Health Reasons for 75 CFM bathroom exhaust

[texanman]

Hi,
Are there any health reasons for mandating (by code) to have 75 cfm exhaust per fixture in public bathrooms? A client has asked that we don't design per 75 cfm code, and that he will get us a variance from the local code authority. The State board of PE's requires us to design with the public health and safety as the main criteria. Any comments?
thanks,

 

[dblyle]

What code are you referring to? Most codes I have seen require minimum of 50 cfm per fixture.

 

[trashcanman]

It comes from Table 403.3 in the International Mechanical Code for public toilet rooms.

 

[willard3]

If you are going to stamp the drawings, follow the code. Code requirements are MINIMUM requirements.

75 CFM is low if there is any real use of the bathroom.

 

[trashcanman]

Willard is right on about heavy use. I.E. football stadium toilets at halftime (heavy fumes) even with fans (air movement type).

 

[DonPhillips]

Getting a building code variance is not the same as a zoning code variance where you must show hardship. For the appeals board to grant the variance, you must present a case where the intent of the code with less than 75 cfm is still met. And since you cannot recirculate toilet room exhaust, the building ventilation system cannot be used to substitute for the exhaust.

Try reading through the IMC commentary. It gives reasons for ventilation so perhaps you can convince your client it is not worth spending the money appealing and preparing for a hearing not likely to be granted.

If your client does want to proceed, it will be worth a call to your building offcial to seek support. When I represent a jurisdiction, I take a "not opposed" stance if the case is not a matter of public safety, like for ADAAG variences. In this particular case, I would not be in favor. Depending on your appeals board, they sometimes grill the building official if they appear in favor so I usually take the not opposed route.

Lastly, depending on your jurisdiction and appeals board make up, it may be worth getting the fire official's support. If you, the BO and FO are all in agreement, it makes it easier for the board to grant a variance.

But as I stated, I think this is an uphill battle.

Oh, without a variance, you have a duty to design to meet the minimum of the code and try to meet the client's needs.



Don Phillips

http://worthingtonengineering.com

 

[cry22]

The only health code I know is the AIA/HHS healthcare design guidelines which recommend 10 Air Changes per hour, with 100% exhaust from from toilets in hospitals.
Often times, you will find that those values are less than required by IMC.

I have used a method for some toilets by including a motion detector with a 10-minutes (Adjustable) timer for the exhaust fan. While you size for IMC, your use is energy conscious and it is triggered automatically when in use, thus complying with codes. This may be an acceptable solution for your client if he is energy concious.

Watch your buidling air balance and pressurization with such a method though.