All clean agent gases, at a concentration above the extinguishing concentration, must be held for a period of 10 minutes in an enclosed environment. (SANS 14520 - 7.8)
CO2 used on all total flooding deep seated fires shall be maintained for 20 minutes. (SANS 306-10.5)
Room flooding
Although in SANS 246-8.2.1 it does acknowledge partial protection it does recommend that the entire enclosure be flooded with suppression gas.
Hold times have been found difficult to achieve for rooms with suspended ceilings, partition walling or glass windows.
Do not be convinced to save money and protect the room space only, you may not get past the room integrity test. Flood the entire volume of the room and voids.
The 10 minute hold time is included in national standards for a reason.
It is important to keep the concentration of the gas to ensure deep seated fires, as can be experienced in most areas, are totally suffocated and make sure that re-ignition does not occur.
