"Freeboard height" means:

1. (a) For a cold cleaner, the distance from the liquid solvent level in a degreaser tank to the lip of the tank;
2. (b) For an open top vapor degreaser tank, the distance from the solvent vapor level in the tank during idling to the lip of the tank;
3. (c) For a conveyorized cold degreaser, the distance from the liquid solvent level to the bottom of the entrance or exit opening, whichever is lower; or
4. (d) For a conveyorized vapor degreaser, the distance from the vapor level to the bottom of the entrance or exit opening, whichever is lower.

Source. (See Revision Note at chapter heading for Env-A 1200) #9933, eff 6-1-11; ss by #12899, eff 10-17-19