A Code of Practice for the safe installation, operation and maintenance of Thermal Spraying Equipment

Introduction | Preface | Contents | Acknowledgements | Issue Details | TSSEA Home Page 7. Operational Stage 7.1 Training 7.1.1 Only those who have been thoroughly trained and shown themselves competent should be permitted to operate thermal spray equipment. The more complicated the equipment, the more extensive is the training required before it is reasonable to leave the operator to work without supervision. Standard BS EN ISO 14918 'Approval testing of thermal sprayers' 55 is primarily concerned with the quality of the coatings produced, and has relatively little on the subject of safety. 7.1.2 The manufacturer's documentation should be made available to the operators, and formal instruction on the material contained in the manuals should be given. All safety recommendations stated in the manufacturer's documentation should be followed. 7.2 Gases 7.2.1 Manifolded cylinder pallets (MCP) of gases will need to be transported and positioned using fork lift trucks. Only trained and appointed fork lift drivers may be permitted to drive these vehicles. They must, in addition, be trained in the handling of manifolded gas cylinders. The HAC will have classified the areas around the gas cylinder store, and access to the fork lift trucks must be controlled. It may be necessary to shut off all the gases, when any are being changed. 7.2.2 Single cylinders should be transported using gas-cylinder trolleys, into which they must be tethered securely. A manual handling risk assessment should be carried out regarding the movement of cylinders, and steps taken to reduce the risk of injury. This should include training in the handling of the loads, should take into account the suitability of the traffic routes that are used to transport cylinders, and the provision of trolleys suited to the location. There is British Compressed Gases Association Guidance available.56 7.2.3 Gas cylinders should always be restrained by chains or straps to prevent them from falling, since in so doing they may cause damage to the equipment, operators or others. 7.2.4 It is essential to train the operators in the safe use of compressed gases. It should include as a minimum the procedures for cylinder changing, operator maintenance, equipment operation, cylinder handling and emergency procedures. Gas safety data sheets are available from the gas supplier, and the information and advice in these sheets should be part of the training of the operators. 7.2.5 As a precaution against leaks it is good practice to turn off the gas supplies during times when the equipment is not being used or is unattended, for example each night. 7.3 Noise 7.3.1 A risk assessment must be undertaken where any person is liable to be exposed to the first action level, 80 dB(A), or above. The design and installation of the equipment should have incorporated measures to reduce noise at source and to isolate the operators from high noise exposure, with the aim to bring the likelihood of exposure below the first action level. However, the assessment may indicate that further measures such as the wearing of hearing protection in certain areas may be necessary to control exposure to noise. 7.3.2 Entry into the spray booth while the equipment is running should be avoided wherever possible. If it is essential, then suitable and efficient hearing protection must be worn. Operators of hand held spraying equipment will always require suitable and efficient hearing protection. 7.3.3 It is worth noting that experiments have shown that the actual protection from most ear muffs and plugs is generally much less than quoted by the manufacturers, since people tend not to wear them properly, and will often take them off for short periods, not realising that they are compromising the efficiency of the protective measures. It is important to mount a programme of education on hearing protection, which would include the information that the equipment must be worn at all times where the noise assessment has shown that noise is at dangerous levels. Management should take the lead in setting a good example in the wearing of hearing protection. 7.3.4 Where employees are exposed to noise that is likely to be above the lower exposure action value (80dB(A)) instruction, information and training needs to be given to include: the nature of the risks from exposure to noise, the measures taken to reduce or eliminate it, the exposure limit values and upper and lower exposure action values, the significant findings of the risk assessment, the availability and provision of personal hearing protectors and their correct use, why and how to report signs of hearing damage, the entitlement to health surveillance and its purposes safe working practices to minimise exposure to noise the collective results of any health surveillance. Training in the use of hearing protection should include how to fit the muffs correctly, and how to inspect and maintain them. Because hearing protection is often not used to its maximum benefit, it is advised that hearing protection of a slightly higher performance than is apparently required should be purchased. 7.4 Radiation 7.4.1 For manual flame spraying operations a face shield is advised. The shade number is related to gas flow rates, and British Standard BS EN 169 should be consulted.57 7.4.2 Where arc or plasma spraying processes are carried out, it is essential that operators and others are protected from the ultraviolet radiation if the process is not enclosed. Full personal protective equipment is required by the operator, including a visor and clothing to cover all the skin; curtains may be used to shield others from exposure. 7.4.3 When these processes are carried out in purpose-built booths, the windows shield the operators and others. 7.5 Fume and Dust 7.5.1 In general, where processes are operated within a dedicated booth, the integral control system (e.g. extraction fans and water curtain) should be set up so as to be adequate to control the fume and dust to a safe level. In particular, the extraction system should be started up prior to the spray equipment being activated, to ensure that the air flow is adequate before fume and dusts are generated. Shutting down of the extraction system should be delayed after spraying has ceased and the operator should remain outside the booth until the dust and fume are adequately cleared from it. 7.5.2 Problems may arise when undertaking hand-held operation of the spray guns, since then the operator is liable to be exposed to dust and fume. The exposure is liable to affect the eyes, but the protection chosen to shield the face from radiation should control this risk. 7.5.3 Exposure to the risk of inhalation of fume and dust must be assessed to comply with the Control of Substances Hazardous to Health Regulations (COSHH)10, and to determine the measures required to control exposure. In special cases, for instance when spraying a toxic material on site, it may be necessary to use an air fed helmet with tinted visor. The air must be of breathable quality, as set out in BS EN 12021 (formerly covered by BS4275).58 7.5.4 Powdered materials should be stored in such a way as to prevent their being blown around the workplace. They should be stored dry in covered containers. In the event of spillages, dry sweeping should not be permitted. Note that many powdered metals can constitute a fire or explosion hazard. When cleaning up work areas, employees should avoid dry sweeping up with a broom. Use extraction equipment or suitable vacuum cleaners fitted with high efficiency particulate arrestor (HEPA) filters. 7.5.5 Operators must ensure that the collection bins in any dry extraction system are checked regularly to ensure that they are changed when required. It is essential that the correct personal protective equipment is provided and used in accordance with the COSHH regulations. Collected dusts and the wet dusts from wet collection should be treated as hazardous waste in accordance with the Environmental Protection Act.14 7.6 Mechanical Hazards 7.6.1 Robots and high speed scan units pose hazards to operators. Adequate interlocking should have been incorporated at the installation stage, and training must be given. Where it is necessary to 'teach' a robot, there must be a secure means of switching it over to the 'teach' mode, in which the speed of the device is limited, so that it cannot be set to run at full speed while the operator is inside the work area. Reference should be made to Health and Safety Executive guidance on robots.49 7.6.2 The layout of cabling and mechanical equipment within the booth can contribute a great deal to the avoidance of trips and being trapped or struck by equipment. 7.6.3 Good housekeeping within the spray area can also contribute a great deal to the maintenance of a safe environment. 7.7 Electrical 7.7.1 Plasma and arc spray guns operate with DC electrical power. Some equipment may be at high voltages, and great care should be taken to avoid any contact with live components. 7.7.2 In those processes that required HAC, great care must be taken to avoid the introduction of uncertified electrical equipment into the classified hazardous areas.