The ability for the gaseous agent to be retained in the protected room for an extended period of time is critical to the performance of any total flooding clean agent fire extinguishing system. NFPA 2001, Standard on Clean Agent Fire Extinguishing Systems, requires that a minimum concentration of 85% of the adjusted minimum design concentration be held at the highest level of combustibles for a minimum period of 10 minutes. Those installing these systems are required to perform a Room Integrity Fan Test to assure the protected room will hold the agent for the required period of time.
A Room Integrity Fan Test, also known as a Door Fan Test, is simply a way to measure the leakage of an enclosure. A large fan is temporarily installed in the doorway of the room to be tested, with the fan blowing into the room (pressurizing the room). The fan speed is adjusted to obtain flow pressure equivalent to the pressure exerted during a fire suppression system discharge. The fan is then reversed on the door to draw air from the room (depressurizing the room). The airflow and pressure readings obtained are entered into a computer program designed to calculate the equivalent leakage area (ELA) for the room. When a room has a suspended (drop) ceiling, then the below ceiling leakage area (BCLA) is calculated as one-half the total ELA and is used in the calculations for retention time.