curved ceiling spacing

[cdafd]

1. An area measures 12 feet across at floor level

2. Ceiling is curved/ barrel shape/ half moon

3. the arc of the curve measures 22 feet

per nfpa 13 you measure spacing along the slope. like on peak ceilings

so are two rows needed??

can both rows start off center?? like is allowed on peaked ceilings??

 

[TravisMack]

If I am picturing this correctly, I would say you need 2 rows. Also, the sprinklers closest to the peak can be no more than 36" from the peak measured vertically. I just treat these domed ceilings like a peak ceiling, to the extent possible.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[chevy4x4trucks]

I believe if you ran the line at the top you would just need one. If you look at how the sprinkler would discharge it would cover you wall to wall.

In this instance (my opinion) as long as you met the obstruction criteria, which if you put the head at the highest point, you would.

 

[SprinklerDesigner2]

I agree with 4x4.

 

[TravisMack]

Would your answer change if you had a sloped ceiling and not a curved ceiling? If it just jumped up at right angles to 5' above the lower ceiling and was only 12' wall to wall, then I could see it being 1 row of sprinklers.

If the ceiling sloped from a low point up 11' on the slope and then back down 11' and the area from wall to wall is 12', would you put in a sprinkler on each side of the slope?

Which one does the curved ceiling more closely approximate? That will give you an idea of how to protect it.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[SprinklerDesigner2]

With 12' across and the arc it has I don't know how you would place heads on two lines maintaining 6' apart and maintain a deflector within 3' of the top of the arc.

I remember reading something on Quonset huts. I think it was a factory mutual handbook that was published long ago that I can't seem to find. It was published in 1954 when a lot of Quonset huts were being built. I misplaced that along with my 1931 edition of NFPA #13 and my Smoley's Tables of Slopes and Rises (before pocket calculators and computers).

If you haven't seen a 1931 edition of NFPA #13 it's a real hoot.

I'll bet Stookey has seen some Quonset hut type jobs.

 

[chevy4x4trucks]

You've got to remember that you are protecting the floor space. I would have to pull out the code book and double check, but you measure along the slope in an "attic" space which would be an area with combustible construction and a large amount of obstructions.

The situation that is being described sounds like it's a finished barrell ceiling and I am guessing would be drywall. If you space a line at the top you would have no issue covering the 12' wide floor space and the sprinklers would not be obstructed.

 

[TravisMack]

You measure along the slope even on a drywall ceiling. We hashed that out a while back on here

You calculate based on floor space, but layout based on sloped areas.

I hope everyone has a safe and happy Independence Day weekend!

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[SprinklerDesigner2]

Agree, always measure long the slope.

"3. the arc of the curve measures 22 feet"

Is that the total distance along the curve or is it the radius?

What does it look like?

http://en.wikipedia.org/wiki/Arch

If the 22 feet were the radius wouldn't it be a three-centered arch? Just about would have to because I'm having trouble visualizing what a arch would look like with 12' between walls and a linear distance along the arch of 22'.

 

[cdafd]

forgot if you have a 2002 nfpa 13 it actualy shows a curved ceiling and the spacing crtiteria

may also be in handbooks after 2002

 

[SprinklerDesigner2]

NFPA #13 2002

8.6.3.2.5 Under curved surfaces, the horizontal distance shall be measured at the floor level from the wall, or the intersection of the curved surface and the floor to the nearest sprinkler shall not be greater than one-half the allowable distance between sprinklers.

 

[cdafd]

forgot if you have a 2002 nfpa 13 """ meant to say handbook""""" it actualy shows a curved ceiling and the spacing crtiteria

may also be in handbooks after 2002

 

[cdafd]

OK OK

here we go again

same exact ceiling, but now we need to install smoke detectors


nfpa 72 seems a little silent, but does have the peaked ceiling rule

so it looks like smoke detector spacing should fall under same rules as peaked?? for a curved ceiling??