Thruogh bolt - stud

You must know all there is to know about piping fittings, valves and flanges. Get the catalogs for all the valves and study them.

A- If a valve is made with a flange on each end (see globe valves) then it takes two sets of bolts.

B- If a valve is not made with a flange on both ends (see wafer check valves) then you must use one set of through bolts.

Now there is an exception

C- The exception to "B" is where you have a valve that is not made with flanges on both ends but you still use two sets of bolts. Some Butterfly valves are made with no flanges but with threaded lugs. For this type of Butterfly valve you need two sets of "Cap Screws", one set from one side and the second set from the other side. The length of the "Cap Screw" is equal to the thickness of the pipe flange + the gasket + one half the thickness of the butterfly body - 1/8" (6mm) and roundrd off down to the closest commercially available length.