Before reducing relative humidity in operating rooms below 30%, hospitals and ambulatory surgery centers should consider the effects on equipment and supplies, according to new guidance from the AHA, its American Society for Healthcare Engineering and Association for Healthcare Resource and Materials Management affiliates and other stakeholders. The American Society of Heating, Refrigerating and Air-Conditioning Engineers revised its international standard for HVAC design parameters in 2010, expanding the minimum end of the range from 30% to 20% relative humidity. The National Fire Protection Association and other organizations have since referenced or incorporated the revised standard. ASHE supports the new standard, as does The Joint Commission. However, it is important for facility personnel to follow the instructions for use specific to all supplies and equipment, including environmental humidity requirements, because relative humidity can affect the shelf life and product integrity of some sterile supplies and electro-medical equipment. For more information, see today’s AHA, ASHE and AHRMM Quality Advisory.