Valves and joints: What are they used for?

July 18, 2016

You'll be one step closer to completing a successful DIY plumbing job by knowing the difference between a valve and a joint, and how they work.

Valves and joints: What are they used for?

A stopped toilet or a leaky sink are no fun. When you’re faced with one of these common plumbing problems, understanding more about the parts needed to fix them comes in handy. The following introduction to valves and joints can help get you one step closer to successfully completing and maintaining your DIY plumbing projects.

An overview of valves and joints

  • A plumbing valve is a device used to regulate and control the flow of water in a potable water or human waste system.
  • Valves are like mechanical switches that can turn pipes on and off and raise or lower the amount of fluid rushing through them.
  • A shut-off valve can be closed during repairs or in an emergency to prevent liquids or gases from escaping.
  • A joint is a connection at the end of a pipe that ensures tight sealing and strength.


Valves are necessary to operate everyday household luxuries such as sprinkler systems, water heaters, toilets, washing machines and sinks.

Types of valves

There are a variety of different valves used in plumbing, each with its own advantages and disadvantages. Some of the most common types include:

Gate valve

  • One of the most common type of valves used in plumbing.
  • Controls water flow by raising and lowering an internal gate, preventing the water from flowing into the other side.
  • Reliable and easy to install.
  • Cannot be opened and closed as quickly as some other valves.

Ball valve

  • A hollowed-out sphere (ball) that sits directly inside a pipe and completely blocks the liquid flow.
  • When the handle turns, the ball swivels 90 degrees, allowing the fluid to flow through.
  • A common and reliable valve in the plumbing industry, a ball valve is often used in toilet tanks.
  • The particles in residual fluids collide with the valve’s surfaces and stick to them, causing possible leakage and abrasion.

Check valve

  • This one-way valve has one inlet and one outlet that allows liquid to travel in one direction.
  • Moves quickly, without a lot of force.
  • Can be difficult to decipher if the valve is opened or closed.
  • The check valve disc can get stuck in one position.

Good to know!

Other types of valves include shut-off valves, butterfly valves, globe valves and pressure-balanced valves.

Types of joints

When it comes to joints, some of the most common types include:

Push fit joint

  • The pipe is pushed into the joint until it meets the internal stop; can be pulled apart by pushing the ring against the joint and slowly pulling the pipe out.
  • A toothed ring grips the pipe and a rubber O-ring creates a seal.
  • It's quick, easy and reliable for most applications.
  • It is available in copper or plastic.
  • It's not suitable for connecting directly to a boiler.

Compression joint

  • There is a soft metal ring (olive) inside with a nut on the outside.
  • The pipe is pushed into the joint and the nut is tightened to compress the olive and form a seal.
  • It is usually used with copper pipe, but can join plastic pipes with a metal insert.

Capillary joint

  • It does not contain an internal rubber seal or gripping ring.
  • A seal is created by soldering around the end of the joint with the pipe pushed inside.
  • The two main types of capillary joints are soldering joints and end-feed joints

Hep2o joint

  • This joint is similar to a compression joint but for use with polybutylene or copper pipes only.
  • It comes with a pipe insert to protect the walls of polyethylene pipes.
  • The pipe is pushed into the joint and the cap nut is tightened to compress the internal grab ring.
  • It can be reused, but requires a special tool to release and remove the grab ring.
  • It is often more expensive and bulkier than other types of joints.

Materials used to make valves and joints

Like pipes, valves and joints are available in a variety of materials. The valve material you choose will determine the type of joint material you require. Some of the most widely used options include:

  • Copper (and copper ductile iron)
  • Metal
  • Plastic (PVC)
  • Brass (an alloy of copper and zinc)
  • Stainless steel
  • Bronze

Good to know!

Each type of valve material comes with its own pressure and temperature limits; if valves are exposed to higher limits than they are designed for, they will not work properly. When in doubt over what material to purchase, consult with a professional plumber or the experts at your home improvement store.

Factors to consider when buying valves and joints

  • If valves will be exposed to any liquid other than water, determine which materials can stand up to any corrosive properties they may encounter.
  • If you wish to lock your valves, select styles that come with padlocks to prevent others from tampering with them.
  • For valves that are used often, look for durable types that won’t need replacing or frequent maintenance.

Understanding the nuts and bolts (or valves and joints) of your plumbing can help ensure your jobs are completed properly. Now that you’ve mastered the basics, you can work on expanding your DIY expertise to take on bigger plumbing projects.

The material on this website is provided for entertainment, informational and educational purposes only and should never act as a substitute to the advice of an applicable professional. Use of this website is subject to our terms of use and privacy policy.
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