Fire Rating for Electrical Rooms

Q: Are electrical equipment rooms required to be fire rated? We have a dry-type transformer in an utility room on one of our nursing units and wanted to know if the room is required to be fire rated.

A: According to the 2000 edition of the Life Safety Code, electrical rooms are not required to be fire rated, although NFPA 13 Standard for the Installation of Sprinkler Systems (1999 edition) does provide an option to provide a 2-hour fire rated barrier around an electrical room in lieu of installing sprinklers (see previous question). But a room that has a transformer in it is regulated by NFPA 70 National Electric Code (1999 edition), article 450-21. This article says any room containing a dry-type transformer which is rated more than 112½ kVA must be 1-hour fire rated. There are some exceptions to this requirement based on the transformer insulation values and vertical mounting. However, transformers that are rated 112½ kVA or less are only required to be separated from combustible materials by 12 inches by a fire resistant heat-insulated barrier. I am aware of some states that require hospital electrical rooms that contain emergency power to be fire rated, so please check with your local and state authorities for their requirements.