Full bore isolation valves are common plumbing components used to shut off the water supply to individual sections of a plumbing system. They're particularly useful when installing or maintaining taps, appliances and other plumbing fixtures, allowing the water supply to be isolated without shutting down the entire system.
But what does full bore actually mean, how does it differ from a standard or reduced-bore valve, and when should you choose one? Here's what you need to know.
What Is a Full Bore Isolation Valve?
A full bore isolation valve is designed with an internal opening that is approximately the same diameter as the connecting pipe. This allows water to pass through with relatively little restriction when the valve is fully open.
Many full bore isolation valves use a quarter-turn mechanism, often with a lever handle, to open or close the flow. When the valve is closed, it isolates the section of pipework downstream of the valve, provided it has been installed in the appropriate position.
Full bore valves are available in different sizes, including common 15mm and 22mm plumbing connections, making them suitable for a range of domestic plumbing applications.
What Is the Difference Between Full Bore and Reduced Bore Valves?
The main difference is the size of the opening through the valve.
A full bore valve has an internal passage that is approximately the same diameter as the connecting pipe. A reduced bore valve has a narrower internal passage, which can create greater resistance to flow.
This difference can affect flow rate and pressure loss, particularly in systems where the valve opening is a significant restriction.
Full bore valves are often a suitable choice where minimising restrictions is important. However, the right valve depends on the pipework, system design, connection type and manufacturer's specifications.
Why Use a Full Bore Isolation Valve?
Full bore isolation valves offer several practical advantages in plumbing installations.
Reduced restriction to water flow
Because the internal passage is relatively wide, a full bore valve generally creates less restriction than a comparable reduced-bore valve when fully open. The actual effect depends on the valve design and the wider plumbing system.
Convenient maintenance
An isolation valve allows a section of pipework or an appliance to be shut off for maintenance or replacement. This can avoid the need to isolate a larger part of the plumbing system, provided suitable valves have been installed.
Simple operation
Many full bore isolation valves operate with a quarter turn of the handle. This makes it easy to identify whether the valve is open or closed, although the handle position and operating instructions should always be checked for the specific product.
A choice of sizes and connections
Full bore isolation valves are available in different sizes and connection types. Selecting a compatible valve helps ensure it can be installed correctly within the existing pipework.
Where Are Full Bore Isolation Valves Used?
Full bore isolation valves can be used in a variety of plumbing and heating applications, subject to the valve's material, pressure rating, temperature rating and intended use.
Common applications include:
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Domestic water supplies: Isolating sections of water pipework.
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Taps and plumbing fixtures: Allowing individual fittings to be shut off for maintenance.
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Heating systems: Isolating suitable sections of compatible heating pipework.
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Appliances: Providing a means of isolating connected equipment where the installation requires it.
Always check that the chosen valve is approved for the fluid, temperature and pressure conditions of the intended application. Not every isolation valve is suitable for every plumbing or heating system.
How to Choose the Right Full Bore Isolation Valve
Before buying a full bore isolation valve, consider the following points.
1. Check the connection size
Common plumbing sizes include 15mm and 22mm. Check the existing pipework and the valve's connection specifications rather than relying on appearance alone.
2. Confirm the connection type
Valves are available with different connection arrangements. Make sure the valve is compatible with the pipe material and fittings used in your installation.
3. Check the operating conditions
Review the manufacturer's pressure and temperature ratings, along with any restrictions on the valve's intended use.
4. Consider access and operation
Choose a valve that can be reached and operated safely once installed. Allow sufficient space for the handle to turn and for future maintenance.
5. Use the valve for isolation
Isolation valves are designed primarily to open or shut off flow, not to regulate it continuously. Unless the manufacturer specifically permits throttling, use a suitable control valve where flow regulation is required.
If you're replacing an existing valve, compare the connection size, type and specifications before ordering.
Find Full Bore Isolation Valves at Plumbco
At Plumbco, we stock plumbing components for trade professionals and the public. If you're looking for a full bore isolation valve, explore our range of valves and isolation valves to find options for your installation.
Check each product's specifications to confirm its size, connection type and suitability for your application. If you're unsure which valve you need, contact our team for assistance.
Choosing the right isolation valve helps make future maintenance more straightforward while ensuring the fitting is suitable for the pipework and system in which it will be installed.
