Why Does a Hydrant Need a Control Valve?

7/10/2020

NFPA 24, Section 7.1.1.2 (2016 Edition), states that control valve shall be installed in each hydrant connection.

What is the purpose of this control valve, other than facilitating maintenance?

Would this be considered a "control valve" per NFPA 24 3.3.3, and does this have to be a post-indicating type valve?

Common hydrant arrangement for illustration purposes.

Based on my limited understanding, this control valve is just a post-indicator valve/isolation valve which is for shutoff when there is an impairment downstream. I'm trying to get a better understanding of its purpose. Thanks in advance.

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9 Comments

Jesse

7/10/2020 10:08:19 am

Its primarily for maintenance. And it doesn't necessarily need to be a PIV. I use NRS (non-rising stem) valves most often

Brian Gerdwagen

7/10/2020 10:38:17 am

This is also to turn off the hydrant after being hit by a vehicle. Some jurisdictions, like Los Angeles County, require that the control valve be a decent distance, like 15 feet, away from the hydrant for this purpose.

If the hydrant were to leak, need to be replaced, et cetera. So yes, impairment downstream. And a PIV would just add one more thing that could be damaged.

Sue

7/10/2020 11:11:27 am

We do not require a PIV at this control valve because the hydrant is so close. If the hydrant is not live, a street key can be used to open the valve.

We do require a PIV if there is more than one hydrant controlled on the same line, then each hydrant would also have their own street valve so the hydrant can be worked on without closing down all of the others.

Jimmy Landmesser, Jr.

7/10/2020 11:22:25 am

As stated previously, yes maintenance is a key component and the other being repairs. The intent is to avoid impairing more than that single hydrant when repairs or maintenance are needed. No, a PIV is not required.

I support a Dept. of Energy national lab and we utilize PIVs for the hydrants, but it is because our local FD conducts IT&M for the fire suppression systems on site. Our FD likes to be able to see the site glass and ease of a PIV over curb valve. Most of our hydrants and PIVs are away from streets in the "yard" near the facility It is not an issue since aesthetics are less a priority and vehicular damage are not common with light traffic to begin with but no traffic in the grass.

7/10/2020 12:17:31 pm

Thanks for all responses.

Yes, I agree it's required for maintenances but adding another ordinary isolation valve (not PIV) for each hydrant connection specially where number of PIVs are already provided on it's mains to segments the Looped FW mains strategically (as conventional FW system design) what value can add other than increasing the cost.

Utilizing PIV located on mains, can still serve the same maintenance purpose even if don't provide individual hydrant isolation valve or am i missing something here against NFPA 24?

Sue

7/10/2020 12:34:43 pm

I sometimes agree with what you are saying SK. I worry about the end users costs.

I work for a fire department and we utilize the water supply for emergency purposes. Having said that we would like as many devices to be available at any given time.

So for us, the valve allows for repair, maintenance, and control of the device during an emergency leaving us with the access to as many devices as possible.

Better to have 1 hydrant out of service than half of a loop of hydrants because the only valve to isolate it the sectional and main control valve for the full undergrounds.

We also have valves on risers and at each floor for the same reason.

Keeping as much as possible in service at all times.

Ken Thackery

7/10/2020 12:40:02 pm

HI, It's called a repair gate (NRS) and not required in every jurisdiction just depends on the site and water/fire loop configuration.

Bruce Verhei

7/10/2020 07:42:53 pm

1. Need for maintenance is sufficient cause to require a foot valve.

2. If your fire engine is connected to hydrant via large soft suction, and the break away cotter pin in safety coupling breaks with hydrant open, you’re in trouble. The engine is out of service, unable to respond to further incidents.

It’s handy to be able to grab the wrench off the rig, turn off the foot valve, and effectively take back possession of your vehicle.

3. PIV.

A. I’ll use the word never here. By now your public water service has the foot valve in their GIS system. They know where the valve is with more accuracy than you know where you left a pen on your desk. You don’t need PIV’s for public water system footvalves.

B. Private. Is the valve off in the lawn, in a campus situation, vs in the driveway of a distribution center? There may be some cases where a signed PIV is needed so you can find valve in ten years. A cheaper solution that might be sufficient is a concrete marker post.

Your water department likely already has a detail you can reference. One example:

https://www.kentwa.gov/Home/ShowDocument?id=3680

Best.

Bruce Verhei

knowledge Sourcing link

10/5/2020 06:41:37 am

Thank you for this valuable information. It is most appreciated.

Why Does a Hydrant Need a Control Valve?

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