Section 25.820

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

(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]

Section 25.820 Lavatory doors.
All lavatory doors must be designed
to preclude anyone from becoming
trapped inside the lavatory. If a locking 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]

VENTILATION AND HEATING

spaschal on DSK3GDR082PROD with CFR

Section 25.831 Ventilation.
(a) Under normal operating conditions and in the event of any probable
failure conditions of any system which
would adversely affect the ventilating
air, the ventilation system must be designed 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 conditions, 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 hazardous concentrations of gases or vapors. 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 purposes, any acceptable carbon monoxide
detection method may be used.
(2) Carbon dioxide concentration during flight must be shown not to exceed
0.5 percent by volume (sea level equivalent) in compartments normally occupied by passengers or crewmembers.
(c) There must be provisions made to
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 systems and equipment.
(d) If accumulation of hazardous
quantities of smoke in the cockpit area
is reasonably probable, smoke evacuation 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 provided 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
supplied to other compartments and
areas:
(1) The flight crew compartment.
(2) Crewmember compartments and
areas other than the flight crew compartment unless the crewmember compartment 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 ventilating air supplied to other compartments are not required if all of the following 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 passenger 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 values shown in the following graph after
any improbable failure condition.

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