Double interlocked preaction system - valves

[SprinklerDesigner2]

Got a project where the owner wants to save some money.

The original project had five Clean Agent systems providing protection to record storage and computer rooms. I guess the price shocked them (I am not very knowledgable on special hazards so I wouldn't know)so the owner elected to extend the wet sprinkler into these areas.

The architect wanted me to incoroporate a normally closed solenoid valve opened by heat/smoke detectors on the brach to each room. Sounded to me like a cheap alternative to a double interlocked preaction system but I told the architect I didn't think it would fly. I don't think there is a UL Listed solenoid valve available that's approved for sprinkler systems.

Can someone confirm I am correct on this?

So I suggested a double interlock preaction system and now the architect wants to know if we could incorporate a normally open shut-off valve above the ceiling in each branch downstream the preaction valve so as to sectional the system. I don't think I can do this. Again, can someone confirm I am correct?

The alternative would be to incorporate five separate preaction valves but that gets kind of pricey too.

Thanks all.

 

[LCREP]

"So I suggested a double interlock preaction system and now the architect wants to know if we could incorporate a normally open shut-off valve above the ceiling in each branch downstream the preaction valve so as to sectional the system."

What are the shut off valves for?? By the time anyone gets to the valves and shuts them off they will be filled with water. They can not keep the valves closed, so I do not see the purpose.

How large of an area are we talking about? Why not one preaction valve for the entire area? You can pipe 1000 heads on one preaction valve.

By the way from an insurance point of view we would not accept heat detection only, must have smoke detection for early detection.

If this is an existing system, and they have pendent heads that is a problem, unless they are on a return bend or u use dry pendent heads.

Many architects have no clue on fire protection, I think this one needs some education on how sprinkler system operate!

 

[cdafd]

The alternative would be to incorporate five separate preaction valves but that gets kind of pricey too.

sounds like this is the only alternative.

but if you can set a dry pipe off a wet system , there you would have a shut off valve supervised open, so it would be strange and not know how it would perform,

but if you do the double interlock and set another wet alarm valve with shut off after this with valve supervised. The alarm and head would release the interlock valve and the air pressure. the water pressure would open the alarm valve and you would have water flowing through the head. ???
you would have to get everyone to bless it. and once again as pointed out someone would still need to get to the valve and shut it off.


Now in freezer units I have seen a valve above the interlock so they can test and not fill up the pipe..

maybe suggest double interlock with vesda system.

 

[SprinklerDesigner2]

Well, they're a little shocked at the price but someone has watched to many movies on television.

We're talking five different areas the largest measuring 600 sq. ft. with all five areas not having over 20 sprinklers. You can imagine how costly per head a preaction system would run when it has only two sprinklers. Imagine the cost per sprinkler with five separate preaction systems. At several thousand a sprinkler it's like I am working in a nuclear power plant again.

The best answer I can come up with, and it is the best answer, as to why a solenoid actuated valve can't be used in conjunction with heat detectors is one isn't listed for that purpose. Good enough reason and the best.

On the plus side the architect seems a good fellow who appears to be willing to listen to ideas.

 

[cdafd]

ok sounds a little strange

 

[LCREP]

"as to why a solenoid actuated valve can't be used in conjunction with heat detectors is one isn't listed for that purpose."

The other reason is how would you test the solenoid valve? You would have to trip it at least annually to make sure it works. Then drain each line with the valve. Over the long run this set up it will result in rust forming in the pipe, and clogging the line. Not to mention weaken the pipe and perhaps fail during a fire and or leak.

With a preaction u can put a shut off valve above the preaction valve and never have water go into the system during testing. They would love this, vs water above the computer, even once a year for testing.

The system will use supervisory air so if a leak does happen they will know it before water flows into the pipe. Great selling feature, they will know IF they have any leaks in the pipe.

I think these are 2 great selling points to your problem. One preaction valve for all small systems.