Recovery room
Recovery room
(OP)
i need help on air change requirement in a recovery room. I have a room of 40x20x8 code says 6 ACH and no recirculation allowed.
CFM = 40x20x8 x(6ACH)/60 = 640 CFM
By my load calculation i need about 1200 cfm for this space. And i will have dedicated unit for this space.
My question is what size unit i should use and do i need to exhaust all the air i am supplying as no recircualtion is allowed. Or can i exhaust only 640cfm.
If i exhaust all the air 1200 cfm then i need a makeup air.
CFM = 40x20x8 x(6ACH)/60 = 640 CFM
By my load calculation i need about 1200 cfm for this space. And i will have dedicated unit for this space.
My question is what size unit i should use and do i need to exhaust all the air i am supplying as no recircualtion is allowed. Or can i exhaust only 640cfm.
If i exhaust all the air 1200 cfm then i need a makeup air.





RE: Recovery room
So, ideally you have to exhaust 1200 cfm if your area doesn't require pressurization. If you have to pressurize the area, then find the leak rate by using Qleak = 2910xAxDP1/2, where A is leak area in sq.ft and DP is differential pressure in inches WG. Then Qreturn = Qsupply-Qleak
If you are worried about energy wastage, go for heat recovery systems.
RE: Recovery room
Will this 560cfm considered as recirculation which as i understand is not allowed by code.
RE: Recovery room
The calculation quark lists is to allow you to calculated a differential airflow for pressurization, if you're required to pressurize.
If there is no requirement to pressurize, a 10% difference between supply air and exhaust air is generally acceptable to create a mild positive in the area.
Another thought, if you used colder air you would need less air to meet your loads. Could be much more energy efficient in the long run. (small DX or chilled water duct coil say to drop the air temp).
RE: Recovery room
You can use variable volume system to limit the minimum supply air to 6 ACPH while using minimum 2 ACPH of outdoor air using central system type AHU with the required filters.