Construction solvents: Spraying
Certain spraying tasks can produce very high exposure to solvents. This page tells you how to control this risk and why. You also need to be aware of the general information on construction solvents.
What you must do
Follow the Assess, Control and Review model. Pay particular attention to the following things:
Identify and assess: The risks from spraying solvent containing materials vary. You need to consider the factors outlined in the general information on solvents . You are generally at lower risk if you are spraying low solvent paints for short periods in an open / well-ventilated space. Other spraying tasks can produce higher solvent exposures. You are particularly at risk if spraying high solvent containing materials in small / enclosed spaces. Seek specialist help if you are unsure.
Follow the precautions for controlling general solvent risks . In addition, you should also consider the issues below. These are guidelines only. The range of solvent containing products available means that you must decide on the specific controls you need based upon your assessment of the risks. Take specialist help if you unsure about this.
- Spray equipment – choose the correct equipment for the work. Be aware of issues associated with different types of spray equipment. ‘Conventional’ spraying uses compressed air to atomise the paint. This can create quite a lot of overspray / mist in the air that can travel significant distances. You may improve this by using high-volume low-pressure (HVLP) spray guns. Alternatively, airless spraying forces paint through a nozzle under high pressure. There is less overspray / mist travel with this method as the speed of the paint droplets quickly falls after leaving the nozzle. However, there is risk of injecting paint etc into the skin if the spray tip is not properly guarded. Use the correct tip sizes and pressure.
- Ventilation – ensure good ventilation. You may need some form of additional ‘mechanical’ ventilation that provides clean air or acts as local exhaust ventilation (LEV). Make sure any extracted air is discharged to a safe place.
- Segregation – keep all non-essential people away from the work area until the risk has been minimised. You may need to barrier off the area. Take into account wind speed and direction if working outside. This can cause spray / vapour to drift large distances.
- Respiratory Protective Equipment (RPE) – you are likely to need RPE is most instances. The level of protection will vary with the risk. Below are some examples that may be suitable for different situations:
- half-face mask respirator with an A1P3 filter(s) for intermittently spraying lower solvent products over a shift with little general ventilation
- powered (fan-assisted) respirator with a visor and A2P3 filter(s) for longer tasks like spraying lower solvent products most of a full shift in one location
- constant flow air-fed breathing apparatus (BA) with a low flow indicator for spraying high solvent products, particularly in an enclosed space. Make sure the breathing air is uncontaminated and meets ‘minimum flow conditions’ in terms of tubing length / internal bore and air pressure.
These are examples only. You must get the correct RPE for the work you are doing. Check with your supplier if you are unsure.
- Work practices – good spraying technique is important to limit overspray and bounce back. Improve visibility by using tear-off visor protectors if needed. Keep RPE on until you have left the work area or the area is clear. Cleaning the spray gun is another potential source of significant exposure if the gun is cleaned with thinner and sprayed through without proper controls.
- Confined spaces – your work may mean that solvent vapours could build up to dangerous levels. You will need special precautions if you are working in a confined space.
- Fire and explosion – sufficient amounts of solvent / vapours create a fire and explosion risk. You may also need special precautions for these risks.
Supervise: Ensure equipment is properly used and RPE is worn correctly. Anyone using tight fitting RPE also needs to be clean-shaven and face-fit tested.
Maintain: Make sure all the controls are properly maintained.
Monitor: You are likely to need exposure monitoring where the risk is high to ensure your controls are working properly. Be clear about what you are going to measure and how you will use the information.
What you should know
Solvents can produce narcotic effects like dizziness and tiredness. High concentrations increase the severity of these effects. Unconsciousness and death can even occur. This means it is very important to have the right controls in place and to make sure they are properly used.
- Safe use and handling of flammable liquids
- Respiratory Protective Equipment at Work
- Controlling airborne contaminants at work: A guide to local exhaust ventilation
- Monitoring strategies for toxic substances