14 C.F.R. § 125.145 Firewall construction.
Title 14 - Aeronautics and Space
Each firewall and shroud must— (a) Be so made that no hazardous quantity of air, fluids, or flame can pass from the engine compartment to other parts of the airplane; (b) Have all openings in the firewall or shroud sealed with close-fitting fireproof grommets, bushings, or firewall fittings; (c) Be made of fireproof material; and (d) Be protected against corrosion.
Title 14: Aeronautics and Space
PART 125—CERTIFICATION AND OPERATIONS: AIRPLANES HAVING A SEATING CAPACITY OF 20 OR MORE PASSENGERS OR A MAXIMUM PAYLOAD CAPACITY OF 6,000 POUNDS OR MORE; AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT
Subpart E—Special Airworthiness Requirements
§ 125.145 Firewall construction.
