The term Category A machinery space means any space and trunks and ducts to such a space that contains:
(a) Internal combustion machinery used for main propulsion;
(b) Internal combustion machinery used for purposes other than main propulsion where the total aggregate power is at least 500 brake horsepower;
(c) Internal combustion machinery that uses a fuel that has a flash point of less than 43.3°C (110°F); or
(d) One or more oil fired boilers or oil fuel units.
[CGD 74-127, 41 FR 3842, Jan. 26, 1976]