Assessment of Gas Usage

Transcription

1 PROACTIVE GAS SAFETY LTD Assessment of Gas Usage Compressed & Cryogenic Gases Safety Assessment Proactive Gas Safety Ltd It is important that personnel associated with the use of Compressed and Cryogenic Gases understand the properties of those gases and are conversant with the relevant Codes of Practice and Guidance Notes issued by the British Compressed Gases Association (BCGA).

2 Compressed & Cryogenic Gases Safety Assessment Safety in the Workplace is Everyone s Responsibility It is important that personnel associated with the use of Compressed and Cryogenic Gases understand the properties of those gases and are conversant with the relevant Codes of Practice and Guidance Notes issued by the British Compressed Gases Association (BCGA). Users should have in their possession Material Safety Data Sheets for the gases being used; these can be obtained from the gas supplier. Personal safety and the safety of others may depend on knowledge of the gas and the equipment in use, as well as the behaviour of the operator and all those involved in gas usage. Training leads to greater awareness of the hazards and risks involved with compressed gases, resulting in improved safety standards. For the purpose of: This is a Guidance Document for Reference only Providing reference to the specific requirements for gas safety Assisting Management in the evaluation of current working practices Providing possible solutions to gas safety issues The contents are not exhaustive and whilst proper care has been taken in the compilation of this document no liability for loss, injury or damage resulting from its use or interpretation can be accepted. Page Assessment of Gas Usage 2-4 Gas Safety Training 5-7 Training Topics 8-10 Confined Spaces 11 Reduced Oxygen Atmospheres 12 Written Schemes of Examination Competent Person Definition Dangerous Substances & Explosive Atmospheres Regulations Page 1 of 16

3 Assessment of Compressed & Cryogenic Gas Usage This Audit tool is designed to allow Managers/Supervisors to make a concise assessment of compressed and Cryogenic gas usage on-site and to identify all staff who may be involved in any way with the use of these products When answering the following include all personnel who are responsible for who use or come into contact with compressed or cryogenic gases Are single cylinder supplies of compressed gases used? Are multiple cylinder supplies of compressed gases used? (MCP or Manifolds (Multiple Cylinder Pallets) Through flexible hose to process equipment? Through fixed installation pipe work? Through flexible hose to process equipment? Through fixed installation pipe work? In mobile pressurised dewars? Yes No Location Staff Are cryogenic gases used onsite? In mobile unpressurised dewars? In small receptacles <20 litre capacity? Page 2 of 16

4 Are bulk storage pressurised vessels located on-site? Cryogenic towers / tanks? LPG tanks? Yes No Location Staff Is there a cylinder gases store? Is there a fixed supply manifold and gas distribution system? Is company transportation used to move gases from the store to the points of use - within the site boundary only? Is company transportation used to move gases on public roads in vehicles? Collecting or returning gases from a supplier? To undertake work at off-site locations? The movement of gases between company sites? Is welding, cutting, brazing or any other Oxy-Fuel gas process undertaken which uses gas from a mobile supply (e.g. cylinders)? Are gases for welding, cutting, or brazing used from an installed supply (e.g. gases piped from cylinders, pallets or liquid vessels)? Page 3 of 16

5 Are gases used for any of the following: Medical purposes? Yes No Location Staff Laboratory work? Inerting, purging, blanketing? Plasma or other process? Refrigeration? Food freezing or packaging? Electronics/ Semiconductor Manufacture? Glass manufacture? Propulsion e.g. Fork lift trucks using LPG fuel? Have the risks associated with welding fumes been assessed? Oxygen, flammables, dissolved acetylene Has a Manual Handling Risk Assessment been carried out covering the movement of gas cylinders? May staff engage in the following: Entering into a confined space of any kind where gases have been or may be present? (The term confined includes lifts, tanks, pits, trenches, basements, silos, and ships holds etc see Page 8) Transferring cryogenic liquids from vessels into dewars or flasks? Yes Yes No No Transferring compressed gases cylinder to cylinder (decanting)? Page 4 of 16

6 Yes No Location Staff Connecting gases to cylinders, gas control equipment or pipework? Entering areas where cylinders are in storage or use? Transporting or collecting gases in vehicles around the site or from external suppliers? Are contractors entering your site to which any of the above may apply? Are contractors trained in the hazards, properties and risks associated with safe use of gases? Page 5 of 16

7 Gas Safety Training The Health and Safety at Work Act (2), imposes a general duty on every employer to provide as much information, instruction, training and supervision as is necessary to ensure, so far as is reasonably practicable, the health and safety at work of the employees. If employees are injured at work, or are engaged in a potentially dangerous activity for which they have been ill-prepared or advised by their employer, criminal prosecution may ensue. To comply with the Act (2) does your Company: Yes No Duties Introduce comprehensive safety rules and procedures and induction training programmes for all new recruits? Provide repeat training (either on the job or in a classroom or equivalent environment) at regular intervals? Ensure that no employees transferred or promoted from one job or activity to another are permitted to start work in their new job until and unless they have received training and instruction sufficient to enable them to perform the job without risk to their health and safety? Ensure that safety representatives are adequately trained? Provide adequate training for managers at all levels? Pay attention to the needs of existing employees? Document details of training given and received? Set out training provision in the Safety Policy Statement? Training Records New Employees Transferred Employees Are there training logs and schedules available for each employee? Are these reviewed annually with the employee to ascertain: There are no knowledge gaps? The employee is confident regarding their proficiency in all aspects of their work? With new employees, immediately after induction and jobspecific training are training logs completed and a review undertaken with the employee? Are both management and employee satisfied that proficiency and competency in the job role has been established? Immediately after induction and job- specific training, are training logs completed and a review undertaken with the transferred employee? Are both management and employee satisfied that proficiency and competency in the job has been established? Page 6 of 16

8 Gas Safety Training Yes No Subcontracted or Temporary Employees With sub-contracted or temporary employees, immediately after induction and job-specific training are Training Logs completed and a review undertaken with the employee? Are both management and employee satisfied that competency in the job role has been established? Changes in workplace procedures? Workplaces Changes Proficiency Assessment Proficiency of Responsible Person Control of Contractors Contractors Using Gases Have employees been identified who are affected by the following: Changes in workplace methods? Changes in workplace processes? Changes in workplace plant or equipment? Has appropriate training taken place because of the changes above and has this been noted in the Training Logs? Has a Responsible Person been appointed with the duty of signing off the proficiency of an employee after any training and before they are allowed to work unsupervised? Is there a method available to validate the training and proficiency of the Responsible Person who undertakes the training and proficiency assessment of employees under training? Where contractors are employed on-site are procedures in place to ascertain: They have undergone Site Induction and this is recorded? Their proficiency has been checked? They have undergone gas safety training related to their role? Have contractors using gases on-site been trained in the hazards and properties of gases? Do they complete before use checks on gas equipment? Do they use the correct equipment light-up and shut-down procedures? (Where applicable) Are their gas regulators and flashback arrestors still within the stipulated service life? (Normally under five years old or within manufacturer's recommended life) Do they avoid wrapping hoses around cylinders when in use? Are they aware of the hazards of using oil and greases in the presence of Oxygen? Is their equipment free from evidence of use of PTFE tape on fittings and joints? Has their gas equipment been subjected to any Annual Inspection and do they have records of this? Note: If you are not confident that your regular contractors have been properly trained in the safe use of gases, contact Proactive Gas Safety - together we can ensure that they are trained to meet your safety requirements Training Topics Page 7 of 16

9 Having ascertained the use of gases and personnel involved, training contents should include: Gas Usage Compressed cylinder gases Compressed cylinder gases practical instruction Learning topic Composition of the air Gas properties and potential hazards Inert gases and oxygen deficiency (asphyxia) Hazards of oxygen enrichment Hazards posed by oils and greases Flammability hazards (including Pyrophoric gas hazards) Toxics Corrosives Hydrogen embrittlement Acetylene and copper. Personal protective equipment requirement Gas cylinders Production design and filling Content identification Safe operation Storage Handling Gas equipment Regulators Hoses Flashback arrestors Pipework Selection of correct gas control equipment Manual handling techniques and the hazards of incorrect techniques Before-use safety assessment of work area Emergency procedures Legislation and Codes of Practice General risk assessment and safe systems of work procedures Manual handling techniques (milk churning) Regulator fitting Before use checks Correct connection Leak check procedures Safe shut down procedures Removal and exchange of cylinders Page 8 of 16

10 Users of mobile Oxy/acetylene Oxy/propane Equipment In addition to compressed cylinder gases training topics Annual Inspection of Oxy/acetylene Oxy/propane Equipment In addition to above user training Design and function of single and multi-stage regulators Backfires and flashbacks How flashbacks occur Avoidance Design and function of flashback arrestors Hoses Correct hose selection Using hoses safely Torches Torch design and selection Correct nozzle selection Correct set-up of an oxy-fuel gas workstation Safe working practices Pre-use visual checks on gas equipment Correct set-up of an oxy-fuel gas unit Correct leak testing Safe shut-down procedures Transportation and handling of oxy-fuel units Regulators Visual checks and inspection Functional tests Date coding Flashback arrestors Visual checks and inspection Reverse flow test Date coding Hose check valves Reverse flow test Hoses Visual checks and inspection Components Hose care Torches and Nozzles Visual checks and inspection Record keeping and documentation Page 9 of 16

11 Cryogenic Gases User behaviour and perceptions Gas and air properties Hazards posed by cryogens Cryogenic burns Expansion rates and oxygen deficiency Oxygen enrichment Embrittlement Hazards posed by pressure Cryogenic Vessels Design, function and operation Key safety features Valve identification Safe handling Safe storage Safe movement Ice plugs Decanting procedures Pre-fill checks Potential oxygen enrichment hazards during decanting Personal protective equipment Safe procedures and vessel pressures Oxygen monitoring and ventilation systems Cryogenic spillage Emergency procedures First aid Before-use safety assessment of work area General Risk Assessment and Safe Systems of Work procedures Page 10 of 16

12 Confined Spaces Definition Any space of an enclosed nature where there is a risk of death or serious injury from hazardous substances or dangerous conditions. Typical Confined Spaces Silos Storage tanks Enclosed Drains The vessels Sewers Ship's holds Less Obvious Examples Vats Open-topped vessels Pits Trenches Ducts Unventilated or poorly ventilated rooms Your Responsibilities The Law states you must carry out suitable Risk Assessments for all work activities to be conducted in Confined Spaces to identify the necessary safety measures. Oxygen Deficiency Oxygen Deficiency is one of the major hazards associated with working in Confined Spaces. Potential causes include: Release of other gases displacing the Oxygen Releases from, or spillages of, Cryogenic liquids Flame, fire and rust Chemical reactions absorbing Oxygen or releasing other gases Poisonous vapours or fumes Dust Tanker residues Note: The above list is not exhaustive and you should refer to the relevant BCGA Codes of Practice and UK HSE Publications for further information. Safe Work in Confined Spaces - Confined Spaces Regulations Approved Code of Practice, Regulations and Guidance L101. HSE Books ISBN Page 11 of 16

13 Reduced Oxygen Atmospheres Any depletion of Oxygen below the 21% found in normal air should be regarded with concern Work place Oxygen concentrations should be maintained above 19.5% Atmospheres of less than 18% Oxygen are potentially dangerous and premises must be evacuated if Oxygen levels fall below this percentage Concentrations below 10% Oxygen lead to rapid unconsciousness, brain damage or death due to asphyxia. Immediate loss of consciousness occurs in atmospheres of less than 6% Oxygen. Inhalation of only two breaths of an Inert or other Oxygen-displacing gas may cause immediate loss of consciousness leading to death. Cryogenic gases have extremely high Liquid-to-Gas expansion ratios. These may be in the order of 1:700 and you should understand the specific ratios for the gases you are using. These are available from the Material Safety Data Sheets which can be obtained from your Cryogen supplier. Important Information The BCGA issue a number of CPs and GNs which contain specific calculations relating to the release of Cryogenic and cylinder gases. These calculations cover both instantaneous and slow releases into the workplace. You are strongly advised to obtain a copy of the CP or GN most relevant to your workplace and carry out Risk Assessments using these calculations. Copies may be purchased either from PGS or direct from the BCGA website. BCGA Tel Page 12 of 16

14 Interpreting the Need for Written Schemes of Examination Important Information Caution needs to be exercised in the interpretation of the 250 bar litre limit referred to in the Pressure Systems Safety Regulations 2000, SI No 128 (ISBN ). Many systems could be technically interpreted as being outside this limit but may still require a formal Written Scheme of Examination. For example, a single cylinder, connected via flexible hoses to a point of use, could be assumed not to require a Written Scheme of Examination for the following reasons: the cylinder is classed as a Transportable Pressure Receptacle and does not fall within the requirement for Written Schemes of Examination, the responsibility for cylinders belongs with the supplier, no other part of the system mentioned would technically require a formal Written Scheme of Examination. However, the Regulations contain the following Provision: 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. Once a suitable scheme has been drawn up, it must be formally approved by the Competent Person. The Health and Safety Executive has stated that only one type of gas system does not require a formal Written Scheme of Examination, and that is portable Oxy-Acetylene or Oxy- Propane welding and cutting equipment. Instead, these require Before Use and Annual Inspections. PGS Ltd provides Training Workshops, Checklists and Manuals for these Inspections. For all other cylinder supplied systems you are strongly advised to do the following: Ask a Competent Person to assess all cylinder supplied systems as to whether they need a formal Written Scheme of Examination. Further guidance is available in BCGA CP4, CP23 or Written Schemes of Examination HSE INDG 178. Your insurance assessors should be able to provide such a Competent Person. Only a Competent Person can state which gas systems do NOT require a formal Written Scheme of Examination. Page 13 of 16

15 Competent Person Definition Sheet Competent Person A "Competent Person" legally cannot be an individual employee, but can be an in-house inspection department within a company. The in-house department can be staffed by just one individual although larger complements are normal. Such departments must have a proper degree of independence from the operating functions of the company. So, for example, individuals within in-house inspection departments who carry out functions in addition to their Competent-Person duties should be separately accountable under their job descriptions for the Competent Person duties. Individuals should not be subject to commercial or financial responsibilities which conflict with their Competent Person duties. As regards the attributes of the person drawing up or certifying the written scheme, there is no need for that individual to be of Chartered Engineer status provided he/she acts under the direction and supervision of a Chartered Engineer or engineer of equivalent status. Selection of Competent Persons Guidance on the selection of competent persons is given in these HSE publications on Pressure Systems: Safety of Pressure Systems Pressure Systems Safety Regulations 2000 Approved Code of Practice L122. HSE Books ISBN X Pressure Systems Safety & You. HSE INDG 261 Revision ISBN Users (or owners) of pressure systems are free to select any Competent Person they wish, however they should take all reasonable steps to ensure that the Competent Person selected can actually demonstrate competence - that is, the necessary breadth of knowledge, experience and independence. In judging levels of competence, users or owners may wish to know that a national accreditation scheme has been developed by the United Kingdom Accreditation Service (UKAS), for bodies that provide services of this nature. UKAS High Street, Feltham, Middlesex. TW13 4UN Website: info@ukas.com Tel: Page 14 of 16

16 Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) 2002 DSEAR applies to all workplaces where potentially explosive atmospheres may be formed by the mixing of dangerous substances such as gases, vapours, mists and dust with air. DSEAR will apply where Flammable & Oxidising gases are in use, although levels of risk will vary greatly between different workplaces. The key issue for users of compressed or cryogenic gases is whether the workplace environment concerned is classified as hazardous or nonhazardous as a result of the use and storage of these products. Therefore, the first step in complying with these Regulations is to determine whether or not the workplace concerned is classified hazardous or non-hazardous under the terms of DSEAR Schedule 2, Regulation 7(1) Part 1. A hazardous environment is one in which explosive atmospheres may form in quantities sufficient to require special precautions to be implemented to protect the workforce. Therefore, a suitable and sufficient Risk Assessment should be produced upon which to make this judgement. If the Risk Assessment provides evidence that the workplace may be considered non-hazardous, it should be retained permanently to support this outcome. If the Risk Assessment leads to a classification of the workplace as Hazardous under DSEAR criteria, then Hazardous workplaces are classified into Zones as per Schedule 2, Regulation 7(1) Part 2. This classification takes into account the frequency with which explosive atmospheres are likely to form, and the duration of those occurrences. In this case, the relevant requirements of DSEAR must then be met. Refer to BCGA GN13 (DSEAR Risk Assessments) for detailed guidance on the generation of DSEAR Risk Assessments for customer installations where compressed or cryogenic gases are in use. Refer to UK HSE Guidance and Approved Code of Practice on DSEAR L138(3) HSE Books 2003 ISBN and UK HSE INDG 370 Fire & Explosion How Safe is Your Workplace? Refer to DSEAR 2002 (ISBN ) for full details or BS EN :2004 Part 10 for guidance on the Zoning requirements & procedures. www. opsi.gov.uk/si/si2002/ htm Page 15 of 16