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Relative Humidity - Requirements

Do we need to monitor the temperature and humidity of the rooms that sterile supplies are stored?

Any examples are for illustrative purposes only. 

When developing Infection Prevention related policies and practices, it's important that you refer to the Infection Prevention Hierarchy, published in the April 2019 Perspectives.

The first level of the hierarchy is that you ensure your organization is compliant with all building code requirements.  Deemed organizations, with new or renovated existing facilities (constructed or plans approved on or after July 5, 2016) the heating, cooling and ventilation must comply with the 2012 edition of NFPA 99 which includes the 2008 edition of ASHRAE 170.  If your local authority has published building codes, then your organization must meet the most restrictive requirement.

ASHRAE Standard 170- 2008 ventilation requirements for sterile storage in CENTRAL MEDICAL AND SURGICAL SUPPLY areas includes the following:
  • Positive air pressure relationship to adjacent areas
  • Minimum outdoor air exchange 2 per hour
  • Minimum total air exchange 4 per hour
  • Maximum relative humidity 60%
  • Temperature range 72 to 78 F or 22 to 26 C

Organizations with existing facilities, constructed or plans approved prior to July 5, 2016, may comply with the 2012 ventilation requirements in NFPA 99 or the version of NFPA 99 in effect at the time of the ventilation system installation. 

The next level of the hierarchy is the manufacturer's instructions for use.  If the manufacturer of the sterile supply requires a specific temperature and humidity requirement for storage, your organization would need to demonstrate at the time of survey that these requirements are being met.  The Joint Commission does not specifically require that these parameters be documented, however your staff should be able to identify if any sterilized supply, whether single use or reprocessed, has been potentially compromised as may occur if the integrity of the package is in question or has evidence of damage from humidity, regardless of where the item has been stored.

Finally, your organization may refer to evidence-based guidelines (EBGs) for guidance as to how sterile supplies should be stored.  For example, most of the EBGs agree that Central Medical and Surgical Supply areas must be clean, well ventilated and protect supplies from contamination, moisture, dust, temperature extremes, and humidity extremes.  Failure to store medical and sterile supplies in a manner to protect from contamination will be scored at IC.02.02.01 EP 4.

NFPA 99-2012: 9.3.1
ASHRAE 170-2008
2018 FGI Guidelines

Additional Resources:
Guidelines for Design and Construction of Health Care Facilities 2018 edition
CDC Guidelines for Environmental Infection Control in Health-Care Facilities, Heating, Ventilation, and Air Conditioning Systems

Last updated on June 23, 2021
Manual: Critical Access Hospital
Chapter: Environment of Care EC

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