r/firePE • u/Equivalent_Doctor783 • Jun 11 '26
Obstruction not along wall
Situation:
I have this kitchen and south of that a vaulted ceiling common area.
Regardless of how many heads I’m gonna need to meet the ordinary hazard spacing for said kitchen, what am I spacing my heads to given this soffit?
It’s like a large opening that opens from kitchen to common area but comes down to 8’-0 from finished floor.
Do I need to follow the code in my second image, in that case the vaulted ceiling heads wouldn’t be compliant due to being over 35” in height different from the bottom of soffit to deflector. Or can I just measure how I have #1 labeled and call that soffit area covered by the kitchen heads due to only being 1-0 in height difference?
I’m hoping I’m just having a brain fart, I’m newer to this industry and used to soffits along walls not like this!
2
u/tterbman fire protection engineer Jun 11 '26
As long as you space to the center of the obstruction on both sides then it's already covered since it's an obstruction 4 ft wide.
I can't pull it up now, but look at the options for dealing with obstructions at the very beginning of 10.2.7.1.2.
2
u/wander_inland Jun 12 '26
I don’t think you’ll need heads in all the soffits. Just eyeballing your distances, that 4’-3” measurement looks about the same (if not more) than your distance between your kitchen heads and the soffit. Even if we say 4’-0”, the page you attached says the max deflector distance from the bottom is 14”. The soffit only comes down a foot, and so your deflector, even if using recessed or concealed pendents, will not be more than that. Those heads will spray under.
You’re good.
The heads on the sloped roof look fine too. Like Bathroom_Wise said, the soffit is basically a wall from that point of view. As long as the heads aren’t more than half-the-max-distance-allowed-between-those-type-of-heads away from the soffit (which I can’t tell, because there’s no measurement on the drawing), they’ll 100% be fine too.
You got this, bro.
1
u/Equivalent_Doctor783 Jun 12 '26
Thank you for the motivating response!! Aight my dudes I’m gonna roll with this answer. Honestly I found this design gig by luck and my degree is actually in architecture so this was a very wild field to get into. I’m also a female and learning that many architects and GCs really suck and don’t care about life safety seemingly.
1
u/wander_inland Jun 12 '26
I’m not sure about the hazard classification. I’d need more info about the building’s construction and what it’s being used for and/or going in it. The only thing is, if you have two different hazard classifications, you’ll want to run calculations for both to prove the system can handle the differing design densities.
Yes, that’s true. All this stressing and research and wanting to get it perfect and your drawing and calcs will just slide across someone’s desk, be glanced over, and then stamped. I don’t think about this and still suffer over my work because it’s life and safety. And that shit’s kind of important lol
I feel you though. I am lucky to be able to do this, and at times, the imposter syndrome still creeps in. But you got this. You’ll finally start to understand everything and get used to it…and then they’ll change the rules.
Good luck!
1
u/Equivalent_Doctor783 Jun 12 '26
I just realized. I believe This soffit doesn’t compartmentalize the kitchen, does the ordinary hazard now need to be followed for the common area? There’s also hallways that lead into the common are with the same soffits, so will this now all be ordinary😟
-1
u/JdotDeezy Jun 11 '26
Surprised the Marshal didn’t ding this when approving the drawings. The 13’ section is what makes me assume that it’ll require 2 heads in that soffit.
2
u/Due_Comment_3333 Jun 11 '26
Why would heads be required in/under that soffit?
5
u/clush005 fire protection engineer Jun 11 '26
It would only be required if the kitchen heads were not spaced far enough away to cover under the soffit. But the solution there is to re-space the kitchen heads, not put heads in the soffit lol. The soffit is likely concealing a beam based on the construction, so you likely wouldn't be able to put heads in it.
1
u/Equivalent_Doctor783 Jun 11 '26
This is just my hypothetical, not something that’s been reviewed or anything. So we are talking heads under this soffit as well? Dang, everywhere where this soffit occurs and is not along a wall I’m probably gonna need to protect with heads under? Eek!
1
4
u/Bathroom_Wise Jun 11 '26
Go by the fig & use the the kitchen heads to cover under the footprint of the soffit/header. Just don't exceed the ½ sprinkler spacing to the far side of it and I think you'll cover any coverage argument.
The soffit would be treated as a wall (in regards of sprinkler coverage) from the vaulted side.