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Water curtain at EERO in load-bearing wall?

Discussion in 'Commercial Building Codes' started by Yikes, Jan 2, 2019.

  1. Yikes

    Yikes Gold Member

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    Happy new Year to you all! Looking for your opinion.

    I have a wood-framed type V-A apartment building design where two of my emergency escape windows face into a courtyard that is less than 10' wide, and therefore my 1-hour loadbearing wall and its openings require protection per CBC 1028.4.2. I planned on utilizing the water curtain for 45 minute protection per CBC 705.8.2 (exception). Although this project is not in Los Angeles, LA has a pretty good information bulletin explaining how this works: http://www.ladbs.org/docs/default-source/publications/information-bulletins/building-code/water-curtain-in-lieu-of-protected-exterior-openings-ib-p-bc2014-106.pdf

    My plan checker is saying that I can't use a water curtain in a loadbearing wall, because NFPA 13 8.15.26 now says that water curtains are allowed only in nonloadbearing walls. Likewise the ESR-2397 for Tyco sprinklers says that water curtains are intended for use in nonloadbearing walls.

    However, a header goes over the window; therefore everything below the header (including the window) is already non-loadbearing; so I should be allowed to use the water curtain substitution, right?.

    What do you think?
     
  2. RLGA

    RLGA Sawhorse

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    The reference is to a loadbearing wall, not a loadbearing opening. If the wall in which the opening is located is loadbearing, then the sprinklers cannot be used for opening protection.
     
    JBI likes this.
  3. Ty J.

    Ty J. Sawhorse

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    I agree with RLGA. The verbiage clearly refers to the wall in which the opening is located.
     
  4. Yikes

    Yikes Gold Member

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    So, let's say I have a 4'-6" wide x 4' high EERO window. I put it in the middle of a 1 hour nonloadbearing wall that is 5' wide x 7' high.
    In turn, that 1 hour wall is set within/underneath another loadbearing wall, with a 5' long overhead beam (header) in the loadbearing wall that transfers all loads away from the 5'x7' nonloadbearing wall.

    Is that acceptable?
     
  5. RLGA

    RLGA Sawhorse

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    I'd say you'd be stretching it. You can try, but I don't have any expectations that it will be accepted.
     
  6. mtlogcabin

    mtlogcabin Sawhorse

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    Why not use a coiling shutter or something similar on a fusible link. I guarantee nobody is going to use a EERO when there is 165 degrees of heat at that window.
     
    JBI likes this.
  7. Ty J.

    Ty J. Sawhorse

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    Hang on here -

    After reviewing ESR-2397, it refers to use with non-load-bearing interior fire barrier assemblies, a fire partition, or an exterior wall assembly. Seems to me, that the only requirement for non-load-bearing walls pertains to an interior fire barrier.
    upload_2019-1-2_13-2-39.png

    However, per NFPA 13 8.15.26 (5), it does not specify.

    upload_2019-1-2_13-7-24.png

    Based upon NFPA 13, it would thereby be IMHO not permissible to use a water curtain as proposed (agree with plans examiner). A header does not constitute justification for a wall being non-load bearing. Load bearing walls by very nature have headers within them.
     
    jar546 likes this.
  8. cda

    cda Sawhorse

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    Boy that is a cool fire, even though that term does not make any sense.

    I would not approve a shutter on an eero
     
  9. Ty J.

    Ty J. Sawhorse

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    Why not? If fire is interior and hot enough to activate the door, anyone in the room is already dead.

    If fire is on the exterior and hot enough to activate the door, then you would not want anyone going out the EERO.
     
  10. cda

    cda Sawhorse

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    I see where you get the 165 now,

    But the window is also there for the firefighter to get in or shoot the wet stuff and than enter.

    Or for the firefighter inside to bale out of.
     
  11. Yikes

    Yikes Gold Member

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    Ty J, thanks for your response. But for sake of discussion, if I may challenge you, let's work it the other way around: Nonloadbearing walls by their very nature also have some type of beam or structural member somewhere above them which carries the weight of the roof or floor or other structure above, right? So what's the actual difference between that, and a header in a bearing wall? And more importantly, what is the intent of the code as to why bearing vs. non-bearing is so critical?.

    Picture an existing building with a covered patio. The patio roof is supported below by beams and columns. The columns are fire rated for one-hour construction. 5 years later, the owner obtains permits to infill the space between the posts with studs and a slip-track on top, exterior plaster, and a window in it, creating a bedroom. Q: Is that new infill wall load bearing? I think not; because the roof is still supported by the same old beams and columns.

    Now, how is that fundamentally different from my scenario of a 5' x 7' nonloadbearing wall described in the previous post? Perhaps the slipjoint in the top track of the infill wall? If that's the case, I can do that in my new apartment building opening as well, to prove it's nonloadbearing.
     
  12. Sleepy

    Sleepy Registered User

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    Don't both NFPA 13 8.15.26 and ESR-2397 5.3 specifically require the glazing to be fixed? How is an EERO fixed glazing?

    For the shutter, it seems it could be ok (IBC-2015 1030.4):
    "...Bars, grilles, grates or similar devices are permitted to be placed over emergency escape and rescue openings provided the minimum net clear opening size complies with Section 1030.2 and such devices shall be releasable or removable from the inside without the use of a key, tool or force greater than that which is required for normal operation of the emergency escape and rescue opening."
     
  13. Ty J.

    Ty J. Sawhorse

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    Further research into why the provision for non-load-bearing was added would be necessary before I could lend any speculation. The research would be up to you, as the AHJ has clearly got the code section behind him.

    As for your example, yes, they are load bearing walls after being filled in. We run into the example you are illustrating all the time wherein someone wants to frame in an existing patio on top of a existing slab. Problem is, as soon as you frame walls tight to the existing beam, deflection of the beam is hindered, and wall is load bearing, thus requiring a continuous footing, etc.

    You need to find out why load bearing walls are not permitted and then make justification based upon the actual reasoning. Right now, your just spit-balling ideas on why you don't want to comply with the code. The code is a minimum standard, do you want to comply with less than that?
     
  14. Yikes

    Yikes Gold Member

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    Of course I don't want to do less than the minimum required by code.

    However, it appears that this distinction of loadbearing vs nonloadbearing was only added in the last few years. And in the example I gave above, I specifically called out for a slip track to prove the wall is nonloadbearing - - a type of curtain wall, if you will.
     
  15. steveray

    steveray Sawhorse

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    It does seem pretty wierd that IBC specifically references this type of protection and NFPA 13 disallows it....

    705.8.2 Protected openings. Where openings are required
    to be protected, fire doors and fire shutters shall comply
    with Section 716.5 and fire window assemblies shall comply
    with Section 716.6.
    Exception: Opening protectives are not required where the building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 and the exterior openings are protected by a water curtain using automatic sprinklers approved for that use.
     
  16. steveray

    steveray Sawhorse

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    There goes all of your glass atriums with that logic.....
     
  17. Yikes

    Yikes Gold Member

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    The consulting and Specifying Engineer magazine has an article that summarized the 2016 changes:
    "Sprinkler-protected glazing: Building code officials have historically permitted the use of sprinkler-protected glazing in various building locations such as atriums and exterior walls. However, previous editions of NFPA 13 have not provided installation criteria for such sprinkler systems. The 2016 edition now contains prescriptive criteria for sprinklers used in combination with glazing as an alternative to a required fire-rated wall or window assembly."​
    I note that the 2016 California Building Code Matrix Adoption Table for Ch. 35 "Referenced Standards" says that California adopted NFPA 13-13 (2013 edition), whereas the California Fire Code Matrix Adoption Table for Ch. 80 "Referenced Standards" says that California adopted NFPA 13-16 (2016 edition), so right there is a source of error.

    What I really need is someone with access to the previous NFPA proceedings that can explain why the change took place, and what is the intent.
     
  18. Builder Bob

    Builder Bob Sawhorse

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    Water curtains were very popular in the 70's for exposure protection in the fire service. The effectiveness of using a water curtain was studied by fire protection engineers (new field in the making at this time) and it was discovered that water curtains were largely ineffective - radiate heat waves easily transmitted thru the water curtain and would allow materials (curtains, drapes, furnishing, etc. to ignite and cause an exposure to catch on fire thus defeating the water curtain. What was effective for reducing fires for exposures was the application of the water mist from the water curtains that cooled the surfaces to prohibit ignition. NFPA may changes to the "water curtain" concept where fixed glazing and direct application of water to the glazing is required.

    Don't know about current trends, but this is a life lesson learned from an old fire dog..... lost a few exposures in my younger days - it generally became more important to us (volunteer fire company) to maximize use of water sources we had instead of wasting it on a water curtain for exposures.

    BTW, we used the water curtain for several years afterwards for family fun day when it was hot outside and the families and kiddos needed something to cool off from the heat. we also used it on occasion for rehab after a house fire in the summer....
     
  19. Yikes

    Yikes Gold Member

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    Thanks, Builder Bob. I'm still trying to find out why load-bearing vs. non-loadbearing makes the difference.
     
  20. Builder Bob

    Builder Bob Sawhorse

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    load bearing threatens the structurally stability, non load bearing not so much.

    Sprinkler systems can be out of service and dependency upon this for structural protection and/or stability in a fire is fool hardy... thus the difference
     

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