Class B Operating Room
Class B Operating Room
(OP)
I need to design a Class B Operation Room. Supposed to have 20 ACH with 4 outdoor ACH, no recirculating room unit. I'm assuming by no recirculating room unit the unit needs to be 100% outdoor air. The 20 ACH with 4 OACH is throwing me off. If I'm 100% outdoor air wouldn't my outdoor ACH by the same as my supply air ACH?





RE: Class B Operating Room
RE: Class B Operating Room
Similar to what you would do in a restroom space, only with laminar flow diffusers over the patient bed and sidewall return grilles near the floor.
RE: Class B Operating Room
RE: Class B Operating Room
RE: Class B Operating Room
RE: Class B Operating Room
ASHRAE Application Handbook Chapter 7 (Healthcare Facilities) requires minimum 25 ACH and 5 OACH for operating rooms. No re-circulation within room, but does not say all exhaust air must be thrown outside.
RE: Class B Operating Room
Table 7-1. Classes B&C operating rooms.
Positive pressure,
Min OA changes 4
Min total ACH 20
All room air exhausted outdoors N/R? Note J. I'm assuming that means not required.
Air recirculated by means of room units No
RH 20-60%
Note J for the room exhausted air: In some areas with potential contamination or odor problems, exhaust air shall be discharged directly to the outdoors and not recirculated to other areas. Individual circumstances may require special consideration for air exhausted to the outdoors, for example, intensive care units in which patients with pulmonary infection are treated and rooms for burn patients.
The area I'm looking at is rather small with an adjacent recovery room and soiled linen closet. I'm thinking of going with and erv unit to handle the exhaust and fresh air requirements. Plus also handles the MERV7 pre-filter requiement.
RE: Class B Operating Room
Rereading these sections again, looks like I have to correct myself and say NFPA does allow a percentage to be recirculated since 6.4.1.3 is referring to smoke originating within the OR.
I'm sure there is a newer version of the code available, but the 2005 version is what I have on hand. It would surprise me if things have changed drastically.
Don't be afraid to ask your AHJ for their interpretation, they are the one's that will be approving your design.
RE: Class B Operating Room
I'm not sure how retrun air would be treated differently than exfiltration air used to keep the OR relative positiv, even under the older codes. The OR's use typically 15% exfiltration air going to the clean core, which then uses exfiltration to stay relative positive to adjoining areas.