NEW HSE GUIDANCE ON CONTROLLING

EXPOSURE TO COATING POWDERS

Martin Stear HSE's Chemical Agents Occupational Hygiene Unit

In April 1999 Product Finishing included an article which reported the results of a HSE survey of occupational exposure to coating powders, carried out in 1994. That article provided a summary of HSE's work to address occupational exposure to particulates during the manufacture and use of coating powders. It reported, in particular, that many users of coating powders were not controlling exposure to total inhalable particulate (TIP) (i.e. the total inhalable dust in the air from all sources), and that these control issues would exist even if TGIC (triglycidyl isocyanurate) was not being used. TGIC is a curing agent for polyester coating powders which is classified as a category 2 mutagen. Controlling TGIC is important, but the survey showed that they may be a risk to workers health even if it is not present in the powder, because of the large amounts of dust that can be breathed in.

The article went on to report that HSE was developing a guidance package to help improve the control of exposure to coating powders. This guidance package has now been produced. It contains:

1. a booklet ‘Controlling exposure to coating powders’ (priced at £10.95) for employers (details for HSE books are included at the end of this article);
2. which includes a free CDROM, containing a training module; and
3. a free leaflet for employees, ‘Working safely with coating powders’.

This new guidance was developed to reduce the risk of ill health in the powder coating industry, through raising employer and employee awareness of the potential risks, by:

• providing employers with a practical reference guide in order that they can compare their powder coating operation with the minimum standards to be achieved;
• providing employees with an informative leaflet in order that they can appreciate the risks to health and the steps that can be taken to reduce exposure to the dust; and
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• providing employers with a training module on CDROM, furnishing them with a ready-made presentation to raise employee awareness.

HSE have focused on training and awareness as this was seen as the underlying reason why exposures have been found to be so high. Occupational exposure levels up to 131 mgm^-3  8-hour TWA (Time Weighted Average) were measured during the use of coating powders. This is significantly above 10 mgm^-3  8-hour TWA, a substantial concentration of inhalable dust as defined by COSHH 1999 . Because of these findings, the guidance focuses on control of total inhalable particulate, rather than just TGIC.

Why such high exposures?

In 1994 HSE found poor awareness of the risks to health amongst employers and employees. For example:

• employers were unaware that exposures were high;
• employers were unaware that they were wasting powder and increasing process costs;
• employers perceived the 10 mgm^-3  8-hour TWA to be a "thick fog", which is more typical of the explosive dust concentration of 10 grams.m^-3; and
• some companies were unaware that they were using coating powders which contained agents of special concern, for example TGIC, where alternatives would have sufficed.

Poor awareness results in poor working practices, with:

• poor equipment set-up;
• operators leaning into spray booths, both manual and automatic, as they believed this to be necessary to ensure a good coating;
• operators spraying towards each other’s breathing zone;
• the extensive use of compressed air and brushes for cleaning;
• the general poor handling of powders;
• significant dermal exposure; and
• poor selection and use of personal protective equipment.

Why such poor awareness?

It would appear that in many cases operators have received little or no training in good working practices. They are not aware that powder is electrostatically attracted to the work piece, and perceive that more is better and simply spray as much powder as possible. Working to deadlines or with the incentive of bonuses they turn-up the gun settings to deliver as much powder as possible. This not only increases their exposure but also wastes powder, increasing process running costs. Workers also lean into booths to ensure a good finish as they believe this to be necessary, again increasing their exposure.

Improving plant set-up, ensuring the correct gun settings are used and increasing employee awareness can overcome many of these problems.

The new reference guide - ‘Controlling exposure to coating powders’.

This new guidance takes each stage of the powder coating operation, discusses how exposure arises and the types of bad practice that can occur, and then advises on what needs to be done to achieve adequate control of exposure. It covers.

The guidance also explains the general principles of assessing exposure; what information is needed and how to go about finding out whether you have a problem. The legal requirements, occupational exposure limits, selection and use of personal protective equipment are also explained. Real-life case studies are included to show how adequate control of exposure can be achieved, and how this can have a beneficial impact on other areas of the business, for example by reducing process running costs.

Training is always a key element in any strategy to reduce occupational exposure. With powder coating the importance of good training for employees can not be overstated. If employees believe that ‘more is better’ they will keep on spraying too much powder. If they don’t understand what electrostatic powder coating means they will keep on leaning in to the spray booth. Employees need to be instructed on the way in which the process works and the safe systems of work they need to follow.

HSE has produced a free leaflet, as reported at the start of the article, aimed at raising awareness. But, the messages in this leaflet need to be reinforced by good training. The CDROM provided with the employer booklet provides a ready-to-use training module to help raise employee awareness.

Using diagrams, photographs and narration the short electronic training module guides employees through the health risks from working with these coatings and the steps needed to reduce the risk of ill health. It provides the opportunity to discuss working practices by asking the audience questions and then pausing to allow discussion. With the inclusion of print options the training module can be used on a desktop computer or delivered to a larger audience using an overhead projector.

This new package of guidance material from HSE has been developed with the help of the British Coatings Federation and the Surface Engineering Association. Users of coating powders have also been consulted. The assistance of these powder coating experts has helped to make sure that it provides maximum benefit to employers. Don’t forget that following the guidelines will not only reduce the risk of ill health, but can also benefit your business by helping to maximise the efficiency of your powder coating operations.

If you would like copies of the booklet (including free CDROM) or leaflet then contact HSE Books on 01787 881165 or www.hsebooks.co.uk.