Health and Safety
Executive / Commission
Local authority circulars
To: Directors of Environmental Health/ Chief Environmental Health Officers of London, Metropolitan, District and Unitary Authorities and Chief Executives of County Councils.
For the attention of: Environmental Services / Trading Standards / Fire Authorities / Other
This circular gives advice to local authority enforcement officers
1 This circular alerts local authority enforcement officers to the possible introduction of drycleaning processes using flammable solvents.
2 The attached Data sheet which may be copied to interested outside parties, describes the precautions which are considered to be necessary.
3 One of the CFC solvents (CFC 113) which is being phased out under the Montreal Protocol is widely used in the drycleaning industry under various trade names including Arklone and Dowclene. It has particular value as a drycleaning solvent for processing garments such as suede, leather and some delicate fabrics which can be easily damaged by perchloroethylene, the solvent used by the majority of drycleaners. For this reason the industry is looking for suitable alternative solvents, and machines using flammable hydrocarbons are now being offered by a number of suppliers.
4 The contents of the Data sheet has been agreed with the Textile Services Association, the Fabric dare Research Association, the Society of Laundry Engineers and Allied Trades and the Home Office Fire Services Inspectorate. It gives advice to those who are contemplating the purchase of machines using hydrocarbon solvents, and is also intended to assist potential suppliers to meet their obligations. It is expected that the Home Office will be issuing similar guidance to Chief Fire Officers.
5 The Data sheet offers the best advice currently available, and is liable to be revised in the light of experience. Copies have been supplied to the organisations mentioned in para 6 and the existence of the Document has been announced in the Trade Press.
6 Copies of the Data sheet may be provided to anyone enquiring about or contemplating the use of hydrocarbon solvents for drycleaning. HSE's Wool, Clothing and Laundries National Interest Group would be glad to receive any comments on the Document or other feedback via your Enforcement Liaison Officer (ELO) (see para 3 of the Information Document).
LAU
HSE Datasheet 571/6
1 This Information Document contains internal guidance which has been made available to the public. The information may not be applicable in all circumstances and any queries should be directed to the appropriate enforcing authority. It has been prepared by a working party with members drawn from the Health and Safety Executive, the Home Office Fire Services Inspectorate, the Textile Services Association, the Fabric Care Research Association and the Society of Laundry Engineers and Allied Trades.
2 With the impending phase-out of CFC solvents under the Montreal Protocol, the Document is intended to help drycleaners who are thinking about changing to hydrocarbon solvent machines to understand the potential hazards, and to ask the right questions of prospective manufacturers or suppliers of machines and/or solvent. It is also intended as a guide to manufacturers and suppliers on the basic safety principles which are likely to be used by Inspectors in considering the safety of these machines.
3 The guidance in the Document is necessarily interim and at present only deals with machines of the "dry to dry" type. Anyone contemplating the use of "transfer" machines should seek additional expert advice on the hazards likely to be presented by transferring damp articles from the washer-extractor to the dryer. Comments on the Document would be welcome and should be sent to your local HSE office.
4 Under the Management of Health and Safety at Work Regulations 1992 and the Control of Substances Hazardous to Health Regulations (1994) (COSHH), all employers have to carry out risk assessments of the processes under their control. The purpose of risk assessments is to match the precautions taken to the actual risks which are presented. The guidance which follows will help drycleaners to do that in respect of hydrocarbon solvent processes.
5 To carry out a risk assessment first identify the hazards which are likely to be presented by the process under consideration. In this case the main hazard is likely to be presented by the flammability of the solvent, and there will also be some health hazards to take account of. Once you have identified the hazards, you can assess the extent of the risk by considering the consequences of the worst possible incident, the numbers of people likely to be affected, and the likelihood of the hazard being realised. You should then determine the controls which are necessary.
6 Users, manufacturers and suppliers of machines should first obtain information about the essential properties of the solvent which is to be used, and the basic precautions to be taken in handling and storage. These are likely to be:
Name and compositional detail; UN number; name and address of manufacturer/supplier; boiling point; vapour pressure; vapour density; flash point; upper and lower explosive limits (at the working pressure of the machine); ignition energy; toxicity, (including occupational exposure limit if available); odour threshold; first-aid treatment; fire fighting advice; spillage treatment; eco-toxicity.
All this information should be available from the solvent supplier, usually in the form of a data sheet which will provide an element of interpretation for the user.
7 All of the solvents on offer are likely to be flammable in some degree, but not "highly flammable" (i.e. with flash points below 32'C) as the use of highly flammable solvents is prohibited in drycleaning (other than for spotting) by The Drycleaning Special Regulations 1949. It is likely therefore that precautions will be necessary to prevent fires and/or explosions occurring during the cleaning cycle and the solvent distillation processes, when flammable vapours are likely to be present inside the machine.
8 Users should find out how the solvent will be supplied both for commissioning and for top-up in use (i.e. in bulk by tanker or in small containers) and what precautions are necessary for the storage of top-up supplies. For storage inside a building you may need to provide for fire-resistant construction, e.g. special purpose metal lockers, and for permanent natural ventilation, but precisely what is required will depend on the fire loading of the building, and expert advice may be necessary. For outside storage you will also have to provide for adequate security. It is good practice to keep only the smallest practicable amount of any flammable liquid on the premises, and to store it separately from other materials. In considering storage do not forget spotting solvents, some of which may also be flammable.
9 Toxicity data are likely to indicate that exposure to the solvent by inhalation of the vapour or skin contact with the liquid should be avoided so far as is reasonably practicable and this aspect of risk will need to be addressed in any assessment. Specific requirements on the assessment and control of substances which are hazardous to health are contained in the Control of Substances Hazardous to Health Regulations 1988 (COSHH).
10 The use of stain removal agents for the removal of stains before drycleaning (pre-spotting) may lead to the progressive contamination of the drycleaning solvent with other solvents. This may alter the properties of the drycleaning solvent over time, eg the flash point will be lowered if significant quantities of low flash point solvents are used. It will be essential therefore that any spotting agents are compatible with the main solvent. Users should obtain the advice of the solvent supplier on this and follow it.
11 This Document deals with machines of the "dry-to-dry" type, using either nitrogen blanketing or vacuum as the primary protection against fire and explosion. Each method lowers the concentration of oxygen in the machine to a point where combustion cannot be initiated or sustained. In each case there should be reliable safety control systems to ensure that the cleaning cycle cannot be started until the designed safe condition has been attained, and that the process is stopped safely if conditions move outside safe limits during the course of a machine cycle. Additional secondary safety features should also be provided to ensure that any fire or explosion which may arise because of failure of the primary protection is contained or dissipated in such a way as not to cause injury.
12 The manufacturer or supplier of the machine should provide the following information as a minimum.
13 (a) The source of the nitrogen (i.e. whether from cylinders or from equipment which extracts nitrogen from the air);
(b) The concentration of nitrogen and oxygen achieved in the drycleaning machine when it is in operation;
(c) The rationale for this concentration, including the margin of safety adopted;
(d) The means for ensuring this concentration is achieved and maintained, including the concentrations at which alarms/interlocks are set.
14 Additional hazards which may need to be taken into account are those of oxygen enrichment if nitrogen is extracted from the air, and of asphyxiation where nitrogen may be discharged into a confined space.
15 (a) The level of vacuum provided;
(b) The rationale for that level, including the margin of safety adopted;
(c) The means for ensuring that the vacuum is achieved and maintained, including the levels at which alarms/interlocks are set,
16 For all types of machine the manufacturer or supplier should provide information on the secondary safety system(s) installed, and their performance characteristics. For example, where machines are constructed to withstand the force of an internal explosion, information on the maximum likely explosion pressure, and the maximum pressure which the machine will withstand, should be given. Where the secondary system relies upon the adequate venting of an explosion it will be important to ensure that doors, viewing panels etc. are sufficiently strongly attached so that they do not themselves act as vents. The vent should discharge to a safe place, preferably outside, and not into an occupied area. Precautions should be taken to prevent vent covers from becoming missiles.
17 Sources which might ignite a combustible atmosphere inside the machine, e.g. sparks from electrical equipment, static electricity, surface temperatures, friction and metal-to-metal sparks, need to be eliminated. Manufacturers or suppliers should provide information on how this is to be achieved, for example by describing specific design features and recommended safe working practices.
18 Outside the machine a flammable atmosphere is only likely to be generated within a horizontal distance of 2 metres and a vertical distance of 1 metre from the source of liquid or vapour. Electrical equipment within these distances should be carefully assessed, taking account not only of the normal operation of the machine but also of foreseeable accidental spillage of solvent.
19 British Standard BS 5345: Part 1 (see Appendix 1, References) provides guidance on the selection of electrical equipment which may be subjected to flammable atmospheres. Part 2 of the same Standard gives guidance on the classification of risk by "zones". It is suggested that the internal spaces of the drycleaning machine, for example the cage and the still, should be classified as Zone 0 ("a zone in which an explosive gas/air mixture is continuously present, or present for long periods") and that areas where solvents are normally handled or may foreseeably be spilt should be classified as Zone 2 ("a zone in which an explosive gas/air mixture is not likely to occur in normal operation, and if it occurs, it will exist only for a short time"). Areas where solvent may be released only as a result of a malfunction, such as a leaking pipe connection or solvent tank, should also be classified as Zone 2.
20 The machine manufacturer or supplier should explain (e.g. in the instruction handbook) how the design of the machine prevents the accumulation of any static electrical charge. For example, by the avoidance of nonconducting surfaces and the bonding of metal parts. Bonding should not rely on a conducting path through moving parts, such as bearings. Efficient static bonding conductors across such bearings should be provided. Guidance is contained in British Standard BS 5958.
21 The safety of all machines will depend on the ability of the control system to ensure that dangerous phases of the cycle cannot be entered until safe conditions exist. Where, as is likely to be the case, programmable electronic systems (PES) are used for safety-critical functions, relevant international standards for the development of the software should be observed. Some guidance on this is given in Appendix 2.
22 The manufacturer or supplier should specify precisely the configuration of the primary protection system, eg a high-integrity safety-related control system; a safety-related control system plus "hardwired" interlocks; or a control system, plus PES-based protection, plus "hardwired" interlocks. They should also specify the correct operation of the system, and provide enough information to enable a field (maintenance) engineer to demonstrate its safe operation.
23 The design of the system should take into account the environment in which the machine is intended to operate including, in particular, the electromagnetic environment (ie susceptibility to interference) and the impact of the drycleaning process (eg the effects of solvent, corrosion and extremes of temperature).
24 Users should obtain information from the manufacturer or supplier on the likely sources of emissions of hydrocarbon vapour from the machine, the design measures taken to control them and the recommended working practices for both routine operation and maintenance operations to reduce residual emissions to a minimum. In practice, it is expected that all machines will operate so that the concentration of hydrocarbon vapour in the workroom atmosphere will be well below any occupational exposure limit. If this is not the case, then the user will have to measure personal exposure as part of the COSHH assessment, to take additional control measures to ensure that the occupational exposure limit is not exceeded, and to review the situation at regular intervals.
25 The manufacturer or supplier should provide information on maintenance requirements, including the routine tasks and safety procedures which can be carried out by the operator, the non-routine tasks which should be carried out by a competent engineer, and the action which should be taken in the event of machine failure in mid-cycle. The information should explain what precautions may be necessary during maintenance to avoid fire or explosion (e.g. by ensuring that machines are cold before carrying out operations which could release solvent or solvent vapour, and by restricting the use of hot processes such as welding or soldering, which may provide a source of ignition). The training of operators and engineers is likely to be of particular importance in ensuring adherence to safe working procedures.
26 The installation of a machine which uses hydrocarbon solvents will have implications for the fire safety of the premises and any building of which it forms a part. Users will need to take into account the adequacy of the existing means of escape, looking at the additional hazard presented by the use and storage of hydrocarbon solvent. The following aspects are also important and should be examined:
(a) the provision of fire extinguishers;
(b) where installed, the fire alarm system;
(c) fire action notices;
(d) training of personnel.
27 Most premises operating a drycleaning service will be subject to the requirements of the Fire Precautions Act 1971. Some will have, or require, a Fire Certificate and occupiers or owners of premises are required to inform the Fire Authority in general terms if it is proposed to make changes which will affect the means of escape and fire safety arrangements. Such changes would include a proposal to install drycleaning equipment using a flammable solvent. Premises which do not need a Fire Certificate are required to provide such means of escape in case of fire and such means of fighting fire as are reasonable in the circumstances. If the occupier is in any doubt about the fire safety arrangements which are necessary advice should be sought from the Fire Authority.
28 The Fire Precautions (Places of Work) Regulations, when enacted, will require most employers to make a fire risk assessment of the workplace and, in doing so, identify fire hazards. These include flammable substances and combustible materials. The aim of the assessment is to identify potential fire hazards, evaluate the likelihood of a fire occurring, consider it's consequences and as a result minimise the risk of fire and make reasonable provision for the safety of anyone in the workplace should a fire occur. An emergency plan should be drawn up on the basis of the risk assessment
29. Sources of ignition extraneous to the machine itself will need to be assessed and action taken to reduce risk. In general machines should not be located in the same room as any equipment which uses a naked flame or produces hot surfaces, e.g. boilers, electric fires or portable heating appliances. Electrical equipment (including switches) located adjacent to the machine should be appropriate, where necessary, for use in the risk zones identified in para 19. Smoking in the room should not be allowed
30 As required in Safety in Drycleaning Guidelines (Parts 4 and 9) users should provide adequate mechanical ventilation in the workroom to remove any solvent fumes which may arise from the normal operation of the machine and to clear the atmosphere in the event of a spillage or leak. The ventilation should be interlocked with the machine so that the machine cannot be operated unless the ventilation is functioning. The design of the ventilation system should take into account the fact that hydrocarbon solvent vapours are heavier than air, necessitating an element of ventilation at low level.
31 Machines should normally be sited on impervious trays, and it is recommended that these have a capacity greater than the largest tank on the machine. The area around machines should be kept clear of rags, fluff, paper and similar materials, since a pool of solvent which cannot be easily ignited becomes a much greater fire hazard if there is something present which can act as a wick.
32 The competence of operators is important in drycleaning, not only to ensure good quality work and customer satisfaction, but also to ensure that the process is operated in a safe manner. High priority should therefore be given to the adequate training of any personnel who will have to work with the new solvent. The manufacturer or supplier of the machine should be able to advise on the nature of the training required and this should include health and safety as an integral part. Various industry organisations and other bodies may be able to offer training courses. Because of the different nature of the hazards compared with perchloroethylene and CFC 113, formal health and safety training (which may be integrated with process training) is strongly recommended.
33 Because of the different hazards presented by hydrocarbon solvents, the user should review and revise emergency procedures for dealing with spillages and with fire. Personnel should be trained accordingly, and notices summarising the action to take should be displayed. Refresher training and/or instruction and practice drills should be undertaken.
34 The following is a list of the principal relevant health and safety legislation. For detailed advice refer to the relevant authority.
Health and Safety at Work etc Act 1974; Management of Health and Safety at Work Regulations 1992; Provision and Use of Work Equipment Regulations 1992.
Control of Substances Hazardous to Health Regulations 1988; Electricity at Work Regulations 1990; Fire Precautions Act 1971.
Supply of Machinery (Safety) Regulations 1992; The Drycleaning Special Regulations 1949.
35 The following statutory authorities and others may need to be consulted or may be able to give advice on the precautions which are necessary and the requirements of the law:
(a) Health and Safety Executive ;
(b) Local Authority (Environmental Health Department)
(c) Fire Authority
(d) Insurance Company;
(e) Building owner.
36 Further advice may also be obtained from the Textile Services Association, the Fabric Care Research Association, and the Society of Laundry Engineers and Allied Trades.
Appendix 1 (para 19)
Supply of machinery (Safety) Regulations 1991- ISBN 0 11 025719 7.
Guide to fire precautions in existing places of work that require a fire certificate; factories, offices, shops and railway premises - ISBN 0 11 340906 0.
Code of Practice for fire precautions in factories, offices, shops and rail way premises not required to have a fire certificate - ISBN 0 1 1 340904 4.
*Management of Health and Safety at work Regulations 1992 and Approved Code of Practice, L21 - ISBN 0 11 886330 4.
*Work Equipment; Provision and Use of work Equipment Regulations 1992; Guidance on Regulations, L22 - ISBN 0 1 1 886332 0.
*Control of Substances Hazardous to Health. Approved Codes of Practice (third Edition), L5 - ISBN 0 11 885698 7. *A step-by-step guide to COSHH assessment - ISBN 0 11 886379 7.
*Electrical apparatus for use in potentially explosive atmospheres - HS(G)22 - ISBN 0 11 883746 X.
They can also be obtained by mail order (cash with order or credit card) from HSE Books. P.O Box 1999. Sudbury, Suffolk, C01 0 6FS. Tel No7 0787 881165
BS 5345 Code of practice for selection, installation and maintenance of electrical apparatus for use in potentially explosive atmospheres (other than mining applications or explosive processing or manufacture).
Part 1: General recommendations. Part 2: Classification of hazardous areas.
BS 5958 Code of practice for control of undesirable static electricity. Part 1: General considerations. Part 2: Recommendations for particular industrial situations.
Safety in drycleaning guidelines.
Control of Substances Hazardous to Health. Guidance note.
The Management of Health and Safety at Work Regulations 1992. Guidance notes (contains guidance on risk assessment).
Appendix 2 (para 21)
1 The manufacturer should be competent in software development, as well as in machinery manufacture, or obtain competent external advice on this aspect of the machine design.
2 Software engineering methods and quality assurance techniques should be adopted during software development. A relevant standard is ISO 9000-3, Quality management and quality assurance, and standards currently being developed by Working Groups of IEC TC65 SC65A -Software for computers in the application of industrial safety-related systems (Working Group 9), and Functional Safety; safety related systems (Working Group 10).
3 To avoid corruption, i.e. inadequately documented changes to software which are otherwise likely to occur over the lifetime of a product, the software should be managed under an adequate scheme of configuration control.