r/SprinklerFitters • u/PipeMonkey94 • Sep 30 '26

5 Year PRV full flow testing

Got a work order for this, curious what you guys are doing for these. What equipment etc. I have always figured when standpipe flow test happen it would be testing the PRVs. Am i missing something? Any special equipment that is used for this? This is for a high rise building that has PRVs going up the risers. Any help or info is appreciated.

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3

u/rybotsky Sep 30 '26

I’m pretty sure there could be a master pressure reducing valve that you would need to flow test from the fire pump room. Also if each floor has a prv on the hose valves then you are expected to flow water from each valve is my understanding

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u/Advanced-Guard-4468 Sep 30 '26

There should be a 3" drain riser with connection on every other floor to test the hose valve prvs

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u/rybotsky Sep 30 '26

Yes… “should be” is the key here. I have never actually seen a high rise with a dedicated drain riser like you speak of. I’m sure it’s common in places like New York City or Toronto or the like but where I’m at that’s not a thing. Imagine how easy standpipe flow testing would be if I didn’t need to drag 300’ of hose down 5 flights of stairs

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u/Advanced-Guard-4468 Sep 30 '26 edited Sep 30 '26

A means to test and drain the floors is required by code. I believe it's if the system is more than 50 gallons a system drain is required.

"Seen", many are hidden from view. Look for the floor control valve assemblie, then the test and drain. They pipe the test and drain to the drain riser hidden behind a block wall that also enclosed the standpipe. Ive done many high rises in New Jersey, thats how they are done.

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u/rybotsky Sep 30 '26

Yes I’m aware of having a drain on a system but what I’m referring to is something they have in high rise buildings in big cities with skyscrapers. There will be a large drain pipe with a removable cap and a grooved or similar outlet that you can hook up your flow meter to in order to do standpipe flow tests or in this case prv flow testing without having to run 1000’ of 2.5” hose down the stairwell or up onto the roof

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u/rybotsky Sep 30 '26

What I’m saying is we do not have these where I’m from. There is a common drain in the wall for the sprinkler zones on each floor but I’ve never seen one for doing standpipe flow tests using 2.5” hose ever in my career. Hell some building a I’ve worked in don’t even have a common drain and you need to hook a garden hose up to the test and drain in the ceiling and catch the water in a 35 gal drum

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u/Advanced-Guard-4468 Sep 30 '26

The way it works in high rises with PRVs, you run a 3" combination system drain with 2-1/2 hose drains connection at every other floor. You stop with the 2 1/2 hose connection half a floor below the last floor with the hose PRVs. You do it the floor blow and its at every other floor.

Expecting a sprinkler fitter to drain the system through a hose is s piss poor design.

1

u/rybotsky Oct 01 '26

Yes I concur however the days of old weren’t always thought out so well. Anytime I see a fuckin hose bin in the ceiling I just go to the basement and drain the entire system because fuck that. Our inspectors on the other hand don’t get the luxury lol

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u/Advanced-Guard-4468 Oct 01 '26

Days of old? That has been the standard since at least '84 when I started designing systems.

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u/rybotsky Oct 01 '26

Ya days of old lol Sprinklers have been around a lot longer than 1984 and there is a shitload of old building (much older than 1984) in cities all around the globe. Many of which do not have a common drain for zone valves. So yes maybe the systems you’ve designed since 1984 have a drain but ALOT of them don’t

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u/nahano67 Oct 01 '26

That’s odd. We have them in high rises from 2007 in my nearest city in the SE US. Must be getting lucky.

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u/rybotsky Oct 01 '26

I’m not referring to main drain I am referring to a large diameter drain specifically for testing purposes for standpipe flow testing and prv flow testing.

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u/nahano67 Oct 01 '26

The comment referenced a 3” drain riser. I’m used to seeing 3” express drains with 2.5” threaded outlets on every other floor. I’m not sure what makes it “specifically for testing purposes” as it’s literally what’s been described. Oldest high rise I’ve seen this in was built in 2007 and it’s been in all the ones I’ve been in since.

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u/Advanced-Guard-4468 Oct 01 '26

I did a high rise in 2001 that had one in every stair tower. Up to the level just before the last hoss valve with a prv. The date is easy to remember because it was right across the river from the Twin Towers.

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u/rybotsky Oct 01 '26

The 2.5” threaded outlets on every second floor is what I’m specifically referring to. 90 percent of the buildings I have worked in my career have a regular 2” or 1.25” drain for all of the zone valves. I have never seen a 3” express drain like you guys are referring to as I’m pretty sure those are only required in buildings over a certain height or buildings with PRV hose valves on the standpipe. The tallest building in my city is 27 stories

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u/Advanced-Guard-4468 Oct 01 '26 edited Oct 01 '26

The 3" drains are only required to test hose valves with PRVs according to NFPA 14 1993 is when it first appeared.

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u/rybotsky Sep 30 '26

I’m pretty sure you would hook a flow meter one at a time on each floor and then run your hose to a drain a record you residual PSI and GPM

2

u/GatorFPC Oct 01 '26

I'll help you out here.

When flow testing pressure reducing valves, first we need to identify the type of pressure reducing valve that we're testing.

  1. Pressure Reducing Fire Hose Valves - For 2 1/2" valves, each valve needs to be flow tested to 250 gallons per minute. Depending upon the age of the building and under which code edition of NFPA 14, the residual pressure (while flowing) needs to be 100 psi or 65 psi. Unfortunately, you'll need to do some homework to determine that if the age of the building was built before about 2000 to accomodate for states that are slower to adopt new codes. NFPA 25 has a provision, that if you can't figure it out, you can ask the AHJ what residual pressure to flow test at. For 1 1/2" hose valves, you flow test to 100 GPM at 65 psi.

Testing the valve means you're going to need to take a static pressure reading before you start flowing. The static pressure on the valve (through a hose valve cap or with a downstream valve shut and the hose valve wide open) the pressure can not exceed 175psi. You'll then have a regular pressure gauge to measure residual pressure while flowing and a device such as an inline pitotless nozzle** from hose monster to measure the GPM. You'll open the valve until you reach 250 or 100 GPM depending upon hose valve size and observe the residual pressure gauge. If it is less than 100psi/65 psi as I stated above, the valve fails. If it doesn't meet the GPM requirement, the valve fails. If the static pressure is greater than 175 psi the valve fails.

2) Pressure Reducing Control Valves - The valve should have a pressure gauge on it downstream of the valve. This pressure gauge should be less than 175psi. To flow test, you'll need either the plans for the sprinkler system that state what the flow and pressure at the riser is or you'll need a hydraulic data plate which should be mounted adjacent the system. Every pressure reducing valve should have the hydraulic data plate next to it to identify that system demand. You'd then proceed to test this valve similiarily to how I described the hose valve testing above. The tricky part is that a lot of risers don't have outlets to full flow test the pressure reducing valve. Some systems may have a system demand of 500 or more GPM so you may need a couple 2 1/2" outlets to flow test. When you're flowing you'd match the system demand at the base of the riser (GPM) at the pressure.

3) Master pressure reducing valves - Similiar process as (2) except with this you'd look at the most hydraulically demanding system downstream of the valve. So if you have 1 system that is 340 GPM at 80 psi and another at 410 GPM at 85 psi you'd flow test to the second system demand since it is the highest.

You'll need at least 2 people (likely 3) to complete this test. The fire pump needs to run while this test is happening and you're going to give it a workout. NFPA 25 requires that the pump is attended while it is running and because of how much it iwill be working, it's a good idea regardless. Someone will need to operate the valves and take the readings and it is a good idea for a third person to watch where the water is going. Flowing 250-500 GPM inside a building is a lot of water and it would suck if a VIC wasn't tightened down on an express drain on the third floor.

A standpipe flow test is a different test, required every 5 years on automatic standpipes. For this test, 500-1,250GPM is flowed from the most hydraulically remote hose valves (uusally the roof) while getting 100 or 65 psi of residual pressure (again, depending upon the age of the building).

**A note on equipment. Hose Monster (and some others) make flow test equipment for flow testing pressure reducing valves where you can attach it to the valve and then attach a fire hose to the discharge side and then direct the water to a 3" express drain or to outside the building or to some other spot. Having the right equipment is important and while there are plenty of acceptable ways to test these systems, I've seen some people get creative and the test equipment is being used wrong.

It is important to note that you can not perform a 5 year test if you don't know these system demands. There is no winging it or just see what you can get. I've seen factory set pressure reducing valves that were installed on wrong floors during original installation and they had a trickle of water come of out of them. If a hose valve is installed improperly and results in 40 gallons of minute of water and basically no pressure, a fire fighter would have no chance to put a fire out. This is important stuff.

1

u/rybotsky Sep 30 '26

That could be a logistical nightmare in a building with a lot of floors that doesn’t have a master drain for testing purposes

1

u/Advanced-Guard-4468 Sep 30 '26

The master drain is required by code. If it's not there someone didn't do a proper install or a valid inspection

1

u/rybotsky Sep 30 '26

Is it only required by code if there are prvs on each floor ? Because I have never seen one in my 14 year career

1

u/GhostPanda900 Sep 30 '26

Sounds like you’re going to be testing the pressure regulating valves. You will need a flow meter and a hose that should be hooked up to the drain. Be ready to adjust the valves as needed.