Sec. 25.832 - Cabin ozone concentration.
(a) The airplane cabin ozone
concentration 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 average during any 3-hour interval above
flight level 270.
(b) For the purpose of this section,
"sea level equivalent" refers to conditions of 25 °C and 760 millimeters
of mercury pressure.
(c) Compliance with this section must be
shown by analysis or tests based on airplane operational procedures 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, will maintain cabin ozone
concentrations at or below the limits prescribed by paragraph (a) of this
[Amdt. 25-50, 45 FR 3883, Jan. 1, 1980, as
amended by Amdt. 25-56, 47 FR 58489, Dec. 30, 1982; Amdt. 25-94, 63 FR
8848, Feb. 23, 1998]