Definition - What does Exempt Solvent mean?
An exempt solvent is a particular type of solvent that falls below specific safety criteria. In certain instances, there are solvents that do not entirely comply with the safety use standards, but are still permitted for use. When a solvent is said to be "exempt," it qualifies or is exempted.
Other terms to describe it include volatile organic compound (VOC) exempt. This simply means the solvent is safer than similar options.
Corrosionpedia explains Exempt Solvent
The use of solvents in various industries has been regulated by state regulators for a very long time. The early classification of exempt solvents was mainly applied to methyl chloroform, methyl chloride and other types of halogenated products. Ideally, volatile organic compounds should be excluded from certain solvents, but there are circumstances where its addition is inevitable; so as the identification of exempt solvents.
For instance, methyl chloroform is a potent ozone destroyer, making it unsuitable for products like coatings and paints. Such materials also evaporate very quickly, which may not be good when used in coatings. The rapid rate of evaporation of halogenated products combined with low boiling points could lead to leveling problems and severe flow problems.
Industries must be critical and adhere to the existing policies when on the use of solvents. This is to guarantee that products like coatings reach their maximum potential for corrosion protection and other properties.