Does this question sound familiar? Every facility manager has probably muttered, or at least thought, this question at some point. With surgeons performing longer and more complex surgeries, requests for colder operating room temperatures has increased and it is not uncommon for surgeons to request room conditions that are outside of “normal” parameters.
The question here is what are “normal” operating room space conditions. The answer is, it depends. ANSI/ASHRAE/ASHE Standard 170-2013 defines that operating rooms should be designed to maintain space temperatures between 68-75 deg F with space relative humidity between 20-60%. While many may consider this as “normal”, the reality is that most surgeons are asking for space temperatures lower than 68 deg F, so it is important to understand the impact that these requests have on your HVAC system.
Standard HVAC systems in hospitals are designed to provide 50-55 deg F supply air. At these temperatures, the systems are capable of maintaining approximately 66-68 deg F space temperature while holding space relative humidity below the upper limit of 60%. If the space temperature is allowed to trend below this range, the space humidity may rise above 60% creating regulatory compliance and patient infection issues.
There are many strategies that can be employed to address low operating room temperature requests. These options range from having informed discussions with the surgical staff to help them understand the practical limitations of the HVAC system to utilizing specialty HVAC systems that either produce low temperature supply air or utilize desiccant wheel technology to “dry out” the air and maintain lower space relative humidity levels at the reduced space temperature. Another option that some facilities explore is providing “cool vest” or shirt solutions for surgical staff to keep them cool during procedures without lowering the overall room temperature which limits the operational impacts on the HVAC system.
There are many factors to consider when addressing low temperature and humidity requests from your surgical staff. There is no one size fits all solution so it is important to be armed with a solid understanding of the thermodynamics and psychrometrics involved as well as the myriad of options and approaches that can be implemented. Having informed and open discussions with your clinical and leadership teams will help you ultimately get to the best value solution for your organization.
For more information on operating room temperature and humidity control concerns, please contact Jon Slagel, PE at 717-845-7654 or firstname.lastname@example.org.