title-14-part-25-sec25-831

300

14 CFR Ch. I (1–1–24 Edition)

§ 25.820

following loss of normal electrical
power generating system.

gency alarm system, audible during
normal and emergency conditions, to
enable crewmembers on the flight deck
and at each required floor level emer-
gency exit to alert occupants of each
lower deck service compartment of an
emergency situation.

(d) There must be a means, readily

detectable by occupants of each lower
deck service compartment, that indi-
cates when seat belts should be fas-
tened.

(e) If a public address system is in-

stalled in the airplane, speakers must
be provided in each lower deck service
compartment.

(f) For each occupant permitted in a

lower deck service compartment, there
must be a forward or aft facing seat
which meets the requirements of
§ 25.785(d), and must be able to with-
stand maximum flight loads when oc-
cupied.

(g) For each powered lift system in-

stalled between a lower deck service
compartment and the main deck for
the carriage of persons or equipment,
or both, the system must meet the fol-
lowing requirements:

(1) Each lift control switch outside

the lift, except emergency stop but-
tons, must be designed to prevent the
activation of the life if the lift door, or
the hatch required by paragraph (g)(3)
of this section, or both are open.

(2) An emergency stop button, that

when activated will immediately stop
the lift, must be installed within the
lift and at each entrance to the lift.

(3) There must be a hatch capable of

being used for evacuating persons from
the lift that is openable from inside
and outside the lift without tools, with
the lift in any position.

[Amdt. 25–53, 45 FR 41593, June 19, 1980; 45 FR
43154, June 26, 1980; Amdt. 25–110; 68 FR 36883,
June 19, 2003]

§ 25.820

Lavatory doors.

All lavatory doors must be designed

to preclude anyone from becoming
trapped inside the lavatory. If a lock-
ing mechanism is installed, it must be

capable of being unlocked from the
outside without the aid of special tools.

[Doc. No. 2003–14193, 69 FR 24502, May 3, 2004]

ENTILATION AND

EATING

§ 25.831

Ventilation.

(a) Under normal operating condi-

tions and in the event of any probable
failure conditions of any system which
would adversely affect the ventilating
air, the ventilation system must be de-
signed to provide a sufficient amount
of uncontaminated air to enable the
crewmembers to perform their duties
without undue discomfort or fatigue
and to provide reasonable passenger
comfort. For normal operating condi-
tions, the ventilation system must be
designed to provide each occupant with
an airflow containing at least 0.55
pounds of fresh air per minute.

(b) Crew and passenger compartment

air must be free from harmful or haz-
ardous concentrations of gases or va-
pors. In meeting this requirement, the
following apply:

(1) Carbon monoxide concentrations

in excess of 1 part in 20,000 parts of air
are considered hazardous. For test pur-
poses, any acceptable carbon monoxide
detection method may be used.

(2) Carbon dioxide concentration dur-

ing flight must be shown not to exceed
0.5 percent by volume (sea level equiva-
lent) in compartments normally occu-
pied by passengers or crewmembers.

ensure that the conditions prescribed
in paragraph (b) of this section are met
after reasonably probable failures or
malfunctioning of the ventilating,
heating, pressurization, or other sys-
tems and equipment.

(d) If accumulation of hazardous

quantities of smoke in the cockpit area
is reasonably probable, smoke evacu-
ation must be readily accomplished,
starting with full pressurization and
without depressurizing beyond safe
limits.

(e) Except as provided in paragraph

(f) of this section, means must be pro-
vided to enable the occupants of the
following compartments and areas to
control the temperature and quantity
of ventilating air supplied to their
compartment or area independently of
the temperature and quantity of air

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Federal Aviation Administration, DOT

§ 25.832

supplied to other compartments and
areas:

(1) The flight crew compartment.
(2) Crewmember compartments and

areas other than the flight crew com-
partment unless the crewmember com-
partment or area is ventilated by air
interchange with other compartments
or areas under all operating conditions.

(f) Means to enable the flight crew to

control the temperature and quantity
of ventilating air supplied to the flight
crew compartment independently of
the temperature and quantity of ven-
tilating air supplied to other compart-
ments are not required if all of the fol-
lowing conditions are met:

(1) The total volume of the flight

crew and passenger compartments is
800 cubic feet or less.

(2) The air inlets and passages for air

to flow between flight crew and pas-
senger compartments are arranged to
provide compartment temperatures
within 5 degrees F. of each other and
adequate ventilation to occupants in
both compartments.

(3) The temperature and ventilation

controls are accessible to the flight
crew.

(g) The exposure time at any given

temperature must not exceed the val-
ues shown in the following graph after
any improbable failure condition.

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25–41, 42 FR 36970, July 18, 1977;
Amdt. 25–87, 61 FR 28695, June 5, 1996; Amdt. 25–89, 61 FR 63956, Dec. 2, 1996]

§ 25.832

Cabin ozone concentration.

(a) The airplane cabin ozone con-

centration during flight must be shown
not to exceed—

(1) 0.25 parts per million by volume,

sea level equivalent, at any time above
flight level 320; and

(2) 0.1 parts per million by volume,

sea level equivalent, time-weighted av-
erage during any 3-hour interval above
flight level 270.

(b) For the purpose of this section,

‘‘sea level equivalent’’ refers to condi-
tions of 25

C and 760 millimeters of

mercury pressure.

must be shown by analysis or tests
based on airplane operational proce-
dures and performance limitations,
that demonstrate that either—

(1) The airplane cannot be operated

at an altitude which would result in
cabin ozone concentrations exceeding
the limits prescribed by paragraph (a)
of this section; or

(2) The airplane ventilation system,

including any ozone control equipment,