Excerpts from 2000 INTERNATIONAL BUILDING CODE®

A fire alarm system shall be installed in Group R-2 occupancies where:

1. Any dwelling unit is located three or more stories above the lowest level of exit discharge;

2. Any dwelling unit is located more than one story below the highest level of exit discharge of exits serving the dwelling unit; or

3. The building contains more than 16 dwelling units.

Exceptions:

1. A fire alarm system is not required in buildings not over two stories in height where all dwelling units and contiguous attic and crawl spaces are separated from each other and public or common areas by at least 1-hour fire partitions and each dwelling unit has an exit directly to a public way, exit court or yard.

2. A separate fire alarm system is not required in buildings that are equipped throughout with an approved, supervised automatic sprinkler system installed in accordance with Section 903.3.1.1 or Section 903.3.1.2 and which have a local alarm that meets the notification requirements of Section 907.9.2.