In light liquid service
In light liquid service means that a piece of equipment in regulated-material service contains a liquid that meets the following conditions:
(1) The vapor pressure of one or more of the organic compounds is greater than 0.3 kilopascals at 20 °C,
(2) The total concentration of the pure organic compounds constituents having a vapor pressure greater than 0.3 kilopascals at 20 °C is equal to or greater than 20 percent by weight of the total process stream, and
(3) The fluid is a liquid at operating conditions.
40 CFR § 63.1001
All terms used in this part shall have the meaning given them in the Act and in this section.