TOPIC:
Impact of the OR Turnover Time on the Design and Operation of the OR HVAC System
Presented by Cindy Beckham & Ionel Petrus, SmithGroup JJR

Thursday, March 28^th, 2019
2:00 – 4:00 PM
Centra Virginia Baptist Hospital, Craddock Auditorium
​3330 Rivermont Avenue
Lynchburg, VA 24503

Abstract:
A typical approach when designing HVAC systems for operating rooms (ORs) is to go to ASHRAE Standard 170 and identify what types of ORs are being designed (i.e., Class B, Class C, etc.). One would then determine the appropriate temperature and relative humidity design set points for all ORs in the suite. The next step would be to calculate the OR sensible and latent loads, follow by the selection and sizing of the related HVAC system. Since the OR HVAC system has been designed and sized per the requirements of ASHRAE 170, one would expect that such system will meet all user expectations and operate as intended. Unfortunately, this “one size fits all” approach does not give the users the flexibility to perform complex procedures while having a reliable and energy efficient mode of operation.

With a continuous pressure to decrease turnover time and in the same time provide the medical staff with utmost flexibility, the design of the HVAC systems for today’s operating rooms requires not just special attention but also complex analyses. As such, it is crucial for the OR HVAC systems to support a wide range of temperature and associated relative humidity set points. For instance, an orthopedic surgery could require a design OR set point of 63°F and 40% RH; such procedure will then be followed by a long and demanding pediatric surgery that requires higher temperature and relative humidity set point (i.e. 75°F and 50% RH). It is important to note that Note O on Table 7-1 of ASHRAE Standard 170 states that “Surgeons or surgical procedures may require room temperatures, ventilation rates, humidity ranges, and/or air distribution methods that exceed the minimum indicated ranges.” Due to various factors that affect the design, different HVAC system configurations must be analyzed in order to meet the ever increasing and ever more complex expectations from the OR HVAC systems.

When designing HVAC systems for Operating Rooms, it is extremely important to engage the medical staff early in the design process. As stated in the ASHE/AORN Guidance, “[the] Design requirements are NOT the same as clinical practice recommendations. Each has a distinct purpose and intent. The ASHRAE/ASHE standards and FGI guidelines are intended to establish the minimum design requirements and criteria that must be met to construct an HVAC system that will support clinical functions during the life of a building. The AAMI and AORN guidelines are intended to guide the daily operation of the HVAC system and clinical practice once the health care facility is occupied.” In other words, there are no single temperature and relative humidity set points that satisfy all ORs within a suite. Instead, the HVAC system should be designed to accommodate a wide variety of OR temperatures. Without this much needed flexibility, there is a risk for the OR HVAC system to negatively impact infection control, OR turnover time and patient recovery time.

The presentation will show how complex OR CFD analyses can be used to inform the design of the associated OR HVAC systems such that the desired OR turnover times are met. Furthermore, this presentation will provide the audience with various recommendations regarding the design of the OR controls systems.

Please RSVP to Dylan Henderson
dchenderson@carilionclinic.org