GP 31-04

Document No.

GP 31-04

Applicability

Group

Date

25 April 2005

Guidance on Practice for Analyser House Entry

GP 31-04

BP GROUP ENGINEERING TECHNICAL PRACTICES

25 April 2005

GP 31-04 Guidance on Practice for Analyser House Entry

Foreword This is the first issue of Engineering Technical Practice (ETP) GP 31-04. This Guidance on Practice (GP) is based on parts of heritage documents from the merged BP companies as follows:

Amoco (ACES) A AR-FBD-PA-P A PC-PA-00-E A PC-PA-00-G A PC-PA-00-P

Architectural—Facility Buildings—Process Anlayzer Shelters—Supply Specification Process Control—Process Analyzers—Engineering Specification Process Control—Process Analyzers—Guide Process Control—Process Analyzers—Supply Specification

ARCO (APCES) Std 312-92

Analyzers

British Petroleum (RPSE) RP 30-02

Instrumentation and Control, Selection and use of Measurement Instrumentation

Copyright  2005, 2004, BP Group. All rights reserved. The information contained in this document is subject to the terms and conditions of the agreement or contract under which the document was supplied to the recipient’s organization. None of the information contained in this document shall be disclosed outside the recipient’s own organization without the prior written permission of Director Manager,ofStandards, Engineering, BP Group, BP Group, unless unless the terms the of such agreement terms of such agreement or contract or expressly contract expressly allow. allow.

Page 2 of 6

25 April 2005


Table of Contents Page Foreword......................................................................................................................................... 2 1. Scope........................................................................................................................................... 4 2. Normative references................................................................................................................... 4 3. Engineering controls & entry procedures......................................................................................4 3.1. General........................................................................................................................... 4 3.2. Forced ventilated analyser houses..................................................................................5 3.3. Naturally ventilated analyser houses...............................................................................5 Bibliography.................................................................................................................................... 6

Page 3 of 6

25 April 2005

1.


Scope This document provides guidance on practice for safe entry into analyser houses.

2.

Normative references The following normative documents contain requirements that, through reference in this text, constitute requirements of this technical practice. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this technical practice are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.

BP Engineering Technical Practices (ETP) GIS 31-011

3. 3.1.

Guidance on Industry Standard for Analyser Houses

Engineering controls & entry procedures General a.

The prime safeguard within an analyser house shall be forced or natural ventilation.

b.

Ventilation systems shall be designed to provide airflow required to dilute sample and/or utility leaks under normal flow conditions to a non-hazardous level.

c.

Each site analyser team shall hold a controlled copy of the design calculations for the ventilation system of each analyser house.

d.

Design calculations for ventilation airflow shall be reviewed for modifications to the equipment within the AH or if applicable Occupational Exposure Limits are changed. If these calculations indicate that OEL levels may be exceeded by releases of material within the unrestricted flowrates of the analyser house, periodic monitoring of exposure levels shall be carried out based on guidance from the site Occupational Health Department.

e.

Sample system and utility supplies shall be designed to ensure that sources of flammable/toxic/asphyxiant material have a limited flow rate.

f.

Restrictors shall be fitted to all hydrocarbon/toxic/asphyxiant gas/liquids entering analyser houses.

g.

Maximum flow should not exceed 50cc/min, unless required by the analyser for successful operation. Special care must be exercised when dealing with samples containing low exposure level chemicals e.g. benzene, H2S. With these substances, the volume of release required to initiate a combustible gas detector can result in the exposure limit being exceeded and additional precautions shall be required to be carried out for these installations.

h.

Releases of large volumes (high flow rate) of flammable, toxic or asphyxiant material within an analyser house shall be treated as hazardous oxygen deficient atmospheres.

i.

Gas detectors shall be provided to alarm when ventilation fails to maintain a nonhazardous atmosphere in the analyser house.

j.

On detection of hydrocarbon gas, equipment within the analyser house shall be isolated in accordance with Engineering Technical Practice GIS 31-011.

Page 4 of 6

25 April 2005

3.2.


k.

Detectors for specific toxic gases, such as H2S, or oxygen deficiency shall be fitted to an analyser house if a toxic substance or asphyxiant could reach a concentration that would present a danger to personnel and would not be detected by hydrocarbon detectors.

l.

Gas detectors located within an analyser house shall have alarm indication on the external local annunciator panel as well as remote indication in the plant/unit control room.

m.

Local audible and visible alarms shall be provided inside and outside the analyser house.

n.

Gas bottles shall not be located within an analyser house.

o.

Access to analyser houses shall be restricted to authorised personnel trained and familiar with their design, construction, operation, and hazards

p.

Analyser house doors should be locked except when authorised personnel are working inside.

q.

Emergency services access shall be provided by a spare key located in a break glass unit at the analyser house or plant/unit control room.

Forced ventilated analyser houses a.

Prior to entering a forced ventilated analyser house, proper operation of the ventilation system shall be verified and recorded without entering the analyser house.

b.

Entrances to forced ventilated analyser houses shall be fitted with the following warning sign: AUTHORISED PERSONNEL ONLY ENSURE VENTILATION SYSTEM IS OPERATIONAL PRIOR TO ENTRY

3.3.

c.

Indication of the ventilation system operational status shall be provided on the outside of the analyser house, adjacent to the main entrance.

d.

Local alarm indication shall be via an annunciator/indicator panel, providing indication of gas detector, fan status, and pressurisation.

e.

In the event of ventilation failure, the analyser house shall be treated as a confined space until the atmosphere has been checked and approved for normal access.

f.

The ventilation system shall be operational for at least one hour after restarting and alarms cleared before normal access can resume.

g.

If entry into an analyser house is required to restart the ventilation system or to isolate the source of leakage, entry shall be in accordance with the local site confined space entry policy.

Naturally ventilated analyser houses a.

Prior to entering a naturally ventilated AH, the sampling flowrates shall be checked and recorded to ensure that they are within their normal ranges (no excessive flows indicated), without entering the analyser house.

b.

A multi gas monitor shall be used whilst entering and working in a naturally ventilated analyser house.

c.

Entrances to naturally ventilated analyser houses shall be fitted with the following warning sign: AUTHORISED PERSONNEL ONLY HAZARDOUS GASES MAY BE PRESENT

Page 5 of 6

25 April 2005


Bibliography [1]

IEC 61825, Industrial-Process Control — Safety of analyzer houses

[2]

IEC 61831, On-line analyzer systems — Guide to design and installation.

Page 6 of 6

GP 31-04

Recommend Documents