Which type of fire alarm key blank must be used for a run that will be installed in a plenum space?

The appropriate type of fire alarm key blank for installation in a plenum space is FPLP. This designation indicates that the cable is suitable for plenum applications, meaning it complies with specific fire safety standards established by the National Fire Protection Association (NFPA) and Underwriters Laboratories (UL).

Plenum spaces are areas used for air circulation in heating and air conditioning systems, and because they can contain flammable materials, it is crucial to use cables designed to minimize fire hazards. FPLP cables are constructed with a low-smoke, non-toxic insulation material, which reduces the amount of smoke produced in the event of a fire, thereby enhancing safety for occupants and aiding in emergency evacuation procedures.

In contrast, other types of cables, such as FPL (Fire Power Limited), FPLR (Fire Power Limited Riser), and FPX, either do not meet the stringent requirements for plenum installations or are intended for different applications. Their use in a plenum space could increase fire risk, making it essential to choose FPLP for compliance and safety.