14 CFR § 29.1181

Designated fire zones are—

The engine power section of reciprocating engines;

The engine accessory section of reciprocating engines;

Any complete powerplant compartment in which there is no isolation between the engine power section and the engine accessory section, for reciprocating engines;

Any auxiliary power unit compartment;

Any fuel-burning heater and other combustion equipment installation described in § 29.859;

The compressor and accessory sections of turbine engines; and

The combustor, turbine, and tailpipe sections of turbine engine installations except sections that do not contain lines and components carrying flammable fluids or gases and are isolated from the designated fire zone prescribed in paragraph (a)(6) of this section by a firewall that meets § 29.1191.

Each designated fire zone must meet the requirements of §§ 29.1183 through 29.1203.