Two Hose Valves at Top of Remote Standpipe?

3/25/2022

In Class I standpipes, I commonly see a pair of hose valves installed at the top landing (or intermediate landing) - One immediately below the other.

Is this an incorrect derivative of the requirement to calculate the two most remote outlets (at 500 gpm), or something that was required in a previous edition of NFPA #14, or is this merely a regional practice that is a result of the shared DNA of my regional contractors?

I thought I had seen an informal interpretation regarding this, but I cannot find it again. NFPA Figures do not appear to support this double-valve arrangement.

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17 Comments

Alex Riley

3/25/2022 07:55:32 am

Hi,

Personally, I have never seen that installed. NFPA 14 (2016 Edition) 7.10.1.1.1 states that for the Class I standpipe, you need a minimum flow for the hydraulically most remote standpipe shall be 500 gpm through the two most remote 2 1/2 inch outlets. I suppose in your case, if your top most floor has two valves, they would be considered the most remote.

Although, section 7.3.2.1 states that hose connections shall be provided at each flow landing and does not state that multiple hose valves are required on the top floor.

Thank you,
Alex

3/25/2022 08:06:37 am

2 hose valves at the top level is easier for ITM testing so you don't have to run hoses up through the stairwells and worry about leaking water in an occupied building. NFPA 14 does not require this and your interpretation that the calculations are based on 500gpm at the two most remote fire hose valves (one on each of the top two levels) is correct.

Wes

3/25/2022 08:13:56 am

I've seen this done a handful of times, and it was to help facilitate testing.

If we're looking at the topmost landing (main level or intermediate) of a stairwell, then there's some benefit to it, albeit perhaps a relatively small benefit.

If the most remote standpipe has a roof outlet and no roof access, then testing the second-from-the-top outlet would be very difficult. You would need multiple long hose runs and careful coordination between testing personnel to flow both the roof outlet and the topmost outlet below the roof. Adding the extra outlet on the roof means you could just hook up and run that standpipe all from the roof. Significantly easier in that setup, in my opinion.

Anthony

3/25/2022 08:10:19 am

Alex got the code spot on and I too have never seen that arrangement.

Are you in a city with a many high rises? I understand that in larger cities it is the plan to fight fires on nearby high-rises from the roofs of adjacent buildings this may be an effort to supply that effort?

Also may be easier to test a stand pipes flow with a hose monster on the roof with the two hoses valves up there? You don't need the extra 50' of hose to come up from a lower landing?

Jack G

3/25/2022 08:10:45 am

I ve only done that when the stairs had access to the roof, and roof manifolds were required. Sometimes the AHJ will allow it inside the roof access door, with a sign, because of freezing winter conditions,

3/25/2022 08:12:55 am

This also could be for ease of testing for the flow test and not having to use a hose valve inside the stairs as one of the two most remote valves. It is a common practice in both existing and new installations in the area I work in.

Jesse

3/25/2022 08:16:35 am

Our largest AHJ also requires this. and yeah its kinda weird to me too

Matt

3/25/2022 08:27:24 am

I agree that it is for ease of testing. It can be messy and time consuming to run a hose from the second most remote standpipe connection to a safe discharge location.

I have see 2 connection manifolds requested by owners, but not fire departments.

Max link

3/25/2022 08:27:50 am

In certain jurisdictions that's exactly what we do to facilitate 5-year test of the standpipe.

Dan Wilder

3/25/2022 09:05:23 am

The wording and interpretation of NFPA 14 over the cycles has created this issue in both the hydraulics and design/install that carried over from editions and reviewers.

For instance, NFPA 14-16 Ed Figure A.11.5.2(a) clearly shows to hose valves at the same level for standpipe testing while (b) shows 2 on different levels....the only difference is where the hoses run.

NFPA 14-07 Ed Section 7.3.2.2 shows the requirement for an additional hose connection at the hydraulically most remote portion of the system to facilitate testing. The 2010 edition has this section removed.

Make sure to review the editions that were active when the building was constructed. You shouldn't apply current editions to existing construction (the building age was not discussed but as a general approach).

Wes

3/25/2022 09:08:46 am

Thanks Dan, this makes much more sense. I didn't know the historical context for this, but around the time we saw this method used was very much when the 2007 Edition of NFPA 14 would have been adopted.

Anonymous

3/25/2022 11:49:04 am

Thanks Dan and everyone. I think testing and incosistencies in the figures in the standard going way back is why it has become a common practice locally.

Danny

3/25/2022 09:44:57 am

I have a hospital that has two of these at most remote standpipes that are two different roofs. Per NFPA 25 to perform a 5 year flow inspection for a fully sprinklered building I need to flow 500gpm then 250gpm out of each additional standpipe until I reach 1000 gpm. Would flowing 500gpm out of both “Siamese/double hose valves” be ok?

Thanks

Wes

3/25/2022 09:49:29 am

No, not in my opinion. The test would need to be conducted as described - 500 gpm at the top of the most remote standpipe, then 250 gpm at each additional standpipe (top or bottom).

Just flowing 500 gpm out of the most remote standpipe would not meet the intent of the test, and would potentially differ substantially from what the original standpipe calculations anticipated (ie: you could fail the test despite the system performing to its original intent).

Danny

3/25/2022 09:53:15 am

Ok, thank you!

sean

3/25/2022 12:40:04 pm

this actually changed from the different versions of nfpa 14. it used to sawy you should have two valves at the most remote location (2 valves at the highest landing). Now it specifically says you can use the two hose valves in the locations they are required i.e. the top floor and the floor below.

Danny

3/25/2022 01:58:15 pm

So you think I would be ok to flow my 1000gpm out of the two standpipes/double hose valves?

It would be great if I could do this. It would allow me to have less manpower and less of a chance for water damage as long as the roof drains can handle it!
That being said I’m prepared to do 500,250,250.

Two Hose Valves at Top of Remote Standpipe?

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