Wafer vs Lug Type Butterfly Valve

Plain wafer is cheapest. Lugged wafer has advantage that the lugs help align the valve with the flanges. Neither allows end-of-line service i.e. close the valve and remove the pipe from the "dead" side. Valve with threaded lugs allows this, but a bit more costly.

Cheers......Codey

With a full lug body valve, you can achieve dead end service. I tend to always specify full lug body valves because I might need to isolate a section of pipe without shutting down or draining half of my system.

If this is not a concern of yours, then the wafer type valve should be cheaper.

You might also find wafer type valves used on plastic piping where metallic piping cannot be used do to corrosion. In these cases you often see metal flange rings used to clamp a wafer style valve to the belled ends of platic pipe.

Lugs can be threaded or unthreaded. Have to be threaded if you want dead end service.

Cheers........Codey

In Texas, when you indicate to a supply house that you want "full-lug body" valves, it is inferred that they are to be threaded.

Yes, of course, the lugs need to be threaded. Very good point.

Recommend blind flange on end of line service, I have never trusted butterfly valves.

EZ to install but no life IMO gate is a much better valve if exercised.

That's OK if you can drain the pipes both sides of the valve, but that's often undesirable for various reasons. If you're worried about the butterfly valve you can fit a blank flange after removing the pipe on the dead side (with a threaded-lug butterfly).

Cheers........Codey