Room integrity testing is considered a critical component for all special hazards fire suppression systems. The room integrity test, which is also frequently referred to as a door fan test, is responsible for measuring an enclosure’s leakage. This test makes sure any gaseous agents remain contained in the room that is under protection for the purpose of extinguishing a fire. Therefore, the room integrity test plays an important role in terms of keeping your employees, facilities, and equipment safe.
According to the National Fire Protection Association’s 2001, Standard on Clean Agent Fire Extinguishing Systems, at least 85 percent of the adjusted concentration for the minimum design needs to be held at the highest level of the combustibles for at least 10 minutes. Whenever a fire extinguishing system is installed, it is necessary to perform a room integrity test to make sure the protected room will be able to contain the agent for the specified amount of time.
What does room integrity testing involve?
During a room integrity test, a large fan will be installed at the room being tested. The large fan will then be turned on so that it is blowing into the room being tested. The fan functions to pressurize the room in preparation for testing. The speed of the fan will be adjusted to create a flow pressure that is similar to the pressure that is typically exerted during the discharge of a fire suppression system. Afterwards, the position of the fan is reversed so that it is drawing air from the room being tested. In this case, the fan functions to depressurize the room.
Throughout the process of pressurizing and depressurizing the room, pressure and airflow readings are obtained and then entered as input into a computer program. The purpose of the computer program is to calculate the room’s equivalent leakage area (ELA). If the room has a drop ceiling, the below ceiling leakage area (BCLA) is 50 percent of the total ELA.
Air is lighter than the vast majority of gaseous chemical agents that fire suppression systems use. Therefore, the agent will start to leak out of any unsealed penetrations at the lower level. The rate of the leak is proportional to the leakage amount for higher elevations. As the gaseous chemical agents leak out, fresh air from above takes up the empty space left behind. The descending interface refers to the point where the concentration air mixture meets with the fresh air.
The design of the door fan test makes sure that it will calculate the leakage for the room being tested in the worst case scenario. The test predicts the suppression agent’s descending interface. One can determine the concentration hold time from a door fan test by measuring the amount of time it takes the descending interface to meet the established minimum protected height.
Importance of room construction
The majority of rooms designed for the purpose of holding mission critical equipment are constructed with “slab to slab” perimeter walls. The perimeter walls are positioned in this way to form a fire-rated barrier. The barrier surrounds the room. This style of construction makes sure that the room will be afflicted with fewer leaks and improves the chance that the room will pass the room integrity test.
Another construction style that gives a room a good chance of passing the room integrity test is where the perimeter walls extend above the suspended ceiling. A room like this cannot be effectively tested with a standard room integrity test. However, there are other tests that can be used for such rooms. Rooms like this have a strong track record when it comes to containing a clean agent for an extended length of time.
All slabs and walls in a room intended to contain a gaseous fire suppression agent need to be inspected for leakage points and penetrations. If any leakage points or penetrations are found, fire retardant doors and materials need to be used to seal them.
For more information about room integrity testing and how critical it is when it comes to special hazards fire suppression, don’t hesitate to contact us.