Min CFM for Bathroom Exhaust 1

[Golestan]

Hi,
Does ASHRAE 62-XXXX have any values for exhaust from rest rooms in public buildings?
What is the min required from Building code perspective.
I am confused because some codes refer to Area, some to People and some to Number of stalls.

Thanks,

 

[willard3]

IMC has this information in chapt 4.

I use 10-15 air changes/hr for fan sizing; nobody wants to smell sewage.

 

[EmeraldCoastHVACR]

depends whether you use ventilation rate procedure or IAQ.

5 cfm per person plus 0.06 cfm/ft^2

 

[AbbyNormal]

2001 it was 50 CFM a person, I would take that as per fixture , toilet/urinal.

Standard Mechanical code was 2 CFM/ square foot of the public bathroom



Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[AbbyNormal]

You would not ventilate a bathroom using 5 CFM a person and 0.06 CFM/sq ft


Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[williamsGA]

I always use 75 CFM per fixture.

 

[MarauderX]

I think the International Mechanical Code lists a minimum of 75 CFM per fixture. I have always designed at 100 CFM per fixture to allow for future expansion, fan rebalancing, etc. Over-designed? Nah, it works as separate as a relief of OA and allows the bathroom to remain negatively pressurized to prevent odors from wandering.

http://www.vanderweil.com

 

[ChrisConley]

4-6 ACH continuous, 10ACH intermittent seems to work well for odour issues.

 

[CountOlaf]

Again I will cite one of my favorite resources, "HVAC Equations, Data, and Rules of Thumb" by Arthur A. Bell...

It basically recommends a design criteria of either 2 CFM/SF, 10 ACH, or 100 CFM/water closet and urinal. It then shows some of the codes and their specific requirements, but it further goes on to say the following:

1. For toilet rooms with high fixture densities (stadiums, auditoriums), 75 CFM/water closet & urinal dictates.
2. For toilet rooms with ceiling heights over 12', the 10 ACH dictates.
3. For toilet rooms with ceiling heights 12' and under, the 2 CFM/SF dictates.
4. If toilet rooms are designed for 100 CFM/water closet/urinal, all three major codes and the 10 ACH can be met.
5. If women's and men's are essentially the same size but have different fixture count (typically less in the women's), use the larger CFM for both toilet rooms when using the CFM/fixture method.

Anyway, since it's an easy calc, I usually check all three and pick the one I like depending on the job. My particular local mechancial code calls for the 75 CFM/fixture at public spaces (less for residential).