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  1. #1
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    Default Mechanial Room Separation

    My AHJ verbally told me that the lower level mechanical room needed 5/8 Type X on the walls. I can't find this anywhere in the 2015 IRC, but maybe I am looking in the wrong place. NM does have some exceptions to the IRC, including requiring Type X 5/8 on the common wall between garage and house.

    I looked into this for a client years ago regarding a forced air furnace closet, and never found a requirement at that time either. Am I missing something? Not a huge deal for one house, but I'll need to make a jamb extension for the door trim which I'd rather not do. I would also rather not drag 5/8 rock down into the lower level for the mechanical room.

    Notes: The mechanical room is in a corner of my lower level shop. Two walls are ICF foam, which will be covered with 1/2" gypsum board. Other two walls are 2x4 frame with a door. Door will be 20 minute steel door. Living space above it, so I could maybe see requiring 5/8 X on the ceiling. I would think a fire would be much more likely above the kitchen range than with a HE gas boiler, but whatever.

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    Jim Robinson
    New Mexico, USA

  2. #2
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    Default Re: Mechanial Room Separation

    Quote Originally Posted by Jim Robinson View Post
    My AHJ verbally told me that the lower level mechanical room needed 5/8 Type X on the walls.
    .
    .
    Notes: The mechanical room is in a corner of my lower level shop.
    Some presumptions:
    - You are referring to your "shop" in your "dwelling unit" (house), correct? If so, then the Residential Code applies.
    - The IRC, without amendments, is the code which was adopted and applicable to your state (if statewide code), county (if countywide code), locally (provided there are no other higher adopted codes). The key to this is "without amendments", otherwise you would need to provide the local amendments to the code.
    - The "lower level" does not include a garage, correct? A "garage" changes some things, but not some other things, and only applies to "the garage" part of the lower level.

    Are the above presumptions correct? (before replying to the question)

    Keep in mind that "current code" is not applicable to your house, "the code applicable at the time of permitting" is what is applicable to your house ... unless you make changes, then the "current code" at the time of the changes is applicable to those changes.

    Jerry Peck
    Construction Litigation Consultant ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  3. #3
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    Default Re: Mechanial Room Separation

    Jim,

    I do not know of any specific residential requirement for 5/8" type X in mechanical rooms. 702.3.5 specifies 5/8" Type X on the ceiling of garages beneath habitable rooms. I do not find anything in the IRC (actually, the CRC) with that requirement. It is possible that New Mexico has some kind of specific requirement that is not in the IRC (the CRC does have a bunch of requirements that have been added).

    Is this the same inspector who said Sch 40 PVC isn't good enough as a conduit above the vaulted ceiling? If so, I contend that this guy might be letting his authority to go to his head.

    I'll be interested to see how Jim Port responds to this.

    Department of Redundancy Department
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  4. #4
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    Default Re: Mechanial Room Separation

    JP, all correct assumptions. No garage, finished basement area on the other sides of the shop, which will technically be more of a brewery than wood shop. I have my local amendments which cover the 5/8 X on the garage which is added. I can't find it anywhere for the mechanical room.
    My permit is under 2015 NM IRC.

    http://www.nmhba.com/wordpress/wp-co...Nov15-2016.pdf

    http://164.64.110.134/parts/title14/14.007.0003.html

    Gunnar that was a different guy. I'll follow back up on that post with my update, but no problems.

    But so far I am not seeing anything that I missed. I do see that I can legally build a 8:9 stairway in NM. I actually did not know that until today. Not that I would want that in my house. As far as I know we have no local ammendments, but that is a good point. It may come via our local fire marshal. They do have a few things in the local codes. I'll have to check on that side of things. If not just for my house, it's something I should know for the day job anyhow.

    Jim Robinson
    New Mexico, USA

  5. #5
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    Default Re: Mechanial Room Separation

    Quote Originally Posted by Jim Robinson View Post
    No garage, finished basement area on the other sides of the shop, which will technically be more of a brewery than wood shop. I have my local amendments which cover the 5/8 X on the garage which is added. I can't find it anywhere for the mechanical room.
    My permit is under 2015 NM IRC
    .

    (bold and underlining is mine)
    "
    - 14.7.3.11 CHAPTER 3 - BUILDING PLANNING: - - B. Section R302. See this section of the IRC except as provided below.
    - - - (4) R302.6 Dwelling/Garage Fire Separation Required. Delete the text of this section and replace with the following: The garage shall be separated from the residence and its attic area by not less than five-eighth inch (15.9 mm) type x gypsum board or equivalent applied to the garage side. Garages beneath habitable space shall be separated from all habitable rooms above by not less than five-eighth inch (15.9 mm) type x gypsum board or equivalent. Where separation is a floor-ceiling assembly, the structure supporting the separation shall also be protected by not less than five-eighth inch (15.9 mm) type x gypsum board or equivalent."

    I'm guessing that the inspector is "reading" (incorrectly) that the above requirement "Where separation is a floor-ceiling assembly" applies to any and all "where separation is a floor-ceiling assembly" to basements, workshops, mechanical rooms, and the like too - even though it only states "(4) R302.6 Dwelling/Garage Fire Separation Required."

    If that is the case, then that would also apply to ANY "separation is a floor-ceiling assembly" (first floor to second floor, second floor to third floor, etc ... regardless of the fact that no "separation" is required in any of those locations. "Separation" is only required where stated "(4) R302.6 Dwelling/Garage Fire Separation Required."

    I do see that I can legally build a 8:9 stairway in NM. I actually did not know that until today. Not that I would want that in my house. As far as I know we have no local ammendments, but that is a good point. It may come via our local fire marshal. They do have a few things in the local codes. I'll have to check on that side of things. If not just for my house, it's something I should know for the day job anyhow.
    Sort of ...

    Keep in mind that they did not delete (at least I didn't find where it was deleted): R311.7.5.3 Nosings.

    That means that the requirements for nosings (as stated in R311.7.5.3 Nosings) still stands - see R311.7.5.2 Treads for the stated way to measure treads ("The tread depth shall be measured horizontally between the vertical planes of the foremost projection of adjacent treads and at a right angle to the tread?s leading edge.") - meaning that a minimum 3/4" to maximum 1-1/4" nosing is required for treads "less than 11 inches" (see Exception to R311.7.5.3 Nosings) for stairs with solid risers.

    Which means, for stairs with solid risers, the tread depth (with nosings) as measured in accordance with G. Section R311.7.5.2 Treads, would be a minimum of 9-3/4" to a minimum of 10-1/4".

    There is a 3/8" variation allowance between greatest to least nosing between stories (not "floors", careful on that as "floors" could include "landings") ... AND ... that there is a 3/8" variation allowance between greatest and least tread depth too ... BUT ... DO NOT add those two together as the "tread depth" .. "includes the nosings" ... thus the 3/8" variation for "tread depth" also includes any variation within the nosings - meaning that the maximum variation in tread depth is still 3/8" greatest to least.

    Jerry Peck
    Construction Litigation Consultant ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  6. #6
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    Default Re: Mechanial Room Separation

    He is out of town all of next week, so I doubt I will get an answer from his back up. His back up will be pretty overwhelmed already. Next part of the equation is that the upper level floor has 1.50" of gypcrete so I can't imagine why I would need any fire separation between the lower level and upper level involving gypsum board. But as I keep telling myself, "whatever keeps it moving forward".

    Jim Robinson
    New Mexico, USA

  7. #7
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    Default Re: Mechanial Room Separation

    Quote Originally Posted by Jim Robinson View Post
    Next part of the equation is that the upper level floor has 1.50" of gypcrete so I can't imagine why I would need any fire separation between the lower level and upper level involving gypsum board.
    Jim,

    The reason for the 5/8" Type X on the underside is that the gypcrete above only helps for a fire originating above, whereas the 5/8" Type X is for a fire originating from below.

    That said, though, unless the stairs going are enclosed and protected with a minimum 1 hour rating for the walls and stairs, and a minimum 20-minute rated door at the bottom, there are two things to consider: 1) it won't matter if the floor-ceiling assembly was 4 hour rated with an open path up the stair and through either door opening; 2) anyone down below ain't gonna have a way up and out to survive a fire from below or above ... unless you have a full egress door to the outside from the basement. (I know, I know, there are things called EEROs, but you want to bet your life on it? Better to have that 1 hour rated stair with rated doors at each end.)

    Jerry Peck
    Construction Litigation Consultant ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  8. #8
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    Default Re: Mechanial Room Separation

    Quote Originally Posted by Jerry Peck View Post
    .

    (bold and underlining is mine)
    "
    - 14.7.3.11 CHAPTER 3 - BUILDING PLANNING: - - B. Section R302. See this section of the IRC except as provided below.
    - - - (4) R302.6 Dwelling/Garage Fire Separation Required. Delete the text of this section and replace with the following: The garage shall be separated from the residence and its attic area by not less than five-eighth inch (15.9 mm) type x gypsum board or equivalent applied to the garage side. Garages beneath habitable space shall be separated from all habitable rooms above by not less than five-eighth inch (15.9 mm) type x gypsum board or equivalent. Where separation is a floor-ceiling assembly, the structure supporting the separation shall also be protected by not less than five-eighth inch (15.9 mm) type x gypsum board or equivalent."
    Is this a proposed change? I cannot find a change from 1/2" gyp on walls.

    If you choose not to decide, you still have made a choice.

  9. #9
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    Default Re: Mechanial Room Separation

    It's a New Mexico amendment for the garage. I had a new inspector for the framing inspection on Tuesday. Also confirmed 5/8 X on the boiler room ceiling and inside walls. All three are saying the same thing so I'm moving forward with it using 5/8. Not worth the time or trouble and if all 3 say the same thing it probably is in there somewhere. It could be a local fire marshal thing.

    Framing inspection is complete and moving forward to in floor tubing, gypcrete and insulation. Trying to get the heat on this December.

    Jim Robinson
    New Mexico, USA

  10. #10
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    Default Re: Mechanial Room Separation

    Quote Originally Posted by Jim Robinson View Post
    Trying to get the heat on this December.
    That would be nice. You are up by Santa Fe if I remember correctly.

    Department of Redundancy Department
    http://www.FullCircleInspect.com/

  11. #11
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    NM
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    Default Re: Mechanial Room Separation

    Quote Originally Posted by Lon Henderson View Post
    Is this a proposed change? I cannot find a change from 1/2" gyp on walls.
    I finished a house up in Angel Fire built under 2014 code. My garage is underneath the residence. The ceiling needed to be 5/8? TypeX as did the elevator shaft. However, there is a wall creating a storeroom that was fine with 1/2?. I think there is an argument to be made that it is not a ?supporting? wall. My mechanical rooms (2), are both located in the residential space within the heated envelope. Neither were required to use 5/8? wallboard.

    Are your inspections out of Santa Fe or Albuquerque?


  12. #12
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    Default Re: Mechanial Room Separation

    The other to be considered regarding walls "supporting" habitable space above is the 'not all walls below are "supporting" (load bearing) walls.

    Many interior walls are non-load bearing and would be exempt - even if in a garage.

    Jerry Peck
    Construction Litigation Consultant ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  13. #13
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    NM
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    Default Re: Mechanial Room Separation

    I agree Jerry so his walls should not require Type X if they aren?t load bearing. But other than ordering a bit wider jambs for the door might as well simply comply with want they want. Not a huge issue over all


  14. #14
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    Default Re: Mechanial Room Separation

    Quote Originally Posted by Jim Robinson View Post
    My AHJ verbally told me that the lower level mechanical room needed 5/8 Type X on the walls. I can't find this anywhere in the 2015 IRC, but maybe I am looking in the wrong place. NM does have some exceptions to the IRC, including requiring Type X 5/8 on the common wall between garage and house.

    I looked into this for a client years ago regarding a forced air furnace closet, and never found a requirement at that time either. Am I missing something? Not a huge deal for one house, but I'll need to make a jamb extension for the door trim which I'd rather not do. I would also rather not drag 5/8 rock down into the lower level for the mechanical room.

    Notes: The mechanical room is in a corner of my lower level shop. Two walls are ICF foam, which will be covered with 1/2" gypsum board. Other two walls are 2x4 frame with a door. Door will be 20 minute steel door. Living space above it, so I could maybe see requiring 5/8 X on the ceiling. I would think a fire would be much more likely above the kitchen range than with a HE gas boiler, but whatever.
    Even if the code doesn't apply , but the inspectors say it does, if the difference in material cost is under $100 I would put the 5/8X on the walls and ceiling. Remember "codes" are usually the minimum standard you have to meet. You will end up with a better dwelling and when it comes time to sell you can point out all the things that exceed the codes and make your home better than the rest. Just like purchasing when you crunch down the price by pointing out all the sub par things you find.


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