When is an Alarm Check Valve Required?

7/16/2024

Is an alarm check valve required in a sprinkler system?

Is there an alternative to an alarm check valve?

Are there any restrictions on where the alarm check valve is required to be (i.e., inside or outside of a fire pump room)?

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9 Comments

Pete H

7/16/2024 07:55:19 am

FROM:

https://blog.qrfs.com/266-fire-sprinkler-system-risers-part-2-wet-pipe-components-and-assemblies/#:~:text=In%20NFPA%2013%20systems%2C%20a,a%20pond%20or%20contaminated%20river.

A few types of commercial, residential, and home fire sprinkler riser assemblies may be used in the most common scenarios
NFPA 13 risers
There are two standard configurations for fire sprinkler risers installed in NFPA 13 systems:

Straight risers
Alarm check risers
Both feature a control valve, a main drain, an alarm bell, a way of sounding an alarm when the fire sprinkler system activates, and pressure gauges. These types of fire riser vary largely in the way they meet NFPA 13’s requirements to sound an alarm when a sprinkler or sprinklers activate.

Straight risers don’t have an alarm check valve. The most basic types—installed when there’s a backflow preventer on the fire service main—don’t even have a check valve. As mentioned earlier, these backflow preventers may already be present when local law requires it or when the system relies on a combination of municipal water supplies and other water sources. To sound an alarm, a straight riser uses a vane-type flow switch (see part one of this series for more on this) connected electronically to a fire alarm bell. This switch installs downstream of the check or control valves.

An alarm check riser has (as the name suggests) an alarm check valve. They can also use a vane-type flow switch. However, an alarm check valve allows for the use of pressure switches. These switches connect to trim piping on the valve—with or without a retard chamber—rather than the riser itself. This configuration allows switches to be replaced without draining pipes downstream and tested without flowing water through the entire system. They also allow for the use of a water motor gong, a type of mechanical bell that sounds using water pressure rather than electricity.

For a detailed (and lengthy) introduction to commercial wet-pipe risers, we recommend that you watch Ben Stewart—a fire protection engineer with Western States Fire Protection—in a teaching session with new sprinkler system designers.

https://www.youtube.com/watch?v=qW4BeOw5BGk

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Anthony

7/16/2024 08:11:59 am

An alarm check is required when there is no electrical waterflow detection and signaling. Basically in any system that would require a water motor gong due to lack of a building alarm system.

The alternative would be a flow switch, or a pressure switch connected to an eclectic alarm bell.

NFPA-13-2016ed:

6.8.2 Waterflow Detection Devices.
6.8.2.1 Wet Pipe Systems. The alarm apparatus for a wet pipe system shall consist of a listed alarm check valve or other listed waterflow detection alarm device with the necessary attachments required to give an alarm.

Jesse

7/16/2024 08:40:19 am

Great answers above. To add, its also not uncommon to see alarm check valves even when there is a riser monitoring panel also.

Casey Milhorn

7/16/2024 08:55:40 am

From a practical perspective, alarm valves are antiquated and used a lot less frequently than they used to be. The only purpose to use an alarm check valve over a "riser check valve" in my opinion, is for the ability to add a water motor gong, as others have said, the advantage of a water motor gong is that they don't require power to operate a local audible alarm.
A new style riser manifold (with or without check valve) does a great job of checking all the boxes required per NFPA 13 at your riser and with a horn/strobe combo they not only give you an audible alarm, but also a visual, that can help responders identify the riser with flow very quickly.
Alarm check valves and water motor gongs still have a time and place to be installed, but for many reasons, a riser manifold is a better solution almost every single time.

Jon N

7/16/2024 10:31:13 am

In almost 40 years as an AHJ, I have never seen an alarm check valve installed on a new wet-pipe sprinkler system. I have seen several on older, existing wet-pipe systems to activate a water motor gong.

Contractors in this area seem to use paddle, vane-type electric water flow switches on wet-pipe systems.

There is one community about 25 miles away that has very high municipal water pressure that fluctuates quite a bit (static pressures over 100 psi are the norm). There are some alarm check valves installed there along with retard chambers and pressure type flow switches. I was told (but cannot verify this) that pressure fluctuations drove the need for retard chambers (which then require alarm check valves).

Mark Harris

7/16/2024 02:07:25 pm

Some great and valid comments but my opinion the backflow prevention requirements (which go back about 40 years) replaced the alarm valve as the system check valve.

Glenn Berger

7/16/2024 08:23:53 pm

The antiqued Alarm Check Valve!

I will this device on sprinkler systems connected to city water systems, especially where the incoming pressure swings greatly. More options exists to prevent false tripping of flow alarms.

Jack G

7/16/2024 10:18:47 pm

As indicated above it is used for a local alarm when electrical supervision is not available.
Of course as Sprinkler systems became a “ shall be electrically supervised” — were nails in the alarm check valve coffin.

Pete D.

7/17/2024 12:05:54 pm

The alarm check equivalent with an electric bell is called a Riser Check Valve. You want some kind of check valve, because when flowing water on adjacent systems connected to the same supply (say during the inspection), without the check valve you can siphon water out of the system not flowed. Then when the adjacent system ceases to flow, your system fills back up and you can get a false alarm. The modern vane-type or paddle flow switches have 2 sets of normally open contacts. One gets wired into an addressable monitor module to signal the authorities when water flows on a system. The other can have voltage landed on it to activate an electric bell local to the riser on the exterior of wall. They come in 120 vac or 24 vdc varieties. Alternately, an existing Alarm check valve can have the alarm port to the water motor gong cut and capped, and an electric bell can be added to the system in the same was as one would install it for a riser check valve.

When is an Alarm Check Valve Required?

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