PVC Valves must upgrade to Steel Valves? (ASAP)

[thien2002]

Dear Gentlemen,

We have 2 PVC Butterfly Valves, within rating parameters, in our Mechanical room within the steel pipelines of Chilled water Supply & Return (40-56F). Should I upgrade 2 PVC Valves to Steel material, should it be the same grade of steel in the pipelines? The PVC Valves are still brand new, just installed last year.

Thank you very much for your prompted response!

 

[MikeONeill]

I'm not sure 'upgrade' is a good term. The pvc valves are twice as expensive as cast iron resilient seated butterflys.

PVC butterfly valves are rated to 150psig@73F for sizes 12"NPS and less and 40F is within it's limitations.

Class 125 (good for 200WOG) cast iron body butterfly valves with EPDM or BUNA-N seats and a standard bronze or aluminum bronze disc would be your best bet provided your pressure is within it's parameters (I've see district chilled water at 230PSI)

 

[thien2002]

How about durability, do you think PVC valves will have durability in the Mechanical Control Room? Thank you.

 

[MikeONeill]

If the control room stays under 140F and you chilled water pressure is under 150psi, they'll be fine.

Mike

 

[thien2002]

I just went back to the Mechanical Room and like you said, we will keep these PVC valves since they are 150 by Spears USA. I think they are durable enough for our 40-56F chilled water system. And I look at all other steel valves, the valve handle are rusty condition. So I think PVC to steel is not an Upgrade but a Downgrade.

 

[MikeONeill]

Hahaha. Spears make a great valve. Any quality iron or steel butterfly valve comes with an epoxy-coated lever. Good choice.

Mike