Types of Valves in Plumbing

Have you ever wondered what goes into managing the flow of water in your home, or through a building? It all depends on a critical component found in plumbing — valves. Valves are essential for starting, stopping, and regulating how water flows through pipes and plumbing systems. They also play a pivotal role in maintaining the safety and efficiency of piping systems. From preventing potential disasters like a pipe burst, to ensuring that you can easily repair a faucet, the importance of plumbing valves cannot be overstated. As we plumb the depths (pun intended!) of this industry, you'll learn more about the variety, functionality, and best practice use of valves in commercial and residential plumbing.

Overview of Plumbing Valves

Why Are Valves Important in Plumbing?

Valves are critical components in any plumbing system, as they control the flow of water and other media within these systems. Essentially, valves allow piping systems to operate efficiently and safely. They help manage water pressure, control the rate of water supply, and prevent backflow. By allowing users to shut off water supply to certain areas of a pipe system, they make maintenance and repair tasks less disruptive, and also help mitigate damage and water loss in case of a leakage or pipe burst.

Common Types of Valves Used in Plumbing

Plumbing systems utilize a range of valves, each selected to provide specific functionality and performance criteria. Here are some of the most common types of plumbing valves:

• Gate Valves: Used to start or stop flow in a pipe system. Operated by lifting or sliding a gate element housed within a valve body, into or out of the fluid path.

• Globe Valves: Designed for flow control. Consists of a movable plug-type element and a stationary ring seat housed within a valve body. The plug element may be gradually opened or closed to control flow.

• Check Valves: Allows fluid to flow in one direction only, preventing backflow. Common designs employ discs, doors, diaphragms or balls to act as the closure element.

• Ball Valves: May be used for shut-off or flow control applications. A ball element with a hollow bore through the ball is used to start, stop or regulate flow through the valve.

• Pressure Reducing Valves: These valves protect plumbing fixtures by regulating water pressure. Pressure reducing valves are a type of control valve that reduce high inlet pressure to low outlet pressure, preventing damage to pipes, fittings and other equipment downstream of the valve.

• Pressure Relief Valves: These safety valves protect piping systems from pressure buildup by dispelling excess water. They are commonly installed on geysers and water heaters.

Let's look at some different plumbing valves in more detail.

Ball Valves

Ball valves, known for their durability and excellent shutoff capabilities, find widespread use in residential and industrial pipe systems. Ball valves use a spherical ball element with a hole bored through its center to regulate flow. The hole aligns with the flow path when the valve is open, and is perpendicular to the flow when closed. Ball valves are favored for applications that require a reliable seal, quick and easy operation, even after periods of disuse.

Ball valves come in various designs including trunnion and floating ball; full, reduced and multi-port; single and split-body configurations. There are also many material options available for the valve body, stem, ball, seal and seat; including brass, stainless steel, and PVC; catering for different fluids, pressure and temperature conditions. Ball valves are commonly available with quarter-turn levers, gearboxes or actuators. Ball valves are easy to operate, repair and maintain, making them a popular choice for managing water flow in homes and industries.

Advantages of Using Ball Valves in Plumbing

The reasons ball valves are often used in residential, commercial and industrial pipe systems include:

• Durability and Reliability: Ball valve designs are relatively simple with few moving parts. This minimizes the risk of malfunction and breakdowns over time.

• Shut-Off Capability: The tight seal formed by the ball and seat ensures that minimal water leaks when the valve is closed, making ball valves well suited to shutoff applications. This is especially true for soft seated ball valves, which are common in plumbing systems.

• Ease of Operation: Operating the small bore ball valves which are typically found in plumbing applications requires a simple quarter-turn of the valve handle. This is an easy task, even for individuals without any plumbing experience.

• Versatility: Ball valves are suitable for the range of temperatures and pressures commonly found in plumbing applications. They are also readily available in materials, sizes and end connections found in plumbing systems.

• Cost: Plumbing ball valves are relatively inexpensive, both to purchase and maintain.

Gate Valves

Gate valves operate by raising or lowering a gate inside a valve body. The water path clears as the gate lifts, and is obstructed as the gate lowers. Gate valves are often used where operation is infrequent, such as in underground pipelines or washout stations. Note that gate valves are not suitable for throttling flow, as partial openings can cause excessive velocity and vibrations leading to valve damage.

Gate valves are available in various configurations, including parallel and wedge gate type, rising and non-rising spindle, metal and resilient seats. Material options include stainless steel, cast steel, bronze and ductile iron. Materials are often selected based on the service fluid, pressure and temperature considerations. Gate valves commonly found in plumbing applications include resilient seal gate valves, which employ rubber encapsulated gates or seats and metal seated wedge gate valves. Knife gate valves are commonly found in wastewater treatment applications. Gate valves are commonly supplied with handwheels, gearbox drives or electric actuators.

When to Use Gate Valves in a Plumbing System

Gate valves are best utilized in applications where straight-line fluid flow and minimal flow restriction is required. They are ideal for use on water main pipelines, and perform well as the main shutoff valve for homes or buildings. They are not recommended for throttling purposes as partial openings can cause the gate to wear or erode over time. Fully open or fully closed are ideal positions for a gate valve.

Note that butterfly valves are another common shut-off valve type found in water systems.

Advantages and Disadvantages of Gate Valves

The primary advantage of gate valves is their ability to minimize pressure drop across the valve when fully open. They are simple to operate and durable. Gate valves generally have a long life span when installed, operated and maintained correctly.

Gate valves do have some disadvantages. They require a relatively large space for installation and operation, due to their long pattern bodies. Additionally, gate valves can be slow to operate, and sealing performance may degrade over time. It's also difficult to immediately tell if gate valves are open or closed, unless they are fitted with some form of visual aid.

Check Valves

Check valves, also known as non-return valves, reflux valves and one-way valves, are specialized devices that allow fluids to flow in one direction only. These valves prevent backflow in plumbing systems, ensuring that water flows in the intended direction. This can be crucial in preventing contamination, or in maintaining the efficiency and correct operation of industrial plumbing.

Check valves contain a closure element which operates automatically, closing as the flow of water stops or begins to reverse. Common non-return valves found in water applications include ball type, lift type, spring type, piston type, single and multi-door swing type, nozzle or 'silent' type. Selection is primarily dependent on the nature of the fluid, velocity and operating pressure of the system, and valve cracking pressure requirements. Other considerations include valve size, and the potential for water hammer and surge scenarios.

Plumbing check valves are available in a variety of materials, with common options being brass, bronze, cast iron, cast steel and stainless steel. Small bore valves typically employ threaded or compression connections. Larger valves may be flanged, with numerous form factors such as wafer, lugged, short or long patterns available.

Types of Check Valves and Their Applications

There are several different types of check valves used in plumbing systems, each suited for specific scenarios:

• Swing Check Valves: These valves use a swinging disc to allow or block flow, ideal for systems that require a low resistance to flow.

• Lift Check Valves: These valves feature a disc that lifts off a valve’s seat with increased flow, and settles back into place when the flow decreases.

• Ball Check Valves: These use a spherical ball element which is lifted into or out of the flow path. The ball closure element is self-cleaning, and hence suitable for plumbing and wastewater applications.

• Each type of check valve has its own unique set of applications, generally chosen based on a plumbing system's specific requirements, such as desired flow rate, pressure rating, and the presence of solid particulates in the fluid being transported. Understanding each application helps one select the most appropriate check valve.

Globe Valves

Globe valves are used to regulate water flow by raising or lowering a disc (also referred to as a plug) located within a valve body. This mechanism allows for precise flow regulation, making globe valves ideal for flow control and throttling applications. The disc moves perpendicular to the flow, allowing the valve to move across a range from closed, to a percentage open, to fully open.

Globe valves are used in situations where flow needs to be adjusted frequently. The range of flow control required, pressure drop across the valve, and duty cycles must be considered in the design of the valve, to prevent early failure and to assure exceptional service.

Globe valves are available in a variety of configurations, including tee pattern, angle pattern and wye pattern. Smaller valves are usually supplied with threaded or socket weld ends, while larger valves are typically flanged. Common materials used in globe valves include cast steel, stainless steel and cast iron. Valves subjected to high-differential pressure-throttling service require specially designed valve trim.

In water applications, globe valves are commonly found at pump discharges, in water distribution networks and at reservoir or tank inlets. Globe valves are durable and reliable, ensuring efficient operation and flow control over a long period.

Note that other valves, such as pinch valves and needle valves, may also be used for flow control applications .

Benefits of Installing Globe Valves in Plumbing Systems

Globe valves in plumbing systems are mainly used to control fluid flow and regulate pressure. Here are some benefits of using globe valves in plumbing systems:

• Precise Control: Globe valve design allows for precise adjustment of flow. 

• Durability: Globe valves are designed to withstand high pressure fluctuations associated with flow throttling applications.

• Versatility: These valves can be used in a broad range of plumbing applications, from water heating systems to pressure control applications, enhancing their utility in residential and commercial plumbing.

Pressure Relief Valves

A pressure relief valve, also called asafety relief valve, is a safety device that helps maintain acceptable working pressures in a system. It works by releasing excess pressure, as soon as the pressure in the valve reaches a preset limit. This is crucial in preventing damage to pipes and plumbing fixtures equipment and fittings. Safety relief valves are found in industrial, commercial and residential plumbing applications.

Safety relief valves come in various forms and functions, including pressure relief, steam relief, and temperature relief valves, each designed for specific scenarios depending on your requirements.

In industrial settings, for example, they protect against risks associated with high-pressure water systems. In homes, they are nearly always found in water heaters, ensuring that temperature and pressure remain within a safe operating range.

Safety relief valves are a broad topic in their own right. Common types of safety relief valves include spring-loaded, pilot-operated, piston, and diaphragm type relief valves.

Specifying and selecting a safety relief valve involves several factors. Material and connection details are typically specified to ensure compatibility with the system. The valve material is based on the process fluid and operating parameters. Materials should be well suited to the intended application, whether it's steam, hot water, or high pressure potable water. Common safety valve materials include bronze, brass, cast steel and stainless steel.

Pressure rating and valve size are other critical factors, as the valve must be capable of handling the system's maximum operating pressure at the required discharge capacity. Compliance with industry regulations ensure that quality and reliability standards are met. Certifications are extremely important as they provide assurance that valves have been adequately tested and are proven to work safely.

Regular inspections and maintenance of safety relief valves are essential to ensure that they function correctly when needed. Over time, these valves can wear out or become clogged with debris, which can impair their ability to release pressure effectively. Periodic testing of safety relief valves is strongly recommended.

Importance of Pressure Relief Valves in Plumbing

Pressure relief valves are critical components in any plumbing system. They help protect equipment, pipes and fixtures from pressure build-up that may cause damage or catastrophic failure. This type of valve automatically releases pressure when it reaches a pre-set limit, thereby preventing potential accidents and ensuring plumbing systems operate within acceptable limits. Their use is crucial in residential water heating systems, air conditioning systems, and in any setup where pressure can build-up to dangerous levels.

Remember that installing safety valves in residential and commercial plumbing systems is not just a recommendation; in many situations, it is mandated by plumbing codes and building regulations.

How Pressure Relief Valves Work and Their Role in Preventing Damage

Pressure safety valves are relatively simple devices that play a critical role in safety. They work by maintaining a balance between the pressure inside a system and a pre-defined safety threshold. Here is how they work:

• Monitoring Pressure: System pressure is hydraulically monitored within the valve housing.

• Activation: Once the pressure reaches the valve's set maximum, the valve opens, allowing excess pressure to escape, either to the atmosphere or to a drainage system, until normal conditions are restored.

• Resetting: After activating, the valve closes, re-sealing the system once the pressure returns to normal. Certain valves may require re-charging, or replacement of components such as bursting discs, after relieving pressure.

• Preventing Damage: By regulating the system's pressure, these valves prevent damage to pipes, fixtures and equipment, which can be costly to repair and pose safety risks.

Closing Thoughts on Valves in Plumbing Systems

Understanding the different plumbing valves is crucial for managing water flow and preventing leaks in plumbing. Whether you are installing new plumbing or maintaining an existing system, choosing the best, high quality plumbing valves can enhance a system’s performance and longevity.

If you’re uncertain, be sure to discuss your needs with a valve professional, to ensure that the correct valve is selected and installed.