The areas where gas extinguishing will be applied should be sealed against the risk of gas leakage to the outer environment. For Halon alternative and inert gases, the minimum holding time of the gas after discharge to the environment is 10 minutes according to NFPA and ISO14520.The fire may be extinguished immediately after the gas is discharged; however, the has should be held in the room for 10 minutes against the risk of reignition.
Objective of the leakage test is to calculate the leakages in the room on the area basis (m2) and to calculate how long the gas can be held inside the room.
The test is conducted with a fan. Firstly, the interior is pressurized, and then the air in the room is sent to the outside via absorption. The air pressure inside the room and passing through the fan is measured with a fan. These values are evaluated by an approved computer software. The differential figure indicates the leakages in the room. If the gas can be held in the room for 10 minutes after the leakage has been calculated, the room passes the test. Otherwise, the insulation of the gaps should be revised.
Gas holding time in the room varies according to whether the internal air conditioning system will be operated during the discharge process.
If the air conditioning system is turned off during discharge, the gas level in the room after 10 minutes should not be less than 75% of the minimum room height.
This level can be determined by the authorized persons or organizations as the highest elevation level of the highest device in the room.
If the air conditioners continue to operate during and after the discharge, the gas concentration in the room after 10 minutes should not be less than the minimum extinguishing concentration.
For example, for class A fires, the minimum extinguishing concentration of 3M Novec 1230 extinguisher is 3,5% according to NFPA standard.
The minimum design concentration for class A fires is 4,2%.
If the air conditioning system in a site protected with 3M Novec 1230 extinguisher continues to operate during and after the discharge, the minimum extinguishing concentration in the room after 10 minutes should not be less than 3,5%.
IMPORTANT NOTE: 80% of the sites tested by our company so far have failed in this test.