When is drywall needed for fire code?
10/30/2021 at 3:35:52 PM
Hi,
We are doing a renovation right now and had the enclosure around our gas fireplace redone to be a floor to ceiling feature.
The drywaller that finished the work above the fireplace didn't do a great job and there was quite a big hump. So the contractor that was building the fireplace actually removed all the drywall above the fireplace where we are going to mount the TV. In it's place he installed 3/4" MDF and left a 1/2" gap between that and the studs.
There's electrical behind for lighting and the TV electrical. As well the duct for the gas fireplace runs up and out the back of that area to vent (so it's an exterior wall).
Does that cause an issue with the fire code not having drywall? it's only roughly a 48" x 32" are that is just MDF on studs.
Thanks,
T
10/31/2021 at 1:31:48 PM
You cannot use a combustible like MDF to meet fire code, you got a bad contractor or one who doesn't care...replace with properly rated 3/4 " drywall or leave but allow the min. distances as per code as well for other materials, usually 6" for most surfaces, (18" is min code for combustibles around fireplace flues), double wall can reduce that too 6". Check the current code for type of unit you installed, it should also be in the instruction install booklet from where you bought it. If you did not allow min. for the flue it needs to be redone.
10/31/2021 at 5:38:49 PM
Thanks for the response John.
So you are saying they can use MDF but it's not ideal? Or it was a typo and you are saying you CAN'T use a combustible material like MDF.
Yes the Project manager has not been great on this job. The city inspector will be coming to do the final inspection so I can bring it up then. But I'd rather get it fixed now if it's an issue. We're already 4 weeks behind schedule.
11/2/2021 at 9:36:04 AM
The Ontario Building Code | Fire-Rated Walls
9.24.3.2. Fire-Rated walls
(1) Steel studs used in walls required to have a fire-resistance rating shall be installed so that there is not less than a 12 mm clearance between the top of the stud and the top of the runner to allow for expansion in the event of fire.
(2) Except as provided in Article 9.24.3.6., studs in walls referred to in Sentence (1) shall not be attached to the runners in a manner that will prevent such expansion.
(3) Framing above doors with steel door frames in non-loadbearingfire separations required to have a fire-resistance rating shall consist of two runners on the flat fastened back to back.
(4) The lower runner required in Sentence (3) shall be cut through the flanges and be bent at each end to extend upwards at least 150 mm and fastened to the adjacent studs.
11/2/2021 at 11:39:36 AM
It seems you may be getting some misinformation; hopefully this will answer your questions. The Alberta Building Code (2019) requires interior wall finishes to have a surface flame-spread rating of not more than 150 (article 9.10.17.1). Flame Spread Ratings and Smoke Developed Classifications are found in Appendix D. MDF is not listed on the table however 1/2" particle board is and has a flame spread rating of 150. I would think the 3/4" MDF should be OK.
Things to watch for are clearances for the vent pipe and if the appliance requires any clearances. Best to find the make and model info and examine the manufacturers installation instructions for all clearance/installation requirements. You could also take some photos and visit a fireplace store.
11/6/2021 at 8:57:23 PM
There are min. codes for distance of combustibles to a heat source and any type of combustible construction material can only be used with "min distance to heat source as per code"...as per the info you sent it will not work, stay away from MDF or change the enclosure sizing to meet the min. distances or put drywall back as it is rated for fire & can be used. It is always better to exceed code then make something fit for convenience.
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