Combination Riser

[FireFreak08]

If two combination standpipes were interconnected, but there was one floor control valve, that would still mean the floor was supplied by two or more combination risers. Correct?

I'm a little confused at a code that states a high rise shall be served from two or more combination standpipes/sprinkler risers.

I am 99.9% sure that means one control valve is acceptable providing that before that valve is double fed. If one standpipe goes down, that control valve still gets it's water.

 

[stookeyfpe]

You are correct. Also, the floor control valves are required at the point of connection to riser on each floor of a high-rise building.

 

[Cidona]

I'm a bit confused. Perhaps I am not visualising properly. What code are you to comply with? Personally I haven't heard of sprinkler systems needing to be supplied by 2 or more risers (not to say it isn't somewhere). Standpipes, yes but not the sprinklers.
It would seem that if you are double feeding each floor sprinkler system with only one floor control assembly, you would not be able to take one standpipe out of service without taking both out of service. NFPA 6.3.2 requires that valves be arranged so a standpipe can be isolated without interupting other standpipes.

 

[stookeyfpe]

If you have a high rise building, as defined by the IBC or NFPA 14, you are required to provide two vertical fire protection water supply pipes. We call them standpipes. You are also required to provide separate, interconnected FDCs, in my mind and in accordance with NFPA 14. Interconnect the vertical water supply pipes at the base of the riser or at the top of the riser, and it complies with NFPA 14. Interconnect the sprinkler control valves, and its perfect reasonable and it is legal under the IBC/IFC and NFPA 14. They are just a isolation point in the system so the rest of the automatic sprinkler system is not compromised.

Here is my real life example: Fire on the 10th floor of a 30 story high rise. FD responds, the sprinklers suppress the fire, and the firefighters close the valve. One hour later, another fire occurs on the 22nd floow. FD responds, along with a bunch of police officers, and finds a working fire controlled by the sprinklers on the 22nd floor. The fire goes out and the cops arrest an arsonist on the 1st floor when the FF recall service traps the stupid bastard. I witnessed this once 25 years ago. My point: the codes work.

It's not that hard of a problem. I think we are getting lost in the terminology.

I hope I didn't offend anyone.

Thanks.

 

[Cidona]

Hi Stookey.

BTW, I really enjoyed the seminar on storage. Thanks for the clarification on the EC-25.

I agree that we are probably getting confused with the terminogy.

While NFPA wants the standpipes interconnected so that FDC flow from a single FDC will flow to all standpipes, my understanding is it also wants to be able to isolate each standpipe for service. Downstream of the connection of the FDC to the common standpipe pipe, there needs to be a control valve to isolate.

I've attached a rough schmathic of what I originally understood Firefreak to be describing with a single sprinkler system floor control valve(assembly) feed from a dual supply.
If this is in fact the arrangement Firefreak was describing it would seem the standpipes cannot be isolated unless you were also going to add in shut off valves on the feeds from each of the standpipes to the sprinkler zone control assembly.

Certainly no offence taken here and hope none on your end either. Just trying to take the opportunity for me to learn something.

 

[stookeyfpe]

Cidona

I'm glad you learned from my seminar.

Your design meets the letter of NFPA 14. The standards require valves so that systems can be maintained or modified to protect the building occupants in the event of changes to a building. Under the IFC, these valve require electric supervision, which I believe has done a great deal for improving the reliability of fire protection systems.

Your design is compliant, and if I could issue you a permit, I would.

 

[786392]

Dear stookeyfpe Hello/Good Evening;
Is it at all possible to get some enlightening on the storage seminar referred in above post?

Best Regards
Qalander(Chem)

 

[LCREP]

Chem,

Here is a warehouse fire protection seminar if you are looking for this type of training

http://www.chubb.com/businesses/service/chubb5944.pdf

Details can be found here

http://www.chubb.com/businesses/service/chubb5972.html

This is NOT the seminar Stookey was/is involved with.

Just an FYI

Tom

****************************************
Fire Sprinklers Save Firefighters’ Lives Too!

 

[FireFreak08]

I am referring to our local building code requirement. It requires a dual feed and in my opinion does not mean two control valves. I've heard it considered that way before which is where my confusion comes from.

From the sounds of it though, you are all in agreement and as long as that one control valve is supplied by two seperate risers, everything is all set. It makes perfect sense because each riser has it's own isolation valve so one goes down, the other stays open.

Thanks everyone!

 

[Cidona]

OK, so I gave myself a day to reconcider but alas, with respect to all, I am going to be a stick in the mud and say that the arrangement in my picture would not be in compliance with NFPA 14.
With this arrangement if you have to change a Fire hose valve or work on any part of say the riser on the left you cannot isolate it. Lets say there's a 'isolation valve' at the bottom of each riser. You close the Isolation valve at the bottom of the riser on the left. The riser of the left is still going to be full of water and pressurised because the water can travel through the Riser on the right and then through the pipe that is connecting the standpipes feeding each floor sprinkler assembly and up and down the riser on the left from there. You may as well not have an 'isolation valve at the bottom of the riser.
To work with the arrangement shown I still think you would need additoinal shut off valves on the feed pipe from each standpipe (another 2 per floor).
If the sprinkler systems are in fact required to be dual feed (and I really like the idea), I think 2 floor control assmeblies would be preferable (one at the stairwell at 2 ends of a corridor or something). A single main connecting them with branchline coming off it. You would be coordinating and installing less pipe as you would not have to connect feeds prior to running pipe to fed sprinklers (better for calcs too). You would also need a check valve (per NFPA 14) for each floor control assembly. Then you would have the ability to shut down one riser by closing an isolation valve at the bottom of each riser and keep and other standpipe and sprinkler systems live.

 

[TravisMack]

Cidona:

I agree with you. You can't isolate the standpipe in the arrangement you have shown. You would need to put a check valve at each connection coming from the riser in order to isolate a given standpipe.



Travis Mack
MFP Design, LLC

 

[cdafd]

FireFreak08

Cidona

do you have a copy of nfpa 14?? look in appendix A and check out some of the riser details around 7.1, not sure if this answers some of the questions.

 

[Cidona]

Travis, I agree you would need the check valves. You would also need shut off valves to service the checks, so you'd end up with 3 shut offs and 3 check valves per floor instead of 2 floor control assemblies.

cdafd. My understanding would be NFPA 14 doesn't show/require the indivigual sprinkler systems being 'dual fed'.

 

[cdafd]

I guess my question is can we get a better plan.

I think A.7.b maybe show a dual feed nfpa 14 2007




6.3.8.3 Where sprinkler system piping supplied by a combined system is supplied by more than one standpipe (“loop” or “dual feed” design), a sign shall be located at each dual or multiple feed connection to the combination system standpipe to indicate that in order to isolate the sprinkler system served by the control valve, an additional control valve or valves at other standpipes shall be shut off.

 

[Cidona]

A.7.1.b shows a system with high and low zones. Each of the zones has 3 separate standpipes feeding multiple floors. It does not show sprinkler control assemblies. The standpipes are interconnected as is 7.1(a) which shows a low zone only high rise and one of teh standpipes being a combination riser. If you take the high zone shown in 7.1.b as being 10 floors, and you have designated the one on the left as being the 'combination riser', those 10 sprinkler systems are being fed from that combination riser. The high zone in 7.1.(b) now looks much like 7.1(a). If you have to replace a FHV or shut it down to do any service on that combination riser, you would be shutting off the sprinkler systems fed off that riser also. The sprinkler systems are therefore not truly 'dual fed'. Unless you link the sprinkler systems and go with one of the designs previuosly discussed on this post.

6.3.8.3 to me would not require sprinkler systems to be dual fed but says when they are being done, signage for isolation valves are required. This would further insinuate that additional valves for isolation would be required.