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.