Isocyanate paint spraying: Safely managing spray booths and
Contents
1. a control panel to program and operate the booth manufactured specifically for the motor or commercial vehicle trade Spray booths are designed to dilute and displace airborne paint mist and reduce the sprayer s exposure The extract fan removes slightly more air than the inlet fan supplies This ensures that the booth is held at a slightly lower air pressure than the rest of the workplace and prevents paint mist leaking out of the booth lsocyanate paint spraying Safely managing spray booths and rooms Page 6 of 23 Health and Safety Executive Spray rooms Spray rooms are not as sophisticated as booths and are usually homemade Typically air is extracted from a spray room through a relatively small fan fitted in an outside wall Inlet air is drawn into the room via openings in one or more walls or in an unplanned way through gaps in the structure The design of spray rooms varies but they tend to have the following characteristics m just an extract fan m the extract air is not filtered though it should be m the inlet air is not always filtered although it should be to assist with paint finish quality m smaller sized inlets and outlets than spray booths m operate at lower flow rates than spray booths Like booths spray rooms are designed to dilute airborne concentrations and retain the invisible paint mist But as spray rooms tend to extract less air the concentration of paint mist in the room is much higher bo2. safely particularly not to lift the RPE visor during spraying activities eg to check paint quality Key message 3 How long your spray booth room takes to clear m All booths rooms take time to clear of the invisible mist m You must know the clearance time of your booth room m Measure the clearance time using smoke and at the same time check that the booth room and ductwork is not leaking m Put the clearance time on the outside of the booth room and tell everyone who needs to know m Clearance time indicators are the preferred method of letting others know when a booth room is safe to enter lsocyanate paint spraying Safely managing spray booths and rooms Page 14 of 23 Health and Safety Executive Appendix 2 Sprayer s steps to safe working m Remember that most airborne paint mist is invisible m Always spray paint in a spray booth room and not in the open workshop m Always make sure your spray booth room runs under negative pressure so any air leakage is inward m Always wear air fed BA during paint spraying m All spray booths rooms have a clearance time you need to know what it is m Keep your mask on during the clearance time or leave the spray booth room safely m Don t raise your visor while in the spray booth room m Regularly check and maintain your spray booth room and air fed BA Appendix 3 The employer s manager s checklist Use this checklist to check on your performance and take the act
3. air movement if le gt gt gt gt wy generated by fan a rd 5 al ri E e ro N g FILTER a8 3 mes IN DOOR 3 iat FILTERED e E 2 EXTRACT 4 N oO aoe 2 Z 39 gt i i gt aoe 8 gt gt gt my E gt gt a 5 AIR IN 8 Figure 9 What really happens lsocyanate paint spraying Safely managing spray booths and rooms Page 9 of 23 Health and Safety Executive Air movement in downdraft spray booths Although spray booths do generally provide better control than spray rooms they still do not perform as effectively as people think For downdraft spray booths it is often thought that the air moves smoothly downwards from the ceiling to the floor of the booth In most if not all downdraft spray booths this does not happen In reality large slow moving vortices are created along all four walls of the booth that typically stretch from floor to ceiling It is in these areas that the fine invisible mist becomes trapped during spraying and for some time afterwards Unfortunately the sprayer normally works in these areas see Figures 10 and 11 FILTER Figure 11 What really happens as demonstrated with smoke and special lighting lsocyanate paint spraying Safely managing spray booths and rooms Page 10 of 23 Health and Safety Executive Air movement in cross flow or tunnel booths Cross flow and tunnel booths also have a haphazard air movement and display similar vortices to downdraft booth
4. carrying out the examination and test m signature or other acceptable means of identifying the person carrying out the examination and test m plant condition at the time of the test and whether this was normal production or special conditions m intended operating performance of the plant for adequately controlling the hazardous substance m whether the plant is still achieving the same performance m the methods used to judge performance eg visual pressure measurements airflow measurements dust lamp air sampling tests to check the condition and effectiveness of the filter m if not achieving the same performance the adjustments and repairs needed to achieve that performance m details of the adjustments and repairs actually carried out including proving the effectiveness of repairs by re test these details should be completed by employers responsible for the LEV plant Further advice is contained in Control of substances hazardous to health Approved Code of Practice and guidance and in Controlling airborne contaminants at work A guide to local exhaust ventilation References 1 Safety in isocyanate paint spraying Leaflet INDG388 rev2 HSE 2013 www hse gov uk pubns indg388 htm 2 EH40 2005 Workplace exposure limits Containing the list of workplace exposure limits for use with the Control of Substances Hazardous to Health Regulations as amended Environmental Hygiene Guidance Note EH40 Second edition HSE Books 2011 IS
5. completely preventable but it will require m using properly designed and maintained spray booths and rooms m using suitable air fed breathing apparatus BA m following correct working procedures What the law says Control exposure The law including the Control of Substances Hazardous to Health Regulations 2002 COSHH requires employers and the self employed to control the risks from harmful substances used or produced at work including isocyanate in paints see www hse gov uk toolbox harmful You need to take account of risks to yourself if you run your own bodyshop employees if applicable and other people who might be affected Once the control measures are in place and have been shown to work commissioning the law requires that the controls are checked and maintained so have them examined and keep records See Further reading for other information on COSHH and controlling exposure to isocyanates The UK has a workplace exposure limit WEL for isocyanates of 20 micrograms per cubic metre ug m of air Exposure to isocyanate should not exceed this see Safety in isocyanate paint spraying but it isn t a guaranteed safe level and exposure should be reduced as far below that level as is reasonably practicable The publication EH40 2005 Workplace exposure limits has more information lsocyanate paint spraying Safely managing spray booths and rooms Page 4 of 23 Health and Safety Executive Levels of
6. of 23 Health and Safety Executive Appendix 4 Example of a clearance time certificate THE CLEARANCE TIME OF THIS SPRAY BOOTH IS Seconds DO NOT raise visor whilst spraying or during the clearance time DO NOT enter without air fed breathing apparatus during the clearance time ISOCYANATES IN PAINT CAN CAUSE ASTHMA Test date Spray booth model Test carried out by Spray booth number Date of next test lIsocyanate paint spraying Safely managing spray booths and rooms Page 19 of 23 Health and Safety Executive Appendix 5 Essential design features of spray booths and rooms Input filter Q in gos oy Negative pressure Qout should be slightly greater than Qin Good lighting u U g g 4 g g You should be able to reach the door while still wearing your BA might mean the plug in point needs to be moved Good physical integrity Filtration may have Q out to comply with environmental legislation Figure 14 Essential features of a spray booth Planned make up air Good lighting You should be able to reach the door while Good physical integrity still wearing your BA might mean the plug in point needs to be moved Filtration Figure 15 Essential features of a spray room lIsocyanate paint spraying Safely managing spray booths and rooms Page 20 of 23 Health and Safety Executive Appendix 6 Commissioning thorough examination and testing Commissioning Spray booths rooms
7. practical the light should be also visible from the inside of the booth room m When spraying stops a timer ensures the light stays on for the clearance time period 4 Leaving a spray booth or room safely Sprayers and other users must know the clearance time of their booth or room The sprayer does not need to stand in the booth room while waiting for it to clear but must know how to leave the booth room safely during the clearance time To leave a booth room safely during the clearance time m walk to the pedestrian door wearing air fed BA The air hose must be long enough and the connection point by the door m open the door unplug the airline and hang it next to the door m step out shut the door and remove the air fed BA lsocyanate paint spraying Safely managing spray booths and rooms Page 12 of 23 Health and Safety Executive Local exhaust ventilation LEV efficiency Commissioning HSE guidance Controlling airborne contaminants at work A guide to local exhaust ventilation LEV gives advice on commissioning systems including diagrams and a description of the system including test points details of the LEV performance specification results such as pressures and velocities at stated points a written description of the commissioning the tests undertaken and the outcome See Appendix 6 for further details Checking and maintenance Engineering controls such as booths rooms and extracted enclosures must be
8. spray fine paint mist changing spares agree booth causing booth room run time or roo exposure to becomes similar appoint other workers pressurised a responsible within the person premises as E Air in out well as in imbalance Daily checks on j j hysical state ee E Poor booth 4 i integrity eg Prior to use damaged or check pressure missing door readings and seals records kept E Failure of automatic over pressurisation shutdown system Filter and Spray booth E Booth room E isocyanate Provide discharge room exhaust extract air not exposure for adequate extracted recirculates filtered those using the exhaust filters air safely into the workplace and two stage that workplace E Poor discharge possibly those discharge to a position nearby safe position including the public Brief E Operator E Little E Very high short Explain the risks train and raises visor or understanding term isocyanate supervise removes BA of the risks exposure Ensure sprayers during awareness of clearance time E Poor lighting levels So can t see the quality of the paint finish E No knowledge of clearance time and procedures E Poor visibility through visor E Poor supervision clearance time provide training Provide and maintain suitable lighting Agree and explain safe methods of working Check and maintain the air fed BA including visor and tear off strips lsocyanate paint sprayi
9. surroundings so that any air is drawn into the booth or room This is commonly referred to as running at negative pressure For spray gun cleaning use an extracted gun cleaning machine or spray wash guns in the spray booth room with the extraction turned on Respiratory protective equipment People going into the booth room when spray mist is likely to be present should always wear suitable air fed RPE See Safety in isocyanate paint spraying for more information on RPE Historically sprayers have lifted their visors to check on the quality of a paint finish This practice should be avoided at all costs It is essential that the sprayer must not flip up the visor of the air fed BA either while spraying or once they have finished spraying and during the clearance time Enclosure design The more effective the spray booth room the lower the isocyanate concentration in the air Spray booths are usually more effective than spray rooms Spray booths Spray booths are specially designed enclosing rooms sometimes called cabins usually including a sophisticated ventilation and control system The most common design of spray booth is the downdraft booth Air enters the booth through a large area of the ceiling and is extracted through a grated opening in the floor There are other booth designs but they tend to have the following characteristics an air inlet fan and an extract fan the inlet and the outlet air is filtered
10. to isocyanate is paint spraying All paint spraying including spraying 2 pack isocyanate paint produces over spray most of which you cannot see under normal lighting The invisible mist will reach all parts of a workplace if not properly controlled It fills the workplace soon after spraying has started and spreads like smoke It can be made visible with special lighting See Figures 1 and 2 Figure 1 Now you see it Figure 2 Now you don t lsocyanate paint spraying Safely managing spray booths and rooms Page 5 of 23 Health and Safety Executive Breathing in this invisible fine mist is what can cause occupational asthma After spraying elevated levels of isocyanates may also be present during curing The only other potentially significant source in bodyshops is cleaning spray guns inappropriately Mist from spray gun cleaning can contain high concentrations of isocyanate Controlling exposure Enclosure Most jobs should be done in an enclosed ventilated spray booth or room However minor work may be carried out in an extracted enclosure specifically designed for the purpose eg a spray cabinet The spray booth room is there to capture all the isocyanate paint mist which effectively protects all other people working nearby Booths rooms should not leak airborne paint mist To prevent fine airborne paint mist escaping into the workplace all soray booths rooms should be run at a slightly lower air pressure than the
11. BN 978 O 7176 6446 7 www hse gov uk pulbns books eh40 htm 3 Health surveillance for occupational asthma COSHH essentials sheet G402 HSE 2006 www hse gov uk pubns guidance g402 padf 4 An automated system for indicating spray clearance times of MVR spray booths and rooms Health and Safety Laboratory research report www hse gov uk research rrodf rr742 pdf 5 Controlling airborne contaminants at work A guide to local exhaust ventilation LEV HSG258 Second edition HSE Books 2011 ISBN 978 0 7176 6415 3 www hse gov uk pubns books hsg258 htm 6 Control of substances hazardous to health The Control of Substances Hazardous to Health Regulations 2002 as amended Approved Code of Practice and guidance L5 Sixth edition HSE Books 2013 ISBN 978 O 7176 6582 2 www hse gov uk pubns books I5 hAtm lsocyanate paint spraying Safely managing spray booths and rooms Page 22 of 23 Health and Safety Executive Further reading General MVR advice including paint spraying m www hse gov uk mvr index htm m Health and safety in motor vehicle repair and associated industries HSG261 HSE Books 2009 ISBN 978 O 7176 6308 8 www hse gov uk pubns books hsg261 htm Paint spraying mg Safety in isocyanate paint spraying Leaflet INDG388 rev2 HSE 2013 www hse gov uk pubns indg388 htm m SMART paint spraying How to control health and safety risks Leaflet INDG473 HSE Books 2013 www hse gov uk pubns indg473 htm m MVR COSHH essentials summary sheet www hse gov uk m
12. Health and Safety Executive isocyanate paint spraying Safely managing spray booths and rooms This guidance is aimed at vehicle body shop owners managers and supervisors their employees particularly paint sprayers and suppliers It will also be useful to industries other than motor vehicle repiair MVR where there is spraying of isocyanate containing paints and lacquers It replaces the previous HSE publication Controlling isocyanate exposure in spray booths and spray rooms HSG276 published 2014 Page 1 of 23 Health and Safety Executive Contents Introduction 3 Who is the guidance for 3 What does the guidance cover 3 What does the guidance not cover 3 Isocyanate paint health risks 3 The bad news occupational asthma 3 The good news there is a solution 4 What the law says 4 Control exposure 4 Monitor exposure 5 Health surveillance 5 Report occupational asthma 5 What you need to know and do 5 Understand exposure 5 Controlling exposure 6 Enclosure 6 Respiratory protective equipment 6 Enclosure design 6 Spray booths 6 Spray rooms 7 Spray booth or room leakage 7 How extract ventilation works 7 How the air moves in a spray room 9 Air movement in downdraft soray booths 10 Air movement in cross flow or tunnel booths 11 Clearance time 11 How long the spray booth or room takes to clear 11 Clearance time sign and indicator 12 Leaving a spray booth or room safely 12 Local e
13. and rooms Page 7 of 23 Health and Safety Executive Figures 5 6 and 7 show the throw of a typical paint spray gun using smoke to make the air jet visible Figure 6 Two seconds after spraying started Figure 7 Four seconds after spraying started To see spraying in practice including the gun throw shown above and related isocyanate exposures watch the videos at www hse gov uk mvr resources videos htm lsocyanate paint spraying Safely managing spray booths and rooms Page 8 of 23 Health and Safety Executive How the air moves in a spray room It is often believed that air moves through a spray room smoothly from the inlet s in one wall to the extract in another wall carrying any paint mist with it Unfortunately this is not the case and air movement in spray rooms tends to be quite random and reasonably well mixed The only areas where the air movement has any noticeable direction is close to the room air inlet s and very close to the extract fan However spraying close to the fan in the belief that the over spray will be easily captured is misguided This doesn t happen because the flow of air from the spray gun easily overcomes the pull of the extract fan and the paint mist spreads throughout the room see Figures 8 and 9 FILTER IN DOOR AIR IN gt Y SN Oe f p e 5 1 a gt l venees gt gt om gt eee iz Rough limit of iy gab gt gt gt ay E detectable
14. ar basis air supply filters and compressor list of replacement parts and part numbers m smoke tests clearance time test leakage test See Further reading m instruction on how to use the enclosure safely m details of thorough examination and testing If you do not have a user manual for your spray booth room you should obtain or develop one with help from the supplier installer manufacturer or other industry advisers Thorough examination and test In addition to regular checks and maintenance the spray booth room or extracted enclosure should be thoroughly examined and tested by a competent person at least once every 14 months This is a requirement of COSHH regulation 9 lsocyanate paint spraying Safely managing spray booths and rooms Page 13 of 23 Health and Safety Executive The thorough examination and test is in effect an audit of your own checking and maintenance over the year Follow the recommendations in the report of thorough examination and test and if it s clear that the spray booth room operation or fabric has deteriorated look critically at your own checking and maintenance Records need to be kept for at least five years See Appendix 6 for further details A thorough examination and test report should include smoke tests for clearance and leakage Velocity measurements within the booth room may also be made as a check on the amount of air entering and on the evenness of air v
15. cle paint sprayers working in MVR bodyshops and in the commercial vehicle lsocyanate paint spraying Safely managing spray booths and rooms Page 3 of 23 Health and Safety Executive and trailer manufacturing industry Their risk is about 90 times greater than the industrial average for contracting occupational asthma Isocyanate paint mist is invisible and breathing it in can cause occupational asthma It is not absorbed through the eyes or skin although liquid paint on the skin can cause dermatitis Typical early signs of respiratory sensitisation to isocyanates include one or more of the following m chest tightness often occurring outside working hours in the evening or early morning persistent cough recurring blocked or runny nose recurring sore or watering eyes wheezing breathlessness flu like shivers If a person has early symptoms and continues to be exposed to isocyanates they may suffer from permanent sensitisation to isocyanates and severe occupational asthma for which there is no cure At this stage asthma could be triggered by everyday smells or even cold air This is a life changing event and even a tiny amount of exposure to isocyanates could trigger an attack It would almost certainly mean the person has to give up their current job They may also have lungs that are affected by asthma over the long term even when exposure to isocyanates has stopped The good news there is a solution The risk is
16. eck and practical checks maintain and equipment maintenance E No spare parts Carry enough are kept in spare parts on store site Keep suitable inspection and maintenance records and audit them lsocyanate paint spraying Safely managing spray booths and rooms Page 17 of 23 Health and Safety Executive Common Common causes Effects What you What you are going Check your exposure control measures are working problems E People don t follow safe working procedures and expose themselves to isocyanate during the clearance time E Controls are assumed to work and no checks are done E ve told them to wear it but what can you do E Some people follow procedures and safe working methods and others don t Control of isocyanate exposure is erratic Risk of occupational asthma rises for some people should do E Measure isocyanate exposure of sprayers and others who need to enter the booth room using urine sampling Do this soon after employing a new starter and annually If exposure is consistently well controlled reduce the frequency of test Provide health surveillance lung function tests and questionnaire to measure lung deterioration and identify early symptoms of ill health that may have been caused by exposure to isocyanate paints Isocyanate paint spraying Safely managing spray booths and rooms to do Page 18
17. efer to this guidance This leaflet is available at www hse gov uk pubns hsg276 htm Crown copyright If you wish to reuse this information visit www hse gov uk copyright htm for details First published 02 14 Published by the Health and Safety Executive HSG276 02 14 Page 23 of 23
18. elocity The measurements allow you to compare performance from one year to the next consistency so measurements should be made at standardised positions for instance at fixed points and heights This is easier and quicker to do with no vehicle present and will give results that are easier to compare After a thorough examination and test it is now industry accepted practice that the spray booth room should have a label attached to it stating when it was tested and examined who did it and when it will be re tested If the booth room fails the annual thorough examination and test eg because it was operating at a positive pressure the examiner should also attach an additional usually red label indicating this The spray booth room should not be used until the fault is rectified and it is shown to be operating as intended Appendix 1 Key messages Key message 1 What spray booths and spray rooms do Contain the paint mist Dilute the paint mist Reduce potential exposure of the sprayer but air fed BA must also be used Prevent the exposure of other people who are outside the spray booth room Filter and discharge the extracted air to the atmosphere Key message 2 Spray booth room operation and sprayer behaviour m The booth room should operate under a negative pressure all leaks must be inwards m You should have a negative pressure indicator fitted m Check the sprayers know how to behave in the booth room and how to leave
19. ion needed to better control exposure to isocyanates Common Common causes Effects problems What you should do What you are going to do Know the Don t know E Cant see the E Regular E Measure the clearance time that a spray booth room has a clearance time Guess at the clearance time paint mist E Think that air flows straight out taking the over spray with it isocyanate exposure to the sprayer Isocyanate exposure to those using the workplace and possibly those nearby including the public clearance time using a smoke test Show the clearance time Clearance time is known but not shown and nobody knows what to do Poor management and communication Regular high short term isocyanate exposure for the sprayer Isocyanate exposure to those using the workplace and possibly nearby including the public Put up a clear sign on all entrances to the spray booth room Explain to all who need to know Install a simple clearance time indicator lsocyanate paint spraying Safely managing spray booths and rooms Page 15 of 23 Health and Safety Executive Common causes Common What you What you are going problems should do to do Contain Booth room E Extract filter E High isocyanate E Manage filter all paint leaks or blocked and exposure to all changing mist in discharges needs using workplace procedure keep
20. isocyanates in the air during spraying and clearance always substantially exceed the WEL People going into the booth room should always wear suitable RPE The spray booth room is there to capture all the isocyanate paint mist which effectively protects all other workers nearby Monitor exposure Currently the only practical way to monitor the personal exposure from isocyanate spraying from all routes of exposure involves the worker providing a urine sample at the end of a shift This checks whether the combination of all the protective measures is working see Safety in isocyanate paint spraying Health surveillance You should also provide health surveillance for paint sprayers see Safety in isocyanate paint spraying and Health surveillance for occupational asthma HSE s COSHH sheet G402 Urine testing only provides information about exposure and has no direct link with the person s health Report occupational asthma The Reporting of Injuries Diseases and Dangerous Occurrences Regulations 2013 RIDDOR require employers to report any medically confirmed cases of asthma or dermatitis caused by exposure to isocyanates at work see www hse gov uk riddor What you need to know and do The key messages about managing spray booths rooms are summarised in Appendix 1 See also Appendices 2 and 3 for the key things sprayers and bodyshop owners managers need to know and do Understand exposure The main source of exposure
21. ks from isocyanate paint what the law says how people are exposed to isocyanate important properties of spray guns and paint spray how spray booths and rooms work clearance indicators and other essential instrumentation testing spray booths and rooms advice on the design and maintenance of booths and rooms advice on how to carry out smoke tests on spray booths and rooms the sprayer s steps to safe working a checklist of good practice common errors and solutions What does the guidance not cover This guide does not cover in detail other health and safety issues relating to paint spraying such as m safe storage and mixing of paints m selection and use of appropriate respiratory protective equipment RPE for spraying isocyanate based paints m health surveillance and biological monitoring requirements for workers involved in spraying isocyanate based paints m small and medium area repair SMART techniques Information on these topics can be found at www hse gov uk mvr and in other HSE publications see Further reading isocyanate paint health risks Almost all bodyshops use paints and lacquers containing isocyanate hardener It is important to remember that water based paints can still contain isocyanates The bad news occupational asthma Materials containing isocyanate have for many years been the single biggest cause of occupational asthma in Great Britain The workers at greatest risk are vehi
22. ld be written down and done in a standard way so that they can be repeated during thorough examination and test work For instance in a down draught booth the supply and extract volume flows should be measured For booths it is also useful to measure internal air velocities at fixed points for instance in front of the supply filter panels and above the extract grilles Then these results can be compared with later measurements as a measure of booth room air flow performance Thorough examination and test Spray booths rooms and extracted enclosures should be examined by a competent person at least every 14 months The examination and test should compare the performance of the booth room extracted enclosure etc with the commissioning test findings Air fed BA should also be examined typically every month in line with the manufacturer s instructions Additionally the air supply quality should be tested every three months Test report The thorough examination and test report should contain at least the following details m name and address of the employer responsible for the plant m identification and location of the LEV plant and the process and hazardous substance concerned m date of the last thorough examination and test lsocyanate paint spraying Safely managing spray booths and rooms Page 21 of 23 Health and Safety Executive m date of the current examination and test m name job title and employer of the person
23. ng Safely managing spray booths and rooms Page 16 of 23 Common problems Common causes What you should do Health and Safety Executive What you are going to do Check E Checks E No E Particularly high Manage spray and maintenance management isocyanate booth room maintain not done or system or exposure for checks your only when appreciation of sprayers but the maintenance spray ventilation fails risks sprayer should and use booth be protected by No user BA Get or develop room manual and or a user manual inadequate E Others in your guidance from workplace may Brief and explain supplier also be exposed procedures for without all concerned protection including the sprayers and Loss of bodyshop production manager Check E No checks are E Air fed BA is E Deterioration in Train sprayers to and made and air assumed to protection check maintain flow and or work without a equipment air fed quality falls any need for Poor visibility before each use BA checks and means sprayer and report E BA equipment maintenance flips up raises defects is not visor checked and Air fed BA is Appoint a maintained not seen as a Sprayer responsible and protection equipment like isocyanate person to check deteriorates the booth or exposure rises and maintain room equipment E Risk of monthly could E No one is occupational be the sprayers made asthma themselves responsible or Increases given time to Agree simple ch
24. oths Guidance on how to perform this test is given at www hse gov uk mvr bodyshop cleartime htm If you have a large commercial spray booth room then a professional smoke generator will probably be required These are more expensive therefore it might be more cost effective to ask the company who carry out the thorough examination and test to do this for you See the section Thorough examination and test Smoke clearance tests are not exact and times measured are approximate The initial test should be done under worst case circumstances for instance just before the extract filters need replacing Measuring the clearance time should also form part of the thorough examination and test Clearance time sign and indicator Once you have determined the clearance time you should place a plain and simple sign at all entrances to the spray booth room that states the clearance time when the test was carried out who carried out the test when the test will be repeated An example of a clearance time certificate is given in Appendix 4 The preferred method of informing workers when a spray booth room is safe to enter is by installing an automatic clearance time indicator For instance m This could consist of a sensor installed in the compressed airline that detects when the spray gun is being used m During spraying a light could be illuminated on the outside of the booth or room indicating that people must not enter m f
25. regularly checked and maintained Details of what an employer should arrange to be done should be provided in the user manual Booth or room user manual Equipment suppliers are legally obliged to provide adequate information about how it should be used how it has been designed and tested and any conditions necessary to ensure it is safe and without risks to health throughout its operating life HSE s guidance Controlling airborne contaminants at work A guide to local exhaust ventilation LEV recommends that just like a car spray booths rooms should be supplied with a user manual The level of detail will depend on the complexity of the spray booth room Typically the user manual should cover the following and include a log book or equivalent so that you can record your findings m a description of the spraying enclosure including a drawing m aregular maintenance schedule and description of the checks needed to ensure the enclosure is operating as designed and commissioned for example daily weekly and monthly checks with example sheets for recording the checks and any actions taken m air quality tests for BA supply to be performed at least once every three months unless you have evidence to demonstrate that air quantity and quality are stable m maintenance filter replacement schedule lights eg replace failed bulbs Keep covers clean consider fitting protective film to the lights which can be replaced on a regul
26. require commissioning The main issues to be covered in commissioning any local exhaust ventilation LEV system are identified in Controlling airborne contaminants at work A guide to local exhaust ventilation These include diagrams and a description of the system including test points details of the LEV performance specification results such as pressures and velocities of stated points calculations a written description of the commissioning the qualitative and quantitative tests undertaken including air sampling results where necessary and the outcome m adescription of operator behaviour for optimum LEV effectiveness Table 17 of Controlling airborne contaminants at work A guide to local exhaust ventilation contains further useful information on the principles of commissioning LEV plant Our understanding of booths and rooms and the most important factors that control exposure has improved The emphasis during commissioning has previously been mainly on the booth room air change rate and in the case of booths the velocity of air at fixed points around a vehicle inside it Now the emphasis is on measuring the clearance time and ensuring that the booth room runs at slightly negative pressure so it doesn t leak during spraying The smoke test is important in achieving that Air velocities and pressures measurement will also be important to establish the technical performance of a spray booth room Measurement procedures shou
27. s see Figures 12 and 13 AIR OUT Figure 13 What really happens Clearance time How long the spray booth or room takes to clear Many spray booth room designers have focused on factors such as the number of air changes per minute that occur the implication being that the more air changes the better for the booth room For the sprayer the most important issue is how the air flows within a booth room and how long it takes to clear the invisible airborne paint mist Carrying out a smoke test on a booth room will allow you and your staff to see how air moves and how long it takes to clear lsocyanate paint spraying Safely managing spray booths and rooms Page 11 of 23 Health and Safety Executive Once spraying stops the air passing through the booth room will dilute and displace the invisible airborne paint mist and eventually remove it The time taken for the fine paint mist to be removed is known as the clearance time The time for your booth room will depend on the design and the volume of air moving through it Typically a booth will clear in less than five minutes but a room could take 20 minutes or longer Everyone involved must know how long their spray booth room takes to clear A practical way to measure the clearance time is to carry out a smoke test You can do this yourself Smoke party fog machines are relatively inexpensive and many are suitable for determining clearance times of standard sized bo
28. th during paint spraying and for a considerable time afterwards Spray booth or room leakage The most practical way to check leakage is not happening is to combine the clearance smoke test with a leak test When you or your contractor fills the spray booth room with smoke have someone outside check that there s no leakage of smoke Sometimes the booth doesn t leak air but the associated ductwork does The smoke test will show this up To check that spray booths rooms are operating at negative pressure they should be fitted with a negative pressure indicator This indicates that the booth room is not leaking and should be checked prior to each spraying operation A simple manometer should be adequate for booths S URRLITIETTR aS Figure 3 Example of a manometer fitted to Figure 4 Example of a swinging vane a spray booth fitted to a spray room How extract ventilation works Don t think that the ventilation will instantly sweep away the airborne paint over spray in the booth room It can t and it doesn t Spray guns are powered by compressed air This leaves the gun s air cap at over 100 metres per second and with a throw of well over 5 metres from the gun Most ventilation only generates air movement of around 0 5 metres per second so the air jet from the spray gun overwhelms the air movement inside a booth room and rapidly fills it with fine paint mist Isocyanate paint spraying Safely managing spray booths
29. vr resources summary paf m Individual COSHH sheets for MVR www hse gov uk mvr topics general coshh htm Clearance testing m Party fog machines suitable for measuring clearance time Review and clearance time method HSL 2006 43 www hse gov uk research hsl_pdf 2006 hsl0643 pdf Extraction systems m Local exhaust ventilation www hse gov uk lev index htm Biological monitoring and health surveillance m Biological monitoring in the workplace A guide to its practical application to chemical exposure HSG167 HSE Books 1997 ISBN 978 0 7176 1279 6 www hse gov uk pubns books hsg167 htm m Urine sampling for isocyanate exposure measurement COSHH essentials sheet G408 HSE 2006 www hse gov uk pubns guidance g408 pdf m Health surveillance for occupational asthma COSHH essentials sheet G402 HSE 2006 www hse gov uk pubns guidance g402 pdf Further information For information about health and safety or to report inconsistencies or inaccuracies in this guidance visit www hse gov uk You can view HSE guidance online and order priced publications from the website HSE priced publications are also available from bookshops This guidance is issued by the Health and Safety Executive Following the guidance is not compulsory unless specifically stated and you are free to take other action But if you do follow the guidance you will normally be doing enough to comply with the law Health and safety inspectors seek to secure compliance with the law and may r
30. xhaust ventilation LEV efficiency 13 Commissioning 13 Checking and maintenance 13 Booth or room user manual 13 Thorough examination and test 13 Appendices Appendix 1 Key messages 14 Appendix 2 Sprayer s steps to safe working 15 Appendix 3 The employer s manager s checklist 15 Appendix 4 Example of a clearance time certificate 19 Appendix 5 Essential design features of spray booths and rooms 20 Appendix 6 Commissioning thorough examination and testing 21 References 22 Further reading 23 Further information 23 Isocyanate paint spraying Safely managing spray booths and rooms Page 2 of 23 Health and Safety Executive Introduction Who is the guidance for This guidance is aimed at vehicle bodyshop owners managers and supervisors their employees particularly paint sprayers and suppliers It will also be useful to industries other than motor vehicle repair MVR where there is spraying of isocyanate containing paints and lacquers It replaces the previous HSE publication Controlling isocyanate exposure in spray booths and spray rooms WEBS36 What does the guidance cover This guidance focuses on the management of m spray booths specially designed enclosing rooms usually including a sophisticated ventilation and control system m spray rooms not as sophisticated as booths and usually homemade typically with simple extraction through a fan fitted in an outside wall It explains health ris
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