Original system installed in 1908 and owner wants to convert to residential 13R but I see problems

[SprinklerDesigner2]

Single story building with sprinkler heads dated 1908 and a dry valve I've never encountered before.

The branch lines do not end in 3/4" pipe but 1/2" I kid you not. Never saw this before.

Here is what we have:

Used to be a ceiling with upright (conventional) sprinklers in the joist space but what the owner wants to do, in order to keep some sort of historical tax credit or what he told me, is keep half of the building open while half will have drywall ceilings. We have a wood beam and on the far side of the beam will be drywall attached to the bottom of the joists while the near side will remain open.

I don't see how we could install a 13R system with the open joists like they are given their depth. As you can see the depth is between two and three feet at the beam but the way the trusses are constructed we have big time obstructed construction.

And as much as I would like to use the existing system the upright sprinklers, both the uprights feeding the old concealed space and the heads below the ceiling, appear to be 7'-6" OC. There goes simply replacing the uprights with upright residentials where the minimum spacing is 8'-0". We would have to go 15' between heads plugging heads where needed.

As far as we can tell the last time the system was operational was 1985.

Bays are 25' wide with 3 lines per bay so head spacing is about 63 sq ft.

I am thinking the owner drywall below the joist and we install residential uprights which I think I can make work as the existing is staggered heads.

Oh, the building was only 40 years old when I was born so it really isn't that old.... am I historical?

 

[cdafd]

How many stories??

And does he want the entire building to be residential?

 

[SprinklerDesigner2]

Building is single story which is all to be residential. The total building is only 7,500 sq ft having six units. Georgia does require it to have sprinklers.

The system was installed as a dry system but will be converted to wet after a thorough internal pipe inspection of course.

I should add they, the historical committee people, would like to keep the original pipe because they want to keep everything as original as possible. That said I do not believe there is any way to get around not installing drywall at the bottom of the existing joists keeping it a 13R system design.

 

[MGXFP]

You've hit on residential sprinklers have more restrictive rules such as deflector distance from ceilings (1-4"). Also with obstructed construction that forces sprinklers into each bay since the joists are 2-3' tall, exceeding the 22" max if you were to choose to use standard spray sprinklers. And sprinklers made before 1920 must be replaced.

Looks like a ceiling needs to be installed no matter how you look at it.

 

[cdafd]

So do you have the job or bidding it???

Sounds like someone needs to set down with the Building Official and Fire Marshal, and come up wit a game plan.



The hysterical people may not like it.

 

[SprinklerDesigner2]

I was convinced when I saw it the only option for a 13R would be to install drywall with pendent sprinklers above OR try to use the existing pipe which "appears" to be useable to me. By usable I am not talking condition but position and head layout.

If there was a 13 system I would tell suggest filling the space with insulation because, given the depth of the joists, it's near impossible but here I am fishing for ideas.

 

[stookeyfpe]

Let us know how the internal inspection of the 113 year old pipe goes. I appreciate the passion of the Historical commission members but you're correct about the issues and solution. Your client has a GA Fire Code issue and you're tasked with solving it. You may be able to leave the old pipe in place for historical context.