14 CFR § 27.1187
Ventilation and drainage
July 13, 2020
Each compartment containing any part of the powerplant installation must have provision for ventilation and drainage of flammable fluids. The drainage means must be—
(a) Effective under conditions expected to prevail when drainage is needed, and
(b) Arranged so that no discharged fluid will cause an additional fire hazard.
[Doc. No. 29247, 64 FR 45095, Aug. 18, 1999]