How to conduct a door fan test
“The last thing we do when we commission a new system is a door fan test,” explains Adam W. Fire Alarm Service Manager at Fire Systems, Inc.
Through a combination of measuring the size of holes and pressure in an enclosure and computer software simulations, a prediction of how long an agent would stay in a room can be generated.
To measure total room leakage, a door fan is temporarily installed in a doorway leading from a test room to a larger open area. The fan speed is adjusted to obtain a pressure between the test room and the volume surrounding the test room. The measurement is done by blowing air out of the room and then into the room. These two readings are then averaged.
The computer then converts flow and pressure readings into an Equivalent Leakage Area (ELA), or the total area of all the cracks, gaps, and holes in the test room.
Adam explains the process: “The door fan test involves the use of a big unit that seals the door with a large fan and basically a fancy pressure gauge. You run the fan at different speeds, for negative pressure and positive pressure, and record the pressure readings. Once you enter these readings into the software for the unit, it tells you how long that room will hold the concentration for.”