Patent ID: 8517116

Claim:
A method for preventing fire or explosion in a first enclosed protected area and/or a second enclosed protected area, comprising: lowering an oxygen content in at least one of the protected areas relative to ambient air, to a base inertization threshold level which corresponds to an oxygen content which allows people to safely occupy the protected area; measuring the oxygen content in the at least one of the protected areas at one or more locations with respectively one or more oxygen sensors; upon measuring an oxygen content which is below the base inertization threshold level and which reaches a maximum inertization concentration level; shutting off a supply of inert gas or inert gas/air mixture into the at least one of the protected areas; and introducing fresh air into the at least one of the protected areas, thereby ensuring that the oxygen content in the at least one of the protected areas remains above the maximum inertization concentration level, wherein the oxygen content does not drop below the maximum inertization level by introducing the fresh air; and wherein the introduction of fresh air is stopped as soon as the oxygen content in the at least one of the protected areas reaches again the base inertization level.