AREA CLASSIFICATION (AMENDMENTS/SUPPLEMENTS TO IP 15)
DEP 80.00.10.10-Gen. November 2003
DESIGN AND ENGINEERING PRACTICE
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DEP 80.00.10.10-Gen. November 2003 Page 2 PREFACE DEPs (Design and Engineering Practice) publications reflect the views, at the time of publication, of: Shell Global Solutions International B.V. (Shell GSI) and Shell International Exploration and Production B.V. (SIEP) and Shell International Chemicals B.V. (SIC) and other Service Companies. They are based on the experience acquired during their involvement with the design, construction, operation and maintenance of processing units and facilities, and they are supplemented with the experience of Group Operating companies. Where appropriate they are based on, or reference is made to, international, regional, national and industry standards. The objective is to set the recommended standard for good design and engineering practice applied by Group companies operating an oil refinery, gas handling installation, chemical plant, oil and gas production facility, or any other such facility, and thereby to achieve maximum technical and economic benefit from standardization. The information set forth in these publications is provided to users for their consideration and decision to implement. This is of particular importance where DEPs may not cover every requirement or diversity of condition at each locality. The system of DEPs is expected to be sufficiently flexible to allow individual operating companies to adapt the information set forth in DEPs to their own environment and requirements. When Contractors or Manufacturers/Suppliers use DEPs they shall be solely responsible for the quality of work and the attainment of the required design and engineering standards. In particular, for those requirements not specifically covered, the Principal will expect them to follow those design and engineering practices which will achieve the same level of integrity as reflected in the DEPs. If in doubt, the Contractor or Manufacturer/Supplier shall, without detracting from his own responsibility, consult the Principal or its technical advisor. The right to use DEPs is granted by Shell GSI, SIEP or SIC, in most cases under Service Agreements primarily with companies of the Royal Dutch/Shell Group and other companies receiving technical advice and services from Shell GSI, SIEP, SIC or another Group Service Company. Consequently, three categories of users of DEPs can be distinguished: 1)
Operating companies having a Service Agreement with Shell GSI, SIEP, SIC or other Service Company. The use of DEPs by these operating companies is subject in all respects to the terms and conditions of the relevant Service Agreement.
2)
Other parties who are authorized to use DEPs subject to appropriate contractual arrangements (whether as part of a Service Agreement or otherwise).
3)
Contractors/subcontractors and Manufacturers/Suppliers under a contract with users referred to under 1) or 2) which requires that tenders for projects, materials supplied or - generally - work performed on behalf of the said users comply with the relevant standards.
Subject to any particular terms and conditions as may be set forth in specific agreements with users, Shell GSI, SIEP and SIC disclaim any liability of whatsoever nature for any damage (including injury or death) suff ered by any company or person whomsoever as a result of or in connection with the use, application or implementation of any DEP, combination of DEPs or any part thereof, even if it is wholly or partly caused by negligence on the part of Shell GSI, SIEP or other Service Company. The benefit of this disclaimer shall inure in all respects to Shell GSI, SIEP, SIC and/or any company affiliated to these companies that m ay issue DEPs or require the use of DEPs. Without prejudice to any specific terms in respect of confidentiality under relevant contractual arrangements, DEPs shall not, without the prior written consent of Shell GSI and SIEP, be disclosed by users to any company or person whomsoever and the DEPs shall be used exclusively for the purpose for which they have been provided to the user. They shall be returned after use, including any copies which shall only be made by users with the express prior written consent of Shell GSI, SIEP or SIC. The copyright of DEPs vests in Shell GSI and SIEP. Users shall arrange for DEPs to be held in safe custody and Shell GSI, SIEP or SIC may at any time require information satisfactory to them in order to ascertain how users implement this requirement. All administrative queries should be directed to the DEP Administrator in Shell GSI.
DEP 80.00.10.10-Gen. November 2003 Page 3 TABLE OF CONTENTS 1. 1.1 1.2 1.3 1.4 1.5 1.6
GENERAL...................................................................................................................4 SCOPE........................................................................................................................4 DISTRIBUTION, INTENDED USE AND REGULATORY CONSIDERATIONS .........4 DEFINITIONS .............................................................................................................4 CROSS-REFERENCES .............................................................................................4 SUMMARY OF CHANGES SINCE PREVIOUS REVISION.......................................5 COMMENTS ON THIS DEP .......................................................................................5
PART II 1. 2. 3.
GENERAL CONSIDERATIONS .................................................................................6 INTRODUCTION ........................................................................................................6 APPLICABILITY OF IP 15 ..........................................................................................6 ADMINISTRATIVE ASPECTS ....................................................................................6
PART III 1. 2. 3.
AMENDMENTS AND SUPPLEMENTS TO IP 15......................................................7 INTRODUCTION ........................................................................................................7 THE TECHNIQUE OF HAZARDOUS AREA CLASSIFICATION ...............................7 THE DIRECT EXAMPLE METHOD FOR CLASSIFICATION OF COMMON TYPES OF FACILITIES IN OPEN AREAS.................................................................7 THE AREA CLASSIFICATION OF DRILLING RIGS EQUIPMENT AND WELL OPERATIONS.............................................................................................................7 CLASSIFICATION OF INDIVIDUAL POINT SOURCES ............................................8
4 5. 7.
SELECTION, INSTALLATION, MAINTENANCE AND USE OF EQUIPMENT IN HAZARDOUS AREAS .........................................................................................10
8.
NON-ELECTRICAL IGNITION SOURCES ..............................................................11
PART IV
REFERENCE ............................................................................................................12
DEP 80.00.10.10-Gen. November 2003 Page 4 1.
GENERAL
1.1
SCOPE This DEP specifies requirements and recommends practices for the determination of hazardous areas in facilities handling flammable fluids. It is based on the Institute of Petroleum Model Code of Safe Practice, Part 15, Area Classification Code for Installations nd Handling Flammable Fluids , August 2002 2 edition (IP 15). Part III of this DEP amends and supplements specific clauses of IP 15. This DEP is a revision of the DEP of the same number dated December 1995; a summary of the main, non-editorial, changes is given in (1.5).
1.2
DISTRIBUTION, INTENDED USE AND REGULATORY CONSIDERATIONS Unless otherwise authorised by Shell GSI and SIEP, the distribution of this DEP is confined to companies forming part of or managed by the Royal Dutch/Shell Group, and to Contractors nominated by them. This DEP is intended for use in oil refineries, chemical plants, gas plants and exploration and production facilities as well as distribution storage depots and installations. When DEPs are applied, a Management of Change (MOC) process should be implemented. This is of particular importance when existing facilities are to be modified. If national and/or local regulations exist in which some of the requirements may be more stringent than in this DEP the Contractor shall determine by careful scrutiny which of the requirements are the more stringent and which combination of requirements will be acceptable as regards safety, environmental, economic and legal aspects. In all cases, the Contractor shall inform the Principal of any deviation from the requirements of this DEP which is considered to be necessary in order to comply with national and/or local regulations. Based on the potential impact on design, construction and maintenance costs, the Principal may decide to consult with the Authorities concerned with the object of obtaining agreement to follow this DEP as closely as possible.
1.3
DEFINITIONS The Contractor is the party which carries out all or part of the design, engineering, procurement, construction, commissioning or management of a project, or operation or maintenance of a facility. The Principal may undertake all or part of the duties of the Contractor. The Principal is the party which initiates the project and ultimately pays for its design and construction. The Principal will generally specify the technical requirements. The Principal may include an agent or consultant authorised to act for, and on behalf of, the Principal. The word shall indicates a requirement. The word should indicates a recommendation.
1.4
CROSS-REFERENCES Where cross-references to other parts of this DEP are made, the referenced section number is shown in brackets. Other documents referenced in this DEP are listed in (Part IV).
DEP 80.00.10.10-Gen. November 2003 Page 5 1.5
SUMMARY OF CHANGES SINCE PREVIOUS REVISION The previous edition of this DEP was dated December 1995. Other than editorial changes, the following are the major changes to the previous edition:
1.6
Section
Change
II-2
Exclusion possibility for short-term facilities such as drilling rigs
III
Revised extensively to reflect the content of new edition of IP 15.
COMMENTS ON THIS DEP Comments on this DEP may be sent to the DEP Administrator at
[email protected]. Shell staff may also post comments on this DEP on the Surface Global Network (SGN) under the Standards/DEP 80.00.10.10-Gen. folder. The DEP Administrator and DEP Author monitor these folders on a regular basis.
DEP 80.00.10.10-Gen. November 2003 Page 6 PART II GENERAL CONSIDERATIONS 1.
INTRODUCTION Area classification is the division of a plant or installation into hazardous areas and nonhazardous areas and the sub-division of hazardous areas into zones. This classification is based on the flammability of materials which may be present and the probability of a flammable atmosphere occurring. The classification provides a basis for the selection and protection of electrical equipment appropriate to the defined areas and for the safe positioning of other potential or continuous sources of ignition, e.g. fired heaters, internal combustion engines, etc. It can also be used in the planning and control of hot work. Area classification refers to normal operating conditions and does not apply to catastrophic situations such as the rupture of a process vessel or large diameter pipe work.
2.
APPLICABILITY OF IP 15 All new facilities that handle flammable fluids shall be classified in accordance with IP 15, as amended and supplemented by section (3) of this DEP. Variations are allowed, provided that they are formally authorised by the Principal, and only if they achieve a similar level of safety. In areas where national codes are available, or codes other than IP 15 are commonly used (e.g. API RP500, API RP505), the codes should be reviewed and supplemented where necessary. Installations which were operating at the date of issue of this DEP may be evaluated against this DEP, which provides current best practice. Any proposal for modification to an existing installation should be assessed on the basis of whether the benefits from applying the DEP outweigh the implementation costs and risks. If it is intended to reclassify an existing installation on the basis of this DEP, reclassification should cover the whole installation and not just part of it. This is to avoid the application of multiple standards within the same installation.
3.
ADMINISTRATIVE ASPECTS Each operating company should have a formal hazardous area classification committee with members drawn from process technology, engineering, operations, and technical safety. Any modification to the hazardous area classification of an existing installation should be subject to a formal change procedure which should include endorsement by the committee; the objective is to ensure a common interpretation of the hazardous area code.
DEP 80.00.10.10-Gen. November 2003 Page 7 PART III AMENDMENTS AND SUPPLEMENTS TO IP 15 This section provides amendments and supplements to IP 15. Numbering of clauses in this section corresponds to the numbering in IP 15. Clauses of IP 15 that are not amended shall remain applicable as written. 1.
INTRODUCTION
1.7.3
Open Area "Add to the existing clause:" Open areas imply free access of the wind to at least two opposite sides. Obstructions such as dense trees, cliffs or other buildings preclude an area being considered "open" unless it can be shown that the wind velocities meet the criteria above within that particular area.
2.
THE TECHNIQUE OF HAZARDOUS AREA CLASSIFICATION
2.3
APPLICATION "Add to the existing clause (f):" Since the vertical and horizontal extent of the hazardous area should be taken into account in the sizing of the firewall, it may be simpler to enclose the potential sources of release and ignition.
2.7
THE AREA CLASSIFICATION DRAWING "Add to the existing clause:" The area classification drawings shall be kept up-to-date, to take account of:
-
new or modified equipment;
-
changes in installation protection;
-
experience in operation of the installation;
-
changes in method or frequency of operations;
-
reclassification as a result of measurements in and around hazardous areas.
3.
THE DIRECT EXAMPLE METHOD FOR CLASSIFICATION OF COMMON TYPES OF FACILITIES IN OPEN AREAS
3.2.1
Fixed roof tankage – Classes I, II(2) and III(2) Figure 3.1(a) – Bunded tanks – Cone or dome "Add to the existing clause:" Note 3 may be ignored if the tank(s) involved are provided with at least one high liquid level alarm and are well maintained (ref. IP-15 chapter 1.4.2), because it is then highly unlikely that the total bunded area will be covered with stored product in the event of a tank liquid overfill or mechanical failure of tank haul or bottom ( ref. IP-15 chapter 1.4.1).
4
THE AREA CLASSIFICATION OF DRILLING RIGS EQUIPMENT AND WELL OPERATIONS
4.2
AREA CLASSIFICATION FOR DRILLING, WORKOVER AND WIRELINE OPERATION IN OPEN AREAS "Add to the existing clause:"
DEP 80.00.10.10-Gen. November 2003 Page 8 In populated areas, the hazardous area around a wellhead should be fully contained within a security fence extending 30 m from the wellhead, to keep out possible ignition sources. That distance may be subject to other considerations. 4.3
SURFACE MUD SYSTEMS
4.3.4
Mud pits and active tanks "Add to the existing clause:" The area classification of a ditch or trench handling active mud should be the same as the area classification of the mud tank.
4.5
WIRELINING "Add to the existing clause:" The depressurising vent of the lubricator should be considered as a source of primary grade release.
5.
CLASSIFICATION OF INDIVIDUAL POINT SOURCES
5.3
METHODOLOGY "Delete from the existing clause:" Delete reference to figure C1 (annex C) since it does not present the overall methodology.
5.3.4
Determine hazard radius
5.3.4.1
Primary and continuous grade releases "Add to the existing clause:" For these type of releases (typical vents and drains) the ‘level’, an input to the tables in section 5.4, should not be relevant due to fact that releases requiring this input are normally categorised as secondary grade releases.
5.3.4.2
Secondary grade releases "Add to the existing clause:" The ‘level’ of release frequency is by default ‘level I’ for pumps, compressors and piping systems, for the following reasons: -
-
-
-
Annex C – Part 1 considers individual personnel exposure only. Multiple labour exposure, societal exposure, environmental consequences or any business impact are excluded. This makes this Part 1 less relevant for the Area Classification process. The probability that a worker is inside a plant dealing with a continuous process containing flammable fluids is very low and will normally be below the lowest assumption of one hour/day in a hazardous zone. The probability of ignition (Pign) at the Zone 2 outer boundary is typically calculated by estimating the proportion of the zone 2 boundary which contains controlled, weak, medium and strong ignition sources and typically results in a Pign comparable to ‘weak’ to ‘medium’. This allows for a rather low value of Pign = 0.154 when the distribution of the time a worker spends in these areas is 10/50/40. As indicated for rotating equipment e.g. pumps and compressors, leak sources other than seal failure such as discharge pipe connections or casing failures are not normally considered for Area Classification purposes. Therefore the assumed hole size related to the seal type as presented under ‘level I’ shall be taken.
DEP 80.00.10.10-Gen. November 2003 Page 9 5.4.4
Vents to atmosphere
5.4.4.1
Determination of hazardous area It is assumed that the provided vents are remote from any structure and, if attached, are elevated sufficiently for the dispersion of gases and vapour to the lower flammability limit to be unaffected by structure induced flow.
5.4.5
Piping systems "Add to this sentence:" It assumes pipe work construction, including small-bore piping (i.e. smaller than 40 mm in diameter), in accordance with recognised codes and standards, i.e. DEP 31.38.01.11-Gen., DEP 31.38.01.12-Gen., DEP 31.38.01.15-Gen. and DEP 32.37.10.11-Gen.
DEP 80.00.10.10-Gen. November 2003 Page 10 7.
SELECTION, INSTALLATION, MAINTENANCE AND USE OF EQUIPMENT IN HAZARDOUS AREAS "Add to the existing chapter:" The selection of electrical equipment for use in hazardous areas should be in accordance with DEP 33.64.10.10-Gen. In case of conflicting requirements between IP 15 chapter 7 and DEP 33.64.10.10-Gen., the latter shall prevail.
DEP 80.00.10.10-Gen. November 2003 Page 11 8.
NON-ELECTRICAL IGNITION SOURCES
8.2
Ignition sources "Add to the existing clause:" The location of fixed sources of ignition should be determined during plant layout work. N.B.: a situation where a fixed source of ignition is located just outside a hazardous area leads to a much higher probability of ignition than electrical equipment located just inside. This is why, in order to keep a consistent level of safety throughout the plant, fixed sources of ignition should be located as far as practicable outside hazardous areas (see 8.2.1). Typical distance for a fixed ignition source will be 15 m away from hydrocarbon emission points.
8.2.4
Fixed combustion engines "Add to the existing clause:" Diesel and gas engines for use in hazardous areas should be in accordance with DEP 31.29.80.30-Gen. and DEP 31.29.90.30-Gen., respectively. In case of conflicting requirements, the DEPs shall prevail.
8.2.6.1
Ignition temperatures and flash points "Add to the existing clause:" The presence of liquid droplets in a gas may change the ignition behaviour of the gas, because droplets can make good thermal contact with a hot surface and on ignition will ignite the surrounding gas. The surface temperature should not exceed the ignition temperature of the liquid droplets in the gas.
DEP 80.00.10.10-Gen. November 2003 Page 12 PART IV REFERENCE In this DEP, reference is made to the following publications: NOTES:
1. Unless specifically designated by date, the latest edition of each publication shall be used, together with any amendments/supplements/revisions thereto. 2. The DEPs and most referenced external standards are available to Shell users on the SWW (Shell Wide Web) at http://sww.shell.com/standards.
SHELL STANDARDS Diesel engines
DEP 31.29.80.30-Gen.
Spark ignited gas fuelled engines
DEP 31.29.90.30-Gen.
Piping - General requirements
DEP 31.38.01.11-Gen.
Piping classes – refining and chemicals
DEP 31.38.01.12-Gen.
Piping classes – exploration and production
DEP 31.38.01.15-Gen.
Installation of on-line instruments
DEP 32.37.10.11-Gen.
Electrical Engineering guidelines
DEP 33.64.10.10-Gen.
INTERNATIONAL STANDARDS The Institute of Petroleum Model Code of Safe Practice, Part 15, Area Classification Code for Installations Handling Flammable Fluids
nd
IP 15. (August 2002 2 edition)
Issued by Institute of Petroleum 61 New Cavendish Street London W1M 8AR United Kingdom.
AMERICAN STANDARDS Recommended Practice for Classification of Locations for API RP500 Electrical Installations at Petroleum Facilities Classified as Class I, Division 1 and Division 2 Recommended Practice for Classification of Locations for API RP505 Electrical Installations at Petroleum Facilities Classified as Class I, Zone 0, Zone 1, and Zone 2 Issued by American Petroleum Institute Publications and Distribution Section, 1220 L Street, North West., Washington, D.C. 20005 USA
Last page of this DEP
