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Workplace atmospheres - LEV us alone!
Friday, 01 September 2006 00:00

Malcolm Griffiths looks at heath & safety in the Finishing industry and says that the HSE is concentrating on the coatings applications field.

Since joining the paint industry in 1963, Malcolm  has worked for several leading coating manufacturers. He is a graduate in chemistry, Fellow of the Institute of Metal Finishing and a Chartered Member of the Institute of Occupational Safety and Health. He now runs the independent coatings advisory service Ad Qual Castech Limited.

Although we both starting in paint development laboratories, my colleague Mike Cowley and I have evolved from slightly different strands of the finishing industry.  Each of us has also been heavily involved in technical support of coating application processes, though Mike worked mainly for equipment manufacturers and I have worked mainly for coating manufacturers.  However, at various times, we have each been on the ‘other side of the fence’.  As independent advisers, we need to be objective and our differing experiences are a definite plus in that respect, though it has frequently led to some interesting conversations!  

The point is that spray booths, fume cupboards and other types of local exhaust ventilation (LEV), are important factors in protecting us from exposure to hazardous materials in the workplace, apart from the risk of fire or explosion. Obviously, there needs to be close liaison between companies supplying equipment, those supplying materials and their mutual customers, the end users applying the coatings.

Due to my involvement as a health & safety advisor, I have noticed that recently the HSE are increasingly concentrating on the coatings application field as part of their drive to minimise occupational illnesses such as emphysema, dermatitis and respiratory or skin allergies.  One aspect that they are particularly interested in is the proper control of solvent fumes and the dust from overspray, especially where coatings are being sprayed.  Insurers too are becoming much more insistent on seeing that proper controls are in place for such processes, because of their potential long term liabilities.

There is a massive range of regulations and guidance that relate directly to coatings and an even larger number that relate indirectly.  There has been a lot of criticism of the HSE that they have created too much red tape and, if any manager ever finds they have a day or two to spare, they could always prove it for themselves by trawling through it. Talk about gilding the lily!  Often regulations seem to be introduced as nothing more than ‘change for change sake.’ Personally, I blame the industry for not arguing its case strongly enough in the past – always on the defensive.  Nevertheless, the rules are in place and many of them are there for good reasons.  

In the design stage, plant manufacturers need to determine the necessary air movements to keep the work area safe.  We shall ignore the added complication of environmental emissions for the moment.  The equipment suppliers have duties under Section 6 of the Health & Safety at Work etc Act 1974 (HWSA) and the Supply of Machinery (Safety) Regulations 1992.  This latter piece of legislation includes a Schedule listing specific risks known as the Essential Health & Safety Requirements (EHSR), which every equipment manufacturer should address at all stages during the design and manufacture of their products.  Many of the points would normally be included in a well-prepared manual but the supplier should also provide certification explaining how they have control any risks and pointing out any that are not covered – the residual risks.  

In a similar way, suppliers of substances must inform users of the likely hazards when using their products, as required by the Chemical (Hazard Information & Packaging for Supply) Regulations 2002 (CHIP3). This is done through labels and safety data sheets. We have found a few exceptions lately, where companies supplying products manufactured in the USA are providing information that is non-compliant. Agents and intermediaries in this country are responsible for re-labelling products and re-writing those data sheets into a format complying with CHIP3.  

Now we come to the end user, spraying his hazardous substance into his shiny new spray booth.  He has general duties under HSWA and the Management of Health & Safety at Work Regulations 1999more specific duties too, not least under the Provision & Use of Equipment Regulations 1998 (PUWER) and Control of Substances Hazardous to Health Regulations 2002 (as amended 2005).  (CoSHH).   At this point that dreaded phrase ‘risk assessment’ rears its ugly head.

As an aside, it always puzzles me that, in this, the age of computers, the Health & Safety Commission, who have been responsible for piling virtually every social ill onto the workplace, are still allowed to produce their regulations in gibberish and then (adding insult to injury) issue an amendment - equally unintelligible – which the average Joe is expected to know and comply with.  Then the HSE – bless ‘em – come along and interpret for us. Anyway, back to the plot …

I look for five factors in a risk assessment:   Substances, Personnel, Arrangements, Conditions and Equipment: spelling out S-P-A-C-E.  As you can see, if the suppliers have done their job properly, end users should be able to find lots of information about the substances and equipment. .  But the suppliers won’t know how their products are used on a daily basis.  For instance, they won’t know how much material is being sprayed, or that a different coating is being used from the one that the equipment was designed for. They won’t know if the operators have allergies or if they are highly training and aware of the hazards or if they are kept uninformed. They won’t know whether the spray booth is running at its proper settings or if filters are blocked, perhaps allowing overspray to contaminate the workshop.  All the training, information, setting up safe systems of works, control and supervision etc is totally in the hands of the user.  

Although it is not generally interpreted that way, CoSHH states that exposure to hazardous substances must be PREVENTED and that, only if that is not reasonably practicable can we revert to risk assessment and control measures. I would point out that absolute prevention is not normally possible when using a material.  Replacement with a suitable alternative is the only sure way of complying but, unless we stop our processes altogether, that is not a serious option.  In the vast majority of cases, we are left having to control our operations.  Air monitoring is the main way of demonstrating that substances are under control but remember that allergic reactions can occur in susceptible individuals at concentrations far below any published exposure standard.  

Just in case anyone is still not yet aware of it, the Workplace Exposure Limit (WEL) is the new standard measure of the concentration of airborne contamination averaged over a specified period as a Time Weighted Average (TWA). This has replaced the original Occupational Exposure Standards and Maximum Exposure Limits.  You can still find the regular issues of the Guidance Note EH40 listing WEL values.  

Interestingly, some powder manufacturers and applicators recycle filtered process air back into the workplace, mainly to avoid environmental issues. If the after-filter were to be ruptured, they would automatically breech regulations by exceeding the WEL for dust-in-air. Such plants really need a failsafe device to automatically detect a breech and to shut down the plant immediately.

A number of regulations in CoSHH relate to those controls – e.g. exhaust fans; spray booths; cyclones; after-filters – and specify that engineering controls must be checked regularly and thoroughly inspected at minimum 14-monthly intervals. In their booklet HSG54 - Maintenance, Examination and Testing of Local Exhaust Ventilation, the HSE again spell what they expect, in terms of static pressures and face velocities. Interestingly, equipment manufacturers rarely provide data in that format but usually talk of air-changes per hour in the workshop and duct velocities.   Obviously, there needs to be more communication.


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