy of facial seal, gas capacity or lack of eye protection. Where contaminants are present in high concentrations which may cause adverse reactions or which may be allergenic, even in low exposures, half facepiece respirators may not provide an adequate facial seal. A high standard of respiratory protection may be obtained in toxic atmospheres not deficient in oxygen, provided that the following requirements are met: (a)

The filter used is appropriate to the specific contaminant encountered.

(b)

The concentration of contaminant in the atmosphere is below the maximum for which the filter is suitable.

(c)

The respirator fits the wearer correctly.

(d)

The protection factor afforded by the respirator is sufficiently high.

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(e)

The respirator is worn while the wearer is in the contaminated area.

(f)

Maintenance of the respirator is carried out when required.

AS/NZS 1715:1994

6.2.4.3 Gas filter life The life of a filter is difficult to assess under normal working conditions, being dependent on the concentration of contaminant in the atmosphere, the humidity and the work rate of the wearer. Extreme caution should always be exercised if the contaminant gives no adequate warning of its presence (see Clause 6.2.8). A spent filter should be rendered unusable and disposed of in the same manner as the contaminant, e.g. a methyl bromide filter used in a fumigation situation must be double bagged for disposal by a competent authority (see also Appendix B). All classes of gas filter should be discarded no longer than six months after opening, irrespective of the number of periods of use. The manufacturer’s instructions should be observed, particularly when special filters are used. 6.2.4.4 Supplied air respirators A supplied air respirator would be required in one or more of the situations described below: (a)

Where there is an oxygen deficiency.

(b)

Where the level of toxic gases or vapours exceeds the capability of an air-filtering device.

(c)

Where the level of contamination is unknown.

(d)

Where the operator is required to remain in the contaminated environment for longer than the estimated life of the filter.

(e)

Where environments are immediately dangerous to life and health.

(f)

Where there is no filter suitable for use against the contaminant.

In some circumstances, the use of a specific type or construction of supplied air respirator may be necessary because of adverse effects of the immediate environment on parts of the body other than the respiratory system. For example, work in a corrosive or solvent-laden atmosphere may require the use of a full facepiece or head covering and body protection. The materials from which the respirator is made would have to be resistant to attack from the specific gases or vapours present. A full face supplied-air respirator, used in conjunction with self-contained breathing apparatus of the escape type (see Clause 5.4.7), is recommended for use in potentially dangerous or unknown situations where an air supply failure would cause loss of protection (see also Clause 6.2.6).


Negative pressure air-line respirators provide protection equivalent to that provided by non-powered air-purifying respirators, however, their use should be discouraged in favour of positive pressure, continuous flow or positive pressure demand systems. 6.2.5 Protection against combined particulates, gases and vapours Subject to the limitations imposed in Clauses 6.3 and 6.4, protection against the combined hazards of particulates, gases and vapours, e.g. spray painting, can be obtained by the use of a combined particulate and gas filter, or a respirator which is fitted with a combination of filters in series, or by the use of any of the supplied air devices. 6.2.6 Protection against oxygen-deficient atmospheres Entry to places where the normal level of oxygen has been depleted or is unknown (see Section 3) requires either the wearing of— (a)

a SCBA of sufficient operational duration; or

(b)

an air-line respirator with escape SCBA attached to the person.

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Particular care should be taken in choosing an air-line or air-hose depending on whether they are to be used in very high temperatures, very low temperatures, or are likely to come in contact with solvents or other deleterious materials. 6.2.7

Additional protection

6.2.7.1 General The extent of the precautions required to exclude the contaminated atmosphere will depend on its effect on the body. Contaminants may have to be kept away from the eyes and skin as well as from the respiratory tract owing to immediate irritation (see Section 2). Depending on the type and amount of contamination in the atmosphere, a number of respirator types with varying facial and body coverage can protect, and if necessary progressively isolate the respirator user from the contaminated atmosphere. The respirator types range from a simple mouth piece to full-body encapsulation. Attention is also drawn to AS 3765.1 and AS 3765.2. The degree to which the contaminant atmosphere may be excluded depends upon the effectiveness of the facial and body seal. 6.2.7.2 Use with goggles or spectacles Most types of filter respirator use a half facepiece and this may interfere with the wearing of protective goggles or prescription spectacles. The need for separate eye protection may be avoided by the use of a full facepiece or a hood or helmet respirator. Prescription lens spectacles can be incorporated within certain types of full facepiece. 6.2.7.3 Use with head coverings In situations where head protection from irritants is required in addition to respiratory protection, a hood or head covering is recommended. It may be worn in conjunction with a full facepiece respirator or may have integral respiratory protection. 6.2.8

Adequacy of the warning given by the contaminant


6.2.8.1 Limitations of odour as a warning of end of filter life In many cases, the first indication of the presence of a contaminant is given by its odour, and no doubt this has often served as a warning against dangerous situations. For this purpose, however, the sense of smell has very serious limitations. Some of these limitations are as follows: (a)

There is considerable variation between individuals, with some persons being unable to detect contaminants by smell, e.g. hydrogen cyanide has a characteristic almond odour which is not detectable by some people.

(b)

The sense of smell in an individual may be considerably diminished temporarily by a cold in the nose or other inflammatory conditions of the nasal passages.

(c)

The odour of a contaminant may be masked by other smells.

(d)

The sense of smell fails to detect high concentrations of many contaminants if such concentrations have been built up gradually, e.g. hydrogen sulfide. A person working in a situation where a dangerous concentration of a contaminant has developed slowly may not detect any odour; yet a person entering the situation from outside could be aware of a very strong odour.

(e)

The threshold of odour for some materials exceeds the level at which such materials may be considered hazardous. Thus, by the time the contaminant can be smelt, the wearer may already have been exposed to a hazardous situation, e.g. toluene di-isocyanate (TDI).

(f)

Some gases have no odour and therefore are not detectable by this means.

(g)

Some gases have very objectionable odours at very low concentrations but do not represent a health hazard at these concentrations.

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It is therefore of fundamental importance in respiratory protection that the sense of smell should never be relied upon to provide warning against dangerous contaminants. 6.2.8.2 Limitations of irritant action as a warning of end of filter life Some contaminants, because of their local irritant action on the upper respiratory tract or eyes will give an early indication if present in harmful amounts. The warning sensation experienced, although perhaps centred in the nose, is not a smell, but a discomfort, a feeling of burning or irritation, e.g. sulfur dioxide. With some contaminants, the warning symptoms are so severe that no one would willingly remain in a dangerous atmosphere, e.g. ammonia and hydrogen chloride (HCl). With other contaminants, the warning may be positive, but insufficient to protect a person who is willing to endure considerable discomfort, e.g. chlorine. 6.2.9 Respirators for use in flammable or explosive atmospheres In the selection of respirators for use in potentially flammable or explosive atmospheres, care should be taken to select equipment that is not likely to be an ignition source. Such ignition sources can include the use of certain alloys which may produce sparks on impact with rusted iron or steel, the use of plastics and fibres with unsuitable antistatic properties, electrical components without a recognized method of protection or communications equipment. Alloys suitable for use in this situation are those in which the total content of aluminium magnesium or titanium does not exceed 15% by mass and in which the content of magnesium and titanium together does not exceed 6% by mass. Non-metallic materials shall have antistatic properties complying with AS 1020. The intrinsic safety of flameproof properties of electrical components of the equipment shall comply with and be certified to the requirements of AS 2380.2 or AS 2380.7 as appropriate.


NOTES: 1

‘Intrinsic safety’ is defined in AS 2380.7 in the following terms: a circuit in which any spark or any thermal effect produced in the test conditions prescribed in this Standard (which include normal operation and specified fault condition) is incapable of causing ignition of an explosive atmosphere.

2

‘Flameproof enclosure’ is defined in AS 2380.2 as an enclosure for electrical equipment that will withstand, without damage, an explosion of a prescribed flammable gas or vapour within the enclosure and will prevent the transmission of flame such as will ignite the external prescribed flammable gas or vapour for which it is designed, and which operates at an external temperature that will not ignite a surrounding flammable atmosphere.

3

‘Antistatic’ is defined in AS 1020 as indicating that a material is, by virtue of its low resistivity, incapable of retaining a significant static charge when in contact with earth.

4

Attention is drawn to the availability of a scheme for the certification of explosion-protected electrical equipment. Equipment so certified conforms to one of the explosion-protected electrical equipment Standards listed in publication MP69.

6.3

SELECTION FACTORS—TASK-RELATED

6.3.1 General The following task-related factors should be considered as part of the respirator selection process: (a)

Whether the device is for regular use or for emergency or rescue purposes.

(b)

The probable length of time during which the wearer will be in the contaminated atmosphere.

(c)

The expected level of activity and mobility required of the wearer.

(d)

The access to and nature of the working environment and its location with respect to a source of air suitable for breathing. COPYRIGHT

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(e)

The need for clear vision and communication.

(f)

The facilities available to maintain the device.

6.3.2 Frequency and length of usage The most commonly used respirators for regular use are half facepiece non-powered air-purifying respirators, because of their comfort and convenience. However, where full facepiece non-powered air-purifying respirators are used, consideration should be given to limiting their use to minimize discomfort and the possibility of heat stress. Half facepiece non-powered air-purifying respirators are not suitable for rescue purposes. When selecting an appropriate gas filter, the contaminant concentration, required minimum protection factor and period of exposure should first be addressed (see Clause 6.2.2.2, Table 6.3 and the filter manufacturer’s instructions). With particulate filters, extended use (or even moderate use in a heavily dust-laden atmosphere) will result in the wearer detecting an increase in breathing resistance caused by progressive blocking of the filter. Depending upon the severity of this phenomenon, users may prefer to employ supplied air equipment. Supplied air respirators are also chosen where facilities to change filters are not immediately available. Powered air-purifying respirators are also restricted by filter life, the necessity for filter changes and battery charging facilities and, in addition, the battery life must be taken into account (see Clause 7.8.6). Compressed air SCBAs are most suitable for routine or emergency work, but should be restricted to short-term use owing to an average supply life of 15 to 50 min. Where longer duration is required, such as for mines rescue and firefighting, compressed oxygen or liquid oxygen SCBAs are preferred. However, the use of such equipment should be limited to specially trained and experienced personnel.


6.3.3 Degree of activity and mobility Although non-powered air-purifying respirators do not restrict the mobility of the wearer, they impose a load upon the breathing process which may increase markedly with higher efficiency particulate filters. Where strenuous activity is required, a supplied-air respirator or a powered air-purifying respirator may be more comfortable. The PAPR has an advantage over air-hose or air-line equipment as there is no restriction of mobility. If SCBA is preferred, the weight and bulk of the apparatus should be considered as these may present difficulties to the users. 6.3.4 Location of the task When contemplating supplied air respirators, consideration should be given to the problems which may be presented by the air hose or air line limiting the distance between the task and a source of respirable air. In addition, such hoses or lines may be a source of danger to others working in the area and may themselves be damaged or severed through accident. Where compressed air-line respirators are indicated, these problems may be alleviated by supplying air from a large cylinder which may be moved to the task location. Air supplied from cylinders only lasts for a short period when used in a continuous flow mode. 6.3.5 Vision and communication Depending upon detailed design, all full facepiece respirators restrict the wearer’s vision to a certain extent. This should be considered if the user needs to be near moving machinery. Where precise communication is important, consideration should be given to selecting a facepiece with appropriate speech transmission facilities, otherwise the tendency will be for the wearer to remove the respirator to speak. 6.3.6 Maintenance Disposable respirators have a clear advantage where adequate maintenance facilities are unavailable. All other types require varying degrees of maintenance. Adoption of a maintenance program is essential (see Section 8).

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6.3.7 Air-hose or air-line Particular care should be taken in choosing an air-line or air-hose. Careful consideration should also be exercised when they are intended to be used in temperature extremes, or are likely to come in contact with solvents or other deleterious materials. 6.4

SELECTION FACTORS—OPERATOR-RELATED

6.4.1 General The following operator-related factors should be considered as part of the respirator selection process: (a)

Basic physiological considerations (see Clause 7.3).

(b)

The importance of facial fit (see Clause 7.3.2).

(c)

User acceptance.

6.4.2 Basic physiological considerations When selecting a suitable respirator, the effect of the working environment upon the user should be investigated. This should establish whether, when wearing a particular type of respirator, the user will be subject to adverse effects from environmental hazards other than atmospheric contamination. If this proves to be the case, a different design which retains sufficient respiratory protection, may mitigate such hazards and increase comfort afforded to the wearer. A common situation which exemplifies the above would be where a user of a full facepiece air-purifying respirator is working in an environment where he or she is subject to a high thermal load. Continued use may well result in hyperthermia (heat stress). The appropriate respirator in this circumstance may be an air-line respirator with cooling attachment, an air hose with a manual or electrical blower supplying cool air from an adjacent environment or a PAPR with a cooling attachment. 6.4.3 The importance of facial fit Facial fit is a prime factor in obtaining good protection when utilizing half or full facepiece respirators. All users must be made aware of the importance of facial fit in the selection of a respirator. Respirators incorporating close fitting facepieces rely on facial fit to prevent inward leakage of contaminants. Such respirators employing a full facepiece or half facepiece must not be used by males who are not clean shaven about the cheeks, neck and jaw. Half facepiece respirators of this type must not be used by those with moustaches where there is any chance of hair coming between the facepiece and the skin. Long hair may also impair the function of valves (see Clause 7.5.3). Nevertheless, even with an excellent facial fit, all respirators will have some inward leakage of the ambient atmosphere as well as the leakage through the outlet valve or valves.


Respirators which maintain a positive pressure in the facepiece at all times provide a higher degree of protection than can be achieved with negative pressure types. Positive pressure respirators may diminish the effect of poor facial fit but will not obviate the effect of leakage caused by facial hair (see Clause 7.5). Where conservation of the air supply is important, e.g. self-contained breathing apparatus, it should be recognized that any leakage, e.g. from the facial seal, increases air consumption and decreases service time. Reference should be made to Clause 7.5 and Appendix E for further information on facial fit. 6.4.4 User acceptance The appropriate respirator should be worn the entire time that a person is at risk of exposure. In practice, the user’s adherence to this principle will be influenced by the wearability of the individual respirator; influencing factors include comfort, field of vision and the need to communicate without removing the device.

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A simple calculation emphasizes the importance of wearing the respirator at all times of exposure. In an atmosphere of 10 times the accepted exposure limit, a wearing time of at least 95% of the exposure time is necessary to reduce the overall exposure below the accepted safe level. This is the case irrespective of the protection factor provided by the respirator during the wearing period. The wear-time factor required for safe exposure increases with increasing concentration of the contaminant. When a respirator is worn routinely or for extended periods, the significance of weight, tight-fitting straps, and skin chafing will increase to the extent that the user may not concentrate adequately on the work in hand. This translates into an increased risk of accident and a reduction in job satisfaction with an attendant drop in productive output.


It should be appreciated that, in some non-powered particulate air-purifying respirators, breathing resistance will increase progressively as the filter pores become blocked with contaminants. Increasing breathing resistance in such particulate filters is thus taken to indicate the end of the filter’s effective life. Continued use, although not resulting in contaminant penetration through the filter, will impose greater discomfort on the user.

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S E C T I O N 7 T H E R E S P I R A T O R Y P R O T E C T I O N P R O GR A M 7.1 MANAGEMENT RESPONSIBILITY If the control of exposure to an occupational hazard requires the use of respirators, the purchase of such equipment forms only a small part of the overall employer responsibility. A respiratory protection program, as outlined in this Section, shall be an integral part of a hazard control strategy. The respiratory protection program should be established by management, and an individual designated to head the program. The person should have a technical and professional background enabling him or her to make sound decisions based on an evaluation and understanding of workplace hazards. Preferably, the individual should be a safety engineer, occupational hygienist, or physician. In a small company, especially where respirator usage is limited, the program may be directed by the company owner, foreperson, or other supervisory personnel. Regardless of who assumes responsibility for the program, the responsible person should have the full support of management. The person should develop a standard operating procedure based upon the following: (a)

The basis for selecting a specific type of respirator.

(b)

Provision for medical screening of each employee assigned to wear respirators to determine if he or she is physically and psychologically suited.

(c)

An employee training program in which the employee can become familiar with the respirators, and which includes the proper use and the limitations of the equipment. (This is discussed in detail in Appendix F.)

(d)

Provision for assigning respirators to employees for their exclusive use, where practicable.

(e)

Provision for testing for the proper fit of the respirators (see Appendices D and E).

(f)

Provision for regular cleaning and disinfecting of the respirators.

(g)

Provision for proper storage of the respirators.

(h)

Provision for periodic inspection and maintenance of the respirators.

(i)

A periodic evaluation by the administrator of the program to assure its continued functioning and effectiveness.


Records of issue, fit tests, cleaning, periodic inspections and maintenance of respirators should be maintained as a part of the respiratory protection program. 7.2 COMPLIANCE OF EQUIPMENT All respirators must conform with the requirements of AS/NZS 1716 where there is an appropriate category. Respirator selection should be based on recommendations and limitations available from Australian and New Zealand regulatory authorities. Where a recommendation for a limitation is not available from Australian or New Zealand authorities information governing the use of respirators may be drawn from recognized international authorities. NOTE: Recognised international authorities includes: •

National Institute for Occupational Administration, USA (NIOSH/MSHA).

•

International Organization for Standardization (ISO).

•

European Committee for Standardization (CEN).

Safety

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MEDICAL SCREENING

7.3.1 General Any psychological stress on should, at least, have respirators. As part of evaluated: (a)

type of respirator may impose some physiological and the user. Persons who are routinely required to wear respirators a medical assessment to determine if they are able to wear the assessment process, the following considerations should be

Physiological considerations Regular wearing of non-powered air-purifying respirators and negative pressure demand air-supplied respirators imposes an extra burden on cardiac and respiratory systems. Thus, a person with a history of disorders in these areas should be medically assessed by an experienced occupational health physician, especially where heavy work or prolonged wearing of respirators is anticipated. State regulations may require regular medical examinations for some respirator wearers, e.g. lead workers. Regular medical examinations should be considered for all employees who rely on respirators for protection from chronic industrial disease. When assessing respirator users, consideration should also be given to the individual employee’s ability over prolonged periods to support the weight of certain respirators (e.g. SCBA) or to handle up to 30 m of line, if equipped with an air-line respirator.

(b)

Psychological considerations Helmet, hood and full facepiece respirators, especially when combined with full body protection, may give rise to feelings of isolation and anxiety in some people. Such people will find it difficult to perform their work satisfactorily under these conditions.

7.3.2 Specific factors affecting performance Some factors which may preclude the use of respirators in situations other than escape are as follows: (a)


(b)

Chronic lung conditions such as— (i)

emphysema—the individual may be unable to breathe adequately against the additional resistance of a respirator; and

(ii)

asthma—a user suffering an asthma attack would be likely to remove the respirator because of an inability to breathe properly.

Circulatory diseases such as— (i)

heart disease; and

(ii)

anaemia.

(c)

Epileptic seizures.

(d)

Additional use of contact lenses or spectacles.

(e)

Facial hair (see Clause 7.5.3).

(f)

Psychological factors should also be taken into consideration when employees are required to wear respirators. Some individuals become claustrophobic when wearing a respirator.

(g)

Facial characteristics such as scars, hollow temples, very prominent cheekbones, deep skin creases, a misshapen nose, lack of a nose bridge and lack of teeth or dentures may cause respirator facepiece sealing problems. Lack of dentures or missing teeth may cause problems in sealing a mouthpiece in a person’s mouth. Full dentures should be retained when wearing a respirator, but partial dentures may or may not have to be removed, depending upon the possibility of swallowing them.

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7.4 ISSUE OF RESPIRATORS Where practical, the user should be given respirators for his or her exclusive use. A record of respirator issue and usage should be established and maintained. This record could also show training courses attended and other relevant information. For respirators on extended personal issue, a system of regular cleaning, inspection and maintenance should be provided. Respirators disinfected disinfected accordance respirator. 7.5

not issued on a personal basis, for example SCBA, should be cleaned and after each use. No device should be issued unless it was cleaned and after its last use. Prior to re-issue, respirators should be inspected in with the manufacturer’s instructions to ensure correct operation of the

FACIAL FIT TESTS

7.5.1 General In order for the designed performance to be achieved by a respirator, it is essential the respirator be properly fitted to the individual to whom it is assigned. Two considerations are relevant to correct fitting: (a)

Assuming that there are several brands and sizes of a particular type of facepiece available, which one fits best?

(b)

How does the user know when the respirator fits properly?

The answers to these questions can be determined by the use of a facial fit test. There are two types of facial fit test—qualitative and quantitative. Qualitative tests are usually simple and fast. The quantitative test is not subjective but requires the purchase of special equipment, and a trained operator. The significant advantage of a quantitative facial fit test is that records can be maintained for future reference. Appendix D describes the various types of fitting test. The program administrator should choose the most appropriate of these and explain and demonstrate them to the respirator users. 7.5.2 Frequency of fitting tests Fitting tests should be performed at appropriate intervals, particularly when there is a change in the wearer’s facial characteristics, e.g. loss of teeth or excessive changes in weight, or where biological tests, e.g. lead in blood, indicate excessive exposure to a contaminant. Facial fit tests should be adopted as a routine when any close fitting respirator is being worn.


The following scheme of testing should be incorporated into the respirator program (see Appendix D for test details): (a)

Before the respirator is issued, a qualitative or quantitative fit test should be performed to assure the choice of a suitable respirator.

(b)

A further facial fit test should be performed at least annually or whenever there is a change in the wearer’s facial characteristics or other features which may affect the facial seal of the respirator.

(c)

At each use, the respirator should be donned before entering the contaminated area so the user can perform a simple positive or negative pressure fit check to test the respirator fit.

7.5.3 Facial hair in respirator fitting Facial hair lying between the sealing surface of a respirator facepiece and the wearer’s skin will prevent a good seal. Beards, moustaches and sideburns prevent satisfactory sealing. Long hair may also interfere with the operation of exhalation valves. The sealing problem is especially critical when close fitting facepieces are used. The reduction in pressure developed in the breathing zone of these respirators during inhalation may lead to leakage of contaminant into the facepiece where there is a poor seal. Therefore, individuals who have stubble (even a few days’ growth COPYRIGHT

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will cause excessive leakage of contaminant), a moustache, sideburns, or a beard which passes between the skin and the sealing surface must not wear a respirator which requires a facial seal. Additional detail on facial hair is given in Appendix E. 7.5.4 Eye correction in respirator fitting Corrective lenses with temple bars or straps should not be worn if these will interfere with the facial seal. Manufacturers of respirators can provide kits for installing eyeglasses in their respirator facepieces. These glasses or lenses should be mounted strictly in accordance with instructions to ensure proper fitting. Persons using half facepieces in conjunction with spectacles should be tested to ensure the effectiveness of each device is not reduced. 7.6

CLEANING AND MAINTENANCE

7.6.1 General It is especially important that an effective storage and regular maintenance program, appropriate to the type of respirator, be followed. Soiled or malfunctioning respirators provide the wearers with a false sense of security. The life of a wearer may be dependent on the effective operation and ready availability of a suitable respirator. In less vital circumstances, wearer cooperation in the use of respiratory protective devices should be more readily forthcoming if the respirator program ensures a readily available supply of clean functional respirators. Care of respiratory equipment should be handled by a centralized maintenance cleaning and storage station. The size and complexity of such a station will vary according to the size of the workforce, the nature of the hazards and the type of respiratory protective equipment available. It should be adequately equipped and staffed by trained personnel. All maintenance programs should follow the manufacturer’s instructions and provision for— (a)

cleaning and disinfection of equipment;

(b)

storage;

(c)

repair; and

(d)

inspection for defects.

7.6.2 Cleaning and disinfection In large programs where respiratory protective equipment is used routinely, respirators should be cleaned daily. In small programs where respirators are used occasionally, periodic cleaning and disinfecting is appropriate. Users who maintain their own respirators should be trained in cleaning procedures.


After removal of any filters, the cleaning may be performed in a number of ways: (a)

The respirator should be washed with detergent in warm water using a soft brush, thoroughly rinsed in clean water, and then air-dried in a clean place. Care should be taken to prevent damage from rough handling. This method is an accepted procedure for a small respirator program or where each worker cleans his or her own respirator.

(b)

A standard domestic clothes washer may be used if a rack is installed to hold the facepieces in a fixed position. (If the facepieces are placed loose in a washer, the agitator may damage them.) This method is especially useful in large programs where respirator usage is extensive.

Caution should be observed with respect to the addition of soaps and detergents to the cleaning water. Some of these may damage the equipment or cause irritation to the wearer.

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Disinfection may be achieved by using a broad-spectrum disinfectant. The choice of preparation should be made after enquiring of the respirator manufacturer and medical authorities. Such enquiries should also assist where protection against the transmission of a specific pathogen is required. With all disinfectants, particular attention should be paid to the manufacturer’s instructions regarding their use, e.g. dilution, temperature, exposure time. The cleaned and disinfected respirators should be rinsed thoroughly in clean water to remove all traces of cleaning agent and disinfectant. This is very important to prevent dermatitis. After rinsing, an anti-fog preparation may be applied to lenses and visors. The respirators should be allowed to air dry away from direct sunlight, on a clean surface, or dried in a low-temperature oven. They may also be hung from a horizontal wire, like drying clothes, but care should be taken not to damage the facepieces. 7.6.3 Storage of equipment Respirators should be located as close as practicable to the workplace. Respirators provided for emergency and rescue work should be at locations where they are readily available but adequately stored, secured and supervised so that unauthorized use or tampering is prevented. All emergency locations should be clearly marked in green and white in accordance with the requirements of AS 1319. Painting green and white diagonal stripes over an area of about 1 m2 has been found to be a satisfactory method of marking such locations. Cylinders of compressed oxygen or air shall be fully charged to the recommended working pressure. All self-contained breathing apparatus and emergency escape equipment should be maintained and stored in a ready for immediate operational use condition. Carbon dioxide absorbent in self-contained compressed oxygen respirators shall be renewed at intervals defined by the manufacturer and after each operational use.


The following shall be observed for storage and protection: (a)

Respiratory protective devices shall be kept clean and dry, and away from oil and exposure to direct sunlight and corrosive atmospheres, to avoid deterioration.

(b)

Where their use is infrequent, it is desirable to enclose facepieces to protect them from dust and corrosive atmospheres. Facepieces shall be stored so that they are not subject to distortion.

(c)

To prevent tampering, filters should be stored in sealed containers bearing the date of the last inspection. The limited life of stored gas filters shall not be overlooked.

(d)

Equipment for emergency use and not permanently issued to individuals should be stored close to the most likely points of use.

(e)

Cylinders shall be recharged before the contents have dropped to below 80% of full working pressure.

7.6.4 Maintenance Continued use of the respirator may necessitate periodic repair or replacement of its components. Such repairs and parts replacement should be carried out by trained individuals. Replacement of parts and repair of air-purifying respirators should, in most cases, present little problem. Equipment manufacturers supply literature which details the components of their respirators and also includes servicing information. The manufacturer will also provide replacement parts. Replacement parts for respiratory protective equipment, including filters, should be those approved by the manufacturer of the equipment. CAUTION: SUBSTITUTION OF PARTS OR FILTERS FROM A DIFFERENT BRAND OR TYPE OF RESPIRATOR WILL INVALIDATE THE APPROVAL OF THE RESPIRATOR AND MAY CONTRAVENE STATE LEGISLATION.

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Defective air-supplied respirators may be repaired and used again if broken parts are replaced by personnel authorized by the manufacturer. Maintenance of SCBA equipment is more difficult, primarily because of the valve and regulator assembly. NOTE: Disposable respirators are not intended to be repaired. Any attempted repair of disposable respirators is to be actively discouraged.

7.7

INSPECTION FOR DEFECTS

7.7.1 General An important part of a respirator maintenance program is inspection of the devices. If performed carefully, inspections will identify damaged or malfunctioning respirators. 7.7.2

Inspection schedules

All respiratory protective equipment should be inspected—

(a)

before and after each use; and

(b)

during cleaning.

In addition, SCBA and equipment designated for emergency use should be inspected in accordance with the manufacturer’s specifications. 7.7.3 Record keeping A record shall be kept of inspection dates and findings for all respirators maintained for emergency use. Maintenance records should be kept for all respirators together with the periods of use of each filter and battery, where applicable. Extra caution should be observed when it is proposed to re-use a filter which has had prior use. (Some filters can only be used once, e.g. filter self-rescuer (mines).) Records need not be kept for disposable respirators or for filters used in half facepiece respirators where these are changed regularly. (See Clause 7.8.4, 7.10 and 7.11.) Where equipment is issued to an individual, each respirator should bear an identifying mark which may be the user’s name, initials, clock number, or other similar identification. The date of issue and subsequent resistance checks, and the identifying mark of the facepiece with which it is used, shall be permanently marked on the filter, if it is to be re-used. 7.8

INSPECTION AND MAINTENANCE CONSIDERATIONS

7.8.1 General This Clause itemizes some of the primary defects to look for when inspecting a respirator. Where appropriate, suggested actions are given in parentheses. In many cases, the inspector may need to contact the manufacturer of the equipment or the equipment vendor.


7.8.2

Disposable respirators

Inspect—

(a)

for physical damage such as holes in the filter [obtain new disposable respirator];

(b)

straps for elasticity manufacturer]; and

(c)

the metal nose clip for deterioration [obtain new disposable respirator].

7.8.3

and deterioration

[replace respirator or straps—contact

Re-usable air-purifying respirators (half facepiece, full facepiece)

7.8.3.1

Rubber facepiece

Inspect for—

(a)

dirt [clean all dirt from the facepiece];

(b)

cracks, tears, or holes [obtain a new facepiece];

(c)

distortion [allow the facepiece to ‘sit’ free from any constraints and see if distortion disappears; if not, obtain a new facepiece]; and

(d)

cracked, scratched, or loose-fitting lenses [contact respirator manufacturer to see if a replacement is possible; otherwise, obtain new facepiece].

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7.8.3.2

Headstraps

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Inspect for—

(a)

breaks or tears [replace head harness];

(b)

loss of elasticity [replace head harness];

(c)

broken or malfunctioning buckles or attachments [obtain new buckles]; and

(d)

excessively worn serrations on the head harness which may allow the facepiece to slip [replace head harness].

7.8.3.3

Inhalation valve, exhalation valve

Inspect for—

(a)

detergent residue, dust particles, or dirt on valve or valve seat [clean residue with soap and water];

(b)

cracks, tears, or distortion in the valve material or valve seat [contact manufacturer for instructions]; and

(c)

missing or defective valve cover [obtain new valve cover from manufacturer].

NOTE: Permissible leakage of outlet valves may be exceeded after a relatively short life. This valve defect is not always recognizable by observation and frequent checks should be made for valve leakage. In the case of full facepiece respirators, valve assemblies should be tested after removal and replacement of valves. Valve leakage can be measured as shown in Appendix G.

7.8.3.4

Inspect for—

(a)

recommended filter for the hazard;

(b)

approval conditions, where applicable;

(c)

increased filter resistance [replace filter];

(d)

missing or worn gaskets [contact manufacturer for a replacement];

(e)

worn threads—both filter threads and facepiece threads [replace filter or facepiece, whichever is applicable];

(f)

cracks or dents in filter housing [replace filter];

(g)

deterioration of gas filter support harness [replace the harness]; and

(h)

service life indicator, or end of service date [replace filter].

7.8.3.5

Corrugated breathing tube

Inspect for—

(a)

cracks or holes [replace tube];

(b)

missing or loose hose clamps [obtain new clamps]; and

(c)

broken or missing end connectors [obtain new connectors].

7.8.3.6


Filter element(s)

Powered air-purifying respirators

Inspect as follows:

(a)

Check the respirator assembly for leaks, tighten filter clamps and replace damaged parts.

(b)

Check the flow rate prior to use. If the flow rate is low, check the battery and recharge if necessary (see Clause 7.8.6) or replace the filter, or both.

(c)

Check flow rate at the end of use. If rate is below minimum specified by manufacturer, replace filter. If still below minimum, check for battery or major faults.

7.8.4

Supplied-air respirators

7.8.4.1 Facepiece, headstraps, valves, and breathing tube respirators. 7.8.4.2

Hood, helmet, blouse, or full suit

Check as for air-purifying

Inspect for—

(a)

rips and torn seams [if unable to repair the tear adequately, replace];

(b)

headgear suspension [adjust or replace as required];

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(c)

cracks or breaks in visor [replace visor];

(d)

integrity and proper fit of protective screen [adjust or replace facepiece or screen as required]; and

(e)

leaking gloves or boots [replace].

7.8.4.3

Air supply system

Inspect for—

(a)

breathing air quality (see Appendix A), ensure that breathing air filtration systems where required are in accordance with Appendix H;

(b)

breaks or kinks in air-hoses and end fitting attachments [replace hose or fitting];

(c)

tightness of connections;

(d)

proper setting of regulators, valves and alarm systems [consult manufacturer’s recommendations]; and

(e)

correct operation of air-purifying elements and carbon monoxide or other warning devices.

7.8.4.4 Self-contained breathing apparatus (SCBA) for applicable inspection criteria.

Consult manufacturer’s literature

7.8.5 Filter self-rescuer (mines) Because the catalyst in this equipment deteriorates on exposure to atmosphere, the complete equipment shall be stored in its sealed carrying case. Routine examination should consist of a visual inspection for dents in the case and to ensure that the seal is unbroken, and weighing of the complete respirator. If weighing shows an increase greater than 1% in mass, the equipment should be discarded or returned to the manufacturer for filter element replacement and resealing. When a batch of these respirators is nearing the end of guaranteed storage life, random samples should be selected for complete testing by a competent authority in accordance with AS/NZS 1716. The guidance of the competent authority should be followed in relation to any batch of equipment which has been so tested. 7.8.6 Care of rechargeable batteries Powered air-purifying respirators normally employ nickel cadmium (NiCd) rechargeable batteries to power the air blower. This type of battery will normally withstand approximately 1000 charge/discharge cycles under typical use conditions and may be stored for long periods in the charged or discharged state without ill effect.


The following points should be observed to properly care for the batteries: (a)

NiCd batteries undergo a process of continual ‘self discharge’ which, for a fully charged battery stored at ambient temperatures in excess of 30°C, means that discharge will be complete after several weeks.

(b)

New or stored batteries should be preconditioned prior to use. This involves subjecting the battery to two full charge/discharge cycles and a final full charge just before use. Each charge/discharge cycle consists of a 14 h charge followed by discharge under normal load conditions lasting at least 10 h.

(c)

Constant current charging should be adopted for batteries in service to assure consistent charge life. Fast charging should be avoided if possible since the resultant elevated temperature can reduce the battery’s effective life.

(d)

Where normal use involves only partial discharge, batteries should be subjected periodically to a full discharge/recharge cycle. This is to overcome an apparent reduction in the charge life of the battery or ‘memory’ effect which may otherwise develop.

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When considering the pattern of use for the PAPR, it should be borne in mind that NiCd batteries display a characteristic sudden voltage drop at the end of the charge period. This will be of concern to the user who expects the batteries to ‘fade out’ progressively. (f) Batteries should be stored in a dry environment, at normal room temperatures and free from corrosive liquids and gases. To maintain an optimum charge life, the manufacturer’s recommendations on use should be followed. Where it is necessary to reconfirm the nominated charge life, the battery or batteries should be given a full charge and then fitted to a PAPR, the facepiece of which is attached to a flowrate/pressure measuring device. The PAPR is operated as it would be in the field and the flowrate/pressure monitored as the battery discharges. 7.8.7 Final inspection Assembled respirators should be carefully checked to ensure that all component parts are in place and all moisture has been removed from surfaces and crevices. Where practicable, all parts through which air is supplied to the wearer should be checked for correct assembly.


(e)

7.9 SAFE WORKING PRACTICES 7.9.1 General Before entry into any area where respiratory protection may be required, it is essential that the likely contaminants, their toxicity and concentration, and the possibility of an oxygen deficiency be known. If there is doubt on any of these points, the worst condition should be assumed and appropriate precautions should be taken, particularly in the choice of suitable equipment. 7.9.2 Provision of assistance It is essential that whenever any respirator is used in an atmosphere dangerous on short exposure, an assistant suitably trained and equipped for entering the dangerous atmosphere be standing by in continuous supervision of the wearer, either directly or with the aid of a signalling device and be able to initiate rescue if the need arises. Such supervision should include constant monitoring of the air supply, where applicable, and constant awareness of the length of time of exposure. Prior to attempting a rescue, the assistant should raise an alarm or contact a third party. 7.9.3 Use of speech transmission devices Speech can cause facepiece or component leakage and should be limited, particularly when a half facepiece is being worn. Some facepieces are provided with speech amplification or transmission devices. If a facepiece is fitted with a mechanical speech transmission device, the diaphragm should be handled carefully to prevent puncture. Electrically operated speech transmission devices are available. (See also Clause 6.2.9.) 7.9.4 Entry to confined spaces Working in confined spaces presents special problems which may include the difficulties of entry and escape, the possibility of oxygen deficiency and the greater likelihood of high concentrations of contaminants. Safe entry is often covered by mandatory requirements and the appropriate statutes should be observed. In general, no entry should be attempted unless the proper equipment is available and adequate assistance (see Clause 7.9.2) is provided. Only air-supplied or oxygen-supplied respirators are suitable for unknown or IDLH atmospheres and any person entering the confined space should be equipped with a safety harness and lifeline. A full discussion of the factors affecting entry to confined spaces can be found in AS 2865. NOTE: Attention is drawn to the additional requirements of regulatory authorities governing entry to confined spaces.

7.9.5 Low and high temperature 7.9.5.1 Low temperatures Use of respirators in low temperatures can create several problems. The lenses of the full facepiece equipment may fog owing to condensation of the water vapour in the exhaled breath. Coating the inner surface of the lens with an anti-fogging compound will reduce fogging. COPYRIGHT

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7.9.5.2 High temperatures Respirator usage in hot environments can put additional stress on the user. The stress may be minimized by using a light-weight respirator with low breathing resistance. In this respect, an air-line respirator equipped with a cooling system may be used. 7.9.6 Use of hoses Care should be taken when using a hose in an area where solvents or other chemicals are used since the solvent may permeate certain types of hose material, or destroy hoses. Heat may also cause the release of objectionable odours into the hose. 7.10

REPLACEMENT OF FILTERS

7.10.1 General There is no overall rule about when filters should be changed. Each situation needs to be treated individually. Advice should be sought from an occupational hygienist on an acceptable change-over time based on likely exposure patterns, so an adequate safety margin is allowed. WARNING: IN SOME FILTER ASSEMBLIES IT MAY BE POSSIBLE TO INSERT THE FILTER IN EITHER DIRECTION DESPITE DIRECTIONAL ARROWS OR INSTRUCTIONS. IF A PREVIOUSLY USED FILTER IS REINSERTED THE OTHER WAY ROUND THEN THE USER IS LIKELY TO INHALE CONTAMINANTS DEPOSITED DURING THE EARLIER USE.

7.10.2 Particulate respirators The breathing resistance of the filter will progressively increase in use as it becomes choked with trapped particles and eventually becomes so high that the filter must be replaced. The time taken for this condition to develop will vary according to the characteristics of the filter, and the type, size and concentration of the particles. As a general guide, the breathing resistance can be considered too high when there is a perceived increase in resistance to breathing. Resistance of particulate filters may be considerably increased if used in damp conditions. A damaged or ineffective inlet valve may lead to condensation on the filter, thereby increasing resistance. In the case of powered air-purifying respirators, clogging of the filters is normally signalled by a fall in the air-flow rate. The use of a pre-filter is advantageous where coarse particulates would otherwise rapidly choke the filter. Resistance of filters can be measured by the method described in Appendix I. The use of backflushing or other methods to prolong the life of a particulate filter is to be actively discouraged since it will reduce the efficiency of the filter.


7.10.3 Gas respirators Filters should be replaced on a regular basis or when an odour or taste is perceived in the inhaled air or when the wearer coughs or experiences discomfort. The breathing resistance does not normally rise during use. The life of gas filters used in powered air-purifying respirators is dependent upon the concentration of the contaminant, the class of filter and the flow rate of the blower unit. It is generally independent of the wearer’s breathing rate. Where rapid failure occurs with a new filter, the adequacy of this equipment for the application should be re-assessed and it may be necessary to use a more effective method of respiratory protection. 7.10.4 Combined respirators The observations in Clauses 7.10.2 and 7.10.3 apply also to combined respirators. In addition, where an operation which generates both gases and particulates, such as spray painting, is being carried out, the use of a replaceable pre-filter is recommended to extend the life of the particulate filter by preventing it from becoming clogged with coarse particulates. This pre-filter should be changed frequently.

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7.11 ENSURING THE CONTINUED EFFECTIVENESS OF THE RESPIRATOR PROGRAM 7.11.1 General Two important ways of ensuring the continued effectiveness of the respirator program are the periodic monitoring of the work areas requiring usage of respirators, and evaluation of the overall respirator program. 7.11.2 Monitoring of atmospheric contaminant concentration Many things such as changes in operation or process, implementation of engineering controls, temperature, and air movement can affect the concentration of the atmospheric contaminant which originally required the use of respirators. To determine the continued necessity of respiratory protection or need for additional protection, measurements of the atmospheric contaminant concentration should be made whenever any of the above changes are made or detected. A record of these measurements should be kept. 7.11.3 Program evaluation In general, the respirator program should be evaluated at least annually, with adjustments, as appropriate, made to reflect the evaluation results. Program function can be separated into administration and operation. Appendix J contains a list of check points to facilitate effective evaluation of a respirator program. 7.12 TRAINING IN RESPIRATORY PROTECTION USAGE Occupational health and safety legislation varies from State to State, but in all cases requires employees to be adequately trained and supervised to carry out their work safely. Where a respirator program is adopted, training should be given. This should occur at the commencement of employment, and at routine intervals thereafter. The frequency of retraining will depend on the complexity of the program and the degree of the hazard, but in any case, should be at least annually. Employees who need to wear respirators should to be trained in the safe use and limitations of the respirator. Supervisors need to be trained in their responsibilities for training and inspection. Special care should be taken when training non-English-speaking employees or those speaking English as a second language to ensure that instructions are fully understood.


A suggested format for a respirator training program is given in Appendix F.

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8

S P E C IF I C M AI NT E N A N C E R E Q U I R E M E NT S

8.1 SERVICING FACEPIECES Where fitted, facepieces and breathing tubes of non-disposable respirators should be detached from the remainder of the apparatus. Where inspection indicates distortion, cracks, hardening, tackiness or other abnormalities, the mask or breathing tube should be replaced. The personal preference of the wearer with respect to the adjustment of straps, buckles and other component parts contributing to personal comfort, should be given due consideration when inspecting the facepiece. 8.2 SERVICING EXHALATION VALVES Wherever practicable, exhalation valves should be removed from valve seats and cleaned each time the respirator is serviced. Valves and valve seats may be cleaned in cold or lukewarm water (hot water should be avoided). Valve seats may need to be scrubbed with a suitable brush. NOTE: Reference should be made to the manufacturer’s instructions for cleaning and disinfecting facepieces. Generally, cleaning and disinfecting solutions should not be hotter than 55°C as higher temperatures can permanently distort facepieces and cause premature deterioration of individual components or the whole assembly.


8.3 SERVICING OTHER COMPONENT PARTS In the case of component parts other than those referred to in the foregoing clauses, the following requirements for servicing should be applied: (a)

Although it is essential that water does not enter adjustment valves, reducing valves, demand valves, pressure gauges and other controlling devices, component parts should be appropriately washed or cleaned as prescribed in the foregoing clauses.

(b)

All parts should be inspected and faulty component parts replaced with those approved by the manufacturer. In the case of simple items such as outlet valve rubbers and head harnesses, this should be done by maintenance personnel, but for complex parts such as demand valves and reducing valves, servicing should only be undertaken by trained and authorized personnel.

(c)

Compressed air or oxygen cylinders should be filled, inspected, tested and maintained in accordance with the requirements of AS 2030. Partly used cylinders should be recharged as soon as possible after use.

(d)

Carbon dioxide absorbent should be recharged at intervals specified by the manufacturer.

(e)

In all cases the manufacturer’s instructions should be observed when servicing self-contained breathing apparatus. CAUTION: OIL OR GREASE SHOULD NOT BE USED ON ANY OXYGEN OR HIGH-PRESSURE AIR EQUIPMENT BECAUSE OF THE RISK OF EXPLOSION. SPECIAL LUBRICANTS ARE AVAILABLE FOR HIGH-PRESSURE (ABOVE 100 MPa) AIR AND OXYGEN EQUIPMENT.

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APPENDIX A

REQUIREMENTS FOR AIR QUALITY (COMPRESSORS OR CYLINDERS) FOR SUPPLIED AIR RESPIRATORS (Normative) A1

AIR SUPPLY

A1.1 Capacity The necessary capacity of any air service for respiratory protection shall be calculated on a minimum requirement of 170 litres per minute for each person measured at the respirator. NOTE: Where air cooling or encapsulated suits are used additional air will be required and advice should be sought from a competent source.

Air used to supply respirators shall— (a)

have no objectionable or nauseous odour; and

(b)

contain not less than 19.5% and not more than 22% by volume of oxygen.

Additionally, at 15°C and 100 kPa absolute the air shall— (i)

contain not more than 11 mg/m 3 (10 p.p.m. by volume) of carbon monoxide;

(ii)

contain not more than 1400 mg/m 3 (800 p.p.m. by volume) of carbon dioxide;

(iii)

contain not more than 1 mg/m 3 of oil; and

(iv)

for cylinders, contain not more than 100 mg/m 3 of water when sampled from a cylinder initially filled to a pressure of at least 12 MPa.

A1.2 Air temperature Air supplied from a compressor to a facepiece, hood or helmet should be at a comfortable breathing temperature within the range 15 to 25°C. A1.3 Avoidance of stale air or moisture Arrangements should be made to avoid the pocketing of stale air in pipelines. The use of ring circuits and controlled draining helps to guard against this hazard. Couplings should be of the ‘safety type’ i.e. requiring at least two deliberate actions to separate the connector or coupling and should be of a different design to those used for other compressed gas and air services. NOTE: The contents of all piping, conduits ducts and other services should be identified and suitably marked to prevent incorrect connection of air-lines. Attention is drawn to AS 1345 regarding the identification of services.


Provision should also be made, at appropriate places, to drain away water from any pipeline. Water traps should be drained prior to using the apparatus. A1.4 Compressors Systems shall incorporate a receiver of sufficient capacity to reduce pulsations from compressor action and reduce compressor overheating. Compressors shall be well maintained and shall not be allowed to run hot, as harmful substances may be produced by the decomposition of the lubricating oils. Filters should be purged or replaced at regular intervals in accordance with the manufacturer’s instructions. Consideration should also be given to the use of oil-free compressors. The air intake to the compressors should be sited in an uncontaminated atmosphere. Particular care should be taken to ensure that this requirement is met if a portable air compressor is being used to supply breathing air. The use of filters on any air intake should be of secondary importance when compared with the foregoing requirements.

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A1.5 General works air supply systems Where the air supply is used in the manufacturing process as well as in the supply of respirable air, particular care should be taken to avoid the risk of contamination. Where the air supply is used in the manufacturing process and there is a risk of contamination, the air supply should not be used for personal protection unless it has been filtered to provide the air quality defined in Paragraph A1.1. In every instance it should be ensured that any back pressures from operating plants using the air supply will not cause contamination of the air used for personal protection. Provision should be made to ensure that the air lines supplying the breathing apparatus receive an adequate supply of respirable air under all plant operating conditions. Plant air supplies are not suitable for air-line respirators unless special precautions have been taken for the elimination of scale, rust, water, oil mist, irritating ingredients and odours. It is preferable that a separate installation be provided for respiratory air purposes, and that it be designed to eliminate the abovementioned contaminants. A1.6 Air quality Regular testing of the air at the respirator shall be undertaken to verify the quality of the air and records kept. A2 COMPRESSED OXYGEN SUPPLY Compressed oxygen of the dry breathing type should be odourless and contain not less than 99.5% by volume of oxygen. At 15°C and 100 kPa absolute, it should contain— (a)

less than 11 mg/m 3 (10 p.p.m. by volume) carbon monoxide; and

(b)

less than 1400 mg/m 3 (800 p.p.m. by volume) carbon dioxide.

When sampled from a cylinder initially filled to at least 12 MPa, it should contain— less than 20 mg/m 3 water; and

(ii)

less than 1 mg/m 3 oil.


(i)

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APPENDIX B

ADVISORY AUTHORITIES (Informative) Advice and assistance on various aspects of occupational hazards and relevant exposure limits as well as regulatory requirements may be obtained from the following authorities: AUSTRALIAN CAPITAL TERRITORY Australian Capital Territory Radiation Safety Section GPO Box 825 CANBERRA CITY ACT 2601

Telephone: (06) 247 2899 Fax: (06) 257 3503

COMMONWEALTH Comcare Australia GPO Box 9905 CANBERRA ACT 2601

Telephone: (06) 275 0000 Fax: (06) 247 2231

NEW SOUTH WALES WorkCover Authority of NSW 400 Kent Street SYDNEY NSW 2000

Telephone: (02) 370 5301

Radiation Control Section Environmental Protection Authority PO Box 136 REGENTS PARK NSW 2143

Telephone: (02) 795 5000 Fax: (02) 649 4470


NORTHERN TERRITORY Occupational and Environmental Health Health Branch Department of Health and Community Services GPO Box 1701, DARWIN NT 0801

Telephone: (089) 89 2983 Fax: (089) 89 2700

Northern Territory Work Health Authority 66 Esplanade Street DARWIN NT 0801

Telephone: (089) 89 5511

QUEENSLAND Division of Health and Medical Physics Department of Health 450 Gregory Terrace FORTITUDE VALLEY QLD 4006

Telephone: (07) 252 5446 Fax: (07) 252 9021

Queensland Health Scientific Services Government Chemical Laboratory 39 Kessels Road COOPERS PLAINS QLD 4108

Telephone: (07) 274 9111

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Department of Employment, Vocational Education, Training and Industrial Relations Division of Workplace Health and Safety Forbes House 30 Makerston Street BRISBANE QLD 4000

Telephone: (07) 857 9490 Fax: (07) 857 9426

SOUTH AUSTRALIA South Australian Occupational Health and Safety Commission 100 Waymouth Street ADELAIDE SA 5000

Telephone: (08) 226 3120 Fax: (08) 212 1864

Department of Labour Occupational Health Division 61 Hindmarsh Square ADELAIDE SA 5000

Telephone Fax:

Radiation Protection Branch South Australian Health Commission PO Box 6 Rundle Mall ADELAIDE SA 5000

Telephone: (08) 226 6521 Fax: (08) 226 6255

(08) 226 6510 (08) 232 0334

TASMANIA Occupational Health and Safety 81-89 Brisbane Street HOBART TAS 7001

Telephone: (002) 33 7668

Senior Health Physicist Department of Health GPO Box 191B HOBART TAS 7001

Telephone: (002) 30 3770 Fax: (002) 310735


VICTORIA Occupational Health and Safety Authority 80 Collins Street MELBOURNE VIC 3000

Telephone: (03) 655 6444

Radiation Safety Section Health Department Victoria GPO Box 4003 MELBOURNE VIC 3000

Telephone: (03) 616 7084 Fax: (03) 616 7147

WESTERN AUSTRALIA Department of Occupational Health, Safety and Welfare 1260 Hay Street WEST PERTH WA 6005

Telephone: (09) 327 8777 Fax: (09) 321 8973

Radiation Health Section Health Department of Western Australia GPO Box X2307 PERTH WA 6001

Telephone: (09) 346 2261 Fax: (09) 381 1423

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APPENDIX C

RESPIRATOR SELECTION EXAMPLES (Informative) C1

EXAMPLE 1

TASK: Tunnelling in rock containing quartz for 8—10 hours per day. PARTICULATE MEASUREMENTS: Tunnelling machine operator 1.5 mg/m3 respirable quartz (TWA)* Other workers in vicinity of operator Exposure standard— respirable quartz


RESPIRATOR SELECTION:

0.3−0.5 mg/m 3 (TWA)* 0.1 mg/m3 (TWA)*

Tunnelling machine operator

Other workers

Required protection factor (see Clause 6.2.2.2)

15

5

Other protective equipment required

Safety helmet, hearing protection, miner’s lamp, faceshield and eye protection

Safety helmet, hearing protection, miner’s lamp and eye protection

General choice (Table 6.1)

— PAPR P2 — P2 filter in a full facepiece — Half facepiece airline respirator

— P1 half facepiece

Final selection

— Helmet type PAPR fitted with lamp bracket and earmuffs

— P1 disposable

Reasons for choice

Air-line unsuitable due to lack of mobility. Full facepiece unsuitable for extended usage

Personal choice — lightweight, no maintenance required

C2

EXAMPLE 2

TASK: Manufacturing operation requiring addition of volatile solvents to a batching tank. Engineering controls not yet operational. Operation performed once per day for half an hour. GAS/VAPOUR MEASUREMENT: During addition of solvent

1500 mg/m3 methyl ethyl ketone (MEK) (peak concentration)3 respirable

Exposure standard, MEK

445/m 3

* (TWA)

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4

General choice (Table 6.3)

— Type A AUS for Type A1 gas filter with half facepiece — PAPR A1 with half facepiece — Air-line with half facepiece

Final selection

— Type A AUS or Type A1 gas filter with half facepiece

Reason for choice

The task is too short to merit selection of a powered respirator or supplied-air equipment

Replacement

The filter should be replaced every week or sooner if the odour of MEK is apparent


Required minimum protection factor

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APPENDIX D

TYPICAL RESPIRATOR FIT TESTS (Informative) D1 GENERAL The proper fitting of respiratory protective equipment requires the use of some type of fit test to determine an adequate match between the facepiece of the respirator and face of the wearer. D2

TEST METHODS

D2.1 Types There are two types of test—qualitative and quantitative. The use of one or both types of test depends on the type of respirator to be fit tested, the extent of respirator usage and the available resources of trained personnel and capital. During any fitting test, the respirator headstraps should be as comfortable as possible. Tightening the straps will sometimes reduce facepiece leakage, but the wearer may be unable to tolerate using the respirator for any length of time. D2.2 Qualitative fit testing Qualitative tests are fast, require no complicated expensive equipment, and are easily performed. However, these tests rely on the wearer’s subjective response, and so are not entirely reliable. There are three major (see Paragraph D2.3(a), (b) and (c)) and two minor (see Paragraph D2.4(a) and (b)) qualitative tests. The first three use a test atmosphere which can be an enclosure into which— (a)

the user can enter wearing the equipment; and

(b)

a ‘test’ contaminant (of low toxicity) can be placed.

Although elaborate enclosures are available commercially, the employer can put together a ‘do-it-yourself’ qualitative fit test enclosure by the use of a plastic bag (a dry-cleaning bag), several hangers, and some cotton. Figure D1 shows a typical enclosure constructed using these materials. D2.3 Qualitative tests


(a)

There are several qualitative tests including:

Isoamyl acetate test Isoamyl acetate is a low toxicity substance with a banana-like odour. It is only suitable for testing the face fit of respirators using organic vapour filters. The substance is applied to the cotton wad inside the enclosure. The prospective user should put on the respirator in an area away from the test enclosure so that there is no prior contamination of the filters by ‘pre-exposure’ to the isoamyl acetate. The user shall enter the chamber and perform each of the following activities for 30 s: (i)

Normal breathing.

(ii)

Deep breathing, to simulate heavy exertion. This should not be done long enough to cause hyperventilation.

(iii)

Side-to-side and up-and-down head movements. These movements should be exaggerated, but should approximate those that take place on the job.

(iv)

Talking. This is most easily accomplished by reading a prepared text loudly enough to be understood by someone standing nearby.

(v)

Other exercises may be added depending upon the situation. For example, if the wearer is going to spend a significant time bent over at some task, it may be desirable to include an exercise approximating this bending. The major drawback of the isoamyl acetate test is that the odour threshold varies widely among individuals. Furthermore, the sense of smell is easily dulled and may deteriorate during the test so the wearer can detect only high COPYRIGHT

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vapour concentrations. Another disadvantage is that isoamyl acetate smells pleasant, even in high concentrations. Therefore, a wearer may say the respirator fits although it has a large leak. This may be because the wearer likes the fit of the particular respirator or is following the respirator selection of someone else. Conversely, a wearer may claim that a particular respirator leaks if it is uncomfortable. Therefore, unless the worker is highly motivated toward wearing respirators, the results of this test may sometimes be suspect.


(vi)

Break respirator seal and expose wearer to test agent to verify the wearer’s sensitivity.

FIGURE D1

(b)

TYPICAL TEST ENCLOSURE

Saccharin mist test This test is suitable for respirators incorporating any particulate filter. It relies upon the wearer’s ability to detect a saccharin aerosol by taste. Individuals vary in their taste threshold, therefore a screening procedure is performed to establish suitability. Prospective test subjects are screened with an aerosol produced from a 0.83% by weight solution of sodium saccharin in water. The test subject remains inside the test enclosure without a respirator and is instructed to breathe through the mouth only. The solution is then puffed, up to 30 times, using a nebulizer through a hole in the enclosure material. The number of puffs required for the subject to taste the

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saccharin is recorded. If the subject is unable to taste the saccharin after 30 puffs, a different method of testing facial fit should be used. A period of at least several minutes should elapse after the sensitivity test before re-testing the subject wearing a respirator. The test subject, having passed the sensitivity test, is fitted with the appropriate respirator. Since the saccharin mist is an airborne particulate, gas filter respirators should be fitted with a particulate filter for the test. The subject is placed in the test enclosure and an aerosol produced from an 83% by weight solution of sodium saccharin in water is puffed through the hole. Initially, the number of puffs is the same as the number taken to produce a response in the screening procedure. Half the number of puffs is delivered each 30 s. The test subject should perform exercises such as those described in Paragraph D2.3(a). If the subject tastes the saccharin, it is interpreted as a leakage of aerosol via the facial seal or through respirator component parts other than the filter or both. This test suffers similar disadvantages to the isoamyl acetate test. Sweet food (or sweeteners, e.g. in coffee) should not be consumed 30 min prior to testing.


(c)

Irritant smoke test This test uses an irritant smoke. It is only suitable for testing the facial fit of air-supplied respirators or respirators incorporating P3 particulate filters. The test substance is an irritant (stannic chloride or titanium tetrachloride) which is available commercially in sealed glass tubes. When the tube ends are broken and air is passed through them (usually with a squeeze bulb), a dense irritating smoke is emitted. In this test, the user steps into the test enclosure and the irritant smoke is ‘sprayed’ into the test chamber. If the user detects any of the irritant smoke, it means a defective fit, and adjustment or replacement of the respirator is necessary. The irritant smoke test should be performed with caution because the aerosol is highly irritating to the eyes, skin, and mucous membrane. As a qualitative means of determining respirator fit, this test has the distinct advantage that the wearer usually reacts involuntarily to leakage by coughing or sneezing. The likelihood of giving a false indication of proper fit is reduced.

D2.4 Quantitative tests Quantitative respirator performance tests involve placing the wearer in an atmosphere containing an easily detectable, relatively low toxicity gas, vapour, or aerosol. The atmosphere inside the respirator is sampled through a probe in the respirator. The leakage is expressed as the concentration inside the facepiece as a percentage of the outside concentration. The numbers generated by quantitative fit tests do not reflect the protection factors likely to be achieved in the workplace. The advantage of a quantitative test is that it does not rely on a subjective response. However, these tests generally require equipment which can be operated only by highly trained personnel. Also, it can be difficult to use because of its complexity and bulk. Aerosol tests generally use particles much finer than those encountered in most industries and so require respirators with Class P3 particulate filters. Each test respirator should be equipped with a sampling probe to allow removal of an air sample from the facepiece. Test facepieces may not be worn in service, since the test orifice negates the approval of the respirator. The most commonly available commercial quantitative tests are as follows: (a)

Sodium chloride (NaCl) test In this test, a liquid aerosol is generated continuously from a saltwater solution (using a nebulizer), dried to produce discrete sub-micrometre salt particles, and dispersed into a test chamber or hood. A means is provided for sampling the atmosphere in the chamber or hood and inside the respirator. These samples are fed to the detector section where the aerosol’s penetration inside the respirator is determined. The amount of penetration is displayed on a meter or recorder.

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(b)

Oil mist test This test uses an air-generated oil mist. It differs from the NaCl test only in that the aerosol particle is liquid. The aerosol is generated using a nozzle atomizer, but, being an oil, the mist does not dry into solid particles when injected into a diluting airstream.

(c)

Particle counters test aerosol.

In this test the natural dusts in the atmosphere are used as the

D2.5 Fit checks These tests (negative pressure test and the positive pressure test) should be used only as a very gross determination of fit. The wearer should use these fit checks just before entering the hazardous atmosphere. These tests are only suitable for respirators with tight-fitting facepieces. Although these tests are simple, they have severe drawbacks, the main one being that the wearer may handle the respirator after it has been positioned on the face, possibly modifying the facial seal. (a)


(b)

Negative pressure fit checks pressure fit checks:

The following methods are suitable for negative

(i)

Disposable respirators The wearer completely covers the filter with both hands or a non-permeable substance, e.g. a polythene bag, and inhales sharply. The respirator may sink onto the face with a very vigorous breath indicating an adequate seal. If an unsatisfactory face seal is indicated by the feel of an airstream channelling through the leak, re-adjust the respirator until a satisfactory seal is indicated.

(ii)

Rubber facepiece The user closes off the inlet of the filter or filters either by covering the intake or by squeezing the breathing tube so that it does not pass air, inhales gently so that the facepiece collapses slightly, and holds a breath for about 10 s. If the facepiece remains slightly collapsed and no inward leakage is detected, the respirator is probably well fitted.

Positive pressure fit checks respirators:

The following tests are suitable only for close fitting

(i)

Disposable respirators (without exhalation valves) The wearer covers the filter or filters either with both hands or a non-permeable substance, e.g. a polythene bag and exhales vigorously. If an unsatisfactory face seal is indicated by the feel of an airstream channelling through the leak, readjust the respirator until a satisfactory seal is indicated.

(ii)

Rubber facepiece The wearer closes off the exhalation valve and exhales gently into the facepiece. The fit is considered satisfactory if slight positive pressure can be built up inside the facepiece without any evidence of outward leakage.

For some respirators, this check may require the wearer to remove the exhalation valve cover which often disturbs the respirator fit even more than the negative pressure test. Therefore, this test should be used sparingly if it requires removing and replacing a valve cover. The test is easy for respirators which have a valve cover with a single small port that can be closed by the palm or a finger.

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NEGATIVE PRESSURE TEST


FIGURE D2

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APPENDIX E

FACIAL SEAL OF RESPIRATORS (Normative) E1 GENERAL Beard growth, some hairstyles and other facial features prevent an adequate seal between the wearer’s face and the fitting surfaces of a facepiece or mouthpiece. Facial hair may also interfere with inhalation and exhalation valve operation. Male wearers in particular shall be made aware of the general rules in Paragraphs E2 to E6. E2 BEARDS Bearded persons cannot expect to achieve adequate respiratory protection when wearing a full facepiece respirator or a half facepiece respirator. Accordingly, no one who requires respiratory protection shall attempt to wear either a full facepiece respirator or half facepiece respirator over a beard. E3 MOUSTACHES Moustaches may spoil the fit of a half facepiece respirator and may interfere with the peripheral seal of a full facepiece respirator. Moustaches should not protrude beyond projected lines, drawn vertically from the corner of the mouth. E4 SIDEBURNS When a full facepiece is being worn, sideburns shall not extend below a line drawn through the top of the tragion (the notch in the cartilage of the ear just above and immediately in front of the earhole) and the canthus (corner) of the eye. This line is illustrated in Figure E1. E5 STUBBLE GROWTH AND LONG HAIR Stubble growth, depending on its length and stiffness, interferes to some degree with proper sealing of a facepiece and it is necessary that male wearers of respirators shave daily. When the hair is worn long, particular care should be taken to ensure that none is trapped beneath the fitting surface. E6 MOUTHPIECE AND NOSE CLIP A mouthpiece and nose clip may not provide adequate respiratory protection to a bearded person.


When the person at risk has a ‘bushy’ facial hairstyle, hair trapped between the lips and mouthpiece may prevent a satisfactory seal being obtained. Because of the varying amount of cartilage in the noses of individuals, there is the added difficulty of obtaining a satisfactory seal of the nasal passages with a nose clip. This problem is worsened by the presence of perspiration which may cause difficulty in maintaining the nose clip in position.

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LEGEND: A = notch in the carti lage of the ear B = canthus of the eye C = line below which the sideburns should not extend

LENGTH OF SIDEBURNS


FIGURE E1

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APPENDIX F

EMPLOYEE TRAINING PROGRAM (Informative) F1 OUTLINE The format of this guide allows the instructor to adapt the training program to the individual requirements of the facility. This may be accomplished in the following way: (a)

Where indicated, record the appropriate information for your facility, e.g. the locations of operations where respirators are required, or where exposures to airborne contaminants necessitate the use of respirators.

(b)

Refer to specific information in this Standard, for example, a discussion of the various types of respirator available (Section 6). Employees need not be aware of all types, but only those that they will be required to wear. Therefore, when the guide indicates that the information is to be inserted at that point in the presentation, only the relevant parts of this Standard need be utilized.


F2 FORMAT When planning the training session, remember that trainees usually retain only about 20% of what they hear, about 40% of what they see, and about 70% of what they both see and hear. For the best results, therefore, a program of lectures, supplemented by audiovisual materials and demonstrations, is recommended. The following suggestions are made to help increase the effectiveness of the program. (a)

Cover the material suggested in the guide.

(b)

Break the lecture into 30-45 minute intervals to allow the trainees to stand up and move around.

(c)

Use blackboard or overhead projector to emphasize subject sequence and major points.

(d)

Obtain slides or films from the National Safety Council, your trade association, or the manufacturer/supplier of the equipment you use and intersperse them in the presentation, as appropriate.

(e)

Illustrate specific areas with personal experiences or examples related to your operations.

(f)

Have examples of the respirators used in your facility available during the training session and highlight areas concerned with their operation and use.

(g)

Supplement the material in this Standard with company operating procedures or instructional material supplied by the equipment manufacturer/supplier.

F3 INSTRUCTIONS TO TRAINEES An integral part of the training program is the free exchange of information—and questions—between instructor and trainees. Therefore, the following comments (made by the instructor) are suggested at the beginning of the training session: ‘During this session your full participation is needed. (a)

If you don’t understand what’s being discussed, ask questions.

(b)

If you have been involved in or are aware of accidents pertaining to specific areas covered, share them with us.

(c)

If you are aware of better approaches to reduce hazardous conditions, give us the benefit of your experience.

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Finally, if there is additional information or guidance we can provide, identify the areas for us.’ EMPLOYEE TRAINING PROGRAM GUIDE

NOTES TO INSTRUCTOR

SUGGESTED PROGRAM FORMAT (a) Identification of the hazard Before we get into the ‘specifics’ about the respiratory protective equipment you will be hearing, a f ew s tatement s abo ut hazar d identification.

Discuss only those contaminant atmospheres representing problems in your facility. See following discussion.

There are several kinds of hazardous atmosphere which may require the use of a respirator. (i)

Gaseous contaminants Gases are the normal form of substances like carbon dioxide or hydrogen sulfide. These substances are solids or liquids only at very low temperatures or extremely high pressures. Carbon dioxide, for instance, is a gas at room temperature. But it also occurs as solid ‘dry ice’ formed at low temperatures.

(ii) Particulate contaminants Particulates are tiny particles, solid or liquid, generated by such processes as grinding, crushing, and mixing of a compound, either a solid or a liquid. There are three types of particulate. Dusts are solid particles produced by such processes as grinding, crushing, and mixing of powder compounds. Examples are sand and plaster dust. By comparison with the following two types of particulates, dust particles are usually large.


Mists are tiny liquid droplets, usually formed whenever a liquid is sprayed, vigorously mixed, or otherwise agitated. Acid mists around diptanks used for metal cleaning, and oil mists near newspaper printing presses are two examples. Fumes are solid condensation particles of extremely small size. Fumes are found in the air near soldering, welding, and brazing operations, as well as near molten metal processes such as casting and galvanizing.

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The two basic forms—gases and pa r ti c ul at e s— f r e qu e nt l y o cc ur together. Paint spraying operations, for example, produce both paint mist (particulates) and solvent vapours (gases). A further discussion of ODAs can be found in Section 3.

O xy g e n- d e f i c i en t a t m os p h er e s (ODAs) are most commonly found in confined spaces which have poor ventilation. Examples are silos, petrochemical tanks, degreasers, and the holds of ships. (b) Reasons for respirators (i)

Name work area (1) List substances (2)

(A) In work areas (1), atmospheric concentrations of substances (2) were found to be above acceptable limits.

Describe activities (1) Describe exposure (2)

(B) During maintenance activities (1) you are exposed to (2) a high concentration for a short period of time. This will lead to excessive exposure.

Describe areas (1)

(C) Several areas (1) were found to be ‘oxygen deficient’.

Name storage areas (1) Describe emergency situation which could exist in your plant (2)

(D) Hazardous substances are stored at (1) and if these substances spill or leak, an emergency condition may exist, for example (2).

Suggested phraseology Accessed by Clough Engineering on 05 Sep 2001

State regulatory authorities These have set maximum exposur e standards for many airborne toxic materials and have set standards governing specific working environments to protect your health. A recent evaluation of your working environment revealed that:

Describe what controls implemented (1)

(ii)

are

being

Status of engineering controls Since the company recognizes that respiratory protection is not the primary method for control of airborne hazards, we are taking steps to implement engineering control solutions. (A) We will install the following engineering controls (1).

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Discuss administrative schedules, e.g. rotating work controls, spreading work over two shifts, job rotation (2).

(B) And the following administrative controls (2). However, while the above steps a r e be in g i m pl em e n t e d, respiratory protection will be required. (c) Respirator selection Selection of the proper equipment normally involves three steps: the identification of the hazard; the evaluation of the hazard; and finally the selection of the appropriate respiratory equipment based on the first two steps:

After explaining to the employee the type of hazar dous atmospher e requiring respiratory protection, you should then discuss the specific hazards. Check vendor literature, toxicologic references, or material safety data sheet.

(i)

H az a r d sp e c if i c at i o ns include—

T h e se

(A) hazard name— —organic vapour (name); —particulate (name); or —gas (name). (B) toxicity data and effects.

Refer to Section 4

(ii) Evaluation of the hazard To determine the concentration of the haz ar d, as ide ntif ied abov e, measurements were made. The concentrations in the work environment examined were compared with the relevant WorkSafe and Australian Standards. (iii) Selection of the respirator After it was determined that respirators w ere r equir ed, this Standar d (AS/NZS 1715) was consulted to find out the appropriate respirator.


(d) Use and proper fitting of respirators A poor facial seal can cause contaminants to be inhaled through the respiratory sealing surfaces, instead of through the filters, or air supply system. Using Appendix E and information supplied by the manufacturer, show the employee how to put on the selected r es p i r a t o r . S ho w t h e v ar i o us component parts of the respirator, and how the respirator functions to remove the contaminants.

(i)

Use of respiratory protective equipment So that respirators using tight- f itting f acepieces give maximum protection, it is most important to ensure a proper ‘match’ between the facepiece and your face.

(ii) Proper fitting

At this time, you should have available at least two different types (from different manufacturers) of respiratory equipment for the employee to try on.

(A) In most cases, there are several different brands of the same type o f r e s pi r a to r y e qu i p me n t approved for use against a specific hazard. COPYRIGHT

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Refer to Appendix D for discussion of fitting tests.

(B) H ow ever , just because a respirator ‘feels comfortable’ it does not mean it is protecting you to the fullest extent from the hazard. The key word is proper fit. To determine if the fit is proper, several tests can be used. Each facepiece may be available in different sizes. (e) Wear time The importance of wearing the respirator at all times the user is in the contaminated ar ea must be emphasized.

Refer to Section 6 for factors in se l ec t io n w hi c h i n cl ud e s u se limitations.

(f) Limitations of respirators The respiratory equipment you will use does have some limitations affecting its use. (g) Maintenance and storage of respirators To ensure the continued pr oper functioning of respirators, they must be regularly cleaned and disinfected, and stored in a convenient and clean location.

Refer to Section 7 for details concerning the cleaning of equipment. Several suggested cleaning methods are given. Discuss provisions.

(i)

Refer to Section 7 and discuss storage provisions by company.

(ii) Storage Equipment should be stored properly at the conclusion of the work shift.

Refer to Section 7 for discussion about inspecting equipment for defects.

(iii) Inspection for defects This is one of the most important functions associated with respirator usage. These inspections can identify pr oblems w ith malf unctioning respirators.

Refer to Clause 7.7.3.

(iv) Record keeping.


Before you discuss this Section with the user, you should first prepare the summary—as it applies to your usage.

Cleaning Your respirator shall be cleaned daily after use. The company has made provisions for doing this.

(h) Summary A summary of the respirator program. Reasons for respirators. (i)

Respirator selection procedure: (A) Identification of hazard. (B) Hazard specification. (C) Evaluation of the hazard. (D) Selection of the respirator.

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APPENDIX G

TYPICAL METHOD OF MEASURING VALVE LEAKAGE (Informative) G1 LEAKAGE METER The leakage meter (Figure G1) consists of a cylindrical vessel approximately 125 mm diameter × 250 mm high, the open end of which is closed by a metal plate and a rubber gasket. Tube A connects the apparatus to a vacuum line and is fitted with a valve to control the rate of flow. Tube B is open to air and the depth of insertion within the glass vessel can be varied by a simple gland. The component under test is attached to tube C which has a gland which allows axial movement at a constant depth. The end of tube C is bent so that it can be positioned centrally under the 30 mL glass measuring vessel which is attached to the air release tap (D) by a rubber sleeve. G2 USE OF METER To prepare the meter for use, the glass vessel is filled with water to the zero mark on the 30 mL measuring vessel. Tube C is closed and suction is applied to the meter through tube A. Bubbles will rise from the bottom of tube B and the valve in the suction line is adjusted until the flow rate is approximately 60 to 80 bubbles per min. A manometer is attached to tube C and the depth of tube B is adjusted until the pressure in tube C is 25 mm of water. In operation the component under test is attached to tube C by a suitable jig or connection and the tube is removed from under the measuring vessel. The air release tap (D) is opened to allow air to escape from the measuring vessel and then closed. When conditions are steady, the end of tube C is moved under the measuring vessel and the time taken for the leakage to fill the measuring vessel to the 30 mL mark is noted.


Valve assemblies can usually be tested in situ and can be connected to the leakage meter by simple jigs which may be fashioned from laboratory grade rubber stoppers.

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LEAKAGE METER


FIGURE G1

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APPENDIX H

COMPRESSED BREATHING AIR FILTRATION SYSTEMS (Informative) H1 SCOPE This Appendix provides information for the purchaser of compressed breathing air filtration systems covering the basic features of a filtration system for oil-lubricated compressors designed to deliver pure, dry, respirable air to the user. H2 COMPRESSOR LOCATION Since compressed breathing air is a processed product, the filtration system should be capable of eliminating harmful matter to produce a suitable end-product. This initially requires that the compressor be correctly mounted and located in an area providing ample space on all sides to ensure good ventilation and maintenance accessibility. The compressor should also be placed in an area where the ambient temperature is as cool as possible. The air intake should be located in open air, away from any source of atmospheric contamination. The use of filters on an air intake should be of secondary importance to this requirement. The possibility of contamination of the compressor intake by discharge from pressure relieving devices on other plant in the vicinity should be considered as well as the effects of changes in wind direction. A particular problem may be presented where the compressor is driven by an internal combustion engine or is located close to motor vehicles. H3 AIR PURIFICATION ELEMENTS The effectiveness of the air purification train requires that the elements comprising the system be placed in the correct sequence (see Figure H1). The first element in the purification system is a mechanical device to remove liquid water. The air, after leaving the mechanical water separator, passes into a coalescing filter or equivalent where oil, aerosol and submicron particles are removed. An air dryer or sorbent filter then reduces the water vapour content of the compressed air to prevent moisture contamination of the next stage, an activated charcoal filter designed to remove oil, odours and some organic and hydrocarbon vapours. If the carbon dioxide content of the compressed air needs to be reduced, an additional sorbent filter may be required. The next step in the purification process may be the catalytic conversion of carbon monoxide to carbon dioxide. In some instances, where the carbon monoxide concentration is high, it may be necessary to reverse the sequence of these last two stages. A dust filter may then be required to protect the air delivery system from disintegrated purification media.


NOTE: Some purifiers are designed to remove a number of contaminants in one vessel.

H4 PERFORMANCE CRITERIA When writing specifications for an air purification package, the user should state that when installed in the user’s premises, the system shall produce air which meets the air quality requirements of Appendix A of this Standard for a specified period of time at a specified air flow rate. H5 MAINTENANCE A record of the periodic replacement of the filter media should be maintained in accordance with the manufacturer’s instructions and specifications. H6 AIR PURIFICATION TRAIN This system will comprise a number of pressure vessels that should be designed and approved in accordance with AS 1210.

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NOTE: Not all purification elements may be required. SEQUENCE OF A TYPICAL BREATHING AIR-LINE PURIFICATION TRAIN


FIGURE H1

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APPENDIX I

TYPICAL METHOD OF MEASURING INHALATION AND EXHALATION RESISTANCE (Informative) I1 RESISTANCE METER Typically, a resistance meter for measuring both negative and positive pressure consists of a control valve, an air flowmeter, a manometer and a measuring tube for connection to the component under test. I2 APPARATUS A typical arrangement of the apparatus is shown in Figure I1. The measuring tube should have an internal diameter of not less than 22 mm and the manometer should be arranged so that true static pressure within the measuring tube is indicated by the manometer. The respirator component to be tested is connected to the measuring tube. Some form of simple jig may be necessary to facilitate the connection of the component to the resistance meter. I3 PROCEDURE The air flow is set at the required rate by means of the control valve and the ‘zero’ setting on the manometer adjusted prior to connecting the component under test. When a jig is used this should be connected to the measuring tube without the component under test and if necessary the flowrate and manometer readjusted before connecting the component under test.


The resistance value is then read from the manometer.

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(a) Sucti on

(b) Pressure


* 1500 Pa = 150 mm H 2O

FIGURE I1

RESISTANCE METER — TYPICAL ARRANGEMENT

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APPENDIX J

CHECKPOINTS FOR RESPIRATOR PROGRAM ADMINISTRATION AND OPERATION (Informative) J1 PROGRAM ADMINISTRATION Program responsibility should be given to someone who is knowledgeable about respirators and who can coordinate all aspects of the program. The coordinator should know the present status of the implementation of engineering controls, if feasible, to alleviate the need of respirators. The coordinator should ensure that there are written procedures/statements covering such aspects of the respirator program as— (a)

designation of administrator;

(b)

respirator selection;

(c)

purchase of approved equipment;

(d)

medical screening of respirator users;

(e)

record keeping;

(f)

issue of equipment;

(g)

fitting;

(h)

disinfection, cleaning, storage, inspection, repair;

(i)

training in proper selection and usage;

(j)

use under special conditions, i.e. confined spaces, escape and atmospheres immediately dangerous to life or health; and

(k)

audit program for effectiveness and ensure that corrective action is undertaken when necessary.

J2 PROGRAM OPERATION Checks should be carried out to ensure adherence to the following matters:


(a)

Respirator selection

Users must ensure the following:

(i)

Work area conditions and employee exposures are properly surveyed.

(ii)

Respirators are selected on the basis of hazards to which the employee is exposed.

(iii)

Selections are procedures.

(iv)

Only approved respirators which provide adequate protection for the specific hazard and concentration of the contaminant are purchased and used.

(v)

Medical evaluation of the prospective users has been made to determine their physical and psychological suitability to wear respiratory protective equipment.

(vi)

Where respirators have been issued to the users for their exclusive use, records covering the issue of these respirators are maintained.

made

by

individuals

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(b)

(c)

(d)

Respirator fitting (i)

Users are given the opportunity to try on several respirators to determine whether the respirator they will subsequently be wearing is the best fitting one.

(ii)

The respirator is fit tested at appropriate intervals, with an appropriate test. Records of such tests are maintained.

(iii)

Those users who require corrective lenses are properly fitted.

(iv)

Wearers check the fit of their respirators each time they are donned.

Cleaning and disinfecting (i)

Respirators are cleaned and disinfected after each use when different people use the same device, or as frequently as necessary for devices issued to individual users.

(ii)

Proper methods of cleaning and disinfecting are utilized.

Storage (i)

(e)


(f)

78

Respirators are stored so as to protect them from dust, sunlight, heat, excessive cold or moisture, or damaging substances.

(ii)

Respirators are stored properly in a storage facility to prevent deformation.

(iii)

Storage in lockers and tool boxes is permitted only if the respirator is in a carrying case or carton.

(iv)

Gas and vapour filters are stored in containers/bags with airtight seals.

(v)

Respirators are stored close to where they will be used.

Inspection (i)

Respirators are inspected before and after each use and during cleaning.

(ii)

Qualified individuals/users are instructed in inspection techniques.

(iii)

Respiratory protective equipment designated for ‘emergency use’ is inspected at least monthly (as well as after each use).

(iv)

A record is kept of the inspection of ‘emergency use’ respiratory protective equipment.

Repair (i)

Replacement parts used in repair are those of the manufacturer of the respirator.

(ii)

Repairs are made by individuals knowledgeable about respirators.

(iii)

Repairs of SCBA are made only by certified personnel manufacturer’s representative.

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INDEX Absorption Filter capacity . . . . . . . . . . . . . . . . . . . . . . . . 5.3.3.3 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 Ingestion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 Inhalation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Through skin . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 Acceptance User . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4.4 Acid gases Filter selection . . . . . . . . . . . . . 5.3.3, 6.2.4, Table 6.4 Filter types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.3 Additional protection Goggles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.7.2 Head coverings . . . . . . . . . . . . . . . . . . . . . . . . 6.2.7.3 Spectacles . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.7.2 Advisory authorities Listing . . . . . . . . . . . . . . . . . . . . . . . . . . . Appendix B Air blower Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.4.3 Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.4.2 Air-hose High temperature use of . . . . . . . . . . . . . . . . . . . 7.9.6 Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.8.4.3 Limiting distance . . . . . . . . . . . . . . . . . . . . . . . . 6.3.4 Respirator categories . . . . . . . . . . . . . . . . . . . . . . . 5.4.2, 5.4.4 definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.2 Use of . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.3.6, 7.9.6 Air-line High temperature use of . . . . . . . . . . . . . . . . . . . 7.9.6 Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.8.4.3 Limiting distance . . . . . . . . . . . . . . . . . . . . . . . . 6.3.4 Negative pressure . . . . . . . . . . . . . . . . . . . . . . 6.2.4.4 Respirator categories . . . . . . . . . . . . . . . . . . . . . . . 5.4.2, 5.4.5 definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.3 Use of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.3.6 Air quality Filtration requirements . . . . . . . . . . . . . . . Appendix H Requirements cylinders . . . . . . . . . . . . . . . . . . . . . . . . Appendix A compressors . . . . . . . . . . . . . . . . . . . . . Appendix A System inspection . . . . . . . . . . . . . . . . . . . . . . 4.3, 7.8 Air sampling see Monitoring Air temperature High . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.9.5.2 Low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.9.5.1 Requirements . . . . . . . . . . . . . . . . . 5.4.1, Appendix A Am monia Effects of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.2 Filter selection . . . . . . . . . . . . . . . . . . 5.3.3, Table 6.4 Indication . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.8.2 Anaesthetics Effects of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.2 Approved equipment Management responsibility . . . . . . . . . . . . . . . . . . . 7.1 Purchase of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2 Asbestos Exposure standard . . . . . . . . . . . . . . . . . . . . . . . . 4.2.2

Filter for . . . . . . . . . . . . . . Filter selection . . . . . . . . . . Hazard evaluation . . . . . . . . Inhalation . . . . . . . . . . . . . . Asphyxiants Effects of . . . . . . . . . . . . . . Atmosphere Composition . . . . . . . . . . . . Oxygen deficiency . . . . . . . Auxiliary protection Escape type . . . . . . . . . . . . Filter type . . . . . . . . . . . . . General . . . . . . . . . . . . . . . Low air warning . . . . . . . . .

.. .. .. ..

. . . . . . . . . . . . . . 5.3.2 . . . . . 6.2.3.3, Table 6.1 . . . . . . . . . . . . . . 4.2.2 . . . . . . . . . . . . . . 2.2.3

. . . . . . . . . . . . . . . . 2.2.2 . . . . . . . . . . . . . . . . . 3.2 . . . . . . . . . . . . . . . . . 3.3 . . . .

. . . .

.. .. .. ..

. .. .. .. . .. . . . . 5.4.7.1, .. .. . .. ... . . . . 5.4.7.1,

5.4.7.1 5.4.7.2 5.4.7.1 5.4.7.3

Banana oil see Isoamyl acetate Batteries Care of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.8.6 Recharging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.8.6 Beards see Hair Body entry Ingestion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 Inhalation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Skin absorption . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 Skin penetration . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 deep wounds . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 Breathing In aircraft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Underwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Breathing air Auxiliary protection . . . . . . . . . . . . . . . . . . . . . . 5.4.7 Continuous flow . . . . . . . . . . . . . . . . . . . . . . . 5.4.3(b) Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.6 Filtration . . . . . . . . . . . . . . . . . . . . . 5.3, Appendix H General . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1, 5.4.1 Mode of delivery . . . . . . . . . . . . . . . . . . . . . . . . 5.4.3 Natural breathing . . . . . . . . . . . . . . . . . . . . . . 5.4.3(a) definition . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.32 Negative pressure demand . . . . . . . . . . . . . . . . 5.4.3(c) Positive pressure demand . . . . . . . . . . . . . . . . . 5.4.3(d) Provision of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1 Self contained . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.6 Supplied . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4, 5.4.2 Breathing resistance Air hose . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.4.2, 6.1 Filter replacement . . . . . . . . . . . . . . . . . . . . . . . . 7.10 Canister see Filter Cartridge see Filter Classifications Air-purifying respirator . . . . . . Gas filter . . . . . . . . . . . . . . . . Hazard . . . . . . . . . . . . . . . . . . Particulate filter . . . . . . . . . . . Cleaning General . . . . . . . . . . . . . . . . . Sanitizing . . . . . . . . . . . . . . . . Coarse particulate filter see Filter

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. . 5.3 . 5.3.3 . 4.1.2 . 5.3.2

. . . . . . . . . . . . . . 7.6.1 . . . . . . . . . . . . . . 7.6.2

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Combined hazards Protection against . . . . . . . . . . . . Communication In flammable or explosive atmospheres . . . . . . . . . . . . . . Requirements . . . . . . . . . . . . . . . Speech transmission devices . . . . Confined spaces Entry to . . . . . . . . . . . . . . . . . . . Safe procedures . . . . . . . . . . . . . Considerations Physiological . . . . . . . . . . . . . . . Psychological . . . . . . . . . . . . . . . Contaminant Atmospheric definition . . . . . . . . Concentration . . . . . . . . . . . . . . . Protection against . . . . . . . . . . . . Warning by . . . . . . . . . . . . . . . . Cylinders . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . 6.2.5

. . . . . . . . . . . . 6.2.9 . . . . . . . . . . . . 6.3.5 . . . . . . . . . . . . 7.9.3 . . . . . . . . . . . . 7.9.4 . . . . . . . . . . . . . 3.1 . . . . . . . 6.4.2, 7.3.1 . . . . . . . . . . . . 7.3.1 . . . . . . . . . . . . 1.5.5 . . . . . . . . . . 6.2.2.3 . . . . . . . . . . . . . 6.2 . . . . . . . . . . . . 6.2.8 . . . . . . . . . . 5.4, 5.6

Deep wounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 Demand valve see valves Dust see Particulates


Emergency locations . . . . . . . . . Equipment Management responsibility . . . . Purchase of . . . . . . . . . . . . . . Storage . . . . . . . . . . . . . . . . . Explosive atmospheres Respirators in . . . . . . . . . . . . . Exposure standards . . . . . . . . . . Eye correction see also Vision In respirators . . . . . . . . . . . . .

. . . . . . . . . . . . . . 7.6.3 . . . . . . . . . . . . . . . 7.1 . . . . . . . . . . . . . . . 7.2 . . . . . . . . . . 7.6, 7.6.3 . . . . . . . . . . . . . . 6.2.9 . . . . . 1.3, 4.2.2, 6.2.2.2 . . . . . . . . . . . . . . 7.5.4

Facial seal Facial hair, effect of . . . . . . . . . . . . 7.5.3, Appendix D Fit check definition . . . . . . . . . . . . . . . . . . . . . . 1.5.13 Fit test definition . . . . . . . . . . . . . . . . . . . . . . . 1.5.14 Fit test frequency . . . . . . . . . . . . . . . . . . . . . . . . 7.5.2 Importance of . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4.3 Tests . . . . . . . . . . . . . . . . . . . . . . . . 7.5, Appendix D Filters Capacity (see also Classification) . . . . . . . . . . . 5.3.3.3 Classification . . . . . . . . . . . . . . . . . . . . . . 5.3, 6.2.3.2 Combination definition . . . . . . . . . . . . . . . . . . . . 1.5.8 Combination gas and particulate . . . . . . . . 5.3.4, 7.10.4 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.15 External . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.4, 7.10.4 Frequency and length of usage . . . . . . . . . . . . . . . 6.3.2 Gas classification . . . . . . . . . . . . . . . . . . . . . . 5.3.3.3 Gas life of . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.4.3 Gas types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.3 Particulate classification . . . . . . . . . . . . . . . . . . . 5.3.2 Pre-filter . . . . . . . . . . . . . . . . . . . . . . . . 5.3.4, 7.10.4 Self-rescue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.5 Self-rescuer (industrial) . . . . . . . . . . . . . . . . . . 5.3.5.4 Self-rescuer (mines) . . . . . . . . . . . . . . . . 5.3.5.2, 7.8.5 Types . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2, 5.4.7.2 Fit checks Facial seal . . . . . . . . . . . . . . . . 7.5.2, Appendices D, E Negative pressure . . . . . . . . . . . . . 7.5, Appendix D2.5 Positive pressure . . . . . . . . . . . . . . 7.5, Appendix D2.5

Fit tests Before issue . . . . . . . . . . . . . . . 7.5.2, Appendices D, E Facial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5 Frequency of . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5.2 Qualitative (definition) . . . . . . . . . . . . . . . . . . . 1.5.44 Quantitative (definition) . . . . . . . . . . . . . . . . . . 1.5.45 Flammable atmospheres Respirators in . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.9 Fume Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.18 Filter selection . . . . . . . . . . . . . . . . . . . . . . Section 6 Inhalation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.2 Gas filter see Filters Gases Acid inhalation of . . . . . Organic . . . . . . . . . . . Toxic (protection against) Goggles Use of . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . 2.2.2 . . . . . . . . . . . . . . . . . . . 5.3.3 . . . . . . . . . . . . . . . . . . 6.2.4 . . . . . . . . . . . . . . . . . 6.2.7.2

Hair Facial (beards) . . . . . . . . . . Long . . . . . . . . . . . . . . . . . Moustaches . . . . . . . . . . . . Sideburns . . . . . . . . . . . . . . Harmful substances . . . . . . . . Hazard Classification . . . . . . . . . . . Combined, protection . . . . . Control . . . . . . . . . . . . . . . Evaluation . . . . . . . . . . . . . Exposure standards . . . . . . . Isolation of . . . . . . . . . . . . Recognition of . . . . . . . . . . Head coverings Use of . . . . . . . . . . . . . . . . Hoses see Air-hose see Air-line

. . . 6.4, 7.5.3, Appendix . . 6.4.3, 7.5.3, Appendix . . 6.4.3, 7.5.3, Appendix . . . . . . . . . . . Appendix . . . . . . . . . . . . Section .. .. .. .. .. .. ..

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E E E E 2

. . 4.1.2 . . 6.2.5 . . . 4.3 . . . 4.2 . . 4.2.2 . . . 4.3 . . . 4.1

. . . . . . . . . . . . . . 6.2.7.3

Ingestion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 Inhalation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Inspection (equipment) see also Cleaning and Maintenance . . . . . . . . . . . . 7.6 Consideration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.8 For defects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7 Record keeping . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7.3 Requirements . . . . . . . . . . . . . . . . . . . . . . . 7.6, 7.7.2 Schedules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7.2 Irritants Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.2(a) Particulates . . . . . . . . . . . . . . . . . . . 2.2.4(a), 2.2.4(c) Isoamyl acetate . . . . . . . . . . . . . . . . . . . . . . Appendix D Isolation of hazard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Issue of respirators . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4 Record keeping . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7.3 Life Gas filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.4.3

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Lung Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.3 Maintenance Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6 Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.8 Periodic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6.4 Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6 Record keeping . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7.3 Respirator . . . . . . . . . . . . . . . . . . . . . 6.3.6, 7.4, 7.6.4 Management Responsibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1 Mask Smoke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.5.3 Material safety data Sheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1.1 Medical screening . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3 Mercury Filter selection . . . . . . . . . . . . . . . . Tables 6.3 and 6.4 Methyl bromide . . . . . . . . . . . . . . . . . Tables 6.3 and 6.4 Mobility Degree of activity . . . . . . . . . . . . . . . . . . . . . . . . 6.3.3 Respirator selection . . . . . . . . . . . . . . . . . . . . . 6.2.3.6 Monitoring Biological . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1(c) Contaminant concentration . . . . . . . . . . . . . . . . . 7.11.2 Environmental . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1 Hazard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1 Personal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2.1(a) Moustaches see Hair Mouthpiece see also Nose clip Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.31 Lack of sealing . . . . . . . . . . . . . . . . . . . . . Appendix E


Negative pressure Demand . . . . . . . . . . . . . . . . Fit test . . . . . . . . . . . . . . . . . Nose clip see also Mouthpiece Definition . . . . . . . . . . . . . . Lack of sealing . . . . . . . . . . .

. . . . . . . . . . . . . 5.4.3(c) . . . . . . 7.5, Appendix D . . . . . . . . . . . . . . 1.5.34 . . . . . . . . . . Appendix E

Occupational Hygienist definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.36 Occupational Hygiene definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.35 Odour Warning properties . . . . . . . . . . . . . . . . . . . . . 6.2.8.1 Oxygen Compressed supply . . . . . . . . . . . . . . . 5.4.6.3, 5.4.6.4 requirements . . . . . . . . . . . . . . . . . . . . . Appendix A Deficiency . . . . . . . . . Section 3, Table 6.6, 7.9.1, 7.9.4 Deficiency — Protection against . . . . . . . . . . . . . . 6.2.6 Generating apparatus . . . . . . . . . . . . . . . . . . . . 5.4.6.6 Liquid supply . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.6.5 Particulates Body entry . . . . Definitions . . . . Fever producing Inhalation of . . . Irritant . . . . . . . Lung damaging .

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. . 2.2.3, 2.4 . . . . . 1.5.39 . . . . 2.2.4(d) . . . . . . 2.2.3 . . . . 2.2.4(c) . . . . 2.2.4(b)

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Nuisance . . . . . . . . . . . . . Protection against . . . . . . . Thermally generated . . . . . Performance, factors effecting Physiological considerations Basic . . . . . . . . . . . . . . . . Medical screening . . . . . . . Respirator selection . . . . . . Poisons Gaseous . . . . . . . . . . . . . . Particulates . . . . . . . . . . . Systemic . . . . . . . . . . . . . Positive pressure Demand . . . . . . . . . . . . . . Fit test . . . . . . . . . . . . . . . Pre-filter see Filters Program Effectiveness . . . . . . . . . . Evaluation . . . . . . . . . . . . Protection factor Definition . . . . . . . . . . . . Determination of . . . . . . . . Exposure standard . . . . . . . Frequency of use . . . . . . . Gas filter respirator . . . . . . Length of use . . . . . . . . . . Psychological considerations .

. . . . . . . . . . . . . . . 2.2.4(a) . . . . . . . . . . . . . . . . . 6.2.3 . . . . . . . . . . . . . Table 6.2 see Medical screening 7.3.2 . . . . . . . . . . . . . . . . . 6.4.2 . . . . . . . . . . . . . . . . . 7.3. . . . . . . . . . . . . . Section 6 . . . . . . . . . . . . . . . . . 2.2.2 . . . . . . . . . . . . . . . . . 2.2.3 . . . . . . . . 2.2.2(c), 2.2.4(e) . . . . . 5.4.3(d), Appendix C . . . . . . . . 7.5, Appendix C

. . . . . . . . . . . . . . . . . 7.11 . . . . . . . . . . . . . . . . 7.11.3 . . . . . . .

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. . 1.5.43 . 6.2.2.2 . 6.2.2.2 . . . 6.2.3 . 6.2.4.2 . . . 6.3.2 . . . 7.3.1

Records Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7.3 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7.3 of issue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7.3 Repair see Maintenance Replacement Components, see Substitution of filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.10 Respirable air see Breathing air Respirator Air-purifying . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3 Air-hose, types of . . . . . . . . . . . . . . . . . . . . . . . . 5.4.4 Air-hose, use of . . . . . . . . . . . . . . . . . . . 6.2.3.6, 7.9.6 Air-hose, types of . . . . . . . . . . . . . . . . . . . . . . . . 5.4.5 Air-line, use of . . . . . . . . . . . . . . . . . . . . 6.2.3.6, 7.9.6 Auxiliary protection . . . . . . . . . . . . . . . . . . . . . . 5.4.7 Chemical oxygen . . . . . . . . . . . . . . . . 5.4.6.1, 5.4.6.6 Combination filter definition . . . . . . . . . . . . . . . . 1.5.8 Compressed air types see Self contained see SCBA Consideration for maintenance . . . . . . . . . . . . . . . . 7.8 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.50 Effectiveness . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.11 Escape type . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.7.2 Eye correction . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5.4 Filter replacement . . . . . . . . . . . . . . . . . . . . . . . . 7.10 Frequency of use . . . . . . . . . . . . . . . . . . . . . . . . 6.3.2 Inspection of . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7 Issue of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4 Length of use . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3.2 Life support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Liquid oxygen . . . . . . . . . . . . . . . . . . . . . . . . 5.4.6.5 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6.4 Non-powered . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.1(a)

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AS/NZS 1715:1994

82


Oxygen generating . . . . . . . . . . . . . . . 5.4.6.1, 5.4.6.6 Particulate . . . . . . . . . . . . . . . . . . . . . . . 5.3.1, 7.10.2 Powered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.1(b) Selection . . . . . . . . . . . . . . . . . . . . . . . . . . Section 6 Selection factors . . . . . . . . . . . . . . . . . . . . . . . 6.3, 6.4 Self contained breathing types (SCB A) . . . . . . . . . 5.4.6 Self-rescuer Industrial . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.5.4 Mines . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.5.2, 7.8.5 Smoke mask . . . . . . . . . . . . . . . . . . . . . . . . 5.3.5.3 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6.3 Supplied air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4 Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.2 When required . . . . . . . . . . . . . . . . . . . . . . . 6.2.4.4 Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.12 Types of . . . . . . . . . . . . . . . . . . . . . . . . . Section 5 Use in flammable or explosive atmospheres . . . . 6.2.9 User acceptance . . . . . . . . . . . . . . . . . . . . . . . . 6.4.4 Safe working practices Communication . . . . . . . . . . . . . . . . . . . . . . . . . 7.9.3 Confined spaces . . . . . . . . . . . . . . . . . . . . . . . . . 7.9.4 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.9.1 SCBA Auxiliary protection . . . . . . . . . . . . . . . . . . . . . . 5.4.7 Batteries, care of . . . . . . . . . . . . . . . . . . . . . . . . 7.8.6 Cleaning general . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.51 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.6.1 Inspection . . . . . . . . . . . . . . . . . . . . . . . . 7.8, 7.8.4.4 Issue of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . 7.6.4, 7.8 Sanitizing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6.2 Screening of users . . . . . . . . . . . . . . . . . . . . . . . . . 7.3 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6.3 Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.6 Screening of users Medical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3 Physiological considerations . . . . . . . . . 6.4.2, 7.3.1(a) Psychological considerations . . . . . . . . . . . . . . 7.3.1(b) Selection factors . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1 Contaminant-related . . . . . . . . . . . . . . . . . . . . . . . 6.2 Operator-related . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4 Task-related . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3 Self rescue see Respirators— Self-rescuer Sensitizing agents . . . . . . . . . . . . . . . . 2.2.2(e), 2.2.3(f) Servicing Cleaning and maintenance . . . . . . . . . . . . . . . . . . . 7.6 Consideration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.8 Cylinder valves . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3 Exhalation valves . . . . . . . . . . . . . . . . . . . . . . . . . 8.2 Facepieces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2 Filter replacement . . . . . . . . . . . . . . . . . . . . . . . . 7.10 Inspection for defects . . . . . . . . . . . . . . . . . . . . . . 7.7 Other components . . . . . . . . . . . . . . . . . . . . . . . . . 8.3 SCBA components . . . . . . . . . . . . . . . . . . . . . . . . 8.3 Sideburns see hair Skin absorption see Absorption Smoke Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.55 Irritant test . . . . . . . . . . . . . . . . . . Appendix C2.1.1(c)

Smoke mask . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.5.3 Sodium chloride test . . . . . . . . . . . . . Appendix D2.4(a) Sorbent Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5.56 Spectacles see Eye correction Use of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.7.2 Speech transmission see Communication Storage Of batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.8.6 Of cylinders . . . . . . . . . . . . . . . . . . . . . . . . 7.6.3, 8.3 Of equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6.3 Provision of . . . . . . . . . . . . . . . . . . . . . . . . 7.1, 7.6.1 Self-rescuer (mines) . . . . . . . . . . . . . . . . . . . . . . 7.8.5 Stubble growth see Hair Substitution Hazard reduction . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Of components . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6.4 Systemic poisons see poisons Temperature High temperature, hoses, use of Low temperature, hoses, use of Respirators, usage Toxic gas see Gases Training Employee program . . . . . . . . . Management responsibility . . . . Respirator usage . . . . . . . . . . .

. . . . . . . . . . . . 7.9.5.2 . . . . . . . . . . . . 7.9.5.1

. . . . . . . . . Appendix F . . . . . . . . . . . . . . . 7.1 . . . . . . . . . . . . . . 7.12

Usage Frequency of . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3.2 Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3.2 Valves Inhalation . . . . . . . . . . . . . . . . Exhalation . . . . . . . . . . . . . . . Demand . . . . . . . . . . . . . . . . . Inhalation, or exhalation . . . . . Leakage . . . . . . . . . . . . . . . . . Servicing . . . . . . . . . . . . . . . . Ventilation Hazard control . . . . . . . . . . . . Visibility Selection factors . . . . . . . . . . . Vision Corrective lenses . . . . . . . . . . Effects of chemicals . . . . . . . . Facepiece restriction . . . . . . . . Field of . . . . . . . . . . . . . . . . . Spectacles, use of . . . . . . . . . Warnings Adequacy of . . . . . . . . . . . By irritant action . . . . . . . . By odour . . . . . . . . . . . . . . Wearers see Screening of users Welding Fume . . . . . . . . . . . . . . . . . Protection factor . . . . . . . . . Respirator selection . . . . . . . Work sets see SCB A

COPYRIGHT

............ . . .. .. .. . .. . . . . . . 5.4.3(c), . . . . . 5.4.3(c), ............ . .. .. .. . .. ..

. . . 8.2 . . . 8.2 5.4.3(d) 5.4.3(d) 7.8.3.3 . . . 8.2

. . . . . . . . . . . . . 4.3(c) . . . . . . . . . . 6.3, 6.3.5 .. .. .. .. ..

.. .. .. .. ..

.. .. .. .. ..

. . . . .

. . . . .

6.2.7.2, 7.5.4 . . . . . . . 2.1 . . . . . . 6.3.5 . . . . . . 6.4.4 . . . . 6.2.7.2

. . . . . . . . . . . . . . . . 6.2.8 . . . . . . . . . . . . . . 6.2.8.2 . . . . . . . . . . . . . . 6.2.8.1

. . . . . . . Figure 2.2, 2.2.3 . . . . . . . . . . . . . . 6.2.2.2 . . . . . . . . . 6.2, Table 6.2


As 1715 Selection Use Maint of Respiratory Protective Device

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