Good afternoon
I have a few constructability thoughts regarding butterfly valves:
-When selecting tapped or through holes, you should consider how the system will be installed and maintained. Consider if the valve will be a maintenance/or construction isolation boundary. A valve with through holes will require flanges on both faces of the butterfly valve to hold it in place, and this may not be possible during maintenance activities if piping needs to be removed. Compare to a tapped lug style where the valve can be secured to one flange and used as isolation boundary, while the down stream flange and piping can be removed and maintained (if needed)
-Consider butterfly valve operational clearances: Had a peer that had a contractor install a branch line with butterfly valve isolation during a system shutdown. Contractor put a reducing flange on the downstream side (blocking the swing of the disc). Contractor then proceeded to “test” valve and smashed disc into reducing flange and discovered valve was blocked from opening…So remove the flange and replace? Nope they used a wafer-style butterfly valve and there was no way to remove the flange and hold the valve and isolation boundary in place. Ended up taking the system down again….
Just my thoughts…been burned before
Jeff
