GUIDANCE NOTE 7 THE SAFE USE OF INDIVIDUAL PORTABLE OR MOBILE CYLINDER GAS SUPPLY EQUIPMENT

Transcription

1 GUIDANCE NOTE 7 THE SAFE USE OF INDIVIDUAL PORTABLE OR MOBILE CYLINDER GAS SUPPLY EQUIPMENT REVISION 3: 2013 Incorporating Corrigendum 1 January 2014

2 GUIDANCE NOTE 7 THE SAFE USE OF INDIVIDUAL PORTABLE OR MOBILE CYLINDER GAS SUPPLY EQUIPMENT REVISION 3: 2013 Incorporating Corrigendum 1 January 2014 Copyright 2013 by British Compressed Gases Association. First printed 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: ISSN

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 fiveyearly 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 3. This document replaces BCGA GN 7, Revision 2: It was approved for publication at BCGA Technical Committee 147. This document was first published on 07/11/2013. For comments on this document contact the Association via the website Corrigendum 1 January 2014 incorporates a correction to the text in Section 4.4. and Table 1.

4 CONTENTS Section Page TERMINOLOGY AND DEFINITIONS 1 1. INTRODUCTION 3 2. SCOPE 3 3. SOME PROPERTIES OF THE GASES USED Oxygen Liquefied Petroleum Gases (LPG), propane, butane, etc Acetylene Hydrogen Methane Carbon Dioxide Nitrous Oxide Inert gases, argon, nitrogen, helium etc Gas mixtures 7 4. PRESSURE SYSTEMS REGULATIONS Introduction Provision of information and marking Written Scheme of Examination Maintenance 8 5. SAFETY PRECAUTIONS: EQUIPMENT Pressure regulators Hose assemblies Non-return valves Flashback arrestors Personal Protective Equipment PROVISION OF SAFETY DEVICES Inert gases Oxygen and flammable gases excluding acetylene Acetylene systems SAFETY PRECAUTIONS: WORKING AREA General Confined spaces Oxygen enrichment CYLINDER HANDLING AND STORAGE Cylinder handling Cylinder storage PREPARATION FOR USE Location of cylinders Cylinders Regulators Safety devices 19

5 9.5 Hoses Pressurising the system CLOSING DOWN PROCEDURE EMERGENCY PROCEDURE: CYLINDERS Key actions for dealing with gas cylinders in the event of fire Fire damaged gas cylinders REFERENCES * 22 * Throughout this publication the numbers in brackets refer to references in Section 12. Documents referenced are the edition current at the time of publication, unless otherwise stated.

6 TERMINOLOGY AND DEFINITIONS The following describes the functions of the main items of equipment and explains the meaning of the significant items in this Guidance Note. The references quoted in Section 12 should be consulted for more detailed and precise information. Excess flow cut-off valve Flow meter Flashback arrestor Hose assemblies May Multifunctional safety device A device which closes in the event of flow exceeding a predetermined value. A device for measuring gas flow by volume or mass per unit time. A device which arrests a flame front (caused by flashback or decomposition) and which is suitable for the most severe type of flame, which may occur, i.e. detonation. It shall be effective in stopping a flame coming from either one or both directions depending upon the application and design. They shall conform to BS EN 730 (20) or ISO 5175 (25). The means by which the gases are conveyed from the pressure regulator to the process equipment. Hose assemblies can be used to convey the gas from the cylinder to the process equipment at pressures up to the maximum regulator outlet pressure. Indicates an option available to the user of this Code of Practice. A unit, which embodies two or more of the safety devices as defined in these items. 1. Flashback arrestor 2. Non-return valve 3. Pressure relief valve 4. Pressure sensitive cut-off valve 5. Temperature sensitive cut-off valve 6. Excess flow cut-off valve Non-return valve Pressure Pressure gauge Pressure regulator A self-actuating valve which prevents the passage of gas in the opposite direction to the normal gas flow. Pressures referred to in this document are gauge pressures except where otherwise stated. An instrument for indicating, by pointer and scale, the amount by which the pressure applied to it differs from that of the surrounding atmosphere. Fitted to the outlet of the gas cylinder valve, the pressure regulator reduces the pressure of the gas from the cylinder pressure to the lower pressure required for the operation of the process equipment. Regulators may be designed to be adjustable in respect of outlet pressure or may be pre-set. For working pressures up to 20 bar they shall conform to BS 1

7 EN ISO 2503 (23) or BS EN ISO 7291 (26). Regulators outside the scope of these standards shall conform to the essential safety requirements of these standards. Pressure reduction within the regulator may be in 1 or 2 stages (single or two stage regulators). Pressure regulators may be supplied with a pressure gauge or indicator to show the cylinder contents and a pressure gauge or flowmeter to indicate the outlet pressure or flow. Pressure relief valve Pressure sensitive cutoff valve A valve, which automatically vents gas to the atmosphere in order to prevent a build-up of pressure in a system when the pressure exceeds a predetermined value. The pressure-relief valve automatically re-seats when the conditions causing the over-pressure are corrected. A valve which automatically stops the gas flow in the event of a slow or sudden back-pressure from the downstream side of the cut-off valve. The valve remains closed until manually reset. Safety device A device which, when correctly used and placed, prevents any damage or injury from misuse or malfunction of the process equipment. The various devices shall conform to BS EN 730 (20) or ISO 5175 (25) as appropriate. Shall Should Temperature sensitive cutoff valve VIPR (Valve with integrated pressure regulator) Indicates a mandatory requirement for compliance with this Code of Practice. Indicates a preferred requirement but is not mandatory for compliance with this Code of Practice. A valve which automatically stops the gas supply when a predetermined temperature is reached. Special cylinder valves known as VIPR s which incorporate a pressure regulator. Manufactured in accordance with BS EN ISO (29). 2

8 GUIDANCE NOTE 7 THE SAFE USE OF INDIVIDUAL PORTABLE OR MOBILE CYLINDER GAS SUPPLY EQUIPMENT 1. INTRODUCTION This Guidance Note has been prepared by the British Compressed Gases Association (BCGA) to provide guidance on the safe use of individual cylinder gas supplies, the gas being controlled by a single cylinder mounted regulator. The Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) (9) put obligations on site operators where oxidising or flammable gases are used or stored. This document explains these obligations in detail and presents model risk assessments, such as BCGA Guidance Note (GN) 13 (37), DSEAR Risk Assessment, for typical installations within the scope of DSEAR (9). It should therefore be of direct interest to any organisation that manufactures, uses, stores or distributes flammable or oxidant gases. BCGA gratefully acknowledges the comments and assistance provided by the Health and Safety Executive (HSE) in the preparation of this Guidance Note. 2. SCOPE This Guidance Note gives a guide to minimum safety standards required for the use, inspection and maintenance of individual portable or mobile cylinder gas supply equipment, the gas being controlled by a single cylinder mounted regulator, which is used to deliver industrial, fuel and air gases to downstream equipment. This guide covers any industry or process where single cylinders or bundles are in use, such as industry, laboratories, schools, universities and colleges, etc. The gases covered include argon, nitrogen, helium, oxygen, hydrogen, nitrous oxide, acetylene, Liquefied Petroleum Gas (LPG), methane, carbon dioxide and mixtures of these gases. Toxic, corrosive and medical gases are not included. The Guidance Note only covers the gas delivery equipment and reference should be made to the literature from the suppliers of the process equipment. It does not apply to permanently piped gas distribution systems, which are covered in BCGA Code of Practice (CP) 4 (30), Industrial gas cylinder manifolds and distribution pipework (excluding acetylene), BCGA CP 6 (31), The safe distribution of acetylene in the pressure range bar (0 22 lbf/in 2 ), and BCGA CP 18 (33), The safe storage, handling and use of special gases in the microelectronics and other industries, for special gases. Oxy-fuel gas systems are covered in BCGA CP 7 (32), The safe use of oxy-fuel gas equipment (individual portable or mobile cylinder supply). The safety standards laid down are the minimum for safe working practice and the importance of the skill and competence of operators, supervisors and managerial staff is stressed. Operators using equipment covered by this Guidance Note shall be trained in the correct 3

9 procedures for the safe use of the equipment and the emergency procedures to be carried out in the event of an incident. Such training should be both practical and theoretical. It should incorporate competency assessment and be formally recorded. Periodic retraining is recommended. 3. SOME PROPERTIES OF THE GASES USED It is a legal requirement that the gas supplier provides a Safety Data Sheet to the customer whenever a product is supplied for the first time, in accordance with the Chemicals (Hazard Information and Packaging for Supply) Regulations (CHIP) (11). The exact requirements for Safety Data Sheets are now included in the Registration, Evaluation, Authorisation and restriction of CHemicals (REACH) Regulations (14), Article 31, Requirements for Safety Data Sheets. Safety Data Sheets can be obtained for all gases and are to be available for the user of the gas. NOTE: The CHIP (11) Regulations brings national legislation into line with the transitional arrangements set out in European Regulation (EC) No 1272/2008 (13) on the Classification, Labelling and Packaging of Substances and Mixtures (CLP). The CLP (13) Regulation entered into force across all EU member states, including the UK, on 20 January The CLP (13) Regulation has applied to substances that are placed on the market since 1 December It is not mandatory to use the CLP (13) classification system to classify chemical mixtures (preparations) until 1 June The CHIP (11) Regulations will be repealed from 1 June 2015, from when suppliers must comply with the CLP (13) Regulation. Refer to BCGA Technical Information Sheet 22 (42), BCGA policy on connecting gas cylinders, when connecting gas cylinders. NOTE: All gases, except oxygen and air, are potentially asphyxiating, i.e. can suffocate. Use in confined spaces is potentially hazardous. See Section 7.2. WARNING: It is never safe to search for gas leaks with a naked flame. 3.1 Oxygen (i) Vigorously supports combustion. Many materials which will not normally burn in air will readily burn in an oxygen-rich atmosphere. May react violently as an oxidant e.g. with oils, greases, some solvents and some metals. (iii) Colourless. (iv) Odourless. (v) Non-toxic, non-flammable. 3.2 Liquefied Petroleum Gas (LPG), propane, butane, etc (i) Usually odorised to give characteristic smell. Colourless (iii) Flammable and will ignite from a spark or by contact with hot metal. 4

10 (iv) A concentration of as little as 2 % of commercial LPG in air will burn. (v) Non-toxic, but asphyxiating by depletion of oxygen. (vi) Is a fire and explosion hazard. (vii) Heavier than air and will collect in pits, drains or trenches. 3.3 Acetylene (i) Naturally colourless. Non-toxic, but asphyxiating by depletion of oxygen. (iii) Flammable and will ignite from a spark or by contact with hot metal. (iv) Concentrations from 2.5 % to 81 % in air will burn. (v) Is a fire and explosion hazard. (vi) Garlic like odour. (vii) Has a distinct fire property which requires special precaution. The heat of a fire may initiate decomposition. This is an exothermic (heat creating reaction) and the risk is that, if not properly dealt with, acetylene cylinders can reheat and even explode some hours after the fire is extinguished. (viii) Lighter than air (will collect in roof spaces, etc). 3.4 Hydrogen (i) Naturally colourless. Non-toxic. (iii) Much lighter than air. May concentrate in roof spaces. (iv) Burns with a very pale blue flame, often difficult to see. (v) Do not carry out any valve clearance procedure by releasing gas. Refer to BCGA Technical Information Sheet 22 (42), BCGA policy on connecting gas cylinders. (vi) Naturally odourless. (vii) Asphyxiating by depletion of oxygen. (viii) Concentration from 4 % to 75 % of hydrogen in air will burn. (ix) Extremely flammable and easily ignited. It will ignite from a spark or by contact with hot metal. (x) Is a fire and explosion hazard. 5

11 3.5 Methane (i) Colourless Lighter than air - May concentrate in roof spaces. (iii) Flammable and will ignite from a spark or by contact with hot metal. (iv) A small concentration in air can burn. (v) Naturally odourless. (vi) Non-toxic, but asphyxiating by depletion of oxygen. (vii) Is a fire and explosion hazard. 3.6 Carbon dioxide (i) Colourless. Heavier than air, so can collect in pits, drains or trenches. (iii) Toxic, with a Workplace Exposure Limit of 5000 ppm (8 hour time weighted average). Refer to HSE EH 40 (17), Workplace Exposure Limits. NOTE: Effects of exposure to substances hazardous to health vary considerably depending on the nature of the substance and the pattern of exposure. Some effects require prolonged or accumulated exposure. The long-term (8-hour time weighted average) exposure limit is intended to control such effects by restricting the total intake by inhalation over one or more work-shifts, depending on the length of the shift. Any exposure to substances hazardous to health should be calculated according to the approved method in HSE EH 40 (17). (iv) Slightly pungent odour at high concentrations. 3.7 Nitrous oxide (i) Colourless. Heavier than air, so can collect in pits, drains or trenches. (iii) Non-toxic, but has a narcotic effect when breathed in high concentrations. It therefore has been allocated a Workplace Exposure Limit of 100 ppm (8 hour time weighted average). Refer to HSE EH 40 (17). (iv) Odourless. (v) Vigorously supports combustion. (vi) May react as an oxidant e.g. with oils, greases and some solvents. 3.8 Inert gases, argon, nitrogen, helium, etc. (i) Chemically non-reactive in most situations. Non-toxic, but asphyxiating by depletion of oxygen. 6

12 (iii) Colourless. (iv) Can be either lighter (e.g. helium) or heavier (e.g. argon) than air, so can collect in pits, drains, trenches or roof spaces. (v) Odourless. 3.9 Gas mixtures These must be treated as if they exhibit the properties of all the component gases, unless their hazard classification demonstrates otherwise. 4. PRESSURE SYSTEMS REGULATIONS 4.1 Introduction It should be noted that the overall intention of the Pressure Systems Safety Regulations (PSSR) (6) is to prevent the risk of injury from the uncontrolled release of stored energy as a result of the failure of a pressure system, or part of a pressure system. Compliance requires that equipment covered by this Guidance Note be properly maintained (see Section 4.4). The HSE has advised owners and users of portable gas (oxy-acetylene or oxy-propane) welding and cutting sets that a Written Schemes of Examination, as described in the PSSR (6) Regulation 8, is not required. However, it is emphasised that such equipment can present a risk of fire or explosion if not assembled, operated and maintained correctly. In the case of other equipment covered by this Guidance Note, the need for a Written Scheme of Examination must be formally assessed in accordance with the PSSR (6) Regulation 8. Many systems will consist only of a cylinder regulator, with a flexible hose feeding the output of the regulator to the process equipment. In such cases, where assessment of the potential risk results in a recognition that injury could result from a failure of the system, then a Written Scheme of Examination is required to be drawn up. Such a Scheme could be based, for example, on Table 1, provided it included information about the nature and frequency of the required examination of all protective devices and parts of the system where a defect would give rise to danger (less the checks listed as Each time the equipment is used, which are part of routine maintenance.) Once a suitable Scheme has been drawn up, it must be formally approved by the Competent Person. The Competent Person, as defined in the PSSR (6), may be, for example, an inspection body appointed by the user s insurers, or any other suitably qualified person. When a Written Scheme of Examination is implemented for the equipment, written records must be maintained by the User covering the Scheme itself and the records of examinations carried out by the Competent Person under the Scheme. NOTE: The equipment within the scope of this Guidance Note is covered by the PSSR (6). However, cylinders are within the scope of the Carriage of Dangerous Goods and Use of Transportable Pressure Equipment Regulations (12). These refer to the controls on cylinders (or Transportable Pressure Receptacles) they are the responsibility of the supplier and filler of the cylinders and, as such, are not addressed in 7

13 this Guidance Note. If the user has any question over the application of the Regulations to any cylinder, it should be referred to the owner of that cylinder. 4.2 Provision of information and marking The supplier or employer of a person who puts into service, modifies or repairs a mobile system, or components of it, shall provide sufficient information to enable the user of a pressure system to determine how to operate and maintain it safely. Such information for equipment for use with individual portable or mobile cylinder supply may include the following: (i) Safe operating limits for pressure and temperature. Operating and maintenance instructions. The above information may be included in the operating instructions supplied to the user, or marked on the equipment. 4.3 Written Scheme of Examination Written Schemes of Examination may be required for equipment covered by the scope of this Guidance Note in certain circumstances, see Section Maintenance Maintenance of equipment is a requirement of the PSSR (6) where failure to maintain could give rise to danger. It is the responsibility of the user to ensure that this is carried out (Regulation 12). Under the Health and Safety at Work etc. Act (1), as well as the Provision and Use of Work Equipment Regulations (4) there are requirements for the maintenance of equipment to ensure safety. In the case of cylinders fitted with a VIPR (valve with integral pressure regulator) the responsibility for the routine replacement lies with the owner, typically the gas supplier. It is essential that routine maintenance, as detailed in Table 1, taking into account manufacturers / suppliers recommendations, is carried out before use by the operator and at least annually. Annual maintenance shall be carried out by a person who has been formally trained to demonstrate that he has: (i) sufficient practical experience of related gas equipment, and theoretical knowledge of the functioning of the equipment, the properties of gases used, the potential defects and hazards which may occur and their importance to the integrity and safety of the equipment. It is the duty of the employer to ensure persons undertaking maintenance activities are adequately trained and to establish competency. All training should be formally recorded. Periodic retraining is strongly recommended. 8

14 TABLE 1: GUIDANCE ON MAINTENANCE EQUIPMENT MAINTENANCE EACH TIME THE EQUIPMENT IS CONNECTED TOGETHER As per the manufacturer s instructions, and to include Carry out a visual examination to determine suitability for service (e.g. gas, pressure rating, damage), oil or grease contamination. EACH TIME THE EQUIPMENT IS USED (by the operator). Carry out a visual examination to determine suitability for service (e.g. gas, pressure rating, damage), oil or grease contamination. ANNUAL ** (This inspection may be more frequent dependant on conditions of use) To include, as per instructions for Each Time the Equipment is Connected Together, plus: REPLACEMENT / REFURBISHMENT INTERVALS (May be more frequent dependant on conditions of use) REPLACEMENT / REFURBISHMENT GUIDELINE 1. REGULATORS and their integral protective devices Check condition of threads and sealing surfaces, oil or grease contamination. Leak test all joints at working pressure. Check that gauges on regulator zeroes correctly and rises smoothly when gas is turned on. Leak test all joints at working pressure. Check that gauges on regulator zeroes correctly and rises smoothly when gas is turned on. Functional tests to ensure correct operation. Typically this will include a creep test to ensure regulator integrity. 5 years from date of manufacture or manufacturer s recommendations. * NOTE: If regulators are refurbished this shall be in accordance with BCGA TIS 19 (41) Replace with a new, or service exchange unit. 2. FLASHBACK ARRESTORS and their integral cut off valves. Check condition of threads and sealing surfaces, oil or grease contamination. Leak test all joints at working pressure. Leak test all joints at working pressure. Check unit for flow restriction. Reverse flow to ensure correct operation of non-return valves. Where pressure sensitive cut off valves are fitted, they must operate at a pressure of no greater than 1.2 bar. If of a pressure sensitive type, check shut off in the tripped condition in the direction of flow. 5 years from date of manufacture or manufacturer s recommendations. * Replace with a new, or service exchange unit. 9

15 3. HOSE ASSEMBLIES (including NON- RETURN VALVES) Check threads and sealing surfaces. Check hoses for condition of cover (e.g. kinking twisting or cracking). Leak test of all joints at working pressure. Check hoses for condition of cover (e.g. kinking twisting or cracking). Leak test of all joints at working pressure. Reverse hose to ensure the correct operation of nonreturn valve where fitted. Bend hose in a tight radius to ensure reinforcement is not visible and there is no sign of collapse or distortion. Determined by local operating conditions. Replace as required. 4. BLOWPIPES Check condition of the nozzle and inlet seatings for damage. Leak test all joints at working pressure. Check condition of the nozzle and inlet seatings for damage. Leak test all joints at working pressure. Test valve functions. Blank exits and leak test for internal malfunction. Determined by local operating conditions. Replace with a new, or service exchange unit. 5. VIPR (Valve with Integrated Pressure Regulator) Check condition of threads and sealing surfaces, oil or grease contamination. Leak test all joints at working pressure. Check that pressure gauge on regulator zeroes correctly and rises smoothly when gas is turned on. Leak test all joints at working pressure. Check that pressure gauge on regulator zeroes correctly and rises smoothly when gas is turned on. Functional tests to ensure correct operation. Typically this will include a creep test to ensure regulator integrity. This is the responsibility of the owner, typically the gas supplier. This is the responsibility of the owner, typically the gas supplier. * Regulator and flashback arrestor elastomers and seals will wear and deteriorate from their date of manufacture whether in gas service or not. Items stored out of gas service for 1 year or over should receive inspection as per the annual maintenance inspection. The owner / user is required to identify the date when equipment is due for inspection / maintenance. Refer to BCGA TIS 18 (40), Gas equipment inspection / replacement date marking. ** This should be carried out by a suitably trained person. Such training will include the following topics: Sufficient practical experience of oxy-fuel gas equipment, and theoretical knowledge of the functioning of the equipment, the properties of gases used, the potential defects and hazards which may occur and their importance to the integrity and safety of the equipment. It is the duty of the employer to ensure persons undertaking maintenance activities are adequately trained and to establish competency. All training should be formally recorded. Periodic retraining is strongly recommended. 10

16 5. SAFETY PRECAUTIONS: EQUIPMENT Managers, supervisors and operators should note suppliers instructions for the correct and safe use of all equipment and materials used in the processes. They should give consideration to the hazards which may be associated with the place of work, in accordance with the Management of Health and Safety at Work Regulations (5). They should make use of the additional references given in Section 12, in accordance with the nature of the work and responsibility. Equipment should conform to appropriate Standards, including those listed in Section 12. An essential requirement of the material from which such equipment is manufactured is compatibility with the gas content. Reference should be made to appropriate standards, for example: BS EN ISO (27). Transportable gas cylinders. Compatibility of cylinder & valve materials with gas contents. Part 1, Metallic materials. Part 2, Non-metallic materials. 5.1 Pressure regulators Pressure regulators should be treated as precision instruments and should not be jarred or knocked. They should not be stressed by rapid opening of the cylinder valve (this is also important to prevent ignition in oxygen systems from adiabatic compression of the gas). Whether they are in store or in use, inlet and outlet connections must be kept free of dust or other debris, any form of oil, grease or solvents. Contaminated units shall not be used and shall be removed from service. A regulator shall not be used with any gas other than that for which it is designed and labelled. It shall be suitable for the maximum cylinder pressure being used and shall be marked with the maximum inlet pressure and delivery pressure. All regulators up to 20 bar working pressure shall conform to: BS EN ISO 2503 (23), Gas welding equipment. Pressure regulators and pressure regulators with flow-metering devices for gas cylinders used in welding, cutting and allied processes up to 300 bar (30 MPa); or BS EN ISO 7291 (26), Gas welding equipment. Pressure regulators for manifold systems used in welding, cutting and allied processes up to 30 MPa (300 bar). These standards state that pressure-adjusting screws shall be captive to prevent interchangeability between regulators. In the case of VIPR s they should conform to BS EN ISO (29), Gas cylinders. Cylinder valves with integrated pressure regulators. Specification and type testing. For regulators with greater than 20 bar working pressure it is recommended that the following is clearly and permanently marked on the pressure-regulator body or cover: 11

17 (i) (iii) (iv) Gas service. Maximum inlet pressure. Maximum outlet pressure. The name or trademark of the manufacturer and / or distributor. Regulators for industrial use shall not be CE marked in accordance with the European Directives. The regulator pressure adjusting screw shall be set to the zero pressure position when the regulator is not in use by turning the control knob fully anti-clockwise. Damaged regulator pressure gauges, inlet or outlet connections, or threads, shall not be used. 5.2 Hose assemblies Hoses shall be compatible with the gas and pressure to be used. Hoses are colour coded or marked with the gas name to prevent inadvertent use of the wrong hose. Hose assemblies are fitted with left-hand threads for fuel gases and right-hand threads for oxygen and inert gases. Refer to Table 2. Hoses and hose assemblies shall conform to the following standards: (i) BS EN 1327 (22), Gas welding equipment. Thermoplastic hoses for welding and allied processes. BS EN ISO 3821 (24), Gas welding equipment. Rubber hoses for welding, cutting and allied processes. (iii) BS EN ISO (28), Gas welding equipment. Rubber and plastics hose and hose assemblies for use with industrial gases up to 450 bar (45 MPa). (iv) Hoses to BS EN ISO 3821 (24) shall be assembled and tested in accordance with BS EN 1256 (21), Gas welding equipment. Specification for hose assemblies for equipment for welding, cutting and allied processes. (v) Hose connections shall conform to BS EN 560 (18), Gas welding equipment. Hose connections for equipment for welding, cutting and allied processes. (vi) Quick action couplings shall conform to BS EN 561 (19), Gas welding equipment. Quick-action coupling with shut-off valves for welding, cutting and allied processes. The condition of the hose is of vital importance to safety. Correct hose connections, properly fitted and tested and retained by suitable clips or ferrules, are also essential. Reusable worm-drive clamps shall not be used. Hoses shall be protected from heat, mechanical damage, sparks, oil or grease. They should not be longer than is necessary. It is recommended that where long lengths of hose are used, a permanent, piped system, in accordance with BCGA CP 4 (30) or BCGA CP 6 (31), should be considered. Since a 12

18 fire in a coiled hose is difficult to extinguish, oxygen or fuel gas hoses should not be coiled around the cylinders, regulators or cylinder trolley during operation. Gas Hose colour Thread Oxygen Blue Right hand Mixed gas (Oxygen and inert) Blue Right hand Inert gases (Compressed air, nitrogen, argon and carbon dioxide) Black Right hand Inert gas mixtures Black Right hand LPG, methane, natural gas and MPS Acetylene, hydrogen 2 and other fuel gases (excludes LPG, methane, natural gas & MPS) Orange Red Left hand Left hand Mixed gas (flammable and inert) Red Left hand Universal fuel gases (included in Red / orange Left hand this table) except fluxed fuel gases 1 Fluxed fuel gases 1 Red - Flux Left hand NOTES: 1. Universal fuel gas hoses (colour coded red /orange) are not to be used for fluxed fuel gas hoses. 2. The manufacturer shall be consulted on the suitability of the hose for use with hydrogen. Table 2: Hose assemblies colours and threads. If using more than one gas for your application and especially if one is a fuel gas, do not tape hoses together. Tape can cover damage to the hose outer layer. To reduce trip hazards hoses can be joined together by hose clips (plastic or metal) specifically designed for that purpose. Siamese hose can be used provided that the hose and the assembly conform to the required ISO standards. It is important to remember that failure in one hose can lead to failure in the other and lead to a potentially more dangerous situation. Always discard hoses when worn. Hose connections with non-standard threads shall be tested in accordance with BS EN 1256 (21) or BS EN ISO (28). As an alternative to hoses, small bore metallic tubing may be used for the same purpose. 13

19 5.3 Non-return valve These shall conform to BS EN 730 (20), Gas Welding Equipment. Safety devices, or ISO 5175 (25), Equipment used in gas welding, cutting & allied processes. Safety devices for fuel gases and oxygen or compressed air. General specifications, requirements and tests, and be capable of preventing back-flow of gases at low and high pressures. Nonreturn valves may be damaged by flashbacks and require periodic testing to ensure that they will not allow reverse flow. 5.4 Flashback arrestors Flash back arrestors shall be used in conjunction with acetylene and are advisable with other fuel gases. 5.5 Personal Protective Equipment Personal Protective Equipment (PPE) is to be provided as required by the Personal Protective Equipment at Work Regulations (7). 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. Due regard is to be given to the requirements of the Control of Substances Hazardous to Health (COSHH) Regulations (8), 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. Eye protection is essential at all times and is a legal requirement in factory premises to provide safeguard against heat, glare and flying sparks. Safety glasses should be used when connecting or disconnecting gas cylinders. In certain locations, or site conditions, other additional protective clothing may be obligatory, e.g. hard hats or ear defenders, plus breathing apparatus. For cylinder handling the use of protective gloves is essential. Safety shoes or boots with metatarsal protection are strongly recommended. 6. PROVISION OF SAFETY DEVICES The following safety provisions shall be followed: 6.1 Inert gases Inert gases, or mixtures of inert gases, do not require non-return valves or flashback arrestors fitted in the system. Where more than one gas is used simultaneously the use of non-return valves should be considered. 6.2 Oxygen and flammable gases excluding acetylene Where oxygen or flammable gases are used in a process as individual gases, the use of non-return valves or flashback arrestors is optional. Where oxygen is used in conjunction with a flammable gas refer to BCGA CP 7 (32). 14

20 6.3 Acetylene systems Flash back arrestors shall be used in conjunction with acetylene and are advisable with other fuel gases. BCGA CP 6 (31) and / or BCGA CP 7 (32) should be consulted. 7. SAFETY PRECAUTIONS: WORKING AREA 7.1 General Risk assessments should be carried out in accordance with the Management of Health and Safety at Work Regulations (5). Some specific guidance is however given as follows. Where fuel gases are used the areas should be kept free of flammable and combustible materials. Fire extinguishing equipment should be provided and made readily available as per the fire risk assessment carried out in compliance with The Regulatory Reform (Fire Safety) Order (10). There are hazards from fumes in some applications, e.g. silver brazing, work on painted or galvanised metals, etc. Staff at all levels need to be aware of the potential hazards. It will be necessary to assess the actual risk in order to comply with the COSHH Regulations (8). Additional advice is detailed in BCGA TIS 24 (43), Welding fumes. Safety alert. Where noise is excessive ear protectors may be required. 7.2 Confined spaces Working in confined spaces is subject to the Confined Spaces Regulations (3). HSE Leaflet 101 (15) ACOP Safe work in confined spaces, provides detailed recommendations which should be followed whenever applicable. Refer also to HSE INDG 258 (16), Confined spaces. A brief guide to working safely. In particular the use of a Permit to Work, which may require a test of the atmosphere for safety and / or continuous monitoring, is strongly recommended. Oxygen shall not be used to freshen the air in a confined space as this will result in enrichment of the atmosphere, presenting increased fire hazard. Gas cylinders should not be taken into a confined space. Equipment shall not be left in a confined space after the actual work has been completed, or at times when work has ceased for more than a few minutes, to prevent the build up of gases from leaks. Oxygen-deficient atmospheres are very difficult to identify. Danger areas may be highly localised as, for instance, the bottom of a tank where heavier gases, such as process combustion products, have collected. The operator, not aware of the hazard, may become asphyxiated. When carrying out work in a confined space, it is essential to have an assistant stationed outside who understands the equipment and can monitor the safe progress of the work. The assistant must comprehend the possible hazards associated with working in confined spaces and know the correct emergency actions required. This subject is covered in greater depth in BCGA Guidance Note 11 (36), Reduced oxygen atmospheres. The management of risk associated with reduced oxygen 15

21 atmospheres resulting from the use of gases in the workplace, which includes methods of calculating the level of hazard. 7.3 Oxygen enrichment The normal oxygen content of the air is 21 %. If this becomes enriched to 23.5 % there is an increase in the speed with which materials will burn. At 30 % enrichment, the typical characteristics of an oxygen-fed fire become apparent. Fire will spread rapidly across combustible materials such as clothing and body hair and is extremely difficult to extinguish. Such fires could result in death or serious injury. A spark or lit cigarette is sufficient as a source of ignition. Oils, greases and some solvents may react violently in oxygen enriched atmospheres and some metals may also burn. Equipment cleanliness is essential and, to avoid possible contamination, clothing, tools and the working area should be kept clean. Oxygen levels greater than 23.5 % are deemed unsafe in which to work. 8. CYLINDER HANDLING AND STORAGE It is essential that proper training and instruction is given to all staff who are involved in cylinder handling and storage. Many accidents are caused by cylinder mishandling and unsafe storage. The destructive potential arising from the uncontrolled release of gas from a high pressure cylinder can be considerable. BCGA TIS 15 (38), Model risk assessment for the storage and use of oxyacetylene cylinders, can be used to assist in developing a site risk assessment. 8.1 Cylinder handling The Manual Handling Operations Regulations (2) require first 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 (35) 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 (2) relating to gas cylinders. BCGA TIS 17 (39), Model risk assessment for manual handling activities in the industrial gas industry, can be used to assist in developing a site risk assessment. The following points are of note: (i) Purpose designed trolleys should be used for moving cylinders wherever practicable. Do not lift cylinders by using the valve protection device unless they have been designed for that purpose. Do not use ropes, chains or slings to suspend cylinders unless the supplier has installed appropriate lifting attachments such as lugs. Suitable cradles, platforms or pallets to hold the cylinders may be used for lifting. Refer to EIGA SI 25 (46), Crane transport of cylinder packages. 16

22 (iii) For moving over even floors and only for short distances the familiar churning method may be used. Gloves and foot protection shall be used. (iv) Cylinders shall not be rolled along the ground since this may damage or even open the valve and will also damage identifying marks and symbols. (v) Cylinders shall not be moved with the valve open. (vi) Cylinders shall not be transported with the regulators and hoses attached, unless on a purpose designed trolley or carrier. (vii) Cylinders shall not be used as work-supports or rollers. 8.2 Cylinder storage BCGA Guidance Note 2 (34), Guidance for the storage of gas cylinders in the workplace, defines the principles of safe practice for the storage of gases in cylinders and cylinder bundles. UKLPG provide additional information on the storage of LPG cylinders, refer to UKLPG CP 7 (45), Storage of full and empty LPG cylinders and cartridges. The following points are of note: (i) (i) Always store cylinders in a secure location, in a vertical position, properly restrained to avoid them falling over. Always store cylinders in an area with good ventilation. Always store cylinders away from sources of ignition or combustible material. Cylinders shall not be exposed to heat. Take care to prevent the heating of cylinders from the process or any other external heat source. (iii) Cylinder valves on empty cylinders shall be closed to prevent the ingress of moisture or other contaminants. 9. PREPARATION FOR USE 9.1 Location of cylinders It is essential to locate the cylinders in a safe place relative to the work about to be carried out. Cylinders shall be restrained to avoid toppling and be protected from mechanical damage. The number of cylinders in a workroom should be kept to a minimum. 9.2 Cylinders The primary method for identifying the gas contents of a cylinder is the label. If the label is defaced or missing the cylinder is not to be used and is to be returned to the gas supplier. Prior to use check the cylinder label and confirm that it is the gas you require. If you are unfamiliar with the hazards and properties of the gas read and follow the guidance on the safety data sheet. If required, seek further advice from your gas supplier. 17

23 Should there be any visible trace of oil or grease on an oxygen cylinder valve, the cylinder shall be put aside for return to the supplier. Contaminated cylinders shall be suitably marked to prevent accidental re-issue. Before assembling regulators and fittings ensure that the cylinder valve outlet is clean, dry, and free from damage and dirt. For further guidance contact your gas supplier and refer to BCGA TIS 22 (42). 9.3 Regulators Before attaching a regulator to a cylinder, check: (i) The regulator is within its expiry date. All regulators have a life, on expiry of which they require either replacement or refurbishment. See Table 1. That the gas inside the cylinder is correctly identified and that the regulator is suitable for that specific gas; (iii) The maximum cylinder pressure; (iv) That the regulator is suitable for the maximum cylinder pressure (regulator inlet pressure); (v) The regulator has a suitable outlet pressure for the application; (vi) That the regulator is in a serviceable condition; (vii) The gauges are not damaged nor show signs of over pressurisation; (viii) That the cylinder valve outlet thread is mechanically compatible with the regulator inlet connection and is clean and free of dirt (use a lint free cloth to clean the outlet). Refer to BCGA TIS 22 (42); (ix) That the regulator outlet thread is in good condition; (x) That the regulator has the manufacturers/suppliers name clearly visible; (xi) The regulator can be fitted at a suitable orientation; (xii) The regulator pressure adjusting screw is set to zero pressure position by turning the control knob fully anti-clockwise; (xiii) Use the correct sized spanner only. BCGA TIS 18 (40), Gas equipment inspection / replacement date marking, provides information on some of the equipment marking schemes used by manufacturers. To prevent ignition of components, oxygen regulators shall be kept free from oil or grease and be suitable for the maximum cylinder pressure being used. The oxygen cylinder valve shall be opened slowly. 18

24 Inspect the inlet connection for damage. If an O ring is fitted to the inlet, check for damage and replace, if necessary, with an O ring recommended by the regulator manufacturer. NOTE: Do not use any form of jointing paste or tape between the regulator and cylinder valve. 9.4 Safety devices When fitting safety devices to hose assemblies, ensure that all threads and seats are in good condition. Fit the device in accordance with supplier s instructions, taking particular care of the correct direction of flow. 9.5 Hoses Before fitting a hose to the safety device or regulator, examine all fittings, threads, connection seatings and clips. Also, check for signs of damage. Reject any hose/ hose assemblies that show signs of any damage or whose condition is in any way unsatisfactory. 9.6 Pressurising the system (i) Ensure that all regulators and downstream valves are closed. Slowly open the cylinder valve fully and then close a quarter of a turn to enable others to distinguish readily between an open and a closed valve. (iii) Where the valve is not fitted with a hand-wheel, use only the gas supplier s recommended cylinder key and ensure that once the valve is open, the cylinder key is left fitted to the valve. (iv) Adjust the regulator to give the required gas pressure and check the equipment for leaks using a suitable leak detection fluid. Adjust flowing gas pressure to the required level. NOTE: Only use leak detection fluids that are free of ammonia. (v) The system should be purged to establish that the correct gas is present in the system. Care should be taken when purging flammable gases to prevent the possible creation of a flammable atmosphere. 10. CLOSING-DOWN PROCEDURE (i) Close down the process equipment according to the manufacturer s instructions. Close the cylinder valve. (iii) Vent away the small amount of residual gas via the process equipment. (iv) Turn the regulator pressure adjusting screw to the zero delivery position (by turning anti-clockwise). (v) Close the flow-meter valve if fitted. 19

25 After use, the following additional operations should be carried out: (vi) Remove the regulators from the cylinder. (vii) Visually inspect the equipment for damage. (viii) Return equipment and cylinders to a safe place of storage, reporting any damage at the same time. (ix) Make a final check to ensure that the cylinder valves are closed and that there is no leakage of gas. (x) Equipment should be removed from confined spaces, whenever it is left unattended, to prevent the build-up of gas. 11. EMERGENCY PROCEDURE: CYLINDERS The user should have a site-specific emergency procedure in place for fire situations in compliance with The Regulatory Reform (Fire Safety) Order (10). BCGA Leaflet 6 (44), Cylinders in fires, provides further guidance on dealing with gas cylinders involved in a fire. Correct location of cylinders, correct assembly of equipment and correct operation will all contribute to minimising the risk of an incident involving gas cylinders. The operator should ensure that fire extinguishers are readily available at all times when oxygen or flammable gas is in use. The most common incidents to occur are ignition of leakages of fuel gas from hose connections or defective hoses. If this occurs: (i) The cylinder valve should be closed and the fire extinguished as quickly as possible, if safe to do so. If this action is not possible, the fire may be first extinguished by prompt use of a dry powder or CO 2 fire extinguisher, followed by the closing of the cylinder valve to avoid re-ignition. If it is not possible to extinguish the fire with the use of an extinguisher, further attempts should not be made. Evacuate the area, if this has not already been done, because of the danger of explosion. As soon as a fire occurs either the works fire brigade or the Fire and Rescue Service should be alerted, even if attempts are being made to handle the situation and it has been dealt with by the time the emergency service arrives Key actions for dealing with gas cylinders in the event of fire: KEEP AWAY, do NOT approach or attempt to move the cylinder or open the valve. 20

26 Sound the alarm. Evacuate the area. Contact the Fire and Rescue Service. If gas cylinders are directly involved in a fire, keep well clear until the Fire and Rescue Service arrive and then follow their instructions. Inform the Fire and Rescue Service immediately of the location and type of any gas cylinders involved in the fire. Also tell them the location and type of other gas cylinders on the premises. Cylinders which are not directly involved in the fire and which have not become heated, should be moved as quickly as possible to a safe place, provided that this can be done without undue risk. Make sure that cylinder valves are closed Fire damaged gas cylinders Do not use any fire-damaged cylinders. Quarantine any fire-damaged cylinders in a safe place. Mark or label fire-damaged cylinders to clearly show that they have been in a fire. Inform your gas supplier whenever a cylinder 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 cylinders at a convenient date. Contact numbers for the gas supplier are available on the product Safety Data Sheet. Refer also to BCGA Leaflet 6 (44). 21