CODE OF PRACTICE 18

THE SAFE STORAGE, HANDLING

AND USE OF SPECIAL GASES
Revision 3: 2014
 CODE OF PRACTICE 18

THE SAFE STORAGE, HANDLING AND USE

OF SPECIAL GASES

Revision 3: 2014

Copyright © 2014 by British Compressed Gases

Association. First printed 1988. All rights reserved. No
part of this publication may be reproduced or transmitted
in any form or by any means, electronic or mechanical,
including photocopy, without permission from the
publisher:

BRITISH COMPRESSED GASES ASSOCIATION

Registered office: 4a Mallard Way, Pride Park,
Derby, UK. DE24 8GX
Company Number: 71798, England

Website: www.bcga.co.uk

ISSN 0260-4809

BCGA CP18 - Revision 3

 PREFACE

The British Compressed Gases Association (BCGA) was

established in l971, formed out of the British Acetylene
Association, which existed since l901. BCGA members include
gas producers, suppliers of gas handling equipment and users
operating in the compressed gas field.

The main objectives of the Association are to further technology, to

enhance safe practice, and to prioritise environmental protection in
the supply and use of industrial gases, and we produce a host of
publications to this end. BCGA also provides advice and makes
representations on behalf of its Members to regulatory bodies,
including the UK Government.

Policy is determined by a Council elected from Member

Companies, with detailed technical studies being undertaken by a
Technical Committee and its specialist Sub-Committees appointed
for this purpose.

BCGA makes strenuous efforts to ensure the accuracy and current

relevance of its publications, which are intended for use by
technically competent persons. However this does not remove the
need for technical and managerial judgement in practical situations.
Nor do they confer any immunity or exemption from relevant legal
requirements, including by-laws.

For the assistance of users, references are given, either in the text or
Appendices, to publications such as British, European and
International Standards and Codes of Practice, and current
legislation that may be applicable but no representation or warranty
can be given that these references are complete or current.

BCGA publications are reviewed, and revised if necessary, at five-

yearly intervals, or sooner where the need is recognised. Readers
are advised to check the Association’s website to ensure that the
copy in their possession is the current version.

This document has been prepared by BCGA Technical Sub-

Committee 5. This document replaces BCGA CP 18, Revision 2,
2005. It was approved for publication at BCGA Technical
Committee 148. This document was first published on 01/05/2014.
For comments on this document contact the Association via the
website www.bcga.co.uk.

BCGA CP18 - Revision 3

 CONTENTS
Section Page
TERMINOLOGY & DEFINITIONS 1

1. INTRODUCTION 2

2. SCOPE 2

3. KEY REQUIREMENTS 2

4. POTENTIAL HAZARDS OF COMPRESSED GAS 4

CONTAINERS
4.1 Mass of containers 4
4.2 Potential uncontrolled release of gas 4
4.3 Temperature effects 4
4.4 Container valve outlets 5
4.5 Identification of container contents 5
4.6 Misuse of containers 6
4.7 General 6

5. POTENTIALLY HAZARDOUS PROPERTIES OF GAS 6

5.1 Flammability 7
5.1.1 Pyrophoric gases 7
5.2 Oxidising potential 7
5.3 Toxicity 8
5.3.1 LC50 / 1 hour 8
5.3.2 Workplace exposure limits 8
5.3.3 Derived no-effect level 8
5.4 Corrosivity 8
5.5 Asphyxiant 9
5.6 Carcinogenicity, mutagenicity and reprotoxicity 9
5.7 Pressure of a gas in its container 10
5.8 Other hazards which may arise from the physical or chemical 10
properties of a gas
5.9 Classification 11
5.9.1 Dangerous substances and dangerous preparations directives 12
5.9.2 Classification, labelling and packaging of substances and 12
mixtures

6. GAS CONTAINER STORAGE AREA 15

6.1 Key principles 15
6.2 External storage location 17
6.3 Store design and construction 17
6.4 Store management 19
6.5 Internal storage 20

7. HANDLING OF GAS CONTAINERS 21

7.1 Handling precautions 21
7.2 Personal protective equipment 22
7.3 In-house transport of toxic gases 22

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8. GAS SUPPLY POINTS 23
8.1 Key principles 23
8.2 Location of gas supply points 23
8.3 Precautions against gas release 23
8.4 External gas supply points 24
8.5 Internal gas supply rooms 25
8.6 Gas cabinets 26

9. GAS SUPPLY SYSTEMS 28

9.1 Key principles 28
9.2 Gas supply source 29
9.3 Purging systems 29
9.4 Pressure reducing regulators 30
9.5 Flow limiting devices 31
9.5.1 Automatic shut down 31
9.5.2 Flow limiting devices 31
9.6 Over-pressure protection devices 31
9.7 Valves 32
9.7.1 Flow control valves 32
9.7.2 Isolation valves 33
9.7.3 Non-return valves 33
9.8 Pipework 33
9.8.1 Design and installation 33
9.8.2 Pressure testing 34
9.8.3 Inspection prior to commissioning 34
9.8.4 Identification of pipework service 35
9.9 Vacuum pumps 35
9.9.1 Vacuum pumps selection 35
9.9.2 Siting 35
9.9.3 Leak testing 36
9.9.4 Gas ballast 36
9.9.5 Exit gas arrangements 36
9.9.6 Cold traps 36
9.10 Special requirements for silane and other pyrophoric gases 37
9.11 Special requirements for oxygen and other oxidants 38

10. DISPOSAL OF WASTE GASES 39

10.1 Disposal arrangements 39
10.1.1 Routine 39
10.1.2 Non-routine 39
10.2 Discharge to atmosphere 39
10.3 Abatement equipment - treatment techniques 39
10.3.1 Incineration 39
10.3.2 Chemical absorption 40
10.3.3 Adsorption 41

11. OPERATING PRINCIPLES FOR GAS SUPPLY SYSTEMS 41

11.1 Key principles 41
11.2 Connection of the gas container 42
11.3 Disconnection of the gas container 42

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12. PLANT MAINTENANCE 43
12.1 General precautions 43
12.2 Permit to work 43

13. SAFETY 45
13.1 Fire safety 45
13.2 Personal protective equipment 45
13.2.1 General requirements 45
13.2.2 Maintenance of personal protective equipment 46
13.3 Training 47
13.4 Standard operating procedures 48
13.5 Audits 48
13.6 Emergency response plan 49
13.7 Hazardous gas monitoring 50

14. REFERENCES * 51

Appendices:

Appendix 1 BCGA OPINION ON THE USE OF GAS CABINETS 56

* Throughout this publication the numbers in brackets refer to references in Section 14.
Documents referenced are the edition current at the time of publication, unless otherwise
stated.

BCGA CP18 - Revision 3

 TERMINOLOGY AND DEFINITIONS

Fire-resisting A fire-resistant construction is one that has a fire-resistance of at least

30 minutes when tested from either side in accordance with BS 476
(32), Fire tests on building materials and structures.

Firewall A firewall shall be imperforate and of at least 30 minutes fire-resisting

construction. Such walls are usually solid masonry or concrete, but
barriers constructed of other materials, e.g. earth banking, may be
equally effective.

Gas To cover single component gases, compressed gas mixtures, liquefied

gases and liquids.

May Indicates an option available to the user of this Code of Practice.

Segregated Grouping together of containers of a given gas or category of gases or

storage segregating full from nominally empty containers.

Separated The separation of containers of a given category of gases from a

storage particular feature (e.g. a building or other containers) by a certain
distance (see Table 4) - or by a physical barrier (e.g. a firewall).

Shall Indicates a mandatory requirement for compliance with this Code of

Practice.

Should Indicates a preferred requirement but is not mandatory for compliance

with this Code of Practice.

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 CODE OF PRACTICE 18
THE SAFE STORAGE, HANDLING AND USE OF SPECIAL GASES

1. INTRODUCTION

This Code of Practice was originally prepared at the request of the “Micro-Electronics
Semiconductor Manufacturer’s Joint Working Group” by a group of experts including
representatives of the British Compressed Gases Association (BCGA), the Federation of the
Electronics Industry and the Health and Safety Executive (HSE) with consultation with Trade
Unions.

NOTE: The Federation of the Electronics Industry was dissolved in 2002.

At the request of the Joint Working Group this Code of Practice was published as a BCGA
document.

Increasing quantities of special gases are produced, distributed and stored each year and
although many companies have developed their own procedures and engineering standards, it
is considered that this Code of Practice will be of benefit to the micro-electronics
semiconductor manufacturing industry, micro-electronics semi-conductor research
laboratories and other industries using special gases. The standards and guidelines in this
Code of Practice reflect the best advice available at time of issue. It is not intended to be
fully comprehensive and further guidance may be sought from BCGA or HSE.

2. SCOPE

This Code of Practice gives technical and safety guidelines and principles for the safe storage
and handling of special gases in transportable containers up to the point where product is
provided at the required pressure and flow at the junction with the user process. Guidelines
on disposal are also given. The Code will assist companies to formulate their own design and
operation policies and practices for the storage, handling and use of special gases. The safe
operation of processes is not included, although many of the principles given in this Code
will apply.

Bulk supply installations, gases in the cryogenic state, gas manufacturing, container filling
and container distribution are not covered by this Code.

3. KEY REQUIREMENTS

Under the Health and Safety at Work etc. Act (1) and as detailed in legislation, such as the
Control of Substances Hazardous to Health (COSHH) (11) Regulations and the Management
of Health and Safety at Work Regulations (8), employers are required to carry out
assessments in order to minimise the risks to the health and safety of their employees. Some
of the products covered within this document will also fall within the scope of the Control of
Major Accident Hazards Regulations (COMAH) (7). Where employers are involved in using
and storing such products the requirements of this legislation shall be complied with.

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To assist in this, employers of personnel using special gases shall:

(i) Be aware of and meet their duties under the Health and Safety at Work etc., Act
(1), and its relevant statutory provisions;

(ii) Be aware of and meet their duties under the Registration, Evaluation,
Authorisation and restriction of CHemicals (REACH) Regulations (23), and its relevant
statutory provisions.

(iii) Follow the requirements of the COSHH (11) Regulations;

(iv) Be aware of and meet their duties under the Dangerous Substances (Notification
and Marking of Sites) Regulations (NAMOS) (3). This regulation requires notification
to the authorities where a total quantity of hazardous products of 25 tonnes or more are
stored, specific exemptions apply.

(v) Ensure that information is provided on the potentially hazardous properties of all
gases used and take the necessary precautions to deal with them safely using the
information and advice given by the supplier’s Safety Data Sheets;

(vi) Ensure that proper equipment and facilities are provided in order to transport and
store containers safely;

(vii) Ensure that proper equipment and facilities are provided to transfer gas safely
from the gas container to the point of use at the required pressure and flow. This will
mean ensuring that the requirements of the Pressure Systems Safety Regulations
(PSSR) (9) are fully complied with;

(viii) Provide a safe means of disposal for waste gases such that health and the
environment are not damaged;

(ix) Provide all the necessary personal protective equipment for the safe handling of
containers including their connection and disconnection to and from the gas system;

(x) Maintain all gas supply systems, and gas disposal systems in a safe state;

(xi) Ensure that all necessary equipment, procedures and training are provided to
enable any emergency situation to be dealt with promptly, safely and efficiently;

(xii) Ensure that all personnel are properly trained in any activity associated with the
handling of containers and the supply and disposal of these gases.

(xiii) Premises used for the handling, use and storage of special gases shall be
adequately protected by security systems.

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4. POTENTIAL HAZARDS OF COMPRESSED GAS CONTAINERS

This section summarises the principal hazards associated with gas containers. Subsequent
sections deal with the practical requirements for overcoming these hazards.

4.1 Mass of containers

Most accidents with containers of compressed gases occur in their handling due to their
mass, shape and size. When moving such containers or working with them they can
present risk of damage to hands, fingers and feet. Refer to Section 7 for advice on
manual handling.

4.2 Potential uncontrolled release of gas

Uncontrolled release of any gas due to inadvertent opening or shearing of the container
valve can present hazards to people and equipment. This hazard could be from the
specific properties of the gas, and/or from the release of a gas under pressure which
could turn the container into a projectile.

4.3 Temperature effects

The amount of gas in a container, as supplied, is carefully controlled to ensure that
unacceptable pressures cannot develop under the highest ambient temperature likely to
be encountered in the climatic area of use, refer to BCGA Code of Practice (CP) 35
(58), Filling ratios and developed pressures for liquefied and compressed gases. Gas
containers shall not be deliberately heated above ambient temperature without prior
consultation with the supplier.

NOTE: For the regulations on the acceptable developed pressures in the United
Kingdom reference should be made to the European Agreement on the Carriage of
Dangerous Goods by Road (ADR) (18), which is implemented in the United Kingdom
by the Carriage of Dangerous Goods and Use of Transportable Pressure Equipment
Regulations (15).

Containers exposed to high levels of radiant heat, e.g. from a local heat source such as a
nearby fire or boiler, may burst due to over-pressurisation. Gas containers are to be
stored in accordance with Section 6. Gas containers in use are to be sited in accordance
with Section 8.

Where containers are exposed to high levels of heat, the contents of the gas container
will also be subject to high levels of heat which may cause ignition.

Aluminium containers shall not be heated above ambient temperature because they may
exhibit permanent softening of the aluminium alloy and could present a possible future
hazard. The majority of aluminium containers within the scope of this document will
have been treated with heat sensitive coatings or high temperature indication which will
indicate any excessive exposure to heat. Where known cases of inadvertent heating of
aluminium containers have occurred, the gas supplier shall be advised, so that suitable
safety measures can be applied.

Steel containers, whilst not as susceptible as aluminium, can still be affected by

excessive heat. Composite containers can be badly affected by fire though melting of
the resin and burning of the fibres.

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 In all cases where a container has been subjected to excessive heat, or has been directly
involved in a fire, the container is to be quarantined, and the gas supplier requested to
collect the container.

Fire damaged gas containers. Do not use any fire-damaged containers. Quarantine any
fire-damaged containers in a safe place. Mark, or label, fire-damaged containers to
clearly show that they have been in a fire. Inform your gas supplier whenever a
containers is involved in a fire. After the fire is out, and the area has been declared safe
by the Fire and Rescue Service, the gas supplier will arrange collection of fire damaged
containers at a convenient date. Refer to BCGA Leaflet 6 (67), Cylinders in fire.

NOTE: Contact numbers for the gas supplier are available on the product Safety
Data Sheet.

Some containers may suffer embrittlement if subjected to temperatures below -20 oC.
Gas containers shall not be deliberately cooled to these temperatures without prior
consultation with the supplier.

4.4 Container valve outlets

Valve outlet connections are manufactured to approved standards. Examples are:

 BS 341 (31), Transportable gas container valves;

 ISO 5145 (34), Cylinder valve outlets for gases and gas mixtures. Selection
and dimensioning;

 German DIN 477 (68), Gas cylinder valves for cylinder test pressures up to
300 bar;

 USA CGA V-1 (70), Standard for compressed gas cylinder outlet and inlet
connections.

It is possible that different container valve outlets for the same gas on the same user site
may be of differing standards. Extreme care shall be taken to ensure that only the
correct connections are used. If any doubt exists, check with the gas supplier.

Additional protection against high discharge rates of pyrophoric and toxic gases (e.g.
flow limiting orifices fitted to the valve outlet) should be fitted where maximum
process demand allows.

Where gas containers are supplied with valve outlet sealing plugs or cap-nuts and valve
protection caps acting as a secondary seal it is essential that these are refitted after use.
Inadvertent opening of the valve or slight leakage across the valve may be hazardous if
these secondary seals are not correctly fitted. This hazard also potentially exists when
containers are nominally empty.

4.5 Identification of container contents

It is potentially hazardous to use a container whose content is not positively identified.
The cylinder label shall always be used as the primary means of identifying the

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BCGA CP18 - Revision 3
 contents of a gas container. Identification is normally by the UN Number and the
Proper Shipping Name. This may also be stencilled on the container. Container colour
is a secondary method of identifying the contents but shall not be relied upon for
positive content identification, as many different colour codes exist.

Refer to Section 5 for further information on the hazards of a gas and their
classification. Refer to BCGA Technical Information Sheet (TIS) 6 (63), Cylinder
identification. Colour coding and labelling requirements, for information on the colour
coding and labelling of gas cylinders.

4.6 Misuse of containers

It is potentially hazardous to use full or nominally empty containers other than for their
designed purpose (e.g. misuse as rollers, roadways, door-stops, etc.). Such misuse may
result in damage to the container or its valve, possibly causing leakage (of a hazardous
product), or creating a hazard during subsequent refilling of the container.

Users shall not refill gas containers without the authorisation of the owner of the
container.

4.7 General
Any container for which the contents cannot be accurately identified, or which is
known to have been misused or subjected to a potential hazard, shall be set aside and
the gas supplier notified so that appropriate safety measures can be taken.

5. POTENTIALLY HAZARDOUS PROPERTIES OF GAS

This section summarises the principal hazardous properties of gases. Subsequent sections
deal with the practical requirements for overcoming these hazards.

There are potentially hazardous properties for many of the pure gases. Gas mixtures are not
covered in detail in this section, however, the same range of potential hazards may exist for
mixtures as with pure gases, the hazards being dependent on the mixture components and
their concentrations. Full details of the hazardous properties of each gas will be given in the
Safety Data Sheet and basic information displayed on the product identification label.
Wherever technically possible the use of less hazardous gases should be considered by users.

It is a legal requirement that the gas supplier provides a Safety Data Sheet to the user
whenever a product is supplied for the first time, in accordance with the Chemicals (Hazard
Information and Packaging for Supply) CHIP (14) Regulations. The exact requirements for
Safety Data Sheets are included in the REACH Regulations (23). Safety Data Sheets can be
obtained for all gases and are to be available for the user of the gas. The information within
the Safety Data Sheet shall be have been considered before design work or handling of any
gas container commences.

NOTE: The CHIP (14) Regulations brings national legislation into line with the transitional
arrangements set out in European Regulation (EC) No 1272/2008 (22) on the Classification,
Labelling and Packaging of Substances and Mixtures (CLP). The CLP (22) Regulation
entered into force across all EU member states, including the UK, in January 2009. The CLP
(22) Regulation has applied to substances that are placed on the market since 1 December

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2010. It is not mandatory to use the CLP (22) classification system to classify chemical
mixtures (preparations) until 1 June 2015. The CHIP (14) Regulations will be repealed from
1 June 2015, from when suppliers must comply with the CLP (22) Regulation.

The potential hazardous properties of many of the pure gases can be found in the following
references:

 European Chemicals Agency (ECHA)

 REACH (23) Registration Dossiers

 ADR (18) Packing Instruction P200

 BS ISO 10298 (39), Determination of toxicity of a gas or gas mixture

5.1 Flammability
For the purpose of this code, a gas is defined as being flammable if it can form mixtures
with air that will freely propagate a flame. The flammable range is normally defined as
the range of concentrations of the gas in air which will propagate a flame. Mixtures of
flammable gas(es) with air or other oxidants within the flammable range have the
potential to explode. The severity of an explosion caused by the ignition of a
flammable gas / air or other oxidant mixture depends on several factors including the
quantity and extent of enclosure or confinement of the gas mixture.

There is an upper and a lower limit defined for each gas or homogeneous gas mixture.
The lower flammability limit can be found in BS EN ISO 10156 (38), Gases and gas
mixtures - Determination of fire potential and oxidizing ability for the selection of
cylinder valve outlets. Refer to the gas suppliers Safety Data Sheet for both the lower
and upper flammability limit. The flammability limits may vary considerably with
pressure and the nature and content of other gases in the mixture.

5.1.1 Pyrophoric gases

Pyrophoric gases may spontaneously ignite and burn in air (or other oxidants).
Under some conditions, spontaneous ignition may not occur, resulting in the
formation of a mixture of the pyrophoric gas with air or other oxidant gas, which
may be unstable and potentially explosive.

Examples include arsine, phosphine and silane. Further information on these

gases can be found in the European Industrial Gases Association (EIGA)
Document 163 (54), Code of practice, arsine, EIGA Document 162 (53), Code of
practice, phosphine, and EIGA Document 160 (52), Code of practice, silane.

5.2 Oxidising potential

Oxidising gases will react with flammable gases and other combustible materials in a
manner similar to oxygen, i.e. they will support combustion.

Some oxidising gases will support combustion more vigorously than air or oxygen and
may react spontaneously with some flammable gases and other materials.

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 Some organic materials, e.g. hydrocarbon based oils, greases, plastics, etc. may react
explosively with oxygen and more powerful oxidants, e.g. fluorine. The severity of
such an explosion will depend on pressure, temperature, reactivity and concentration of
the reactive components and temperature. Metal – oxygen, or metal fires in the
presence of other oxidants, may be initiated by the presence of hydrocarbon oil, grease,
other organic contaminant or particulate matter, refer to Section 9.11. Oxidising
potential can be assessed by the use of the data in BS EN ISO 10156 (38).

HSE has determined that for normal working a level of oxygen concentration between
19.5 % and 23.5 % is necessary. Oxygen levels above 23.5 % create an oxygen
enriched atmosphere which greatly increases the flammability of material.

5.3 Toxicity
A toxic substance is one which, in low quantities, can cause death or acute or chronic
damage to health when inhaled, swallowed or absorbed by the skin. In the case of
gases, the route of bodily ingress is usually by inhalation.

Further information is available in the EIGA Document 130 (49), Principles for the
safe handling and distribution of highly toxic gases and mixtures.

5.3.1 LC50 / 1 hour

The LC50 / 1 hr is the concentration of a toxic gas in air which is expected to
result in the death of 50 % of an animal population (normally rats) when exposed
for a period of 1 hour. These values are provided in BS ISO 10298 (39) which is
based on a wide range of data from published papers.

5.3.2 Workplace exposure limits

HSE Guidance Note EH 40 (24), Workplace exposure limits, gives details of the
workplace exposure limits which should be used for purposes of determining the
adequacy of control of exposure by inhalation of substances hazardous to health.
Reference to the current HSE Guidance Note, which is regularly reviewed and
revised as necessary, should be made.

5.3.3 Derived no-effect level

The (REACH) (23) regulations define the derived no-effect level (DNEL) as the
level of exposure to a substance above which humans should not be exposed.
Refer to the REACH (23) registration dossiers on the European Chemicals
Agency (ECHA) website, as well as the suppliers Safety Data Sheet for further
information.

NOTE: ECHA website link: http://echa.europa.eu/web/guest/information-on-

chemicals/registered-substances

5.4 Corrosivity
A corrosive gas is one which, on direct contact, may harm human tissue.

Many corrosive gases may also react with certain materials of construction causing
material damage and possible failure. Corrosive gases may only react with a material
in the presence of water or moisture from the atmosphere or other sources. Products of

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 corrosion can include other gases, e.g. hydrogen, giving rise to possible pressure and
flammability hazards.

To prevent any potential impact from water, gas suppliers carry out additional
procedures to ensure cylinders are dry before filling and that filling systems are
designed to prevent the ingress of air and moisture during filling. Further information
on the extra management controls in place for the supply and storage of cylinders in
corrosive gas service can be found in BCGA TIS 33 (66), Good industry practice for
the supply of cylinders containing corrosive gases, for gas suppliers and for users’ in
BCGA TIS 16 (64), The storage of gas cylinders containing corrosive gas at users’
premises.

5.5 Asphyxiant
Asphyxiation hazards exist with any gas or gas mixture which does not contain
sufficient oxygen to support life. Such gases or gas mixtures will displace the available
oxygen in the atmosphere to a level which is unsafe or may not support life.

For normal working a level of oxygen concentration at or above 19.5 % is necessary.

Atmospheres containing less than 18 % oxygen are potentially dangerous and entry into
such areas must be prohibited unless appropriate safety controls are adopted.

It should be noted that all gases except oxygen, air and gas mixtures manufactured
specifically for breathing can be asphyxiant at atmospheric pressure. Many such gases
may well present other hazards such as fire or toxicity risks. The concentrations at
which these other hazards can arise are likely to be well below those at which
asphyxiation occurs.

BCGA Guidance Note (GN) 11 (61), Reduced oxygen atmospheres. The management
of risk associated with reduced oxygen atmospheres resulting from the use of gases in
the workplace, provides further information on the management of risk associated with
reduced oxygen atmospheres resulting from the use of gases in the workplace.

5.6 Carcinogenicity, mutagenicity and reprotoxicity

There are a few gases which may exhibit one or more of the hazards of carcinogenicity,
mutagenicity and reprotoxicity (CMR). Where this is the case, information shall be
given in the supplier’s Safety Data Sheet and indicated on the gas container contents
label.

Under REACH (23) it is possible for products to be added to the Candidate List for
potential future Authorisation. Some CMR’s may become designated “Substances of
Very High Concern” (SVHC’s). Authorisation is the process under REACH (23)
whereby the risks from SVHC’s are properly controlled and progressively replaced by
alternative safer substances.

Any substance classified as a CMR, PBT (persistent, bioaccumulative and toxic) or

vPvB (very persistent and very bioaccumulative) or any substance which may cause an
equivalent level of concern (e.g. respiratory sensitisers, endocrine disruptors) may be
recommended for inclusion on the Candidate List for Authorisation.

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 Although it is not explicitly stated in the REACH (23) text, it is expected that
companies who supply products / mixtures containing substances on the Candidate List
above a concentration of 0.1% (weight by weight) will communicate the presence of
such SVHC via their Safety Data Sheet. This is to enable producers and importers of
articles (i.e. a finished product) to meet their obligations under REACH (23).

REACH (23), Article 7(2) states that producers and importers of articles have to notify
to ECHA the substances listed on the Candidate list which are present in their articles,
if both the following conditions are met: the substance is present in their relevant
articles above a concentration of 0.1 % weight by weight and the substance is present in
these relevant articles in quantities totalling over one tonne per year. However, a
notification is not required if the producer or importer of an article can exclude the
exposure of humans and the environment to the substance during normal or reasonably
foreseeable conditions of use of the article, including its disposal or the substance has
already been registered by a manufacturer or importer in the European Union for that
use.

Furthermore, REACH (23) Annex II is more explicit in stating that substances subject
to Authorisation (i.e. included in REACH (23) Annex XIV) should be declared in
Section 15 of the Safety Data Sheet.

5.7 Pressure of a gas in its container

Gases are supplied in containers manufactured to approved standards, e.g. cylinders and
drums.

The most significant hazards that can arise directly from the gas pressure in a container
are:

(i) Exposure of the container to excessive heat, which could result in its
rupture due to over pressurisation and / or heat weakening its material of
construction;

(ii) Mechanical or corrosion damage to the container valve, or some other part
of the container, which could result in a rapid escape of gas which may generate
sufficient thrust to propel the gas container or other adjacent objects.

Containers should not be allowed to be exposed to chemicals which could affect their
mechanical properties. This is particularly important with containers manufactured
from composite materials.

5.8 Other hazards which may arise from the physical or chemical properties of a
gas
It is beyond the scope of this code to cover all possible hazards. Details should be
sought from suppliers’ Safety Data Sheets and, in cases of doubt, by direct consultation
with suppliers.

Examples of other gas properties that may be relevant include:

(i) Densities of gases including liquid phases where appropriate, e.g. for design
of ventilation systems. Some gases are heavier than air, some are lighter.
Heavier than air gases may accumulate in confined spaces at or below ground
level, lighter than air gases may accumulate in roof spaces;

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BCGA CP18 - Revision 3
 (ii) Relative Densities. The densities of gases are commonly quoted as having
a relative density to air, where air is equal to 1. In addition, for liquefiable gases,
the liquid phase density is given relative to water, where water is equal to1. Refer
to the gas suppliers Safety Data Sheet.

(iii) Vapour Pressure. The pressure exerted by a vapour in equilibrium with a

liquefiable gas e.g. ammonia, in a container. It is important to consider the
relationship between vapour pressure / temperature for liquefiable gases, e.g. to
avoid unwanted liquefaction of gases in, or over pressurisation of, gas handling
systems. Refer to the gas suppliers Safety Data Sheet.

(iv) Polymerisation potential, e.g. certain gases may polymerise readily under
some conditions, e.g. heat, contact with acid / alkaline radicals, etc. Such
reactions may generate heat and pressure which may present a hazard if
uncontrolled;

(v) The latent heat of vapourisation of liquefied gases - most liquefied gases are
capable of causing cold burns when spilt on the skin or in the eyes.

(vi) Environmental hazards such as ozone depletion, aquatic toxicity,

greenhouse effect. Such hazards will be identified by reference to the Safety Data
Sheet and the product identification label as required by legislation.

5.9 Classification
All gases are classified based on their intrinsic properties. When in use they have to be
classified against the CLP (22). When being transported they comply with the UN
Recommendations on the Transport of Dangerous Goods, Model Regulations (16),
which in the UK means compliance The Carriage of Dangerous Goods and Use of
Transportable Pressure Equipment Regulations (15) which implements ADR (18) for
road transportation. It is mandatory for all containers to have a product identification
label displayed identifying the product and advising of any associated hazard or safety
requirements.

In January 2009, the CLP (22) regulations were introduced in to the European Union to
align previous European Union legislation on the classification, labelling and packaging
of chemicals with the UN Globally Harmonised System of Classification and Labelling
of Chemicals (GHS) (17). The CLP (22) Regulation amends and repeals European
Directive 67/548/EEC (19) on the classification, packaging and labelling of dangerous
substances.

The CLP (22) Regulation is being implemented in stages:

 All pure substances have had to have been classified, labelled and packaged
in line with the CLP (22) regulations since the 1st December 2010.

 All mixtures will need to be classified, labelled and packaged according to

the CLP (22) regulations by the 1st June 2015, but may be implemented earlier.

 The hazards of both pure substances and mixtures need to be notified to the
European Chemicals Agency (ECHA) regardless of quantity.

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BCGA CP18 - Revision 3
 NOTES:
1. There is a two year period of grace to allow cylinders, which have already
been supplied, to be used with their existing classification.
2. Non-European Union imports may be supplied with classifications which
are not in accordance with CLP (22).

5.9.1 Dangerous substances and dangerous preparations directives

Gas classifications (which summarise the key hazardous properties) are given, as
listed in Annex 1 of the European Directive 67/548/EEC (19) on the
classification, packaging and labelling of dangerous substances.

The classification symbols currently used are defined in the CHIP (14)
Regulations and are as detailed in Table 1. These remain extant until 1st June
2015.

Symbol Classification
O Oxidant
F+ Extremely flammable
F Highly flammable
T+ Very toxic
T Toxic
Xn Harmful
C Corrosive
Xi Irritant
Carc (1,2,3) Carcinogenic
Mut (1,2,3) Mutagenic
Repr (1,2,3) Toxic for reproduction
N Dangerous to the environment

Table 1: Classification symbols

A dash in the list indicates that the gas is treated, for classification purposes, as
not exhibiting any of the above properties. There may, however, be other hazards
such as pressure, asphyxiant risk, etc.

5.9.2 Classification, labelling and packaging of substances and mixtures

GHS 01 GHS 02 GHS 03 GHS 04 GHS 05

GHS 06 GHS 07 GHS 08 GHS 09

Table 2: GHS Pictograms

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BCGA CP18 - Revision 3
 The pictograms and Hazard statements which are to be used under the CLP (22)
regulations are detailed in Tables 2 & 3. These are to be applied for pure
substances and are applicable for mixtures from 1st June 2015. For further details
please refer to EIGA Document 169 (55), Classification and Labelling Guide.

Pictogram Hazard Classification Phrase

statement
GHS 02 H220 Flam. Gas 1 Extremely flammable gas
No additional
pictogram H221 Flam. Gas 2 Flammable gas
required
No additional
May react explosively even in the
pictogram H230 Chem. Unst. Gas A
absence of air
required
No additional May react explosively even in the
pictogram H231 Chem. Unst. Gas B absence of air at elevated pressure
required and/or temperature
GHS 03 H270 Ox. Gas 1 May cause or intensify fire; oxidiser
Contains gas under pressure;
GHS 04 H280 Press. Gas (Liq.Gas)
may explode if heated
Press. Gas Contains gas under pressure;
GHS 04 H280
(Comp.Gas) may explode if heated
Press. Gas Contains gas under pressure;
GHS 04 H280
(Diss.Gas) may explode if heated
Press. Gas Contains refrigerated gas;
GHS 04 H281
(Refr.Liq.Gas) may cause cryogenic burns or injury
GHS 06 H310 Acute Tox. 1 Fatal in contact with skin
GHS 05 H314 Skin Corr. 1 Causes severe skin burns and eye damage
GHS 07 H315 Skin Irrit. 2 Causes skin irritation
GHS 05 H318 Eye Dam. 1 Causes serious eye damage
GHS 07 H319 Eye Irrit. 2 Causes serious eye irritation
GHS 06 H330 Acute Tox. 1 Fatal if inhaled
GHS 06 H330 Acute Tox. 2 Fatal if inhaled
GHS 06 H331 Acute Tox. 3 Toxic if inhaled
GHS 07 H332 Acute Tox. 4 Harmful if inhaled
GHS 07 H335 STOT SE 3 May cause respiratory irritation
GHS 07 H336 STOT SE 3 May cause drowsiness or dizziness
May cause genetic defects (state route of
exposure if it is conclusively proven that
GHS08 H340 Muta. 1
no other routes of exposure cause the
hazard)
Suspected of causing genetic defects
(state route of exposure if it is
GHS08 H341 Muta. 2
conclusively proven that no other routes
of exposure cause the hazard)
May cause cancer (state route of exposure
GHS08 H350 Carc. 1 if it is conclusively proven that no other
routes of exposure cause the hazard)

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BCGA CP18 - Revision 3
 Suspected of causing cancer (state route
of exposure if it is conclusively proven
GHS08 H351 Carc. 2
that no other routes of exposure cause the
hazard)
May damage fertility or the unborn child
(state specific effect if known)(state route
GHS08 H360 Repr. 1 of exposure if it is conclusively proven
that no other routes of exposure cause the
hazard)
Suspected of damaging fertility or the
unborn child (state specific effect if
GHS08 H361d Repr. 2 known) (state route of exposure if it is
conclusively proven that no other routes
of exposure cause the hazard)
Causes damage to organs (or state all
organs affected, if known) (state route of
GHS08 H370 STOT SE 1 exposure if it is conclusively proven that
no other routes of exposure cause the
hazard)
May cause damage to organs (or state all
organs affected, if known) (state route of
GHS08 H371 STOT SE 2 exposure if it is conclusively proven that
no other routes of exposure cause the
hazard)
Causes damage to organs (state all organs
affected, if known) through prolonged or
repeated exposure (state route of
GHS08 H372 STOT RE 1
exposure if it is conclusively proven that
no other routes of exposure cause the
hazard)
May cause damage to organs (state all
organs affected, if known) through
prolonged or repeated exposure (state
GHS08 H373 STOT RE 2
route of exposure if it is conclusively
proven that no other routes of exposure
cause the hazard)
GHS09 H400 Aquatic Acute 1 Very toxic to aquatic life
Very toxic to aquatic life with long
GHS09 H410 Aquatic Chronic 1
lasting effects
Toxic to aquatic life with long lasting
GHS 09 H411 Aquatic Chronic 2
effects
No additional
Harmful to aquatic life with long lasting
pictogram H412 Aquatic Chronic 3
effects
required

Table 3: Commonly used CLP classifications

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BCGA CP18 - Revision 3
6. GAS CONTAINER STORAGE AREA

All gas containers are to be stored in accordance with BCGA GN 2 (59), Guidance for the
storage of gas cylinders in the workplace. All storage areas shall be located with due regard
to the minimum recommended separation distances specified in Table 4.

6.1 Key principles

Additional principles for the storage of special gases are:

(i) That they are contained in a secure store (but with clear access). Some
special gases require a higher level of security. Only personnel authorised to
handle/use special gases are to be allowed access to them. Access to keys is to be
controlled. A key log is to be maintained. Keys are to be made available to the
emergency services in the event of an incident.

(ii) Provided with clearly marked areas for each category of gas;

(iii) The location of special gases is to be clearly designated and shown on the
site plan. This site plan is to be available to the emergency services in the event
of an incident. The emergency services are to made aware of the additional
hazards which may be encountered with special gases;

(iv) Special gases being prepared for distribution, or during carriage, are to
comply with the security provisions of ADR (18), Chapter 1.10. All persons
engaged in the carriage of dangerous goods have to consider the security
requirements of ADR (18), commensurate with their responsibilities. High
consequence dangerous goods require additional security arrangements.

(v) The gas supplier may agree with the customer safe and appropriate practice
for the management of certain special gases, this may include audits of the
customer’s storage site. All personnel who are required to handle / use special
gases are to have received appropriate training, this is to include the general
properties of gases as well as the specific physical and chemical properties of the
gases they are handling. Refer to Section 13.3.

(vi) All personnel who are required to handle / use special gases are to be
authorised and a list of those personnel is to be maintained.

(vii) The store has to be appropriately marked and labelled to indicate the special
nature of its contents. A list of personnel who are authorised to access the store is
to be displayed.

(viii) Inventories of gases shall be managed so that they are kept to a practicable
minimum.

(ix) Consideration is to be given to the provision and location of fire fighting

equipment. Special gases may require additional precautions to be applied when
fighting a fire. This is to be considered as part of the fire risk assessment carried
out in accordance with the Regulatory Reform (Fire Safety) Order (13). Refer to
Section 13.1.

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BCGA CP18 - Revision 3
 (x) All personnel handling special gases are to be provided with appropriate
Personal Protective Equipment (PPE). The presence of special gases may require
additional PPE to be provided. Refer to Section 13.2.

(xi) If required, an appropriate gas detection system is to be provided and

installed. Any gas detection system shall be fitted with audible and visible
alarms. The alarm system is to be set to operate at an appropriate level e.g. in
accordance with the Workplace Exposure Limit, refer to HSE Guidance Note EH
40 (24). All gas detection systems and alarms shall be maintained in accordance
with the manufacturers requirements and tested at regular intervals. Refer to
Section 13.7.

Minimum
Typical type of exposure Features to be separation
separated distance
(in metres)
Smoking, naked flames Storage area 3
Bulk storage of flammable gases and liquids Storage area 3
Unprotected electrical equipment Flammable gases 3
Site boundaries
Air compressors and ventilator intakes
Roadways (other than those required for access) Toxic and flammable 3
gases
Bulk storage of cryogenic liquids
Building openings
Site boundaries
Air compressors and ventilator intakes
Roadways (other than those required for access) Other gases 3
Bulk storage of cryogenic liquids
Building openings
Pyrophoric gases in store Other gas containers 2
(Refer to Section 8.5)
Pyrophoric gases connected for use Other gas containers 2
(Refer to Section 8.4)

NOTE: These distances are recommendations only. The risk assessment may suggest other
distances.

Table 4: Minimum recommended separation distances

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BCGA CP18 - Revision 3
 6.2 External storage location
The first principle for the location of any store is for it to be in the open air where there
is good natural ventilation. The storage areas should be well defined. Stores
containing special gases are to be located in an area where they are secure. Under
specific circumstances containers may be stored internally, refer to Section 6.5.

The store shall be located with due regard to the minimum recommended separation
distances specified in Table 4. The special properties of some gases may require these
to be extended.

The store shall be located in an area away from sources of fire and/or ignition.

There shall be good access and egress for delivery vehicles.

6.3 Store design and construction

Gas containers should be stored at ground level.

The store should be covered by a roof to protect containers from the weather and to
provide some protection against corrosion. The roof should be designed with vents so
that gas cannot accumulate in the roof-space.

The storage area shall be constructed so as to allow a high standard of natural

ventilation. Therefore as well as providing protection from the weather the store shall
be constructed in such as way as to provide no opportunity for the build up of gases in
an enclosed volume. The store shall be arranged so that gas leaks cannot collect in
confined spaces, e.g. drains, pits, basement entrances, etc.

The design of the store is to take into consideration the density of the gases to be stored.
Low-level ventilation is particularly important since many gases are heavier than air,
but high level ventilation may also be required. The storage area shall have at least two
sides that are sufficiently open so as to provide a high degree of natural ventilation.
Open wire mesh of industrial quality or steel louvres are suitable materials for these
free venting sides. Where practicable the two free venting sides should be opposite
rather than adjacent.

The types of gases being stored may require an assessment of the number of air changes
per hour that occur. Natural ventilation may be acceptable, but in some cases, forced
ventilation systems may be required. Any forced ventilation systems are to be
synchronised with the gas detection system.

Where reasonably practicable all parts of the storage area shall be constructed of non-
combustible materials.

The floor shall be flat and constructed of concrete or other non-combustible, non-
porous material. It should be laid to a fall, to prevent the accumulation of water. The
slope of the floor shall be such that any product spill is directed to a low risk area.

The store will be required to be secure. Special gases often have hazardous properties,
requiring that access to them is restricted to authorised personnel. Additionally, some
gases need to be secured because they are attractive to thieves, for example, for drug

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BCGA CP18 - Revision 3
 misuse or for the purposes of terrorism. The design of the store is to take account of the
level of security necessary to protect the type of gases being stored.

Storage areas shall be located away from areas of fire risk. Fire extinguishing
equipment should be readily available in all working areas. A water spray system that
will operate either automatically or can be operated manually should be considered.
All fire equipment as required in the fire risk assessment carried out in compliance with
The Regulatory Reform (Fire Safety) Order (13) shall be provided. Refer to Section
13.1.

NOTE: In the event of a fire a water spray will ensure that containers are cooled in
order to minimise the risk of rupture and with some gases water spray may also help to
minimise the spread of any escaping gas.

Where flammable or oxidising gas containers are stored, a risk assessment in

accordance with the Dangerous Substances and Explosive Atmospheres Regulations
(DSEAR) (12) shall be carried out. Only electrical equipment certified as suitable for
use in a Zone 2 area (or better) and constructed to a recognised standard shall be
installed. As a minimum all electrical installations shall conform to BS 7671 (37),
Requirements for electrical installations. IET wiring regulations. All fixed electrical
equipment in the hazardous zones shall have the appropriate ATEX rating, refer to BS
EN 60079, Part 14 (43), Explosive atmospheres. Electrical installations design,
selection and erection. This restriction shall be applied within storage areas and
outside the storage areas to the minimum recommended separation distances specified
in Table 4.

NOTE: ATEX is the name commonly given to the two European Directives for
controlling explosive atmospheres. These are:

 European Directive 99/92/EC (21) (also known as 'ATEX 137' or the

'ATEX Workplace Directive') on minimum requirements for improving the
health and safety protection of workers potentially at risk from explosive
atmospheres.

 European Directive 94/9/EC (20) (also known as 'ATEX 95' or 'the

ATEX Equipment Directive') on the approximation of the laws of Members
States concerning equipment and protective systems intended for use in
potentially explosive atmospheres.

In the UK the requirements of Directive 99/92/EC (21) were put into effect
through DSEAR (12). The requirements of Directive 94/9/EC (20) were
implemented by the Equipment and Protective Systems Intended for Use in
Potentially Explosive Atmospheres Regulations (EPS) (5). Compliance with
DSEAR (12) and the EPS Regulations (5) is sufficient to confirm
compliance with Directive 99/92/EC (21) and Directive 94/9/EC (20)
respectively. Further guidance is available in HSE L138 (29), Dangerous
substances and explosive atmospheres. DSEAR 2002. Approved Code of
Practice and guidance, and additional information is available in EIGA
Document 134 (50), Potentially explosive atmospheres EU Directive
1999/92/EC.

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BCGA CP18 - Revision 3
 Where applicable, electrical equipment, which is necessary for the installation shall be to
BS EN 60529 (44), Specification for degrees of protection provided by enclosures,
protection class IP54 or better. For more severe environmental conditions protection
class IP55 (designed to protect against water jets) should be used.

Adequate means of escape shall be provided. Liaison with the local Fire Authority is
necessary to determine the number of exits required and appropriate travel distances.
Any gates should be outward opening and wide enough to provide for an easy access and
exit of personnel. Consideration should be given to the provision of an additional
emergency exit where the size of the fenced area or store necessitates this. Where
installed, all emergency exits are to open in the direction of escape and are to be fitted
with panic furniture of a type not requiring a key, card, or code to open. They are to
provide an unobstructed means of escape and in operation are not to obstruct any other
escape route. These exits are to be properly identified by signage, and maintained in a
serviceable condition at all times. The main gate should have two wings, each at least
0.6 m wide. The emergency exit gate should have one wing, at least 0.8 m wide.

Where necessary, protection shall be provided to prevent damage from vehicles. This
may be a low wall, bollards or a crash barrier.

6.4 Store management

The store shall be used exclusively for the storage of gas containers.

The store shall be clearly labelled with the type or classification of containers it
contains. Appropriate safety signs, e.g. “NO SMOKING”, shall be erected in
accordance with the Health and Safety (Safety Signs and Signals) Regulations (5). A
sign shall be displayed detailing any specific action to be taken in the event of an
incident/emergency and showing whom to contact in the event of an
incident/emergency, with all appropriate contact details. This is to include the contact
details for the gas supplier and the gas supplier’s 24-hour emergency contact telephone
number. The location of any access keys, as well as the contact details for the
authorised key holder shall be displayed.

Sources of ignition shall neither be permitted within the storage area nor within the
minimum recommended separation distances specified in Table 4. Accumulation of
combustible materials shall not be permitted within or close to the storage area.

Where flammable or oxidising gas containers are stored a risk assessment shall be
carried out to assess the suitability of portable electrical, electronic devices and other
equipment that may be required for use. As required, appropriate controls are to be
applied e.g. flammable gas monitoring.

Containers shall be stored upright, when designed for this, and measures taken to
prevent them toppling over. Special arrangements may be required to secure small or
round-bottomed containers.

Containers shall be grouped within the store according to a formal plan. This plan
should take into account the hazards and the requirements of good storekeeping.

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BCGA CP18 - Revision 3
 Used containers shall be segregated from full containers. They shall be clearly marked
and stored in the same way as full containers.

Pyrophoric gas containers shall be separated from other categories of gas containers. It
is preferable to use a separate store or a firewall. The minimum recommended
separation distances in Table 4 shall apply.

The store shall be kept secure and access shall be restricted to authorised personnel.
Some special gases require additional security measures e.g. very toxic gases, where the
store is kept locked and the access keys are held by authorised personnel.
Arrangements shall be made for unlocking the store in the event of an emergency.

The container inventory should be managed to ensure that the oldest stock is used first.
The inventory shall be regularly reviewed to ensure that stock holdings are not
excessive and that there is a regular turnover of all containers. Many special gases are
given a shelf life and this stock should be managed to ensure that all these gases remain
within their shelf life. Stock holdings should be formally inspected on a regular basis
paying particular attention to older stock. Gases for which the shelf life has expired,
which are no longer required, or which are used / empty should be returned to the gas
supplier as soon as is practicable.

An inventory shall be kept listing all high hazard special gas containers e.g. very toxic
or pyrophoric gases, held on site, whether full, in use or nominally empty. This
inventory should be updated each time deliveries / collections to / from site are made by
the gas supplier. A periodic physical audit (at least annually) should be made on the
inventory and any deficiencies recorded, investigated and a report made to
management.

The hazard from certain special gases may require a physical audit by the gas supplier,
on the customers premises, on a routine basis, to ensure the customer has appropriate
stock control and storage procedures in place.

On any occasion when leakage, excessive corrosion or excessive damage is detected the
container is to be quarantined and appropriate safety precautions taken. The container
is to be returned to the gas supplier as soon as practical. As necessary, the advice of the
gas supplier should be sought.

6.5 Internal storage

Gas containers should be stored in an external location, refer to Section 6.2. Internal
storage within a building is not recommended and should not be considered for new
locations for container stores. The exception is where it is necessary to maintain
specific gas properties that can only be carried out in a controlled environment.

Where it is necessary to store containers internally, in addition to the other

requirements detailed in Section 6, the following applies:

(i) A formal risk assessment shall be carried out. Consideration shall be given
to the probability of fire, gas density, explosion risk from flammable gas, valve
leakage, ventilation, access / egress, cylinder handling, gas detection, fire
protection, exposure of personnel.

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BCGA CP18 - Revision 3
 (ii) The number of containers shall be kept to a minimum.

(iii) Where practicable the store shall be constructed of non-combustible

materials. The walls, floor and ceiling shall be manufactured from materials
complying with BS 476 (32) Fire tests on building materials and structures.
Where it forms part of a building, it shall be separated from the rest of the
building by a wall of at least 30 minutes fire-resisting construction, preferably of
brick or concrete.

(iv) The store shall be adequately ventilated as determined by the risk

assessment.

(v) Any forced ventilation system shall be linked to a suitable visual / audible
alarm system to warn of failure.

(vi) Consideration should be given to atmospheric monitoring within the store

depending on the perceived risk. If required, an appropriate gas detection system
is to be provided and installed.

7. HANDLING OF GAS CONTAINERS

Most accidents and injuries in the compressed gas industry occur whilst moving /
manhandling gas containers. Examples include back strain, bruised fingers and feet, etc.

The Manual Handling Operations Regulations (4) require that an assessment of manual
handling operations is conducted. Following the assessments, training should take place.
Where the assessment indicates that the work exceeds guideline limits, wherever practicable
the operation should be mechanised or handling aids provided. BCGA Guidance Note 3 (60)
Safe cylinder handling and the application of the manual handling operations regulations to
gas cylinders, defines the principles of safe practice for handling and moving cylinders and
provides a basic understanding of the Manual Handling Operations Regulations (4) relating to
gas cylinders. BCGA TIS 17 (65), Model risk assessment for manual handling activities in
the industrial gas industry, can be used to assist in developing a site risk assessment.

7.1 Handling precautions

Personnel should:

(i) Be trained, as required within Section 13.3, following an assessment carried

out as required by the Manual Handling Operations Regulations (4);

(ii) Take account of the total mass of the container (this can be very significant,
especially if it contains a liquefied gas);

(iii) Beware of trapping fingers between containers whilst they are being
moved;

(iv) Seek help and observe the correct lifting posture and method when it is
necessary to lift heavy containers manually.

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BCGA CP18 - Revision 3
 (v) Use a purpose-built trolley or other suitable device or technique for
transporting heavy a heavy container, even for short distances, ensuring the
container is adequately secured;

(vi) Ensure valve protection devices (e.g. valve covers, guards, etc.,) and valve
outlet plugs or caps are fitted to containers whilst they are being moved;

(vii) Never permit oil, grease or other readily combustible substances to come
into contact with valves or containers;

(viii) Check by suitable means that there are no leaks from the valve and beware
of inadvertently opening container valves fitted with hand-wheels;

(ix) Ensure that suitable measures are taken to prevent upright containers from
toppling over.

7.2 Personal protective equipment

Personal Protective Equipment (PPE) is to be provided as required by the Personal
Protective Equipment at Work Regulations (10). PPE may only be considered as a
control to achieve an acceptable level of residual risk after other levels of control have
been addressed. The risk assessment will determine the requirement for the use of PPE.
Where PPE is required a PPE Assessment is to be carried out. Refer to Section 13.2.

For cylinder handling, the appropriate use of protective gloves, safety footwear and eye
protection is necessary. Boots with metatarsal protection are strongly recommended.

All PPE shall be maintained in good condition.

7.3 In-house transport of toxic gases

ADR (18) details the regulations for the carriage of toxic gases. Vehicle operators
responsible for the distribution, delivery or collection of large loads of gas containers
should use open vehicles that have plenty of natural ventilation. The vehicle should
have a gas tight bulkhead separating the driver from the load. The use of closed
vehicles should be avoided, but they may be used for a small number of containers of
toxic gases if specifically designed for the purpose. Vehicles used for this purpose
should have adequate ventilation with vents located to encourage a free flow of air
through the load compartment.

NOTE: The HSE are producing guidance on the acceptable levels of ventilation inside
vans transporting dangerous goods.

Gas containers should be left on board no longer than is required to make the journey
and should be removed immediately the destination is reached.

Further information for toxic gases is available in EIGA Document 130 (49). General
information on the carriage of gas cylinders is available in BCGA GN 27 (62),
Guidance for the carriage of gas cylinders on vehicles.

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BCGA CP18 - Revision 3
8. GAS SUPPLY POINTS

Gas supply points are defined as the points where the connected gas containers and associated
valves and fittings, etc., are housed.

8.1 Key principles

Each gas supply point shall be the subject of a formalised risk assessment. Gas supply
points should be:

(i) Secure (but with clear access);

(ii) Well ventilated

(iii) Free from naked flames and unprotected electrical equipment which could
act as sources of ignition;

(iv) Well separated from fire hazards and populated areas;

(v) Used exclusively for containers;

(vi) Clearly labelled with the name of the gas and principal hazard(s);

(vii) Well maintained;

(viii) Provided with arrangements to stop containers from falling over;

(ix) Provided with a means of remote isolation of the supply, as close as is

practicable to the supply container where a hazard could arise from an
uncontrolled gas release in the downstream equipment.

8.2 Location of gas supply points

Gas containers of toxic, corrosive, pyrophoric or flammable gases which are connected
for use shall each have a separate supply point and be located as follows:

(i) External gas supply points in a safe place outside buildings, refer to Section
8.4. This is the preferred location for all gases;

(ii) Within purpose-built internal gas supply rooms, refer to Section 8.5;

(iii) Inside purpose-built gas cabinets, refer to Section 8.6.

It is recommended that containers of other gases are kept as above. However, they may
be connected for use at points in the workroom provided attention is paid to the key
principles above and the number of containers is kept to a minimum.

8.3 Precautions against gas release

Precautions shall be taken both to minimise the risk of gas release taking place, and to
minimise the effects should any occur. The former is a matter of sound engineering
and working practices as set out in this code. The latter requires giving attention to
factors including:

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BCGA CP18 - Revision 3
 (i) Quantity of gas in the supply container;

(ii) Maximum discharge flow rate from the supply gas container;

(iii) Dilution extent of toxic gas in the ventilation / extract system;

(iv) Location, height above ground of vent to atmosphere;

(v) Velocity of discharge to atmosphere; location of air intakes, buildings and

people;

(vi) Gas scrubbing or other treatment techniques to deal with accidental releases
(refer to Section 10) where necessary;

Where the processes or substances used are those which are defined within
environmental legislation, the Waste Regulator (the Environment Agency or the
environment agencies within your jurisdiction) and the Local Authority shall be
consulted as appropriate. Refer to Section 13.6 on gas monitoring.

8.4 External gas supply points

This is the preferred location as there is usually good natural ventilation. Even outside,
it is recommended that containers of very toxic gases should be enclosed inside a
suitably ventilated enclosure or a gas cabinet as described in Section 8.6.

The area where the gas containers are connected should comply with the general
principles of Sections 6.2, 6.3 and 6.4. A suitable enclosure for containers of hazardous
gases (except where a cabinet is provided - see above) is a secure wire mesh cage
located in a safe, well-ventilated place, with no ignition sources and away from
occupied areas.

It is particularly recommended that pyrophoric gas containers are installed outside

whenever this can be reasonably achieved. In the event of a leak of pyrophoric gas, a
delayed spontaneous ignition may result, refer to Section 5.1.1. In a confined space this
could lead to an explosion. If located in the open air where there is plenty of natural
ventilation, pyrophoric gas containers need not be housed inside a cabinet.

Where necessary a limited number of gas containers, not containing very toxic gases,
may be secured against building walls, provided that the requirements above, in Section
8.4, and the following are met:

(i) The area complies with the general principles of Sections 6.2, 6.3 and 6.4;

(ii) The wall is fire-resisting, to a minimum of 30 minutes in accordance with

BS 476 (32);

(iii) The containers are away from windows, drains, air intakes, etc., to prevent
the escape of gases into buildings and to protect the containers against fires
within the building;

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BCGA CP18 - Revision 3
 (iv) The containers are well ventilated.

Pyrophoric gas containers, which are connected for use, shall be separated from other
gas containers (purge gas containers excluded) either:

(v) By a minimum distance of 2 metres, refer to Table 4; or

(vi) by a firewall, provided it does not significantly reduce the ventilation; or

(vii) by placing them inside ventilated gas cabinets, refer to Section 8.6.

8.5 Internal gas supply rooms

Gas supply rooms comprise a separate room used solely to contain the supply gas
containers and associated equipment. No other plant or machines shall be kept in these
rooms and access shall be kept to a minimum and for authorised personnel only. Such
rooms shall comply with the requirements of BCGA CP 4 (56), Industrial gas
manifolds and gas distribution pipework (excluding acetylene).

In addition to the requirements below the general principles described for container
storage in Section 6 also apply.

The numbers of containers in gas supply rooms shall be restricted to the minimum
required for operational and standby / reserve purposes.

Gases and gas mixtures classified as pyrophoric and very toxic gases may be kept in
internal gas supply rooms, provided they are enclosed in ventilated gas cabinets which
meet the requirements of Section 8.6. It is recommended that ventilated gas cabinets be
used for all toxic gases.

Where toxic gases are not housed in gas cabinets it shall be demonstrated that there is
adequate ventilation and atmospheric monitoring to ensure that a safe working
environment is maintained.

The airflow in the extract system shall be monitored and provided with a low / no flow
alarm in case of failure. The alarm shall be audible or visible at the entrance to the gas
supply room.

NOTE: For gas supply rooms containing heavier than air gases not housed in gas
cabinets, the ventilation air should enter at high level and exit close to floor level in
addition to any high level ventilation required for lighter than air gases.

Containers of inert purge gases serving gas supplies may be located in the same room
as their appropriate process gas.

Where gas supply rooms are to be heated, this should be by indirect means, e.g. steam,
hot water or warm air. Containers shall be protected from excessive heat, refer to
Section 4.3. Measures taken shall not adversely affect the ventilation system.

For toxic, pyrophoric and flammable gases a clearly marked emergency isolation valve
shall be provided on the gas supply system as close as possible to the container. The

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BCGA CP18 - Revision 3
 emergency isolation valve shall be operable remotely from both outside and inside the
gas supply room. This may take the form of a remotely operable cylinder valve.

For flammable gases, ignition sources shall be separated from potential sources of
leaks, refer to Table 4. All equipment shall be electrically earthed. Electrical
equipment shall be specified as in Section 6.3.

Although it is preferable for gas containers to be kept outside working areas, this may
not always be practicable. In this case, gas cabinets fitted with forced draught
ventilation may be used to keep gases inside the facility near to their point of use, or
they may be located next to the machine using the gas in accordance with Section 8.2.

8.6 Gas cabinets

A gas cabinet is a purpose-built enclosure for the containment of gas supply containers.
Refer to the BCGA policy statement on the use of gas cabinets at Appendix 1. Its
function is to provide security, separation and localised ventilation. Gas cabinets used
for the containment of toxic or flammable gases should:

(i) Be provided with forced air extraction ventilation which is safely

discharged (for flammable gases the fan motor shall have a suitable ATEX rating
or shall be excluded from the air stream);

(ii) Contain any purge gas supply container(s) associated with the toxic or
flammable gas container(s) within the cabinet;

(iii) As far as is practicable, contain the pressure / flow control / purging

equipment associated with the toxic or flammable gas supply container(s) within
the gas cabinet.

Where practicable, gas cabinets should be separated from any other working areas by a
wall of fire-resisting construction.

Used containers should be removed from the gas cabinet to an external storage area as
soon as is practicable.

Spare full containers shall be stored in a purpose-built storage area (see Section 6).

Gas cabinets should be dedicated to a specific gas and should be shared only with their
appropriate inert purge gas container. If this is not practicable, for gases other than
pyrophorics, the gases shall be chemically compatible.

Gas cabinets shall be constructed of non-combustible materials. BS EN 14470-2 (42),

Fire safety storage cabinets. Safety cabinets for pressurised gas cylinders, gives the
performance requirements for fire safety cabinets used for storing pressurised gas
cylinders.

The strength of the cabinet should be such that it offers sufficient support for the gas
containers and associated equipment during normal use and container changing. The
strength and mechanical integrity should not be unduly weakened under abnormal
conditions likely to be encountered, e.g. a toppling container or local fire.

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BCGA CP18 - Revision 3
 A suitable material to meet these requirements for cabinets containing more than one
large (50 litre) container would be sheet steel of 2 mm nominal thickness. For cabinets
housing flammable gases, the ventilation ducting shall be made of non-combustible
material.

The cabinet door(s) shall be designed to give full opening to change containers and a
smaller opening for valve manipulation.

Within the cabinet there shall be facilities to locate and secure the gas container to the
cabinet.

All demountable joints shall be positioned inside the cabinet. All the associated valves,
regulators and connections shall be adequately supported to avoid strain on joints and
components during the connection and disconnection of containers.

Consideration shall be given for the provision of a water spray system at the top of the
cabinet to cool the containers and associated equipment in the event of an external fire,
and to prevent a fire from escalating.

There shall be a label and a hazard warning sign, in accordance with Health and Safety
(Safety Signs and Signals) Regulations (6) / BS EN ISO 7010 (36), Graphical symbols.
Safety colours and safety signs. Registered safety signs, displayed on each cabinet
identifying the gas and its potential hazard. A further sign shall be displayed in the area
in a clear and visible location, giving emergency information (including emergency
telephone numbers, action to be taken in an emergency and a list of the gases present in
the area).

Consideration shall be given to the monitoring of the air inside cabinets containing
toxic gases and / or flammable gases (refer to Section 13.6).

The cabinet shall be provided with sufficient extraction ventilation to achieve the
following:

 Prevent any escape of any hazardous gases to the workplace, with or

without the valve manipulation window open;

 Maintain the potential concentration of flammable gases in the extracted air

to below 25 % of the lower flammable limit, except in the event of a catastrophic
leak.

The ventilation system shall be provided with a control and monitoring system of high
reliability, to give warning of extraction ventilation failure.

Where flammable gases are connected, the cabinet and ventilation shall be designed
such that the possibility of a flammable atmosphere inside the cabinet is prevented
under normal operating conditions. Other precautions should be considered to cover
abnormal conditions such as ventilation failure, catastrophic gas leak, etc. Suitable
precautions could include one or more of the following:

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BCGA CP18 - Revision 3
  Exclude electrical equipment;

 Electrical equipment inside the cabinet meeting Zone 2 requirements;

 Automatic gas / electrical shutdown in the event of ventilation failure;

 Automatic gas / electrical shutdown coupled to a flammable gas detector.

The cabinet and all the equipment within the cabinet shall be electrically bonded to
earth. This shall be separate from the electric power supply earth.

Gas cabinets may share the same extraction ducting providing the mixing of
incompatible gases is not possible within the ducting and back feeding of an
incompatible gas is not possible in the case of failure or shutdown of the extraction
system.

9. GAS SUPPLY SYSTEMS

9.1 Key principles

All systems shall comply with the requirements of the PSSR (9), including having a
current Written Scheme of Examination. For additional guidance refer to HSE Leaflet
122 (28), Approved Code of Practice for the Pressure Systems Safety Regulations.
Safety of Pressure Systems, and BCGA CP 23 (57), Application of the Pressure Systems
Safety Regulations 2000 to industrial and medical pressure systems installed at user
premises.

Gas supply systems shall safely supply gas from the supply container to the point of use
at the required pressure and flow without degradation of quality.

Gas supply systems shall be designed to ensure that cross-contamination of

incompatible gases cannot occur between their systems and / or containers.

Gas supply systems shall be designed, installed, tested, inspected, commissioned and
maintained to recognised codes by competent and suitably qualified engineers and
technicians. Any modification to the systems or their designed mode of operation shall
be properly authorised and documented. Advice and assistance can normally be
obtained from reputable suppliers of equipment and gases, and guidance is given in
BCGA CP 4 (56) and BCGA CP 23 (57).

All gas-wetted parts in the gas supply system shall be chemically compatible with the
supply gas, in accordance with BS EN ISO 11114 (40), Gas cylinders. Compatibility of
cylinder and valve materials with gas contents. The complete system shall be designed
for the maximum foreseeable operating pressure, and subjected to appropriate pressure
and leakage testing during commissioning. Gas supply system components should be
stored in a clean, dry environment.

The principal components of a gas supply system include, among others, gas supply
source, purging systems, pressure reducing regulators, flow limiting devices, over-

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 pressure protection devices, flow control valves, isolation valves, non-return valves, gas
pipework, vacuum pumps, filters, purifiers.

9.2 Gas supply source

Gases will normally be supplied from transportable containers located in accordance
with Section 8. This includes cylinders, tubes, bundles and drum tanks containing
compressed or liquefiable gases.

9.3 Purging systems

Purging is necessary to maintain the integrity of the system under the following
circumstances:

 During commissioning, to remove air and moisture from the system;

 During supply container changeover, to remove process gas or air and

moisture from the container connection;

 For system maintenance purposes, to reduce process gas to a safe

concentration level prior to opening the system and to remove air and moisture
before re-introducing process gas;

 During an emergency, when it may be necessary to purge a gas quickly

from the system.

Three purging techniques are commonly used:

(1) Evacuation;

(2) Cycle purging, where the system is alternately evacuated and pressurised
with an inert purge gas for a specified number of cycles. The house vacuum
system shall not be used. A dedicated vacuum system is recommended, such as a
vacuum venturi operated by the purge gas (or dedicated external supply) or a
vacuum pump;

(3) Dynamic (or diffusion) purging, where inert gas is purged through the
system at a sufficient flow and for sufficient time. (Complete purging using this
technique can be time-consuming, especially for complicated systems).

The purging techniques and the extent of purging will often be governed by quality
requirements of the production process. However, for safety purposes:

 The oxygen content of systems prior to introduction of flammable gases

shall not exceed 1 % v/v;

 Flammable gas systems shall be purged until the concentration of the

flammable gas in the purge gas is less than 25 % of its lower flammability limit in
air if known, or less than 0.1 % v/v in other cases;

 Toxic gases within piping shall be purged using any of the three techniques
above, in such a way so as to ensure that, if piping is disconnected, concentrations

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BCGA CP18 - Revision 3
 of toxic gases released do not present a health hazard. Refer to the workplace
exposure limits in HSE EH 40 (24) and the appropriate Safety Data Sheet.

The following supply requirements apply:

 Purge gas sources should preferably be dedicated to single process gas

applications to avoid back contamination (piped house supply nitrogen shall not
be used). Where this is not practicable, purge gas should only be shared by
compatible process gases;

 Purge gas supply containers shall be fitted with appropriate pressure

reducing regulators and flow control valves;

 Purge gas supply system materials shall be chemically compatible with the
process gas(es) being purged;

 If the process gas container is located inside a gas cabinet then the
associated purge gas container should also be located within the same or other gas
cabinet;

 The purge gas system, including the container, shall be capable of

withstanding the maximum pressure that could be delivered from the process gas
container (e.g. in the event of back feeding);

 A means shall be provided to ensure that sufficient purge gas is available to

complete the purging operation (e.g. Pressure gauge and instruction to change
purge gas container when a minimum specified pressure is reached);

The following procedural requirements apply:

 Precautions shall be taken to prevent contamination of the purge gas supply

system and container with process gas;

 Precautions shall be taken to prevent the mixing of incompatible gases

through the vacuum venturi or the venturi gas supply / vent system:

 Detailed instructions shall be provided for all normal and emergency

purging operations:

 Purging should be carried out against a checklist to ensure all operations are
properly and completely executed.

9.4 Pressure reducing regulators

Pressure reducing regulators are used to reduce and control the pressure from that of the
supply source to that required by the process.

NOTE: Regulators do not control gas flow.

The choice of regulator depends upon:

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BCGA CP18 - Revision 3
  Compatibility with process gas;

 Supply pressure;

 Delivery pressure or required pressure range;

 Accuracy requirement of delivery pressure;

 Required flow range.

Regulators with metal diaphragms possess higher integrity than those fitted with non-
metallic diaphragms and shall, therefore, be specified for toxic, pyrophoric and high
purity gases and their associated purge gases.

Suitability of a regulator for a particular application shall be checked with the supplier.

9.5 Flow limiting devices

9.5.1 Automatic shut down

Supply systems for hazardous gases should include automatic shut-off devices
which are actuated in the event of system failure or other emergency.

Examples of automatic shut-off devices include excess flow shut-off valves and
remotely actuated gas container or supply valves. For very toxic and pyrophoric
gases, supplied from a remote supply point, which is not normally manned,
remotely operable isolation valves shall be fitted as near to the gas container as
practicable. These shall be capable of activation from a readily accessible
position. These valves may also be activated by gas monitoring or fire detection
equipment or other means.

9.5.2 Flow limiting devices

In addition, where practicable, flow limiting devices should also be provided
within or as near as possible to the gas container valve for all pyrophoric and / or
very toxic gases.

The preferred type of flow limiting device is a flow-restricting orifice fitted in the
container valve outlet (by arrangement with the gas supplier). The use of flow
limiting orifices may not be appropriate for certain corrosive gases.

WARNING: Flow limiting orifices in the supply system will considerably

reduce flow rates during purging operations. Excess flow shut-off valves
normally require a bypass for purging purposes which, if left open, could
negate the advantage of the shut-off valves in the event of down-stream line
failure.

9.6 Over-pressure protection devices

Gas supply systems shall be designed to withstand the highest pressure that could
foreseeably build up within the system. The use of over-pressure protection devices
may be necessary. The danger of liquids or readily liquefiable gases giving rise to high

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BCGA CP18 - Revision 3
 pressures should be considered. Release of gas or liquid shall be to a safe place refer to
Section 10.

Five types of over-pressure relief devices are commonly available:

(1) Pressure sensor with automatic shut-off and / or vent valve. For very toxic
and pyrophoric gases, the pressure sensor with automatic shut-off is the preferred
device;

(2) Spring loaded relief valve - will re-seat when excess pressure has been
relieved. Spring loaded relief valves shall be tested regularly to ensure that they
relieve at the set pressure and reseal when the pressure is removed;

(3) Bursting disc - will not re-seat and will vent entire gas content of system,
refer to Notes Section 9.6 (5) 2 below;

(4) Fusible plug - will be actuated by excess temperature and vent entire gas
content of system.

NOTE: Fusible plugs do not provide total over-pressure protection.

(5) Barometric leg or lute - used for low pressure applications only (e.g. for gas
disposal scrubbing system), will normally reseal when excess pressure has been
relieved.

NOTES:
1. Seek advice from the gas and / or equipment supplier when selecting
overpressure protection devices for hazardous gases.

2. On occasions the use of more than one relief device can be preferred, e.g.
bursting disc discharging to relief valve often with pressure gauge between to
indicate bursting disc failure.

9.7 Valves
General requirements for valves are:

 All valves shall be labelled to identify their function;

 Valves should be located in well-ventilated areas and away from air intakes.
Remote operation should be considered;

 Where practicable, there should be a positive indication of the status of the

valve, i.e. open or shut.

9.7.1 Flow control valves

Flow control valves are used to control gas flow through a supply system to a
process. They can be used to open or isolate a gas supply or can control the gas
flow rate in a pressure controlled system.

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 NOTE: Flow control valves do not control gas pressure and might not provide
shut-off.

9.7.2 Isolation valves

Isolation valves are a means of positive isolation, in addition to the gas container
valve, and shall be provided in each gas supply system as close to the source as
possible. The means of operation shall be in an accessible position and clearly
marked. This may require the possibility of remote operation.

9.7.3 Non-return valves

These valves are designed to permit flow in one direction only but shall not be
relied upon as the sole means of isolation. They should be periodically checked
for performance or replaced.

9.8 Pipework

9.8.1 Design and installation

Where practicable, all joints in pipelines should be made by non-mechanical
means, i.e. by welding, brazing or silver soldering. This is particularly important
for:

 Pipelines carrying very toxic or pyrophoric gases;

 All pipelines located in inaccessible places;

 Where gas quality is critical.

Where mechanical joints are used, care shall be taken to ensure that the joints are
correctly assembled using only compatible components. Particular care shall be
taken when components from different manufacturers are being assembled into
the same system. Rigorous cleaning of all sections prior to installation and
subsequent capping of all open ends before and during construction is necessary
to ensure absence of contamination within the finished system.

Failure to properly clean pipework could result in one or more of the following:

 Risk of fire in oxidant gas service;

 Particulate contamination adversely affecting valve seats;

 Shortening of the life of point of use filters and other downstream

equipment;

 Presence of moisture resulting in corrosion within the system;

 Presence of air in systems resulting in oxide build-up within system

components, e.g. silica in systems handling silanes.

Other requirements include a general requirement that the design and location of
pipework shall comply with BCGA CP 4 (56), and in particular:

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BCGA CP18 - Revision 3
  Pipework systems shall be adequately earthed where a static
discharge could ignite flammable substances;

 Pipework shall be adequately supported using materials which will

not give rise to electrolytic corrosion;

 Systems shall comply with the PSSR (9). For additional guidance
refer to HSE L 122 (28) and BCGA CP 23 (57);

 Underground pipework shall be adequately protected against damage,

e.g. by corrosion or by external load.

NOTE: Underground pipelines are not recommended for very toxic,

pyrophoric and corrosive gases because of the difficulties in inspection and
maintenance;

 Ducts or channels carrying pipework shall be well ventilated;

 Pipework shall not be installed in ventilation shafts;

 Pipework shall not be installed in confined spaces where leakage

could give rise to hazards, e.g. Lift shafts, confined roof spaces, etc.;

 Pipework shall be installed such that the possibility of mechanical

damage is minimised;

 Pipework shall be protected from external corrosion and excessive

heat;

 Suitable sleeves shall be used where pipework passes through

building fabric;

 Pipework carrying flammable or toxic gases should be routed outside

buildings, where practicable. Where this is impracticable purged sleeving
should be considered. Piping should be sized (bore and length) so as to
minimise the quantity of flammable or toxic gas in the system.

9.8.2 Pressure Testing

Pressure testing of systems shall comply with the requirements of BCGA CP 4
(56), including certification.

9.8.3 Inspection prior to commissioning

This should be undertaken after pressure testing as required by the design code
and should include:

 The final visual inspection of the total system to ensure

compliance with design and absence of damage;

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BCGA CP18 - Revision 3
  A leak test at 110 % of the maximum operating pressure using an
inert gas and a detection system appropriate to the specified leak rate
acceptance criteria for the process gas concerned.

 Where the test necessitates the removal of vulnerable equipment

(e.g. pressure gauges, relief valves etc.) a final leak test at an appropriate
pressure should be carried out after their reinstatement.

 A record shall be kept of the leak testing carried out.

NOTE: Never attempt to tighten leaking joints in gas supply systems

whilst the gas system is under pressure.

9.8.4 Identification of pipework service

Pipework shall be labelled with its gas service at appropriate points along the
system and at points of access. Care should be taken to ensure that the method of
fixing the labels (e.g. clips, adhesives, etc.) does not damage or corrode the
pipeline.

9.9 Vacuum pumps

9.9.1 Vacuum pumps selection

Vacuum pumps should be selected and installed in conjunction with the pump
manufacturers to ensure:

 Chemical compatibility of components and lubricants with the

process gas;

 Design suitability for the intended application (e.g. flow rate,

containment of hazardous gases, provision of pump case purges, process
gas quality);

 Compatibility with the electrical zone classification of the area in

which the pump will be sited, refer to Section 6.3.

9.9.2 Siting
In the siting of a vacuum pump, provision shall be made for:

 Adequate access for maintenance and checking;

 Catchments for any oil leakage or spillage;

 Collecting oil during oil changes;

 Ventilation, including allowance for any extra hazards such as

process gas absorbed in oil when maintenance work is in hand;

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BCGA CP18 - Revision 3
 9.9.3 Leak testing
Vacuum pumps handling hazardous gases shall be included in the leak testing
inspection carried out on the gas supply system. This shall include leak tests on
the pump itself and on the exhaust from the pump to the safe discharge point.

9.9.4 Gas ballast

Where hazardous gases or gases likely to condense or introduce solids are used a
suitable gas ballast into the vacuum pump should be considered.

Means are required to ensure that the flow of ballast gas is maintained. A clearly
visible flow indication is a minimum requirement, preferably with an alarm or
automatic cut-out if the ballast flow is interrupted. Non-return valves shall be
fitted to all gas ballast feed-lines.

Where corrosive gases are used, the pump and the flow of ballast gas needs to be
operated in such a way that the corrosive environment is removed from the pump.

9.9.5 Exit gas arrangements

The exit pipe from the vacuum pump shall incorporate safety features to cater for
fire, explosion and toxic hazards for all hazardous gases. It shall be designed to:

 Take special account of the requirements resulting from the use of

common exit lines;

 Be free from any leaks which could give rise to an external hazard,
or ingress of air sufficient to give a fire or explosion risk in the system;

 Avoid features such as negative gradients, traps, loops or

corrugations where fluids cannot be drained;

 Incorporate where possible a nitrogen feed into the exit line to

make it possible to fill the whole of the exit line with nitrogen before
admitting process exhaust gas. The anti-suck-back valves commonly
fitted to oil-based vacuum pumps shall not be used when the pump is
used for pyrophoric gases, as these do not prevent air ingress;

 Allow appropriate disposal arrangements where necessary for all

exit gases (refer to Section 10);

 Be constructed from non-combustible materials where flammable

gases are being exhausted.

 Use appropriate diameter of tubing to avoid back pressurisation.

9.9.6 Cold traps

Where cold traps are used in conjunction with vacuum pumps they can present
problems by condensing and hence concentrating hazardous compounds,
including any which may have been formed by the processes involved. There is
also a danger if oxygen from the atmosphere is allowed to enter the system and

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BCGA CP18 - Revision 3
 condense in a trap cooled by liquid nitrogen. Cold traps shall not be used in
conjunction with pyrophoric gases.

When it is necessary to empty a cold trap, provision shall be made for preventing
exposure of personnel to toxic fumes. Some condensed compounds could react
with components of the atmosphere and form other hazardous products. Where
this possibility exists, precautions are needed to avoid access of the atmosphere to
the contents of the trap. Arrangements shall be made for the safe disposal of
hazardous materials from cold traps.

9.10 Special requirements for silane and other pyrophoric gases

NOTE: While this section refers only to silane the principles apply equally to other
pyrophoric gases.

Silane does not always ignite spontaneously when brought into contact with air. It may
mix with the air to form an unstable mixture which may subsequently explode with
considerable force. For additional guidance on silane refer to EIGA Document 160
(52), and USA CGA G-13 (69), Storage and handling of silane and silane mixtures.

Special attention is drawn to the following:

(i) Always store silane at a positive pressure and avoid condensing silane. Air
or other oxidant leaking into systems containing silane could result in explosion
or could react slowly with silane, depositing silica and causing possible failure of
regulators, non-return valves, etc.

(ii) Always ensure air or other oxidant gases are purged out of systems before
introducing silane. If this is not done, an explosion or fire may occur. In addition
silica dust will be produced which may block or cause failure of the pressure and
flow control equipment, including non-return valves. This precaution also applies
to silane vent and disposal systems;

NOTE: Serious incidents, including fatalities, have occurred when silane and
nitrous oxide for example have inadvertently mixed due to component failure.

(iii) Always design and test all systems handling silane to:

 Minimise the risk of leakage;

 Maximise the ease with which they can be efficiently purged;

 Enable easy isolation of the silane supply if a leakage (or other

problem) occurs;

 Eliminate “dead” spaces which may be difficult to clean/purge;

 Minimise internal volume.

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BCGA CP18 - Revision 3
 (iv) Always use non-combustible materials to construct those gas cabinets /
ventilation systems, etc., which may contain silane;

(v) Never enclose silane handling equipment inside unventilated cabinets or

enclosures. Leakage of silane into unventilated spaces could result in explosion
and rupture of the enclosures. (This includes the removal of backplates from
pressure gauges / rotameters, etc.);

(vi) Never allow silane to contact even small amounts of halogens or heavy
metal halides. This includes ensuring all components of the silane handling
system are purged free of halogens that might derive from degreasing agents or
halogenated hydrocarbons.

These precautions shall also be applied to other pyrophoric gases.

9.11 Special requirements for oxygen and other oxidants

NOTE: While this section refers only to oxygen the principles apply equally to
other oxidant gases, some of which have a higher oxidising potential than oxygen. For
example, refer to EIGA Document 92 (48), Code of Practice, Nitrogen Trifluoride.

Oxygen will propagate the combustion of many materials, including the steel and
aluminium alloy components of gas systems, once an ignition has occurred. Ignition
energies required for common flammable materials such as oils, greases and some
plastics, etc., are extremely low in an oxygen-enriched atmosphere.

Examples of circumstances, which have led to ignition of components in oxygen or

oxidant service, are:

 A small particle in a high velocity gas stream.

 Adiabatic compression caused by rapid opening of valves (heat sinks or

slow operating valves can be used to prevent this problem).

Pipework and systems for handling oxygen shall be degreased and free from particulate
contamination. All materials in the system shall be suitable for oxygen service.
Special attention shall be paid to the suitability of sealing materials and plastic
components that may be found in valves, pressure regulators, etc. For details consult
your gas supplier.

Systems for all other oxidants require the precautions given above. In addition, for the
more powerful oxidants (e.g. fluorine and chlorine trifluoride) the system shall be made
passive prior to use with a dilute mixture of the oxidant in accordance with the gas
supplier’s instructions.

Normal explosion-protected electrical apparatus is not to be assumed as being

necessarily suitable for use in oxygen, or other oxidant, enriched atmospheres.
Electrical apparatus for use in these areas shall be given special consideration.

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BCGA CP18 - Revision 3
10. DISPOSAL OF WASTE GASES

10.1 Disposal arrangements

Discharges may be subject to controls under the Environmental Protection Act 1990.
(2) or other environmental legislation in your geographical area. Guidance on
environmental aspects of disposal is given in the Semiconductor Environmental Safety
and Health Association (SESHA) Environmental Code of Practice for the Micro-
electronics Industry (71) and the EIGA Document 30 (45), Disposal of Gases.

All waste gases must be disposed of in a manner which will not endanger people or
harm the environment.

The disposal of waste gases may be considered under two general categories:

10.1.1 Routine
Those waste gases which occur on a regular basis as part of the process. Toxic or
very toxic gases shall not be routinely discharged directly to atmosphere - such
gases shall be treated by appropriate processes.

10.1.2 Non-routine
Those waste gases which may occur infrequently, such as in the event of an
emergency release. Consideration shall be given to the means of treating,
controlling and discharging potential non-routine gas releases so as to ensure
there is no danger to people.

NOTE: Toxic or corrosive compounds can be formed from non-hazardous

gases during processing.

10.2 Discharge to atmosphere

Where waste gases are discharged directly to atmosphere, the principles set out in Table
5 shall be observed.

10.3 Abatement equipment - treatment techniques

The efficacy of all abatement equipment shall be monitored, preferably continuously, to
ensure permitted emission levels are not exceeded. The abatement equipment is likely
to be based on one or more of the following treatment techniques. Choice will be
determined by considerations of safety, the effect on the environment, and the need to
comply with regulations.

10.3.1 Incineration
The waste gas is mixed with air and passed through a separately fuelled burner or
heated chamber, operating at a suitable temperature well in excess of the auto-
ignition temperature of the waste gas so as to ensure complete oxidation.

The properties of the resultant oxidised material, which may be gaseous, liquid or
solid, shall be considered with a view to establishing further treatment required
for its safe disposal. Gaseous waste may require chemical scrubbing. Liquid and
solid wastes may need to be referred to a specialist disposal contractor.

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 Hazardous Principles
Property of Gas

Routine: Discharge via appropriate process equipment.

Monitor efficiency of equipment.

Toxic and Harmful Non-routine: Consider means of treating, controlling and

discharging. If discharged to atmosphere, must
be to a safe place and diluted with air so as to
ensure people are not exposed to levels in excess
of the Workplace Exposure level. Refer to HSE
EH 40 (24).

All disposal operations Avoid risk of explosive gas / air mixtures in

equipment and the workplace. Avoid ignition
sources where there is a risk of unintended
flammable gas ignition.

Flammable gases If discharged directly to atmosphere, must be to a

safe place, away from personnel and air intakes.

The fitment of flash-back arrestors should be

considered. Consider electrical classification of
the area.

Oxygen and All disposal operations Avoid oxidant enrichment of the atmosphere
Oxidants which could enhance fire propagation.

Asphyxiant gases All disposal operations Avoid atmospheric oxygen depletion which
could result in an asphyxiant hazard.

Table 5: Waste gas discharge to atmosphere

10.3.2 Chemical absorption

Reactive gases can be removed from a waste gas stream by a suitable liquid or
solid state chemical scrubber. The design of such equipment is largely dependent
on the reactive gas concentration, flow rate and rate of reaction of the waste gas.
Generally, equipment to remove low flow rates with high concentrations of
reactive gases are simpler and less expensive than equipment designed to handle
high flow rates such as those which air extraction systems may deliver. It is,
therefore, desirable wherever practicable, to treat reactive waste gases before
dilution with air.

The chemical reagents used in all such equipment shall be closely monitored to
ensure efficacy. The spent chemical scrubber material, which may be liquid or
solid or a mixture of both, must be disposed of safely. Such material may need to
be referred to a specialist disposal contractor.

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 10.3.3 Adsorption
Some waste gases can be adsorbed on suitable adsorbent materials such as
charcoal and molecular sieve.

Where adsorption is considered as a means of treating waste gases, the following

must be taken into account:

 Heat may be generated during adsorption;

 Adsorbed gases may be released if the adsorbent material is

heated;

 The adsorbent should be purged with an inert gas before use,

particularly if the waste gas or the adsorbent material is flammable, e.g.
Charcoal;

 There may be a fire risk if the spent adsorbent containing some

gases, e.g. phosphine, is exposed to air. Where such a risk is thought to
exist, special precautions shall be taken to ensure air is excluded by the
use of an inert gas atmosphere during transfer and packing of the spent
adsorbent;

 Personnel handling adsorbent material shall wear adequate

personal protective equipment. Hazards may include dust, toxic fumes
and corrosivity;

 Spent adsorbent material shall be placed in a sealed container and

referred to a specialist disposal contractor;

 Oxidant gases shall not be adsorbed on charcoal.

Further advice on the disposal of waste gases can be found in the EIGA
Document 30 (45).

11. OPERATING PRINCIPLES FOR GAS SUPPLY SYSTEMS

11.1 Key principles

Key principles for gas container connection and disconnection include:

 Provision of appropriate training and supervision;

 Positive identification of the container;

 Provision and use of appropriate personal protective equipment;

 Ensuring the presence of back-up personnel for toxic / pyrophoric gases;

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BCGA CP18 - Revision 3
  Ensuring that sufficient inert purge gas is available;

 Reporting any gas container leakage;

WARNING: Never attempt to tighten leaking joints whilst the pipework system
is under pressure. First depressurise the system (and if appropriate purge with
inert gas) returning it to atmospheric pressure before tightening the joint.

NOTE: For the connection and disconnection of gas containers, the use of a check
list is recommended to ensure procedures are correctly followed, all necessary safety
precautions are taken and all valve outlet plugs / caps, valve protection devices, etc., are
fitted prior to removing from the supply point.

11.2 Connection of the gas container

When connecting a gas container:

(i) Secure the gas container at the supply point before removing the valve
protection device;

(ii) Ensure that the valve is closed and no visual signs of damage are present
before removing the valve outlet plug / cap nut;

(iii) Ensure that the valve outlet and supply point connections are clean and
undamaged before connecting to the supply point;

(iv) Purge and leak test in accordance with the system operating procedure,
before opening the gas container valve.

When the gas container is ready for use open the gas container valve slowly. Check
pressure, flow, etc., to ensure the system is operating in accordance with system
operating procedures. It is recommended practice to check and record these parameters
regularly.

11.3 Disconnection of the gas container

When disconnecting a gas container:

(i) Ensure that the gas container valve is closed.

(ii) Ensure that the system is shut down and purged of hazardous gas, in
accordance with system operating procedure, and re-check that the gas container
valve is closed before disconnection.

(iii) Fit a protective device to the supply point connection to prevent

contamination if the replacement gas container is not being connected
immediately.

(iv) When the gas container is disconnected, leak check the gas container valve
outlet and refit the outlet plug / cap and valve protection device (where supplied).

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 (v) Contact the gas supplier in the case of inability to fit securely the valve
outlet plug / cap or valve protection device; or

 if any leakage is detected; or

 if there is any suspected contamination which may have occurred

during use.

Do not remove from supply point until advised to do so by the gas supplier.

The nominally empty gas container should be moved as soon as practicable to the ‘used
container store’.

NOTE: The container will still contain residual gas and is not to be regarded as
empty.

12. PLANT MAINTENANCE

12.1 General precautions

Planned, regular preventive maintenance of all equipment used to control hazards is
required by the COSHH (11) Regulations. It is, in any case, necessary to ensure that
the continued efficiency and integrity of a gas handling plant is maintained. This
includes supply systems, vacuum systems, disposal systems and ventilation equipment.
The frequency and method of maintenance operations will depend on manufacturer’s
recommendations and user’s experience. Any specific instructions issued by
manufacturers shall be followed. The COSHH (11) Regulations set out specific needs
for checking and maintenance in relation to all control measures, particularly with
ventilation.

Where the installation is a pressure system as defined by the PSSR (9), the
requirements for maintenance and examination given in these regulations shall also be
taken into account.

Maintenance work shall not be attempted unless all the appropriate knowledge, skills,
experience and specialised tools, etc., are available and ‘work permit’ forms have been
issued, refer to Section 12.2.

12.2 Permit to work

A permit to work form shall be used to cover all maintenance work on systems and in
areas where a hazard may exist. Requirements for the issue of a permit to work include
that it shall:

(i) Be issued by the authorised person with direct responsibility for the system
or area to a named person who will be doing or personally supervising the work;

(ii) Certify that the system / area has been made safe for the maintenance work
to proceed and detail how this has been done;

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 (iii) Specify any further tests, precautions, etc., necessary during the valid
period of the work permit;

(iv) Specify personal / protective equipment to be used;

(v) Only be issued for a defined period (normally only one day or shift);

(vi) Detail any necessary restrictions on personnel entering the area;

(vii) Detail or refer to other instructions or checks to be carried out after

completion of maintenance work before handover to normal operating staff;

(viii) Detail or refer to other instructions on the treatment and disposal of waste
materials removed from the system (e.g. contaminated lubricants, system
components);

(ix) Detail any backup arrangements necessary to ensure the safety of

maintenance personnel;

(x) Give details of actions in the event of an emergency;

(xi) Only be varied by the originator, and then it shall be revalidated in

accordance with the above, before re-issue;

(xii) All gas systems shall be made safe before any plant maintenance work
commences. This includes:

 Depressurising the system;

 Purging / testing to ensure all hazardous materials have been removed

from the system and safely disposed of;

 Isolation of gas supplies to the system using a minimum of two

valves or other high integrity means. The isolation valves should be locked
in the closed position and labelled appropriately.

NOTES:
1. A permit-to-work will be specific in its reference to the precautions and
hazards associated with the task to be undertaken. It is also important that the
general hazards of the area are not forgotten.

2. For further guidance on permit to work systems refer to HSE HSG 250
(26), Guidance on permit-to-work systems. A guide for the petroleum, chemical
and allied industries, and EIGA Document 40 (46), Work Permit Systems.

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13 SAFETY

13.1 Fire safety

A Fire Safety Risk Assessment shall be carried out on all storage sites and is to be
incorporated into the Site Fire Safety Management Plan. Each site should keep a record
of the location of its hazardous store(s), this is to be made available to the emergency
services in the event of an incident. Refer to The Regulatory Reform (Fire Safety)
Order (13).

Special gases may require additional precautions to be applied when fighting a fire.
The location of special gases is to be clearly designated and shown on the site plan.
The emergency services are to made aware of the additional hazards which may be
encountered with special gases;

Fire fighting facilities as identified in the risk assessment for the storage facility shall be
provided. Consideration is to be given to the volume and pressure of available water.
Refer to BS 5306 (35), Fire extinguishing installations and equipment on premises.

Adequate means of giving alarm in the event of a fire shall be provided. These should
be clearly marked and suitably located, including at all emergency exit points.

Wherever practicable, the storage infrastructure should be constructed of non-

combustible materials.

All gas storage areas shall be designated as “NO SMOKING” areas. Suitable signs are
to be displayed.

Appropriate emergency procedures shall be drawn up based on the findings of the Fire
Safety Risk Assessment. Refer to Section 13.6 for further information on an emergency
response plan.

To reduce the fire hazard to a minimum the area surrounding the storage site is to be
kept clear. Long grass, weeds and any overhanging branches are to be removed. A
space of 3 m around the storage area is to be kept clear of all vegetation and
combustible material. In addition, the undergrowth is to be kept as short as possible for
a total distance of 9 m around the storage area. Chemicals such as sodium chlorate and
other oxidising agents which may cause a risk of fire shall not be used as a weed killer.

For all stores an appropriate number and type of extinguishers shall be provided and
correctly located. Fire extinguishers should be positioned in a readily accessible
position close to the exits. Additionally, positive pressure breathing apparatus, a water
shower and eye wash bottle may be required, refer to Section 13.2.

13.2 Personal protective equipment

13.2.1 General requirements

Personal Protective Equipment (PPE) is to be provided as required by the
Personal Protective Equipment at Work Regulations (10). PPE may only be
considered as a control to achieve an acceptable level of residual risk after other
levels of control have been addressed. The risk assessment will determine the

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BCGA CP18 - Revision 3
 requirement for the use of PPE. Where PPE is required a PPE Assessment is to
be carried out. Due regard is to be given to the requirements of the COSHH (11)
Regulations, any relevant equipment publications, manufacturers information and
the product Safety Data Sheet. The PPE selected is for a particular task and
location and must be appropriate and chosen to reduce the overall risk effectively.
Thus there are different PPE requirements for differing products and different
tasks.

HSE L25 (27), Personal Protective Equipment at Work, provides guidance on the
Personal Protective Equipment at Work Regulations (10). EIGA Document 136
(51), Selection of personal protective equipment, provides guidance for selecting
and using PPE at work.

PPE shall be provided for the use of all personnel involved in handling gas
containers and operating / maintaining gas handling equipment, supply and
disposal systems.

Requirements for the use of such protective equipment shall be clearly defined in
the operating instructions.

All PPE shall be stored in clearly marked areas which are away from areas likely
to become contaminated. Where appropriate e.g. self-contained breathing
apparatus, equipment should be stored in containers and in the manner
recommended by the supplier.

Adequate spare equipment should be available to replace equipment removed for

maintenance or repair. Any unserviceable equipment should be clearly labelled
and personnel advised of its non-availability.

Recommended PPE is detailed in Table 6.

13.2.2 Maintenance of personal protective equipment

All personal protective equipment shall be inspected regularly against a check
list, to ensure that it is kept in good functional condition, is in the designated
storage area, and is ready for immediate use. Inspections shall be recorded.

Portable Monitors shall be calibrated and checked regularly in accordance with

the manufacturer’s instructions.

Self-contained breathing apparatus shall be regularly cleaned and checked to

ensure correct operation and air container / spare air container(s) are fully
charged. Refer to BS EN 529 (33), Respiratory protective devices.
Recommendations for selection, use, care and maintenance. Guidance document.
Such maintenance should also be carried out each time the equipment is used. If
an in-house air container charging facility is available it shall be regularly
maintained in accordance with the manufacturer’s instructions. Air quality is to
the specification in BS EN 12021 (36), Respiratory protective devices.
Compressed air for breathing apparatus.

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 Activity Recommended PPE
Handling gas containers:  Safety footwear.
 Heavy duty gloves.
 Safety eye / face protection.

Handling gas containers or Flame retardant clothing with flammable, pyrophoric and
operating gas supply systems: oxidising gases.

For prevention of ignition risk:  Anti-static soles on footwear.

 Anti-static clothing.
 Anti-spark tools.

For protection against potential  Portable toxic gas monitor.

gas leakages:  Portable oxygen enrichment/depletion monitor.
 Positive pressure breathing apparatus (only to be used
by persons who are adequately trained and checked as
being medically fit).
 Portable flammable gas monitor.

When handling corrosive  Face shield / goggles.

chemicals:  Chemically-resistant gauntlets.
 Chemically-resistant apron or overalls.
 Chemically- resistant boots.

For emergency use:  Self-contained, positive pressure breathing equipment

(e.g. to BS EN 529 (33) with an adequate supply of
spare air containers.
 Face shield.
 Chemically-resistant gauntlets.
 Complete body protection suit (e.g. for area
contaminated with corrosive gas).
 First aid equipment, including eye wash and shower.
 Fire extinguishing equipment - water hose systems,
carbon dioxide and dry powder.

Table 6: Recommended PPE

13.3 Training
All personnel involved in the handling of gas containers and the operation and
maintenance of gas supply and disposal systems shall be trained to a level appropriate
to their involvement. Training shall be planned, recorded and regularly reviewed and
updated, and shall be undertaken against documented operating and safety procedures.
Trainees shall be checked to ensure they have a full understanding of the topics /
material on which they have been trained and such checks shall be recorded and signed
by both trainer and trainee.

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 Training topics include:

 The requirement for safe working, which is a general duty for all personnel
as set out in the Health and Safety at Work etc. Act (1). Site safety rules and
company safety policy (e.g. when and where protective equipment shall be worn,
designation of no smoking / smoking areas, when a “Permit to Work” is
required);

 Gas container handling;

 Gas container contents identification and hazard identification;

 Gas properties (physical, chemical, hazardous);

 Potential hazards of high pressure containers, equipment and systems;

 Gas container changing and associated purging procedures;

 Gas supply, disposal and associated equipment (physical layout, operation

and maintenance);

 Personal protective equipment (selection, location and use);

 Emergency equipment (location and use);

 Emergency procedures (site evacuation in event of gas leak or fire, plant

shutdown, etc., refer to Section 13.5);

 Maintenance and “Permit to Work” procedures;

 Atmospheric monitoring equipment;

 Safety checks on gas containers on receipt and before return to suppliers.

13.4 Standard operating procedures

Written standard operating procedures with relevant engineering drawings covering all
aspects of safe handling of gases and associated plant and equipment shall be available.
Standard operating procedures shall be prepared by competent personnel, formally
approved and regularly reviewed and updated. A system shall be followed to ensure
that only the latest issued standard operating procedures and drawings are in use and
that new plant or modifications to existing plant are not put into use until standard
operating procedures and drawings have been issued or revised.

13.5 Audits
Regular audits shall be carried out and recorded. Particular requirements to be included
are that:

 All operations are covered by authorised procedures;

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  Latest issue of all drawings, standard operating procedures and relevant
Safety Data Sheets are readily available;

 All standard operating procedures are being followed;

 Unauthorised modifications have not been made to the systems and

procedures;

 All personnel are adequately trained. It is the duty of the employer to

establish competency. All training should be formally recorded. Periodic
retraining is strongly recommended;

 All safety and emergency protective equipment specified is available and in

good condition.

13.6 Emergency response plan

There shall be a published emergency response plan which is periodically practised.
This plan shall take account of all potential hazards and all safety and legal
requirements relating to the gases (and other materials), processes and equipment, etc.
The plan shall have a primary regard to the safety of personnel. In drawing up the plan
reference may be made to EIGA Document 80 (47), Handling gas container
emergencies.

NOTE: This document is primarily intended for gas suppliers.

Key points for consideration when formulating the emergency response plan include
the following:

(i) Alarm systems;

(ii) Plan for site evacuation and roll call;

(iii) Consultation and communication with the emergency services (e.g. Fire &
Rescue Service, ambulance, police, local hospital, gas / other suppliers, etc.);

(iv) Search for unaccounted personnel;

(v) Evacuation of affected personnel via prepared evacuation routes;

(vi) Safe emergency shutdown of equipment and processes;

(vii) Consultation and communication with neighbours;

(viii) Communication with media;

(ix) Procedure for advising personnel that areas are safe for re-entry;

(x) Evaluation of hazards associated with gas escapes;

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 (xi) Site emergency response team including individual’s medical fitness,
responsibilities, means of communication and backup when entering hazardous
area;

(xii) Provision, location, regular checks and personnel training in the use of
emergency equipment (e.g. fire fighting equipment, first aid requisites, breathing
apparatus and special protective clothing);

(xiii) Re-instatement of emergency equipment after use;

(xiv) Provision of site plans showing location of hazardous materials and

emergency equipment;

(xv) Provision of safety data on all hazardous materials;

(xvi) The plan should also cover out-of-normal working hours;

(xvii) Formal training and updating of those involved in the emergency response
team;

(xviii) Response to power failure and power back up requirements.

(xix) After conclusion of emergency prepare report to authorities.

13.7 Hazardous gas monitoring

Monitoring equipment shall be considered where there is a foreseeable risk of a gas
escape causing injury or environmental damage.

The output from the gas detection system can offer two warnings:

(i) Level One: Give an audible / visual alarm to warn personnel to take the
appropriate emergency / corrective action prior to dangerous concentrations being
reached.

(ii) Level Two: Give an audible / visual alarm to warn personnel to shut off
the gas supply or to trigger automatic shut-down procedure.

Records of testing and calibration of the equipment shall be kept.

Where asphyxiation is identified as a potential hazard, consideration shall be given to

the installation and use of oxygen monitoring equipment.

Further information on gas monitoring is provided in the HSE HSG 173 (25),
Monitoring strategies for toxic substances, and the HSE MC series of publications
providing guidance on the COSHH (11) Regulations in the microelectronics industry,
e.g. HSE MC0 (30), COSHH essentials for the microelectronics industry. Advice for
managers.

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14. REFERENCES

Document Number Title

1 Health and Safety at Work etc. Act 1974.

2 Environmental Protection Act 1990.

3 SI 1990 No. 304 The Dangerous Substances (Notification and Marking of

Sites) Regulations 1990.

4 SI 1992: No. 2793 Manual Handling Operations Regulations 1992 (as

amended).

5 SI 1996 No. 192 The Equipment and Protective Systems Intended for Use in
Potentially Explosive Atmospheres Regulations (EPS).

6 SI 1996: No. 341 The Health & Safety (Safety Signs & Signals) Regulations
1996

7 SI 1999: No. 743 Control of Major Accident Hazards Regulations 1999 (as
amended) (COMAH).

8 SI 1999: No. 3242 Management of Health and Safety at Work Regulations

1999.

9 SI 2000: No. 128 Pressure Systems Safety Regulations 2000 (PSSR)

10 SI 2002: No. 1144 Personal Protective Equipment at Work Regulations 2002.

11 SI 2002: No. 2677 Control of Substances Hazardous to Health Regulations

2002 (COSHH).

12 SI 2002: No. 2776 The Dangerous Substances and Explosive Atmospheres

Regulations 2002 (DSEAR).

13 SI 2005: No. 1541 Regulatory Reform (Fire Safety) Order 2005.

14 SI 2009: No. 716 The Chemicals (Hazard Information and Packaging for
Supply) Regulations 2009. (CHIP 4)

15 SI 2009: No. 1348 The Carriage of Dangerous Goods and Use of Transportable
Pressure Equipment Regulations 2009 (as amended).

16 United Nations UN Recommendations on the Transport of Dangerous

ST/SG/AC.10/1 Goods, Model Regulations.

17 United Nations UN Globally Harmonised System of Classification and

ST/SG/AC.10/30 Labelling of Chemicals (GHS)

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BCGA CP18 - Revision 3
 Document Number Title

18 European Union European Agreement concerning the International Carriage

ECE/TRANS/225 of Dangerous Goods by Road (ADR)

19 European Directive European Directive on the classification, packaging and

67/548/EEC labelling of dangerous substances (as amended).

20 European Directive European Directive on the approximation of the laws of

94/9/EC Members States concerning equipment and protective
systems intended for use in potentially explosive
atmospheres. Also known as ‘ATEX 95’ or the ‘ATEX
Equipment Directive’.

21 European Directive European Directive on minimum requirements for

99/92/EC improving the health and safety protection of workers
potentially at risk from explosive atmospheres. Also known
as ‘ATEX 137’ or the ‘ATEX Workplace Directive’.

22 EC Regulation European Regulation on the Classification, Labelling and

No 1272/2008 Packaging of Substances and Mixtures (CLP).

23 EC Regulation Registration, Evaluation, Authorisation and restriction of

No 1907/2006 CHemicals (REACH).

24 HSE Guidance Note Workplace Exposure Limits.

EH 40

25 HSE HSG 173 Monitoring strategies for toxic substances.

26 HSE HSG 250 Guidance on permit-to-work systems. A guide for the

petroleum, chemical and allied industries.

27 HSE L25 Personal Protective Equipment at Work. Personal Protective

Equipment at Work Regulations 2002. Guidance on
regulations.

28 HSE L122 Approved Code of Practice for the Pressure Systems Safety
Regulations. Safety of Pressure Systems.

29 HSE L138 Dangerous substances and explosive atmospheres. DSEAR

2002. Approved Code of Practice and guidance.

30 HSE MC0 COSHH essentials for the microelectronics industry. Advice

for managers.

31 BS 341 Transportable gas container valves.

32 BS 476 Fire tests on building materials and structures.

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 Document Number Title

33 BS EN 529 Respiratory protective devices. Recommendations for

selection, use, care and maintenance. Guidance document.

34 ISO 5145 Cylinder valve outlets for gases and gas mixtures. Selection
and dimensioning.

35 BS 5306 Fire extinguishing installations and equipment on premises.

36 BS EN ISO 7010 Graphical symbols. Safety colours and safety signs.

Registered safety signs.

37 BS 7671 Requirements for electrical installations. IET wiring

regulations.

38 BS EN ISO 10156 Gases and gas mixtures - Determination of fire potential and
oxidizing ability for the selection of cylinder valve outlets.

39 BS ISO 10298 Determination of the toxicity of a gas or gas mixture.

40 BS EN ISO 11114 Gas cylinders. Compatibility of cylinder and valve materials

with gas contents.

41 BS EN 12021 Respiratory protective devices. Compressed air for

breathing apparatus.

42 BS EN 14470 Fire safety storage cabinets.

Part 2 Part 2. Safety cabinets for pressurised gas cylinders.

43 BS EN 60079 Explosive atmospheres. Electrical installations design,

Part 14 selection and erection.

44 BS EN 60529 Specification for degrees of protection provided by

enclosures (IP code).

45 EIGA Document 30 Disposal of gases.

46 EIGA Document 40 Work permit systems.

47 EIGA Document 80 Handling gas container emergencies.

48 EIGA Document 92 Code of Practice, Nitrogen Trifluoride.

49 EIGA Document Principles for the safe handling and distribution of highly
130 toxic gases and mixtures.

50 EIGA Document Potentially explosive atmospheres EU Directive 1999/92/EC.

134

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 Document Number Title

51 EIGA Document Selection of personal protective equipment.

136

52 EIGA Document Code of Practice, Silane.

160

53 EIGA Document Code of Practice, Phosphine.

162

54 EIGA Document Code of Practice, Arsine.

163

55 EIGA Document Classification and labelling guide.

169

56 BCGA Code of Industrial gas manifolds and gas distribution pipework

Practice 4 (excluding acetylene).

57 BCGA Code of Application of the Pressure Systems Safety Regulations

Practice 23 2000 to industrial and medical pressure systems installed at
user premises.

58 BCGA Code of Filling ratios and developed pressures for liquefied and
Practice 35 compressed gases.

59 BCGA Guidance Guidance for the storage of gas cylinders in the workplace.
Note 2

60 BCGA Guidance Safe cylinder handling and the application of the manual
Note 3 handling operations regulations to gas cylinders.

61 BCGA Guidance Reduced oxygen atmospheres. The management of risk

Note 11 associated with reduced oxygen atmospheres resulting from
the use of gases in the workplace.

62 BCGA Guidance Guidance for the carriage of gas cylinders on vehicles.

Note 27

63 BCGA Technical Cylinder identification. Colour coding and labelling

Information Sheet 6 requirements.

64 BCGA Technical The storage of gas cylinders containing corrosive gas at

Information Sheet users’ premises.
16

65 BCGA Technical Model risk assessment for manual handling activities in the
Information Sheet industrial gas industry.
17

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 Document Number Title

66 BCGA Technical Good industry practice for the supply of cylinders containing
Information Sheet corrosive gases.
33

67 BCGA Leaflet 6 Cylinders in fire.

68 Germany Gas cylinder valves for cylinder test pressures up to 300 bar.
DIN 477

69 USA, CGA G-13 Storage and handling of silane and silane mixtures.

70 USA, CGA V-1 Standard for compressed gas cylinder outlet and inlet
connections.

71 SESHA Environmental Code of Practice for the Microelectronics

Industry.

Further information can be obtained from:

UK Legislation www.legislation.gov.uk

Health and Safety Executive www.hse.gov.uk

British Standards Institute (BSI) www.bsigroup.co.uk

European Industrial Gases Association (EIGA) www.eiga.eu

British Compressed Gases Association (BCGA) www.bcga.co.uk

USA – Compressed Gas Association (CGA) www.cganet.com

USA - American National Standards Institute (ANSI) www.ansi.org

Germany - Deutshes Institut fűr Normung e.V. (DIN) - www.din.de

The German Institute for Standardization

Semiconductor Environmental Safety and Health www.seshaonline.org

Association (SESHA)

European Chemicals Agency (ECHA) echa.europa.eu

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 APPENDIX 1
Sheet 1 of 1
BCGA OPINION ON THE USE OF GAS CABINETS

A European standard, BS EN 14470, Part 2 (42), exists for gas cylinder storage cabinets,
though BCGA was not involved in the creation of that standard.

BCGA advice generally is to recommend external (outdoor) storage of gas cylinders in well
secured compounds or cages and piping into buildings where needed. But we acknowledge
that internal storage is sometimes necessary where the above is not suitable / practicable or
does not suit the gas product or process (see below). In that case our recommendation is a
well signed dedicated store room.

The Fire & Rescue Service view is unambiguous. They do not like to encounter gas
cylinders in cabinets at all, regardless of the nature of hazard of the gas, or its potential
contribution to fire load (all gas cylinders, even those containing inert gases will ultimately
rupture if exposed to fire). If the contents are a fuel gas or oxygen then the fire load will be
significantly increased.

Firefighters want to be able to see and apply cooling water to cylinders from a distance in a
fire, but they also want cylinders secured against theft, so external storage in locked cages is
very much their preference.

Whether a cabinet has 30 or 90 minutes fire resistance makes little difference to

Firefighters, since they won't likely know where they are on that timescale in a real fire
scenario. But even with the higher fire rating it is questionable whether such cabinets
would keep cylinders below the 60 °C temperature norm, which guides the maximum
developed pressure most cylinders are designed for.

HOWEVER, we also recognise that in some specialised gas uses, storage in suitable
extraction cabinets may have merit:

a) Where there is a personal safety or process quality consideration, e.g. toxic or

ultra high purity gases are needed, for example in the electronics industry.

b) Where gases / mixtures require to be temperature controlled for process reasons.

In such cases cabinets should only be used for cylinders which are connected and in current
use and not for storage of full inventory or ‘empty’ cylinders awaiting return, both of which
should be held in secure external storage.

Where cylinders are held in cabinets, prominent and fire resistant signage should be visible
on the outside of storage cabinets and on the buildings/rooms which house them and
consideration should be given to notifying the local fire service of the existence and
whereabouts of gas cylinders in buildings.

The placing of cylinders into cabinets and their removal also presents manual handling
risks, for which suitable training should be given. BCGA GN 3 (60) refers.

56
BCGA CP18 - Revision 3
 British Compressed57Gases Association
BCGA CP18 - Revision 3 www.bcga.co.uk