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HVAC Forums => HVAC Help => Topic started by: Matthewl14 on August 11, 2018, 02:48:33 PM

Title: Building Code - Finishing Basement and HVAC
Post by: Matthewl14 on August 11, 2018, 02:48:33 PM
Good afternoon,
I am hoping one of the many experts on here can point me to where something is in the Ontario Building Code. I have finished 3 basements in the last 10 years and have never had an issue with the building departments when it came to not changing the HVAC and leaving it in the ceiling but in my recent basement this is the one thing they are saying I have to change as they want them at the floor. So I am hoping somebody on here can point me to where it says that when finishing a basement the hot air registers needs to be dropped to the floor. I plan to drop the cold air return to improve the balance but other then that I wanted to try and leave the HVAC alone as the vents come right out at the windows which is perfect in my world.

Appreciate any and all help.

Thanks
Title: Re: Building Code - Finishing Basement and HVAC
Post by: brad_monty10 on August 11, 2018, 02:57:40 PM
Is the basement a walkout ?
Title: Re: Building Code - Finishing Basement and HVAC
Post by: Matthewl14 on August 11, 2018, 03:49:33 PM
No it's not a walk out
Title: Re: Building Code - Finishing Basement and HVAC
Post by: Admin on August 11, 2018, 04:44:22 PM
There is no Code that says heat runs must be changed from ceiling to low wall in a finished basement.  Usually the HVAC designer will require low wall heat runs if your home is slab on grade, or a walkout.  I think it's a good idea regardless, but it's not required.

There is nothing in the CAN/CSA-F280-M Code or SMACNA Manuals that require low wall supply vents.  Ask the inspector to provide you with a Code that says otherwise.  Maybe there's a Municipal Bylaw or requirement.

See Building Code Article 6.2.4.4;

Quote
6.2.4.4. Warm-Air Supply Outlets

(1) In a dwelling unit, a warm-air supply outlet shall be provided in each finished room that is located adjacent to unheated space, exterior air or exterior soil.
(2) Except as provided in Sentence (3), when a room described in Sentence (1) is located adjacent to exterior walls, such outlets shall be located so as to bathe at least one exterior wall or window with warm air, except in bathrooms, utility rooms or kitchens, where this may not be practical.
(3) Where the heating system is also designed to provide ventilation air, ceiling outlets or outlets located high on interior walls may be installed, provided the outlets are,(a) designed for this purpose, and
(b) installed with diffusers.

(4) At least one warm-air supply outlet shall be provided for each 40 m² of floor surface area in unfinished basements serving dwelling units, located so as to provide adequate distribution of warm air throughout the basement.
(5) At least one warm-air supply outlet shall be provided for each 80 m2 of floor surface area in heated crawl spaces serving dwelling units, and it shall be located so as to provide adequate distribution of warm-air throughout the crawl space.
(6) Except for pipeless furnaces and floor furnaces, the capacity of warm-air supply outlets serving dwelling units shall be not less than the design heat loss from the area served and shall not exceed 3 kW per outlet.
(7) In basements and heated crawl spaces, the calculated heat gain from the supply ducts and plenum surfaces may be considered in calculating the design heat loss.
(8) The temperature of supply air at the warm-air supply outlets shall not exceed 70°C.
(9) Warm-air supply outlets located in finished areas shall be provided with diffusers and adjustable openings and shall not be located on a furnace plenum.
(10) Air duct systems serving storage garages shall not be interconnected with other parts of the building.

A standard 4x10” vent with louvers is considered a diffuser.
Title: Re: Building Code - Finishing Basement and HVAC
Post by: Hvacpimp on August 11, 2018, 04:47:55 PM
I wouldn't know where to find it but I've had inspectors mention it as a potential fault in their inspections. I never had this issue because I always run them low. I've asked tin bashers and they have said low as well. Honestly, it's a workmanship thing.  Yes you see them in the ceiling in a a lot of places but it doesn't mean they are right. The inspector is right. It's probably in the tin basher code if not in the building one.
Title: Re: Building Code - Finishing Basement and HVAC
Post by: Matthewl14 on August 12, 2018, 06:35:36 AM
Thank you all for your assistance! Much appreciated
Title: Re: Building Code - Finishing Basement and HVAC
Post by: Porcupinepuffer on August 12, 2018, 09:38:54 AM
Never seen this requirement in the building code or sheet metal construction standards. If someone is asking for it to be done to existing ceiling runs, there's also a sizing issue. The runs create a good amount of restriction and can cause airflow to be drastically reduced by continuing to the wall and going down without the entire branch from the trunk being upsized.
Title: Re: Building Code - Finishing Basement and HVAC
Post by: Sergroum on August 12, 2018, 01:00:32 PM
At the same time, in terms of comfort and efficacy of the airflow, bringing the registers down does improve things considerably. It's not a requirement, and it does sometimes eat up space, it costs more as well obviously. More work, more space, more intricate, greater size of the pipe on occasion. But it does work better that way.
Title: Re: Building Code - Finishing Basement and HVAC
Post by: Hvacpimp on August 12, 2018, 05:51:55 PM
I've seen 5" heat runs go up to a second storey of a house many times. Upsizing vent to bring it down the side of the wall? hmmmmm. To me, leaving it in the ceiling is a lack of workmanship when finishing a basement. If the customer is cutting corners with a tight budget than the ceiling it goes.  It's the little things in workmanship that can have a guy busy all season long or sitting in the off season! I've been in the business for 18 years now next month and I've learned that it's some of the little things like this that can make a difference! Just my opinion.
Title: Re: Building Code - Finishing Basement and HVAC
Post by: Porcupinepuffer on August 14, 2018, 07:06:02 PM
Upsizing vent to bring it down the side of the wall? hmmmmm. To me, leaving it in the ceiling is a lack of workmanship when finishing a basement.

Yeah I actually remember seeing it in some video. It may have been holmes on homes. The hvac expert was showing how a general contractor extended existing basement runs to come down, and that the extra resistance was enough to drastically reduce the the cfm output to almost diddly squat. When he got rid of them and returned it back to the ceiling height, the cfm's were back up and it was working well. He used a velometer to show before/after... I doubt it would happen every time, but maybe the runs were already pushed to their max.
Title: Re: Building Code - Finishing Basement and HVAC
Post by: Tim W on September 12, 2019, 11:52:18 AM
In reference to the Admin’s reply#3, in section 6.2.4.4.(3), it says “Where the heating system is also designed to provide ventilation air, ceiling outlets or outlets located high on interior walls may be installed, provided the outlets are,.....”.
Are all heating outlets classified as providing ‘ventilation air” or does this only apply to homes that have an ERV or HRV system?
Title: Re: Building Code - Finishing Basement and HVAC
Post by: Admin on September 20, 2019, 05:14:55 PM
That's a good question.

Quote
(9) Warm-air supply outlets located in finished areas shall be provided with diffusers and adjustable openings and shall not be located on a furnace plenum.

Looking at subsection 9 I still don't see any reference to using low wall supply vents.

Also unless you have a very creative designer using a Performance Package you will never build a new home in Ontario without using an HRV / ERV.

I only work for one builder that seems to be able to eliminate HRV / ERV's in townhouses.  They interlock the principal bath fan with the furnace fan, however we do not install a fresh air duct into the return air which I believe would be a requirement for ventilation, otherwise we're only providing circulation.  In some cases a make up air unit may be required to preheat the incoming air in this type of interlocked system if an outdoor air supply was used.

I attached a document that seems to imply an outdoor air supply is required with an interlocked system, when no HRV is used.