Exhaust from Apt suites into parking garage

[WinniPEng]

According to the National Building Code of Canada, the practice of exhausting air from occupied spaces into a parking garage is normally prohibited, due to the risk of air flowing back from the garage into the occupied areas. However, in the explanatory section of the code, it indicates that the practice is permitted under limited circumstances (but does not explain what those circumstances are). Is anyone here aware of any examples where this practice has been done, and what safety measures are required, in addition to maintaing positive pressure in the occupied spaces and negative presasure in the garage, and backdraft dampers on the exhaust ducts? It seems that this practice would provide great savings in energy usage. Additionally, if anyone is aware of any handbooks that deal with this practice, and its application, that would be helpful as well.
Thanks you

 

[MintJulep]

Where do you see energey savings? Only if the garage is heated that I can see. In that case, how about an air-to-air heat exchanger to capture the waste heat, but still allow exhaust outside of the garage.

In addition to the backflow hazard, there is potential noise problem.

 

[Drazen]

Maybe you think about savings in purchasing and operating of supply ventilators for garage that will be avoided if you use building exhaust fans for that function.

I can only give suggestion that it is necessary to be conservative regarding mixing grage ventilation with anything else, because CO is so dangerous poison.

I wouldn't prefer common sense, backflow-preventing dampers or similar to even slight opportunity that in strange circumstances there is any posssibility that any guantity of garage air will enter occupied spaces.

 

[ChasBean1]

Yes, Drazen. Between a general exhaust source from an occupied building and potentially CO laden garage exhaust, the general exhaust is the cleaner of the two. A parking garage is essentially a contaminated, unfiltered, outdoor space. The only limitations to exhausting building air to a garage are from contaminated sources such as chemical fume hoods. I like the idea of using building exhaust to help heat a garage. Unless the airstream were contaminated, I don't see any reason not to do so.