Make-Up Air for Condo 2

[MechEng1977]

Hello, I am on the Board of Directors for my condo in Toronto and I'm wondering what is the code for the Make-Up air for a condo hallway. Is it dictated by ASHRAE or by the local building code?
What is a typical value for such measurement. I assume it is listed in Air Exchange / hour? Is there a temp requirement?

Thanks in advance!

 

[MECHJAMIECTA]

Stuff like this is always dictated by Code. Code is what is required by law. Often ASHRAE Standards (or at least parts) are adopted into the Code and only then are the ASHRAE standards *required*. (Note required by law is not always the same as good design practice).

I don't know what codes Toronto has adopted so you would need to find that out. The 2009 International Mechanical Code requires 0.06 CFM/ft² of floor area for corridors. However you need to determine if that code/version of the code applies and also read the assumptions and definitions that are attached to this rate to determine if it applies.

 

[cry22]

Typically, your common sense design for hallways always exceeds the required ventilation rate. i.e. hallway need to be under positive pressure to limit infiltration into the building (about 75 CFM/door, connecting directly to outside or exit stairs, not to units), this is far in excess of what Mechjmieca indicated as code value.

 

[MECHJAMIECTA]

cry22. While you are technically correct in terms of OVERALL air supplied, I believe MechEng1977 was asking for the minimum code or standard required outside air/makeup air.

Yes, 0.06 CFM/ft2 is not the total amount of conditioned air that may need to be supplied to meet whatever temperature and pressure requirements are desired. However, 0.06 CFM/ft2 would arguably be the minimum acceptable *outside air* to meet ventilation/breathing requirements.

 

[317069]

Cry22
could you please explain a lilttle more what did you mean by connecting directly to outside not to units?

 

[cry22]

by units, I meant the apartments.
ex-filtration (positive pressure) should be for adjacent un-conditionned space or outside doors only, i.e you should consider only exit stair doors and the lobby doors, and not every single apartment door connecting to the corridor when figuring the amount of air needed for positive building pressurization.

 

[317069]

Do you mean if we have for example one story building has 10 appartments, with one corridor and one main door, that means we need 75 cfm make up air for corridor?

 

[GMcD]

Refer to the Ontario Provincual Building Code - the first step is to determine the vintage of the Apartment building - what year it was built - then you need to go to the Library and get a copy of the Ontario Building Code that applied at the time the building was constructed. I'll say this "generally" - since the late 1980's there has been a Building Code requirement to provide a minimum of 0.35 air changes per hour (ACH) for each suite. "Generally" the acceptable industry practice is to provide that amount of air via the corridor ventilation supply, hoping that the air enters the suites via the doors as each suite uses it's range hoods or bathroom exhaust fans. Typically I've seen the rule of thumb to be anywhere between 60 to 80 CFM (cubic feet per minute) of supply air per suite on each floor as the design airflow for the corridor ventilation supply sizing.

Recent studies have shown that, in fact, 60% or more of the corridor ventilation air is leaking up stair and elevator shafts and not even getting to the suites (by the way - in the last 20+ years of this practice, no one has yet to answer my question - how does the corridor air "leak" through the Code required fire and smoke-proof Suite Door....?). Current trends are heading towards new buildings using in-suite heat recovery ventilators, or in the case of suites with fan-coils or heat pump air conditioners, they will have a balanced fresh air supply ducted to the in-suite air conditioner. Then the corridor ventilation air supply can be reduced to a small amount to just pressurize the corridor for cooking odour control between suites.

 

[317069]

GMcD
what about natural ventilation for each suit comming through windows, doors which still a part of building codes anywhere either in old or recent days?

 

[GMcD]

317069: Natural ventilation hasn't been accepted as a verified suite ventilation "system" since before 1980 as far as I can recall. Since the early '80's most Provincial Building Codes required a "mechanical ventilation system" to assure the ACH in suites. Another method of achieving the suite ventilation in mild climates (in Canada- that means Vancouver/lower mainland exclusively) one can use either a timer controlled fan in the suite (pick the largest bathroom exhaust fan) and a fresh air duct from a wall cap that terminates in the space behind the refrigerator. One can also use a humidistat to automatically cycle a suite exhaust fan to provide the ACH, which, at the end of the day is all about controlling the humidity inside the suite for cold climates.

I don't know many occupants who would voluntarily crack open a window all winter to provide their suite ventilation.

 

[317069]

- Current OBC says:
9.32.1.3. Ventilation of Rooms and Spaces
(1) Except as permitted in Sentence (2), rooms or spaces in a dwelling unit shall be ventilated
by natural means in accordance with Subsection 9.32.2.

- exhaust fan in kitchen and washroom provide mechanical ventilation.
- people who would like to open windows in winter are more than people who like to istall HRV's in thier apartment even though one of HRV manufucturer recomend to NOT install thier unit under the bedroom of the upper story.
- what about building using hydronic system (hot water) for heating and widow AC type for cooling like the most ?
- what about tight unit doors?
- do you think the oevrhead duct system is suitable for residential units?
- also for houses how many do you think people use HRV, and HRV is not required for a house by current OBC.(for myself I strongly support using HRV, but peopl don't like to pay and code dosn't force them to do)

 

[317069]

why code ask for make up system for residential and did not ask for nonresidential?

 

[MechEng1977]

Great info guys, I appreciate it!

 

[msquared48]

Now that your question has been answered, I just want to let you know that women do not put their makeup on in the hallway - generally the bedroom or bathroom. Hope that helps.

Mike McCann
MMC Engineering

 

[MechEng1977]

msquared48, not sure I understand your joke but I will say its too bad they don't because there are some hot ones in my building!

 

[houseman20]

There has been a trend toward supplying make-up air directly to the condo units instead of the old practice of supplying air via corridor. This practice of supplying thru the corridor appears to violate a basic code principle.

IMC 2009 Section 601.2 Air movement in egress elements. Corridors shall not serve as supply, return, exhaust, relief or ventilation air ducts.