The other critical reason that an Enclosure Integrity Test has to be conducted on an enclosure where a fire extinguishing system is installed is to evaluate how tight the enclosure may be for the purpose of assessing pressure relief venting.
All gaseous extinguishing systems create negative and/or positive pressures on discharge. The magnitude of these pressures will be dependent on the integrity of the enclosure. If an Enclosure Integrity Test has not been conducted then there is no way to assess whether the pressures on discharge will create a structural integrity problem for it.
Under ISO 14520, NFPA 2001, EN15004 and AS ISO 14520, all enclosures must be evaluated to ensure that structural integrity is not likely to be compromised during a discharge. A critical part of this evaluation is to perform an Enclosure Integrity Test.