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Return air distance from sprinkler head

Discussion in 'Commercial Fire Codes' started by chris kennedy, Jul 15, 2017.

  1. chris kennedy

    chris kennedy Sawhorse

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    I was told today that a return air opening must be 3' from a fire sprinkler head. Makes sense to me but can't find the art.

    Little help please.

    Thanks
     
  2. cda

    cda Sawhorse

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    It is in NFPA 13

    Can give a section Monday

    Another option is to use a higher temp head, if it needs to be less than three feet
     
  3. cda

    cda Sawhorse

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  4. cda

    cda Sawhorse

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    Do you need this for

    Commercial or residential??


    Also what edition of 13 and 13 R are you under
     
    #4 cda, Jul 15, 2017
    Last edited: Jul 15, 2017
  5. chris kennedy

    chris kennedy Sawhorse

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    Sorry, commercial.
     
  6. cda

    cda Sawhorse

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    Will look on Monday


    More than likely the link and chart above is what I will find


    Which edition of 13 would you like
     
  7. steveray

    steveray Sawhorse

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    I "know" it is there for detectors, not sure on sprinklers....
     
  8. cda

    cda Sawhorse

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    In the 2016 NFPA 13

    Check section 8.3.2.4 and 8.3.2.5 with tables

    And one option in some cases is to change the sprinkler temp to higher level
     
  9. Paul Sweet

    Paul Sweet Sawhorse

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    I can see the need to locate a smoke detector a distance from a return grille, because the grille might pull air away from the detector.

    A return grille is pulling room temperature air, so I don't see how it would affect sprinkler operation.
     
  10. tmurray

    tmurray Sawhorse

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    That's for diffusers though. I'm not finding anything about return air openings...It makes sense you would want to locate them away to ensure that the heat is not being pulled from the area and preventing the sprinkler from discharging until the fire has increased in size beyond where a single head will be able to contain...
     
  11. cda

    cda Sawhorse

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    I guess I should read each word.

    Will look again, but have not heard of a distance requirement for return air.

    Unless there is a tremendous velocity, I am thinking the heat plume will activate the sprinkler, even with the hvac going
     
  12. tmurray

    tmurray Sawhorse

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    Probably. I'm just worried about the buoyancy of the hotter air being the one that gets removed first and is replaced by cooler air around the head.
     
  13. cda

    cda Sawhorse

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    If there is enough fire to activate the sprinkler,

    There is enough fire to activate the sprinkler.

    Plus you also get into spacing, there may be a sprinkler nearby that might activate, if the return air is messing things up.
     
  14. tmurray

    tmurray Sawhorse

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    As with sprinkler jumping, would you not have portions of the fire potentially outside of the spray of the head in this scenario? Isn't this why there are minimum head spacings? Not being sarcastic, I'm honestly asking. I know enough about NFPA 13 to be dangerous, not helpful.
     
  15. cda

    cda Sawhorse

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    I would say minimum is so one does not spray on another, depending where you apply minimum

    Such as four inch minimum away from a wall

    I do not think return air vents are normally a problem
     
  16. Pcinspector1

    Pcinspector1 Platinum Member

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    TABLE 8.3.2.5 (C) Front of wall-mounted hot air diffusers 36".
     
  17. steveray

    steveray Sawhorse

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    That table is only residential
     

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