Powder Coatings Health & Safety

The British Coatings Federation (BCF) have published a booklet `Code of Safe Practice for the Application of Thermosetting Coating Powders by Electrostatic Spraying’. This is available from the BCF. Other European countries recommendations are contained in `Safe Use of Powder Coatings’ which is issued by the Confederation of European Paint Manufacturers (CEPE).

Health and safety risks: The main risks involved in powder coating arise from the possibilities of dust explosion, fire electric shock, exposure to hazardous materials, compressed air etc.

Dust explosion and fire hazards: Processes which involve mixing air and combustible organic powders can be dangerous. A dust explosion may take place when both:

1) The concentration of powder in the air is above the lower explosive limit (LEL)

2) A source of ignition with the required degree of energy is present at the dust cloud; such sources of ignition can be hot surfaces, open flames, electrical or electrostatic discharges.

A fire can occur when a layer of deposited powder material or a powder cloud comes in contact with an ignition source mentioned in b) above. This type of fire can result in an explosion.

Thermosetting powders are only hazardous when within a certain range of powder-air mixture concentrations. In a well designed and operated powder coating plant these concentrations can only occur within the spraying and recovering system and this is therefore taken into account in their design.

Ignition temperature for usual powder-air concentrations is very high. A typical epoxy powder ignition temperature is approximately 500° C.

Electrical hazards: The main sources of electrical hazard are:

1) Improper or defective grounding systems that may lead to the build-up of electrostatic electricity and subsequent sparking or shock

2) Broken-down or overheated electrical equipment that could lead to fire or shock.

Exposure to hazardous materials: Powder coating materials contain many different components. Some of these substances may, depending upon the formulation, present a health hazard to the operating personnel, but only if they are allowed to escape into the working area because of improper handling or insufficient ventilation.

A particularly hazardous component in the powder coating material, if any, must be indicated by the supplier of the material on the product label and on the provided `Safety Data Sheet’ (SDS). Guidance will be included on the `Workplace Exposure Limits’ (WEL) and the precautions will be indicated which have to be taken in case of skin contamination or respiratory inhalation.

The HSE has developed 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 
• providing employers with a training module on CDROM, furnishing them with a ready-made presentation to raise employee awareness.

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 was developed with the help of the British Coatings Federation and the Surface Engineering Association.