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#83 -- Guide to Trim Valves for Fire Protection: Three-way, Angle, In-Line Check, Swing Check, Pressure Relief, and Globe Valves

Posted by Jason Hugo and Anna Hartenbach on 11/16/2017 to Valves
Within a fire sprinkler system, there are many parts and pieces that make up the whole of the system. While most focus centers on the main components of the system (e.g., sprinklers), there are many supplementary parts that contribute to the accuracy, dependability, and overall function of the system.

The biggest selection of additional parts is known as trim valves. By definition, trim neatens and sets things in good order. This is exactly the function of devices that are part of the trim on a fire sprinkler system.

In this article, we’re going to set our focus on trim valves in a fire protection system. Specifically, we’ll cover three-way valves, angle valves, ball valves, in-line check valves, swing check valves, pressure relief valves, and globe valves. Our goal is to give you an overview of what they are, how they function, and a brief introduction to what the National Fire Protection Association (NFPA) says about these helpful devices. 

As always, feel free to jump around in this article using the headers. Already know what you need? Feel free to hop on over and view our selection of trim valves. Don’t see what you need? Contact us, we’re happy to help!

Otherwise, let’s get started!

Three-way Valve

A 3-way valve for fire protection has one inlet and two outlets. It diverts the flow of water in one direction or the other, which makes them a useful tool for testing or performing maintenance on the system. In most cases, three-way valves are made of brass.

Three-way valves are versatile in that they are usable with air or water gauges. One outlet can be connected to a pressure gauge to monitor the system pressure while leaving the remaining valve functional. During testing, the Authority Having Jurisdiction (AHJ) can add another pressure gauge in the second outlet. Furthermore, because it has two outlets, it provides an uncomplicated way to replace the pressure gauge without shutting off the water supply to the system.

Three Way Valve

Angle Valve

An angle valve’s two main purposes are for trim or drain. They are suitable for use in all types of sprinkler systems, including those with a higher working pressure. 

Its main use is to regulate the flow of liquid or air through the system. Air or fluid entering the angle valve is pushed through at a right angle, from the bottom through the opening at the side – hence the name. Angle valves function through manual operation.

Angle valves are generally made of brass or cast brass and come in sizes ranging from ½” to 2.” The 2” angle valve can serve as a system drain at the riser. It is suitable for use on alarm check valve and grooved shotgun check valve riser assemblies.

Angle Valve

Ball Valve

A ball valve has an internal, rotational ball. The internal ball is what allows the valve to rotate a quarter turn to an open and closed position and it permits the flow of water through it. 

A ball valve has many viable uses on a fire sprinkler system: to control the flow of water, on the system riser to drain the system, and it can be paired with a sight glass to test the system. Ball valves are not the most precise option, but they are a very durable and cost-effective solution.

Ball Valve

In-line check valve

Like other check valves, an in-line check valve is designed to permit the flow of water and prevent backflow. Backflow occurs when water flowing into the system travels backward, usually unintentionally, to the source. 

Internally, it is built with a lifting spring. Once the proper amount of pressure is applied to the upstream side of the valve, the spring mobilizes the device to allow water to flow through. If the pressure decreases beyond the threshold, the lifting spring lowers so water can no longer pass through.

In-Line Check Valve

Swing check valve

A swing check valve is another device that only permits water to flow in one direction within a fire sprinkler system. It’s known as a swing check valve because its internal disc “swings” to stop backflow or off of the seat to permit flow. 

Swing check valves can cause water hammer in certain instances. Water hammer occurs when the internal disc closes too quickly, which causes a surge of pressure.

Swing Check Valve

Pressure relief valve

Pressure relief valves for fire sprinkler systems serve the system by relieving and removing excess system pressure. Excess pressure can be caused by surges or temperature changes.

Pressure relief valves are required in all gridded wet pipe fire sprinkler systems unless they are built with an auxiliary air reservoir to absorb pressure increases. They should be placed downstream from all pressure reducing valves. They must operate at 175 psi (12 bar) or 10 psi (0.7 bar), but not exceed the maximum system pressure rating. Pressure relief valves cannot be less than ½ in (15 mm). For more information about pressure relieve valves, click here.

Pressure Relief Valve

Globe valve

Globe valves feature a spherical body shape, which is where they get their name, and a baffle. A baffle is a device that restrains or regulates the flow of liquids or air. They have a wheel valve and a stem, which operates a moving internal disk in the globe. 

Their main purpose within a fire sprinkler system is to limit the flow of water. The baffle inhibits the free flow of water and forces it into a z-pattern, which limits the amount of water that can pass through at one time.

Globe Valve

What does the NFPA say about trim valves?

The NFPA and specifically NFPA 13 has little information specific to trim valves. These standards refer to valves more in the general sense, with the exception of check valves and pressure relief valves. Because check valves are covered at a greater depth within NFPA code, we created a separate guide to check valves here.

One big takeaway in NFPA 13 is that any valve that plays a role in controlling the flow of water must be accessible by authorized personnel in the case of an emergency. According to NFPA 13 (Chapter 8), Building managers, facilities maintenance personnel, and other managers are responsible for the supervision of the valves installed and used within a fire sprinkler system. It is their duty to ensure the valves remain in proper working order as well as proper position, whether it be open or closed. For this purpose, it’s crucial for individuals holding these roles to become familiar with the system so they can quickly notice and mitigate any system issues. 

One method to ensure the system is in good working order is to set up a consultation with the local Authority Having Jurisdiction (AHJ). The AHJ is a useful ally to a new building or maintenance manager. They can provide feedback about the type of supervision and maintenance the manager must provide for the system. 

NFPA 25 loosely defines trim valves as peripheral equipment to the primary equipment. It does set standards for inspection, testing, and maintenance for some trim items, but not all, in chapter 13. 

Why choose QRFS?

At QRFS we offer a wide selection of trim valves to meet the needs of your sprinkler system. In addition to the valves mentioned above, we have many more in-stock and ready to help you build your system today!

Additionally, when you purchase through QRFS, you benefit from our quality customer service and customer dedication. It’s our goal to remain up to date on NFPA Code and industry best practices, so we can help you make the most informed selection possible.


Still have questions? Comment below and we’ll reply as soon as possible to get your project flowing. Or give us a call at 888-361-6662 or write us an email here

This blog was originally posted by Jason Hugo and Anna Hartenbach at QRFS.com/blog on August 10, 2017. If you found this article informative, check us out at Facebook.com/QuickResponseFireSupply or on Twitter @QuickResponseFS.

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