Valves

[skoob]

I am trying to get opinions on what would be best practice for a chilled water line. The company I work for says that a valve of 2 1/2" should be a butterfly valve. I have learned recently that a ball valve would be less expensive to purchase.
What are the rest of you doing in this circumstance? Do you go with cost only or is there something else I am missing(hence the reason to use a butterfly valve for this app) Thanks.

 

[JLSeagull]

My valve selection applies to regulatory control and automated shutdown valves. Butterfly valve consideration applies to lines NPS 10 and larger. My preference would be ball valves through NPS 36 but the initial capital cost is much higher for large ball valves. If I select a butterfly valve it is normally flanged or lugged to avoid wafer valves in flammable hydrocarbon or hazardous chemical applications.

 

[DRWeig]

Skoob,

What's the purpose of the valve? Isolation? Control? What sort of close-off pressure rating?

Lots of choices besides simply ball or butterfly...

Give us some more info.

Good on ya,

Goober Dave

 

[skoob]

It will be used cut off the line and capped for future use. We will be adding an A/C unit at a later date. Pressure is about 60 psi.

 

[roydm]

2-1/2" is small for a butterfly. The shaft in a valve that size will cause a significant pressure drop. I would use a ball valve for On/Off or a globe valve for throttling.
As others have said we need more details.
Roy

 

[JimCasey]

2 1/2" is a b*st*rd size. There are extremely few valves offered in this size. Your available choices will increase vastly if you use 2" or 3" pipe.

That being said, a butterfly valve with a one-piece stem and disc would pose little restriction (Keystone 9-series)

Small ball valves can be very inexpensive and may be threaded onto the pipe instead of needing an accompanying flange pair supplied and welded to the pipe. So a quality 3-piece ball valve (such as Worcester 44 series) would have a significantly lower total cost of installation. Even then, 2" threaded ball valves are on every shelf, and 3" threaded valves are rare because if for no other reason it's hard to find a guy strong enough to work the business end of a stillson wrench that big.

 

[vpl]

It will be used cut off the line and capped for future use.

I would not recommend a butterfly valve to isolate a line that is then being cut off and capped. Ball or gate.

Patricia Lougheed

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