Patent ID: 7186371

Claim:
A method of sterilising a sealed enclosure comprising: continuously recirculating a gas through the enclosure and through a preparation region for a period of time; and dispensing a mixture of decontaminant gas and water vapour into the recirculating gas in the preparation region to flow therewith through the enclosure to reach a concentration in the enclosure above the dew point of the gas and water vapour mixture for the ambient temperature in the chamber and thereby to condense onto surfaces in the enclosure to sterilise such surfaces; wherein the gas temperature in or exiting the enclosure or entering the preparation region, decontaminant gas concentration in or exiting the enclosure or entering the preparation region and condensation of the decontaminant gas on the surfaces of the enclosure are measured and the dispensing of the mixture of decontaminant gas and water vapour into the gas in the preparation region is controlled in response to the levels determined by said measuring to provide a requisite level of condensation of the decontaminant gas/water vapour in the enclosure.