Current guidelines provide ranges for acceptable humidity levels in healthcare sterile storage areas of 30 – 60% relative humidity. The CSA Sterilization Standards.
Committee has recommended that the range for acceptable relative humidity for sterile storage should be 30-70% (unless contraindicated by device manufacturer). This range is to replace the current 30 – 60%, and is based on the recommended range in the American Standard; ANSI/AAMI ST79 “Comprehensive Guide to Steam Sterilization and Sterility Assurance in Healthcare Facilities”.
Note: The upper limit of 70% is only for dedicated sterile storage areas – all other areas (e.g. reprocessing depts.) have the upper limit for humidity as 60%.
The relative humidity is affected by the temperature1,2 however, since the problems associated in healthcare sterile storage are primarily related to excessive moisture, this consensus statement focuses only on how to deal with excess humidity issues.