Two common types of ventilation in spray painting
Two common types of ventilation used in spray painting are:
- Local exhaust ventilation captures the overspray and solvent vapour as close to the source of release as possible by drawing the contaminants into a capture hood. They should be fitted with a particulate filtration system to filter overspray. Wherever possible, local exhaust ventilation should be used when a spray booth cannot be used. It may be necessary to use it in combination with other control measures. Information on local exhaust ventilation designed for hazardous areas is available in AS 1482: Electrical equipment for explosive atmospheres – protection by ventilation.
- Dilution ventilation dilutes and displaces contaminated air with fresh air which is supplied to the work area by mechanical supply fans or natural air currents through doors, windows or other openings in the building. It can be used to supplement local exhaust ventilation.
When using dilution ventilation:
- the spray painting operator should stay between the air supply inlet and the source of vapours or aerosols generated
- temporary barriers may be needed to channel the dilution ventilation through the spray zone and to restrict cross currents
- make sure the contaminated exhaust air does not re-enter the work area
- use auxiliary mixing fans to disperse the spray painting emissions towards the outlet and to enhance the rate of air dilution.