"A listed outside screw and yoke (OS&Y) gate valve shall be installed in the suction pipe. No valve other than a listed OS&Y valve shall be installed in the suction pipe within 50 ft (16 m) of the pump suction flange."There have being incidents on which a butterfly valve was installed and when th pump activated the flapper on the butterfly did not fully open causing the piping and valve to cavitate. This will not happend with the OS&Y valve. This requirement has being in the code for quite some time now. I have seen incidents where the spacing in the fire pump room did not allowed for an OS&Y screw yolk type valve and a butterfly was installed. Not a good practice. You also have the stainer distance requirement 10 times pipe diameter away from suction.

MORE NEWS