Some rooms, such as a server room, must have particularly stringent safety and fire protection conditions.
Extinguishing gases
An effective and safe, as it involves low losses, method of extinguishing fires is the use of extinguishing gases. An additional advantage of this technique is the significantly reduced time required to resume operation of protected facilities and the lack of negative impact on electrical equipment. In the case of server rooms, this is crucial.
The extinguishing gases in use today can be classified according to the following division:
- Inert gases (e.g.: IG-100 [nitrogen], IG-01 [argon] and their mixtures IG-541, IG-55);
- Halogenated hydrocarbons (HFC-236fa, HFC-227ca, FK-5-1-12, NOVEC 1230);
- carbon dioxide (CO2);
They are used primarily in Fixed Fire Extinguishing Systems (SUGs).
Gas retention time
The effectiveness of the extinguishing system used is determined by the retention time of the gas. The retention time is called the holding time, that is, the expected time during which the extinguishing concentration in the protected space does not fall below a certain level. This time must not be less than 10 minutes. Its value depends largely on the tightness of the room and the density of the extinguishing gas used.
Methods for testing gas retention time
There are two methods for testing gas retention time:
- actual measurement of the change in the value of gas concentration over time by the discharge of the extinguishing agent;
- execution of air tightness test of the room Using a supply door.
The second method is by far more efficient, safer and, above all, cheaper, requiring no consumption of extinguishing agent and no refilling. With the help of a leak test and subsequent analysis of gas discharge models, we can determine the expected retention time.
Method of testing the airtightness of rooms by the method of blower door test for the purpose of obtaining retention time is the same as for testing buildings to reduce heat loss. A special supply door is installed, which, with the help of a fan, creates a pressure difference. The flow rate of the passing air is then analyzed.
The known value of the pressure inside and outside the room allows you to determine the total size of the leakage. Leakage tests should be carried out in accordance with EN ISO 9972:2015, and the results obtained should be interpreted in accordance with the applicable standards: NFPA 2001, ISO 14520, EN 15004 and VdS.
If the size of the leak is found to be too large to maintain the specified minimum concentration of the extinguishing gas at a given retention time, the escape routes of the extinguishing agent should be located and sealed.
Leak detection is not such a simple matter. In addition to the leakage test itself, TERMOCENT also performs a test to locate significant air leaks. Such detection can be carried out in several ways: with a thermal imaging camera when a vacuum is created, with ultrasound or with a smoke generator. The use of thermal im aging is the most efficient and less time-consuming approach. However, it involves temperature requirements, i.e., a necessary temperature difference of at least 12ᵒC between the two sides of the partition under investigation.
Are you interested in investigating gas retention time?
The company TERMOCENT offers measurements are performed by specialists in the relevant fields. This is confirmed by the qualifications held: ISO 18436-7 (thermal imaging) and ISO 18436-8 (leak localization “ultrasound”).
TERMOCENT uses top-of-the-line equipment to ensure reliable, high-quality measurements. The best commercially available FLIR T1020 thermal imaging camera, smoke markers, UE Systems ultrasonic measurement equipment and professional RETROTEC brand leak test equipment from an authorized distributor are used for testing.
Want to know more?
Call 530 105 398 or email kontakt@termocent.com
