NFPA 14 Class I Manual Combined Standpipe

[dumor]

Per 2010 NFPA 14, 7.10.1.2.2 I'm providing 250 Hose allowance at all three (3) 2-1/2" Hose Connections of a Class 1 Standpipe System.
per 7.8.1, I'm providing 100psi at the most hydraulically remote single 2-1/2" connection.
The System is Manual and Combined with two separate Wet pipe Sprinkler Systems.

 

[TravisMack]

What is your question?

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[pipesnpumps]

Let me try and guess the answer to the unstated question.,
If it's manual wet combined system then pumper truck provides the 750@ 100 psig reqd by NFPA 14,

The water supply has to support that flow from an exterior hydrant without dropping below 20 psig on any portion of the underground piping (adjusted for elevation).

The water supply has to supply the worst case sprinkler demand, plus the required exterior hose stream.
But it does not have to supply both the standpipe demand (nfpa14) and sprinkler demand (NFPA 13) at the same time.

Real world knowledge doesn't fall out of the sky on a parachute, but rather is gained in small increments during moments of panic or curiosity.

 

[dumor]

Sorry...fairly new at this.
My Question is, Is it the intent of 7.8.1 to require 100PSI at all outlets simultaneously, or just the one most remote..?

 

[skdesigner]

You already answered it in your first post. Pressure at the hydraulically most remote outlet can't drop below 100 psi while flowing your total demand.

Logic would dictate that if you can provide at least 100 psi at the most remote, you are providing more than that at the less remote outlets.

 

[dumor]

Yes...this is where it gets a bit tricky. The Stdp System is a Horz. type and is Combined with 2 Wet Pipe Sprinklers. Of the three Hose Valves, One Connection comes off one of the Wet Sprinkler Sys and Two Connections come off the other. They Share the FDC. All three valves are at the same elevation, which is 30" AFF.

 

[TravisMack]

You must have 100 psi at all outlets at a minimum of 250 gpm.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[dumor]

Does it matter where the Hose Connections are in relation to one another? Seperate Fire area, Building Etc?

 

[dumor]

The Fire Department is only allowing 150 PSI from their Truck, and the most remote Connection is 1200 ft away. I can Prove that each has valve can deliver 100/250 w/ 250 flowing as allowance at each of the other connections, but not 100/250 at all simultaneously.

 

[pipesnpumps]

Hmm. If the hose connections "comes off the sprinkler sys", as in connects downstream of the sprinkler system riser, that is NOT an NFPA 14 standpipe system.. My opinion that is NFPA 13 system that has interior hose connections..

No wonder the calcs are not working, you are having to push that water though all the sprinkler system components.

These used to be used for storage, for workers to use to 'fight the fire', until it was finally admitted they did more harm than good by delaying the FD response.

I sketch scanned and added as an attachment would greatly benefit you at this point. People would be able to help point you in the right direction and get a full understanding of the situation.




Real world knowledge doesn't fall out of the sky on a parachute, but rather is gained in small increments during moments of panic or curiosity.

 

[pipesnpumps]

*A* sketch scanned and added as an attachment.. would do you good.

Real world knowledge doesn't fall out of the sky on a parachute, but rather is gained in small increments during moments of panic or curiosity.

 

[dumor]

Here's the current flow diagram.

 

[dumor]

It is a Class 1 Combined per NFPA 14 in a County Jail w/ an I-3 occupancy and the local FM's interpretation of 905.3.9 of the (Ca) CFC 2007 for a "Class 1 Standpipe System ...provided in all areas where 50 or more inmates are restrained". Given this, three Separate Detention Pods meet this criteria and so three single 2-1/2" hose connections are being provided, one at each of the Pods exterior sallyports.

 

[TravisMack]

You may need to increase your pipe sizes in your A1-A2-C1-A1 loop. It doesn't matter that your particular installation has 1200' from the FDC, per NFPA 14, you are required to provide 100 psi at all outlets as a minimum. If you calc through the hoses and such, you may be able to include your city pressure. After all, the fire truck is just a "portable booster pump."

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[cdafd]

Do you also have a problem of going above 175 psi on the sprinkler piping?????

If say your main pressure is 80psi. And you add 120 psi from the brt you will be at 200

 

[dumor]

Taken literally, NFPA 14 7.8.1 and 7.8.1.1 clearly states "100psi at most remote or top most outlet." Not all.
I understand that in a vertical standpipe due to elevation, 100psi is implied as available at all connections, but at "any and all connections" and at the same time?
I just have a hard time thinking that that's the intent.
Seems to me that the Water Allowance of 500/250 for additional standpipes/connections is more of the objective. From a Fire Fighting Standpoint, I would agree that if you had 2 or 3 standpipes and/or hose connections in the same area.. like a roof top or open Mall Structure, the 100PSI at each at the same time makes sense. But in a "horizontal" arrangement with connections in completely separated fire areas, with no common means of access to one another...?

 

[dumor]

Cdafd, Tried to convince the FD that the 100 psi static city pressure in addition to their 2500GPM booster pump (Hale Qmax)on thier 300Hp Engine should be more then sufficient to meet anything they wanted. Unfortunately and for some unknown reason, the FM is only allowing us 150PSI at the FDC, in a flat curve @ 750GPM.

 

[dumor]

FYI...and although not shown on the Flow Diagram, All pipe is 6" and 4". 6" feeding 3 connections, 4" feeding everything else.

 

[TravisMack]

I think everyone on here has stated that you need 100 psi at each outlet flowing simultaneously. If you can prove that the FD will not be able to use 2 or 3 hose valves at the same time to fight a fire, submit the plan as you want it and see if it gets approved. Then make sure you have insurance paid up just in case something goes wrong during a fire event. I think a good lawyer would eat you up on your detail there, but I am not an attorney, so I don't know for sure. I always tend to err on the side of being conservative if I find what I feel is a grey area. Only you can make the call on this and see how it plays out.

Good luck on it. Let us know what gets approved by all agencies involved. I find it pretty interesting how some of these things end up turning out.



Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[cdafd]

Dumor

The fd is probably saying they have a 750 gpm pump

They will crank it to maybe max 150 psi

That does not take into account the city main pressure added to it

Not a FPE but if you calculate a remote area I take it is assumed the rest of the heads have the same needed pressure

Same as the other posts if you hit 100 psi at the remote you should have at least 100 at all connections before it

Fd sometimes depending on nozzle used , it needs around 100 psi for it to work correctly