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What is a Shut Off Valve? Meaning, Working, Types, Application

shut off valve

In any flow system, the shut-off valve is the unsung hero, the crucial but often overlooked fitting. It cuts off the supply of liquid or gas in an emergency and isolates subsystems for maintenance. Its application also varies—you can use it in a home plumbing system, industrial pipeline, or manufacturing plant.

What is a Shut Off Valve?

A shut-off valve is a valve whose purpose is to cut off flow in a liquid or gas-carrying system. Various valves, such as gate and ball types, can do that, with some allowing partial flow restriction.

The valves that don your home are mostly shut-off types. You will usually find them installed at various positions after the mains meter, behind individual fixtures or appliances, etc.

In the oil and gas sector, you will also find this type of valve or the automation systems of various industries. The list is endless, plus you can use it with different media types, from water and gas to chemicals and liquefied solids.

Shut-off valve for a gas line
Shut-off valve for a gas line

Shut Off Valve Function

The primary function of shut-off on/off valves is to cut off supply in a flow system. They isolate specific sections, allowing maintenance work without disrupting the entire installation. Other functions are;

  • To turn off a water or gas pipeline in an emergency, such as a leaking line
  • To close the supply to a water fixture, appliance, or section of the plumbing system for replacements
  • To cut off flow to the subsystem of a manufacturing facility as part of an automation process
  • To start and stop flow in an intermittently used piping network or line
Shut-off valve working principle
Shut-off valve working principle

How Does a Shut Off Valve Work?

A shut-off or on/off valve has a flow control mechanism that opens and closes when you turn a handle. The control element is typically a ball or disc.

  • The valve may be a “normally open “or “normally closed” type.
  • When closed, the valve element presses against a seat, providing a sturdy seal.
  • Upon turning the handle, the valve opens fully to let media through.

The traditional valve is a manually operated fitting. Today, the automatic valve is preferred instead. The valve design also varies, as the next section explains.

Angle shut-off valve
Angle shut-off valve

Types of Shut Off Valves

Buyers can choose from various types of shut-off valves categorized by their design features. They include manual and automatic, straight and angled, single port and multiport, and the quarter turn and multi-turn configuration.

Manual vs. Automatic Shut Off Valve

The manual type has a twist handle, wheel, or knob that you turn to either close or open the flow control component. These are common in older homes and pipelines.

Automatic on/off valves are electrically or mechanically actuated. They cut off the flow without human intervention and can be remote-operated types.

The automatic valve is a more versatile type. Using it with leak-detecting sensors prevents damaged supplies or outlets from causing havoc when you are not around.

Straight vs. Angled Shut Off valve

A straight valve aligns with the pipes it connects to. It requires more space and often does not suit wall connections, such as those leading to fixtures like sinks and toilets.

The angled type has the inlet and outlet perpendicular to one other. It takes up less space and is best for confined spaces such as under the sink or behind water fixtures and appliances like washing machines.

Single vs. Multiport Shut Off Valve

The single port valve has the most basic design, with only one opening for the inlet and outlet. It typically stops the flow to a single pipe, such as the mains valve, or it may serve to isolate a single fixture.

The multiport type has several openings. The number varies from two to 4, although as many as six ports are available. The valve has an application where redirection of flow or redistribution is required.

Quarter Turn vs. Multi-Turn Shut Off Valve

Like many other valves, shut-off types can make quarter turns or full turns to open or close. A quarter-turn valve turns 90 degrees and suits applications that need fast operation.

The multi-turn valve requires a 360-degree turn to open or close. These are mainly large valves with massive flow control components for industrial pipelines.

Shut-off valve for toilet
Shut-off valve for toilet

Shut Off Valve Uses

You can install a shut-off or on/off valve for water and other fluids anywhere you want it to stop flow. Most often, these are water systems and gas lines.

Shut Off Valve for Water

The on/off valve is a plumbing fixture for homes, commercial buildings, and other water systems. In these applications, you install it in various points, from the main supply to where pipes branch to fixtures and appliances.

In farms, water shut-off valves form part of irrigation systems. In this use, the valve helps isolate sections of the irrigation system and equipment when needed.

Shut Off Valve for Gas Lines

A gas leak can be dangerous. In such emergencies, the on/off valve provides a quick and convenient fitting to cut off its flow.

These are often installed at convenient positions outside the home and next to the metering device, just like the water cut-off valve.

Replacing a shut-off valve under the sink
Replacing a shut-off valve under the sink

How to Choose a Shut Off Valve

The applications of cut-off valves are as varied as their design features. When selecting the type to use, you want it compatible with your type of system. Ask yourself these questions:

1. What flow control mechanism suits you best? A shut-off ball valve offers a full on/off function, while gate styles can partially open to control flow.

2. Where do you intend to install the valve? Angled valves are better for small spaces than straight types. Choose yours based on the installation space and location.

3. What is the system pressure or flow rate? Your valve should be able to handle these or risk getting various components damaged.

4. Where do you intend to use the valve? Some conditions or media can corrode your valve, making material selection a critical factor. Brass and stainless steel are popular options in many applications. Others include bronze, PVC, and more.

5. What valve size and connection do you need? Always select the correct shut-off valve sizes to avoid compatibility issues. Connection types also vary from solder to thread and compression or push-to-fit types.


The shut-off or on/off is an essential fitting in the plumbing systems of homes or other buildings and the manufacturing systems of industrial facilities. By providing a leak-proof seal, they allow you to stop or start flow whenever needed. In homes, they isolate fixtures for repair or to prevent hazardous situations. In industries, it forms part of automation and fluid transfer systems.

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