Section 25.1189

14 CFR Ch. I (1-1-19 Edition)

(1) Effective under conditions expected to prevail when drainage is
needed; and
(2) Arranged so that no discharged
fluid will cause an additional fire hazard.
(b) Each designated fire zone must be
ventilated to prevent the accumulation
of flammable vapors.
(c) No ventilation opening may be
where it would allow the entry of flammable fluids, vapors, or flame from
other zones.
(d) Each ventilation means must be
arranged so that no discharged vapors
will cause an additional fire hazard.
(e) Unless the extinguishing agent capacity and rate of discharge are based
on maximum air flow through a zone,
there must be means to allow the crew
to shut off sources of forced ventilation
to any fire zone except the engine
power section of the nacelle and the
combustion heater ventilating air
ducts.

spaschal on DSK3GDR082PROD with CFR

Section 25.1189

Shutoff means.

(a) Each engine installation and each
fire zone specified in Section 25.1181(a)(4) and
(5) must have a means to shut off or
otherwise prevent hazardous quantities
of fuel, oil, deicer, and other flammable
fluids, from flowing into, within, or
through any designated fire zone, except that shutoff means are not required for - 
(1) Lines, fittings, and components
forming an integral part of an engine;
and
(2) Oil systems for turbine engine installations in which all components of
the system in a designated fire zone,
including oil tanks, are fireproof or located in areas not subject to engine
fire conditions.
(b) The closing of any fuel shutoff
valve for any engine may not make
fuel unavailable to the remaining engines.
(c) Operation of any shutoff may not
interfere with the later emergency operation of other equipment, such as the
means for feathering the propeller.
(d) Each flammable fluid shutoff
means and control must be fireproof or
must be located and protected so that
any fire in a fire zone will not affect its
operation.

(e) No hazardous quantity of flammable fluid may drain into any designated fire zone after shutoff.
(f) There must be means to guard
against inadvertent operation of the
shutoff means and to make it possible
for the crew to reopen the shutoff
means in flight after it has been closed.
(g) Each tank-to-engine shutoff valve
must be located so that the operation
of the valve will not be affected by
powerplant or engine mount structural
failure.
(h) Each shutoff valve must have a
means to relieve excessive pressure accumulation unless a means for pressure
relief is otherwise provided in the system.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25-23, 35 FR 5677, Apr. 8,
1970; Amdt. 25-57, 49 FR 6849, Feb. 23, 1984]

Section 25.1191

Firewalls.

(a) Each engine, auxiliary power
unit, fuel-burning heater, other combustion equipment intended for operation in flight, and the combustion,
turbine, and tailpipe sections of turbine engines, must be isolated from the
rest of the airplane by firewalls,
shrouds, or equivalent means.
(b) Each firewall and shroud must
be - 
(1) Fireproof;
(2) Constructed so that no hazardous
quantity of air, fluid, or flame can pass
from the compartment to other parts
of the airplane;
(3) Constructed so that each opening
is sealed with close fitting fireproof
grommets, bushings, or firewall fittings; and
(4) Protected against corrosion.
Section 25.1192 Engine accessory section diaphragm.
For reciprocating engines, the engine
power section and all portions of the
exhaust system must be isolated from
the engine accessory compartment by a
diaphragm that complies with the firewall requirements of Section 25.1191.
[Amdt. 25-23, 35 FR 5678, Apr. 8, 1970]

Section 25.1193

Cowling and nacelle skin.

(a) Each cowling must be constructed
and supported so that it can resist any

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