Valves – what they are & the basic types

what is a valve

Both a check valve and stop valve. Snazzy.

For today’s post, we are going to briefly talk about valves.  We have talked about a few systems or components you might see as a building engineer or facility maintenance person, equipment like pumps and systems like chilled water.  Today we are going to keep on truckin’ along the mechanical equipment side, add this one to the pumps.

Valves are everywhere.  They control a lot of things, can be any size pretty much, and are a wonderful invention.  When was the last time you saw or used a valve?  Um, how about all the time?  Your shower, sink handle, garden spigot are all different types of valves.

If your kitchen sink has only one handle and combines the hot and cold water, that’s a mixing valve.  If it has like two bladed handles, those are individual stop valves.  Your car has valves.  Your bladder or whatever has a valve kind of.

What is a valve?

A valve is any device used to control fluids in a system.  Mind blown.  It can start, stop, or throttle flow completely between pieces of equipment, systems, whatever.

Below are probably the most common types of valves you will see or come across in the day-to-day operation and maintenance of building or facility engineering systems.  Valves are installed according to their required use or purpose in a system.

Valve Construction

Valves can be made of bronze, brass, cast/malleable iron, or steel.  Steel valves are either cast or forged and are made of either plain steel or alloy steel.  Alloy steel valves are used in high-pressure, high-temperature systems.

Brass and bronze valves shouldn’t be used in systems where temperatures exceed 550°F per Navy standards lol.  Steel valves can be used above 550°F and in lower temperature systems where internal or external conditions of high pressure, vibration, or shock would be too severe for valves made of brass or bronze or other similar, weaker materials.

Valve Types

valve symbols

Variety of valve symbols.

Although many different types of valves are used to control the flow of fluids, the basic valve types can be divided into two general groups: stop valves and check valves.

Besides these basic types of valves, many special valves, which cannot really be classified as either stop valves or check valves, are found in the engineering field.  For example, some valves serve to control the pressure of fluids and are known as pressure control valves.  Then other valves named to indicate their general function or purpose, such as thermostatic recirculating valves.

Soon (hopefully) each of these types of valves will be clickable.  I just need to want to make the time to get them up separately.  For now, just a simple description and then some examples.  And this list is not meant to be all inclusive either, just most likely what we’ll run across leaking one night above a ceiling below a toilet.

An intersting building engineering note is that all of these valves have different symbols on the architectural drawings, blueprints, and schematics.  A plain valve looks like a bow tie.  Wait, bow tie is two words?  A ball valve looks like a bow tie with a ball in the center.  Hopefully.  It has been a while.


Stop Valves
globe valve

Shiny globe valve.

Stop valves are used to shut off or partially shut off the flow of fluid.  Stop valves are controlled by the movement of the valve stem.

Stop valves can be divided into four general categories:

Check Valves

Check valves are used to allow fluid flow in a system in only one direction.  They are operated by the flow of fluid in the piping.

A check valve may be:

  • swing
  • lift
  • ball

Check valves are cool because they are like a bouncer letting people in to the club.  He doesn’t.  He only lets them out, flowing out in one direction.  Check valves can protect equipment such as pumps by not allowing fluid to flow backwards or in the wrong direction.

Wrapping it up


Easy today.  Valves.  A vital component to building engineers, homeowners, and people everywhere.  Fire hydrants are valves for crying out loud!

We went over what a valve is, a device used to control fluids, and typical construction.  Then a few paragraphs about valve types which brought us to stop and check valves and then their respective types.  Of course there are more, way more.

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