Room Leakage Test
With the room leakage test, the test of the environments to be extinguished with gas is carried out. It must be impermeable against the possibility of gas escaping to the external environment. For halon alternative and inert gases, the minimum residence time of the gas in the room is 10 minutes, determined by NFPA and ISO14520. The fire in the environment may be extinguished immediately after the gas is discharged, but the gas should not be kept in the room during this 10-minute period against the risk of re-ignition-flaming.
Purpose of Room Leakage Test
It is to determine the leaks in the room on the basis of area (m2) and to calculate how long the gas can stay in the room. The test is done with the help of a fan. First, the interior of the space is pressurized, then the air in the space is sucked and sent out of the environment. The air pressure inside the room and passing through the fan is measured with the help of manometers. These values are evaluated by an approved computer program. The room test is considered to have passed if the differential difference between the room leaks is calculated and the gas residence time is 10 minutes. Otherwise, revisions are made in the isolation of the openings.
Gas Retention Time
It varies in proportion to whether the internal air conditioning system will operate at the time of discharge. If the air conditioning system is turned off during discharge, after 10 minutes the level of gas in the environment should not be lower than 75% of the minimum room height. This level can be determined by evaluating the highest device in the environment, as well as the highest level, by the person or institutions competent to decide. If the air conditioners will continue to operate during and after the discharge, the concentration value of the gas in the environment should not be below the minimum extinguishing concentration value after 10 minutes. For example, the minimum extinguishing concentration value of 3M Novec 1230 extinguisher for Class A fires is 3.5% according to the NFPA standard. The minimum design concentration for Class A fires is 4.2%. If the internal air conditioning system will continue to operate during and after discharge in a space protected by a 3M Novec 1230 extinguisher, the minimum extinguishing concentration in the room after 10 minutes should not be less than 3.5%.
What is a Room Leakage Test and Why is it Important?
The Door Fan Test is a room tightness test. It consists of testing the air flow delivered with low or high pressure values in the chamber under test. This means that a fan creates a certain overpressure (and/or underpressure) in a room protected by a permanent fire suppression system. Analysis of the airflow flowing by the fan allows you to calculate the area of the room leak and its effect on the residence time. Another important term emerged, “Dwelling Time”. What is Duration of Stay? The holding time, called the “Dwell Time”, is nothing but the time to ensure the correct gas concentration in the room, which ensures the correct operation of the permanent fire suppression system. Based on the definitions above and the working principle of Gas Extinguishing Systems, it should be noted that the gas must be kept in the room volume for an appropriate time (residence time) in order to effectively extinguish a possible fire. Based on the data from the Door Fan Test, it is possible to determine how large the room leak zone is. The size of the site affects the maintenance of the required design concentration and the residence time of the appropriate concentration. The Door Fan Test first shows us the tightness of the room and secondly, based on the results obtained, whether the extinguishing action of a permanent extinguishing system will be effective. By performing such a test, you can minimize the costly and time-consuming trial testing of installations. Accurate results allow us to confirm that the designed system is ready to operate as intended. The Door Fan Test can also be done to experimentally calculate the natural ventilation area of the space. It provides an estimate of the number and size of overpressure dampers that will be fitted to limit the pressure to a specified value after a gas discharge. The gases used in gas extinguishing systems penetrate the points where water cannot reach, providing three-dimensional extinguishing. It will not be an effective and healthy solution to apply a water extinguishing system to a place where a gas extinguishing system should be installed. Gas extinguishing system should be used in places that are sensitive to water extinguishing system such as critical company information systems (data centre), data centers, control and command rooms, archives, museums. If gas extinguishing systems are not used, it is inevitable that critical systems, data and valuable materials in fire protected areas will be damaged by the water-based extinguishing system. Our aim in gas extinguishing systems is to provide adequate fire protection for the space, to reduce or eliminate the damages of water-based fire extinguishing systems .
Test duration and impermeability conditions are determined with NFPA 2001, EN 15004, ISO 14520 standards. In NFPA2001 Annex C and ISO14520 Annex E, it is stated that the Room Leakage Test, which proves the airtightness of the leak test, is necessary and mandatory for the space protected by Gas Extinguishing Systems. EN 15004 / ISO 14520 standards for gas extinguishing systems are mandatory in the European Union and in our country. NFPA 2001 is widely used in the USA and some other countries. For clean gases, the minimum residence time in the room after the gas is discharged to the environment, determined by NFPA 2001 and ISO 14520, is 10 minutes.
The success of gas extinguishing systems does not depend on reaching the required extinguishing concentration for the desired time in the environment in which they are applied. In order for the test to be successful, it must be designed in such a way that the pressure that will occur in case of discharge of gas does not collapse any wall of the room or blow out the window. The type of gases discharged into the space and the pressure they have are important in terms of design.
Precautions
Among the measures to be taken for the volumes that fail the test, the sealing of the room must be improved. Cables are generally the most common problems in wall, floor and ceiling penetrations, cable trays, gaps under door jambs of wall, floor and ceiling transitions, glass openings, non-sealed doors, dampers not sealed and not sealed. The test performed and the calculated results are reported. The report should include the following information along with the door fan-room leak test: the date of the test, whom the test was performed and according to what volume, the name and surname of the user accompanying the test, the room volume measurements to be protected, the brand and model of the test device, the serial number of the test device , the measured air characteristic, the amount of clearance calculated for a pressure of 10 Pa, the type of extinguishing gas, the design concentration of the extinguishing gas, the residence time of the gas in the room and the information that it passed the tightness test.
What are the Mistakes Made in the Room Integrity Test or the Door Fan Test in Gas Extinguishing Systems?
You are required to document (certify) the tests and the accuracy of the applications. It is extremely important to document (confirm) the possible fire protection of the room. Room Sealing Test should be done after all civil and mechanical works on the room walls are completed. Any pipe, cable, etc. from the room walls after the test. If a switch is made or a change is made, the test must be performed again. We would like to help you to interpret the results and to carry out the Chamber Tightness Test with state-of-the-art calibrated devices in accordance with the most up-to-date national and international codes and standards.