Hydraulic Area for Residential with Comubstible concealed space. 4

[EJP-21]

Hello,

I am working on a project of a 4 floors of residential apartments with combustible concealed spaces.

the height of the concealed space is 22 in. and is made of wood that is why i provided it with upright heads with 5.6 K-factor. And below are pendent heads for the apartment.

Now im not sure what hydraulic area i must use,

can i still use the hydraulic area of the 4 most demanding heads?
am i gonna calculate for the concealed spaces?

Thank you guys in advance.

Attached pic is what i initially did. calculated 4 most demanding heads at the concealed space.

 

[skdesigner]

What standard are you using for design?

 

[EJP-21]

im using NFPA 13 in this design, is this what your asking?

and also

i initially used KFCR-CCS of reliable for the upright sprinkler heads for the concealed spaces but the contractor said that it is too expensive, i am now using F1FR56 of reliable for the upright heads

 

[skdesigner]

It was indeed what I was asking.

NFPA 13-2013 8.15.1.6 states that sprinklers installed in horizontal combustible concealed spaces between 12" and 36" deep are to be listed for such use. RASCO KFR-CCS sprinklers are listed for such use. F1FR56's are not (regardless of price difference).

The Reliable datasheet for the KFR-CCS contains the hydraulic calculation requirements (see page 4, bottom left-hand side of the datasheet for specifics).

Note that there are several other important factors to keep in mind with these sprinklers (draft-stopping, CPVC installation guidelines etc.)

 

[skdesigner]

Also, since it's a 13 design, you might want to think about adding a couple more sprinklers to that drawing (in the closets, specifically).

 

[EJP-21]

Thank you skdesigner for this clarification,

However, where can i reference the UL listing that F1FR56 cannot be used in this concealed spaces?

And also i didnt show the draft stops on the plans because on my understanding, the fire rated wall that separates the apartments will extend to a draft stop do the concealed spaces, do i still need to show this on the plans?

 

[skdesigner]

I suppose it's a matter of semantics as much as anything. I doubt you will find anything stating that a standard spray sprinkler is not listed to protect the combustible concealed spaces addressed in 8.15.1.6. It's that you won't find anything stating that it is. NFPA 13 requires that sprinklers in these spaces shall be listed for such use.

Specific application sprinklers like the KFR-CCS are specifically listed to provide protection in horizontal combustible concealed spaces, thus satisfying the requirements of 8.15.1.6.

Regarding the full-height suite partition walls, I would use a note to indicate to the plan reviewer that you are (a) aware of the requirement and (b) have adequately addressed it.

 

[cdafd]

Was NFPA 13 specified for the job?? and not 13 R?

 

[TravisMack]

Please find a local mentor.

Doesn't matter what the contractor wants on price. You can't use SSU in a concealed combustible space ≤36" clear depth and ≤2:12 slope. 8.15.1.6 is pretty clear on this and has been in the standards since 2002. Anyone that is not following this needs to go back and review the standards because they have not kept up with the requirements over the last 18 years.

Based on your wording, it sounds like you are not working in the contractor office. You, or your employer, are liable for the design you are doing.

Also, as noted above, if you are designing to NFPA 13, you need to look at those closets. They will be required. If you are also under NFPA 101, then you may be able to omit the sprinklers in the closet.

As far as calculations, you calculate both the 4 residential sprinklers (note these must be the most demanding and may not all be in one compartment) AND the concealed space sprinklers. Sizing will be based on the most demanding.

Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC

http://www.mfpdesign.com

 

[EJP-21]

Thank you for you help Travis Mack and skdesigner this really helps me to understand my options,

I am working for the contractor and this more is like a design - build project that is why i followed the instructions to use SSU sprinkler instead of KFR-CCS. However i already raised this concern to the contractor and im still waiting on their response but i dont think they will change this.

Its really hard to find a local mentor, im working remotely from the Philippines and you guys are big a help to fresh engineers in this industry like.

 

[TravisMack]

If they don't change it, then you don't do it. We have to draw the line with our integrity somewhere. Where do you draw the line next? We deal with life safety and property protection every day.

Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC

http://www.mfpdesign.com

 

[SprinklerDesigner2]

While we are on concealed space sprinklers what am I missing here?

Looking at a job with open wood trusses in a concealed space about 2'-6" deep.

I will be using steel pipe and my question has to do with baffles.

COIN® QUICK RESPONSE UPRIGHT SPRINKLER VK950 (SPECIFIC APPLICATION)

Draft curtains are NOT required when sprinkler spacing is up to 14' X 14' (4,3 m X 4,3 m) for solid wood joists or trusses on edge for wet systems only; see Figure 11B.

I am pretty sure these trusses will be on edge so I don't have to worry about baffles as long as I keep spacing to 14'x14' or less?

 

[DennisR4]

@sprinklerdesigner2 you said your job has OPEN wood trusses, yet the quote from the submittal mentions SOLID wood joists or trusses. doesn't sound like apples and oranges?