§ 27-521.3 Construction.
AC § 27-521.3
(a)Atriums may be constructed only in buildings in noncombustible construction groups 1-A, 1-B and 1-C.
(b)An atrium shall be fully enclosed except that openings of any size into the two lowest levels of an atrium shall be permitted if such openings are provided with opening protectives having a fire-resistance rating of at least one and one-half hours or are provided with sprinklers no more than six feet apart.
(c)The minimum horizontal clear dimension of an atrium shall be forty feet, provided, however that this dimension can be reduced to twenty feet where sprinkler spacing on the occupied side adjacent to glass panels authorized by subdivision (d) of this section is no more than four feet or the minimum atrium area is twelve hundred square feet.
(d)Atrium enclosing walls shall be of at least two hour fire-resistant construction or of glass that is wired, laminated, or tempered and is provided with sprinklers on the occupied side spaced no more than six feet apart, except as otherwise permitted by subdivision (c) of this section.
