Degreasing solvents for metal finishing
Your fabricated metal product business may use solvents to remove grease and oil. You can apply solvents using rags, vapour or immersion degreasing baths.
If your business carries out vapour degreasing you will use chlorinated solvents, including:
- trichloroethylene (trike)
- methylene chloride
- n-propyl bromide (stabilised)
Organic solvents can have a significant impact on air quality.
What you must do
Comply with conditions in your permit
If you have a permit, licence or exemption you must comply with its conditions, including any conditions about solvent emissions or other air emissions.
Do not use ozone depleting substances (ODS)
You must not use ozone depleting substances for most degreasing or solvent applications, including:
- hydrochlorofluorocarbons (HCFCs)
- chlorofluorocarbons (CFCs)
- 1,1,1 trichloroethane
- bromochloromethane (CBM)
- carbon tetrachloride.
Some vapour degreasing baths use banks of refrigerant-filled coils in the condensing zone. If you use F-gases or have old equipment with ODS you must make sure that your staff or contractors who service and repair refrigeration equipment comply with the controls on F-Gases and ozone depleting substances.
Comply with your waste responsibilities
You must comply with your duty of care responsibilities when dealing with waste.
You may need to deal with the following materials and substances as hazardous/special waste:
- degreasing solvent
- sump contamination (still bottoms)
- soiled, solvent-impregnated rags
- water collected in water and solvent separators.
For further information, see our guidance on hazardous/special waste.
Check if you need any discharge consents
Do not discharge to public sewers, surface waters or ground waters without consulting your regulator. You may need a discharge consent or other authorisation. For further information, see our guidance on discharges to water and sewer.
Use less hazardous products and techniques
Trike is classified as a category two carcinogen. If you use Trike you should try to replace it with a less harmful alternative.
Reduce your solvent use and losses
Choose a closed-top system when you replace your equipment as it will reduce your solvent consumption and energy use.
To avoid excessive solvent loss, locate your vapour degreasing machines away from draughts from doors, windows and heating.
Use slow, controlled withdrawal rates when removing components from your degreasing baths. This will reduce solvent loss.
Put lids on your solvent containers when you are not using them to reduce solvent loss. Fit your lids below the exhaust extraction slots.
Consider fitting lids to any open-top degreasing baths. Fit your lids in the free-board zone.
Control your lip extraction rates to ensure your staff are safe and to prevent excessive loss of solvent.
Jig the work so that the solvent drains freely from the piece that has been cleaned.
Use 'squeeze' type bottles for transferring solvent onto rags.
Manage your solvent waste and prevent contamination
Do not mix different waste solvents as this could be dangerous and prevent your solvents from being reclaimed.
Consider laundering and reusing the rags you use for surface cleaning.
Monitor the boiling temperature of your vapour degreasing bath. Heavily contaminated solvents have higher boiling points. This indicates that you need to change your solvent.
Reduce the risk of spillage and land contamination by filling your degreasing systems from fixed pipework lines.