AIR CHANGES

[Zeroman]

When I read, for example, 8 air changes per hour I get the impression that I must replace the room 8 times in one hour with FRESH AIR. Is it FRESH AIR?

Thanks

 

[lilliput1]

Not unless it specifically says it is Outdoor Air Changes per Hour or that the room is to be 100% exhausted. A hospital patient room for example is designed for minimum 6 ACPH with minimum 2 ACPH of outdoor air (introduced in the central AHU).

 

[ChasBean1]

Also worth noting is when they split outside air and total air requirements (such as 2 ACH OA and 6 ACH total), it carries an assumption that the supply air stream contains a portion of recirculated air from that particular space. If the air entering that room is a mixture of OA and recirculated air not from the room, all entering air can be considered fresh with respect to the requirements of that room.

 

[Zeroman]

Thanks guys, once again you have come to my rescue.

Dave