Room integrity testing calculates the leak-tightness of a room and predicts how long it takes for the interface between the extinguishing agent and air to descend to a given level. The test equipment comprises of variable speed fans, expandable door panels, pressure gauges and a dedicated portable computer.
The fan unit is fitted into a doorway of the room being tested by means of the special expandable door panels designed to fit most door frame sizes. The fan is used to increase the pressure in the room by an amount approximately equivalent to the column weight exerted by the extinguishing agent following a discharge. This is then maintained whilst readings are taken from the pressure gauges.
The measured rate of air input needed to maintain this pressure level is equivalent to the amount leaking from the room. The test is then repeated in reverse by de-pressuring the room and the results of both tests are averaged. From this information, the computer is used to calculate the equivalent or effective leakage area (ELA). The data is then processed using a specially designed computer program, in compliance with the National Fire Protection Association (NFPA) or British Standard that predicts the period of time that the concentration will be held in the room at a given height.
This retention time can be calculated for different heights that might correspond to the known height of a particular combustible hazard. The computer program is conservative in its predictions as it assumes the worst-case scenario, in which 50% of the openings are at low level where the heavier gas/air mixture will seep out and 50% are at a high level where lighter air will enter to displace it. Due to this conservative approach, the results are extremely reliable and any system that passes the room integrity test would have been virtually certain to pass a full discharge test.
At the end of the tests the computer generates a print-out with full details of the input and test results. Failure is indicated if it takes less than 10 minutes for the agent/air interface to drop below the minimum specified protected height. A minimum holding time of 10 minutes is the period suggested by BS5306 Section 5.1 and NFPA, however, the computer can easily be reprogrammed to give a longer or shorter period to suit the characteristics of the hazard or agent employed. During the pressurising period it is possible to identify leaks with smoke pencils enabling the room to be sealed as much as practicable prior to the final test.
Room integrity testing features
* Proven, practical alternative to full discharge testing.
* Conservative testing procedure provides fail-safe results.
* Little disruption to normal working practices.
* Fully repeatable service.
* Versatile, may be used for rooms protected by any gaseous fire fighting agent.
* Complies with BS150 14520-1.
For more information contact Devtrade Distribution, +27 (0)21 552 6891, brigitta@devtrade.co.za
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