As used in this article, the following terms shall have the meanings indicated:
Two or more interconnected smoke detectors.
The area of a dwelling unit in which the bedrooms or sleeping rooms are located. Bedrooms or sleeping rooms separated by another use, such as a kitchen or living room, are separate sleeping areas, but bedrooms or sleeping rooms separated by a bathroom are not separate sleeping areas.
An instrument approved by an approved rating organization for the detection of ionized gases or products of combustion produced by burning or smoldering materials.