Valves1. Function: Valves can serve many different purposes—control of flow, regulating pressure, on/off, temperature regulation, and many more. Each function requires different valves and configurations.

2. Process: What is the process medium in the application your valve will be servicing? For instance, if a valve is on -320 F liquid nitrogen, it requires different seats, seals, and bonnets than a valve that is used for 70 F potable water.

3. Size: This may sound quite elementary, but many people think the valve they need should be line size. Sometimes purchasing a valve that equals line size makes a lot of sense, but other times you can specify a smaller (less expensive) valve that will do the exact same thing as a valve that equals line size.

4. Automation: Do you need your valve automated? What type of actuation— pneumatic, electric? Double-acting, fail-open, fail-close? If pneumatic, how much air do you have available for actuation—60 PSI or 80 PSI? Would you like a solenoid or limit switch?

All of these questions (and more) are questions you should consider while specifying and purchasing your valves.

Gilbert Welsford Jr. is managing director of valve supplier ValveMan ( He can be reached at

Editor’s Note: This blog post originally appeared on and has been adapted with permission.