Clarification of composite wood joist construction and NFPA 13 system 1

[SprinklerDesigner2]

I am pretty sure I have the correct answer but I would feel better checking.

This is the first composite wood joist construction building I've seen in over 12 years that requires a 13 system.

Four story motel with composite wood joist construction requires a system designed in accordance with NFPA #13.

For the areas protected by standard quick response sprinklers the area of application is 3,000 sq ft which basically includes the entire lobby area.

In areas protected with residential sprinklers the number is eight sprinklers or the entire area within one hour construction.

The corridor will require 8 residential sprinklers in the design area and not 4.

If I have a suite with living and bedroom then I have to calculate all residential sprinklers in that unit up to 8 sprinklers. I believe each "dwelling unit" is a one hour enclosure so I would not have to include additional heads in corridor or adjacent rooms as long as the room or suite is enclosed by one hour rating.

Is that one hour or is it 30 minutes?

Good thing is I've got a very good water supply (a nice change) and the way it is laid out I'm just going to run 3" main everywhere so getting 8 residential heads anywhere won't be a problem.

Thanks all.

 

[TravisMack]

Your stuff sounds correct. Check more in 13. There are provisions that won't require the 3000 / 8 calc with TJI. It is followed out here quite a bit, but in other areas, not so much.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

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[SprinklerDesigner2]

Travis,

I have lots of pressure and lots of water along with good money on the project so I feel real good about putting in some good overkill.

 

[stookeyfpe]

In the IBC (edition not relevant), the fire resistance rating between each dwelling/sleeping unit is reduced to 30 minutes when the building is protected in accordance with NFPA 13. Your corridor opening protective (door) is reduced to 20 minutes fire resistance rating and is listed to resist the spread of smoke.