NFPA 13-2002 Location of the Inspector Test Valve

[DonPhillips]

I am reviewing a set of construction documents that show the inspector test valve right off the main. This is a single story building so I am not as concerned about its location relative to the riser base.

If this were a, say, 4 story building, shouldn't the test valve be located on the highest level to ensure adequate pressure to trip the flow switch?



Don Phillips

http://worthingtonengineering.com

 

[LCREP]

"I am reviewing a set of construction documents that show the inspector test valve right off the main."

Not sure what u mean by right off the main. But if the sprinkler system has more then 20 sprinklers it is required to have a water flow alarm. To test the alarm the inspectors test must be past the water flow device, see below for details.

See NFPA 13, 07 section 8.17.4.2.4 it can be located downstream of the water flow alarm. The 02 edition required it at the end of the system. If it was a dry pipe or double interlocked preaction it would have to be at the end of the system.

 

[cdafd]

sounds good, if it is a wet system, the inspector test can be any where, you are just testing the flow switch.

look at floor control valves the inspector test is directly after the flow switch. for example

 

[Cidona]

Usually if you have a 4 story building, each floor would have it's own floor control assembly which would include a flow switch and inspectors test for that floor.

 

[DonPhillips]

Thank you all for the responses. It is a wet system, and there are more than 20 heads. Ohio is under the 2002 version until 1/1/08, which does not have an 8.17 section.

Don Phillips

http://worthingtonengineering.com

 

[LCREP]

"Usually if you have a 4 story building, each floor would have it's own floor control assembly which would include a flow switch and inspectors test for that floor"

You may to take a look at NFPA 13, 02, sec 8.16.1.6 a floor control valve is only required for high rise building. A 4 story building is usually not considered a high rise bld, usually buildings more then 6/7 stories are a high rise.

 

[Cidona]

I knew I was being vague saying 'usually'. While not required, most of the 4 story buildings I've worked on have had floor control assemblies though I'm sure other places/different projects it may be more common to have multiple floor from 1 valves.

 

[TravisMack]

Cidonna:

I agree with you. Most of the 4 story or so buildings I do have floor control valves. Afterall, once you hit 30' above FD Access, you are going to need standpipes. They can be calc'd as manual wet, so no site pump, but still need all of the standpipe requirements.

The only place I see 4 stories with no control valve is in smaller hotels / motels.

I hope y'all have a safe and happy new year!

Travis

 

[LCREP]

Just pointing out what is required by code. I see it both ways, I prefer a separate floor control valve. I have had this code section referenced for why they did not want to do it. Sometimes I win sometimes the building owner wins depending on what insurance $ cycle we are in and how big the account is. If the owner only cares about $ and not the hassles of living with only one valve for a building then I do not get it. Sometimes common sense prevails.

Have Happy 2008, boy did 07 fly by!

Tom

 

[Cidona]

You must have had a fun year Tom!

Happy New Year all.
Thank you to all of you who participated on the forum for your great work throughout 2007.

Damien.

 

[SprinklerDesigner2]

I think this is my last post for 2007 so happy new year to everyone.

All you are doing is testing the water flow switch and if you think about it in a 40' storage building you will get nearly the same amount of water from an inspector's test located at the far end of the system as you would with the connection coming off the riser. Coming off a branch line 40' in the air the pressure will still be the same at the outlet 1' above the floor. Siphon.

 

[DonPhillips]

You do not think the 39' hydrostatic head will reduce the flow, perhaps enough to not trigger the paddle in the flow switch?


Don Phillips

http://worthingtonengineering.com

 

[SprinklerDesigner2]

You do not think the 39' hydrostatic head will reduce the flow, perhaps enough to not trigger the paddle in the flow switch?

If the inspector's test outlet was 39' in the air an argument might be made that it *might* but the 1" valve is located 5' above the floor with the outlet 1" above the floor it the height of the system wouldn't matter.

Take a building 200' high with a 60 psi static and 59 residual pressure and it's obvious you wouldn't get a drop of water from an open sprinkler head as the column of water would only reach 138' high. But what if we were able to completely fill the system using a test pump expelling all trapped air in the process? If the system was totally filled in this manner you would get a normal flow from the inspector's test regardless of the height of the building because the system would be acting just like a siphon hose on a can of gasoline. If you installed pressure gages located 5' above the floor on the riser and just above the inspector's test valve they would both read around 58 psi but a gage 200' up on a branch line would read a negative or minus 29 psi but water would still flow due to the siphon effect.

Given these conditions if a sprinkler head were to discharge the vacuum would be broken and your sprinkler head would suck air until the water column reached 138' at what point it would stabilize all assuming the system didn't have a check valve at the riser.

I recognize this is a stupid analogy only to prove a point.

The best setup would be to have the inspector's test valve and discharge up at the highest sprinkler but that wouldn't work very well.

In a typical 40' building with a normal type water supply, 60 static, 50 residual @ 800 gpm for example, an inspector's test at the riser and one located at the far end of the system would each put out identical rates of flow less the small decrease in the far inspector's test compensating for a very small expected friction loss in the longer 1" drop. The only place you would have any friction loss, with only one head open, would be the 1" inspector's test line and at a typical flow of 20 to 40 gpm that wouldn't be a whole lot. Maybe 5 to 8 psi at most?

Typically these flow switches activate with around 8 gpm and if you've ever tried to refill a system by slightly *cracking* a control valve so as not to set off the flow switch you know this is near impossible. Like a dumb ass I've tried but I was never was successful.

The only reason an inspector's test is there is to test the flow switch.

Given a typical water supply I don't see any advantage to having an inspector's test located at the far end of the system. With a typical water supply if the flow switch works it is going to work regardless of where the head is that goes off.

And on a wet system you really don't need a flow switch a pressure switch on an alarm check valve works just as well and with that to work all you need is a slight trickle of water flowing.

 

[FFP1]

As most everyone has stated: For wet systems, NFPA 13 2007 allows the ITC to be located anywhere downstream of the flow switch and NFPA 13 2002 requires the ITC to be at the most remote point of the system. However, there is a huge problem no one has mentioned.......

Anyone who conducts system acceptance tests or regular inspections knows this arrangement can lead to serious consequences. Systems with no ITC at the remote locations inevitably have pockets of air (depends primarily on the system elevation differences) which can cause false alarms, alarm tests to fail when ITC is opened, increased rust on the interior portions of the piping and scale build-up inside the system piping over time. I have personally seen each of these issues at several facilities due to the lack of ITC's at the most remote locations.

I would like for NFPA to change this requirment back to the 2002 version.

P.S. How are you planning to remove all of the water from a 4 story building if your ITC is at elevation 1 ft. and the highest sprinkler head is at 39 ft.?????????????? Do you really expect future sprinkler contractors to loosen a sprinkler head and bleed the air from the system (when the building is occupied and furnished) every time the system is drained and refilled. The risk of water damage and the odor associated with the air inside the occupied building is no problem for the installer is it.....POOR DESIGN!!!!!!!

 

[cdafd]

FFP1

i did not know the ITC was to be used to drain the system, i thought the main drain ans aux drains were for that purpose, along with a few thousand other exceptions for draining

 

[Cidona]

FFP1: NFPA 2002 did not 'require' the Inspector's test at the end of the most remote branchline. It used the term 'should' rather than 'shall' and this is mentioned in the Annex (this is nonmadatory material is purely explanatory in nature) rather than the main body of the standard. In the same section (Annex) of NFPA 2002 (A.8.16.4.2) it references a floor control valve assembly which has the inspectors test next to the riser. If you have access to the 2002 automatic sprinkler systems handbook, it specfically states that '...such a location is not however required', and references a test connection located in a pump room.
In reagrds to the corrosion, I noticed in the Annex (A.8.17.4.2) of the 2007, they mention that putting the IT at the most remote part of the system 'causes the introduction of fresh oxygen into a large part of the system each time the alarm is tested and increases the corrison that will occur in the piping'.
At the same time though there is also a diagram showing the IT and a note saying 'preferably from remote branchline'. So there seems to be some confusion/conflict within the standard.
I don't think there is justifaction to require the IT at the most remote branchline due to venting as this only addresses certain sections of a system. If you had a buliding that was center fed, the IT would be only addressing the venting for one side of the system and you'd still have the negative issues you mentioned in regards to air in the system on the side that didn't have the IT.

 

[FFP1]

I did not say the ITC is required to drain the system; however, opening the ITC when draining will decrease the amount of time required to drain a system. The ITC helps to remove the air pockets when the system is refilled.

I am simply stating that it can be difficult to remove the air pockets if your drain and ITC are both located at the riser. Temperature changes can cause false alarms due to air pocket expansion and contraction. Air pockets can also lead to cycling flow switches......most contractors adjust the delay to 5-10 seconds to make the switch operate and this also leads to false alarms when the public water pressure surges. I have seen it too many times.

Most installing contractors do not bleed the air out of the system when the drain and ITC are both located at the riser. In many cases, the installing contractor does not even hear about the false alarms because the alarm company or building owner deals with the frustration. I have permanently resolved this issue at several locations by bleeding air pockets or providing an ITC at the most remote location. Bleeding the air from a system when the building is already occupied can be time consuming. All I am saying is that it is a better design when the ITC is located at the most remote point........it is even better when the most remote point ends up being at the high point of the system (not possible in most situations).

I did not mention this problem in my previous post, but large air pockets can also lead to excessive pressure (well above 175 psi) on the systems during summer months; this problem is not soley associated with gridded systems.......if the system piping has large air pockets which expand due to temperature increases, the system pressure increases. Anyone who conducts inspections should be well aware of these potential problems and know how to resolve the issue.

 

[cdafd]

Cidona

Thanks for the clearasel, I did not have a copy of 2002, but did not thank it rerquired the itc remote, if so than have been missing a requirement for a number of years.

 

[Cidona]

FFP1: I don't get to see the ammount of systems that you would since you are doing the inspections. Honestly I was not aware that it was commonplace for contractors to fill the system without venting properly. Obviously having excess air in the system could have the negative effect you spoke of. Thank for the benifit of your experience on the matter.
I just wanted to make sure that it wasn't a requirment because as cdafd mentioned, there are a number of us that have been putting the IT by the riser while workng to 2002 NFPA.