Cal. Civ. Code § 103

  § 103. Egress from apartments.  1. a. Except as provided in paragraph
b of this subdivision, there shall be at least one means of egress from
each apartment on each and every story of such apartment, and a second
means of egress if the first means is not within fifty feet of every
living room in such apartment on such story. When two means of egress
are required, they shall open from different rooms.
  b. In any class A fireproof dwelling or section thereof erected under
plans filed in the department after September first, nineteen hundred
fifty-one, an apartment occupying parts of not more than two stories
shall have at least one means of egress. Such required means of egress
shall be not more than forty feet from any room within such apartment
and shall open directly upon a public hall. Such public hall shall
provide access to at least two fire-stairs. Any stair within an
apartment shall be at least two feet six inches in width and a terminus
shall be not more than twenty feet from the door which provides the
required egress to a public hall, provided, however, that such stair
within an apartment shall extend downwards or upwards to the story which
provides the required access to at least two fire-stairs.  In the event
of but one such means of egress, and if the stair within the apartment
extends downwards to provide egress to a public hall, there shall be a
balcony upon the upper story of the apartment. If, however, such stair
extends upwards to provide egress to a public hall, the balcony shall be
located on the lower story of the apartment.  Such balcony shall provide
access from the apartment to a room of an adjoining apartment on the
same story. Such balcony shall be constructed of incombustible material
and be capable of sustaining a load of at least eighty pounds per square
foot. Access to such balcony shall not be obstructed by sinks or kitchen
fixtures or in any other way, and shall be maintained unobstructed at
all times. Bars, gates, grilles or other obstructing devices on any
window or door giving access to or egress from such balcony shall be
unlawful.
  2. Except as otherwise expressly provided in paragraph b of
subdivision six of section one hundred two for certain dwellings six
stories or less in height, at least one fire-stair shall be within
seventy-five feet of at least one means of egress from each apartment on
each story thereof.
  3. When any such fire-stair serving any apartment as a required means
of egress from the dwelling opens on the entrance story of the dwelling
exclusively into an entrance hall, no other fire-stair serving the same
apartment as a required means of egress from the dwelling shall open on
such story exclusively into the same entrance hall. Any required
fire-stair not opening on such story exclusively into an entrance hall
shall open on a street or in a yard, court or passageway affording
continuous, safe and unobstructed access to a street; but any such
required fire-stair serving any apartment as a means of egress from the
dwelling may have a supplementary entrance into the same entrance hall
as that into which any other fire-stair serving the same apartment as a
required means of egress from the dwelling opens exclusively.
  4. When any apartment occupies parts or all of three or more stories,
every stair within such apartment leading to the third or any higher
story of such apartment shall be enclosed with fireproof partitions with
a fireproof door and assembly with the door self-closing at the second
story landing of such stair and at every higher story landing from which
the stair continues upward within the apartment; or in lieu of such
fireproof partitions and doors at least two means of egress from such
apartment opening from different rooms shall be provided on the first,
third and alternate higher stories, if any, of such apartment.
  5. No means of egress from any apartment shall open into any stair,
fire-stair or fire-tower required under the provisions of this section
except through a vestibule or public hall.