[newnesy]

Thanks, that’s cleared it up.

The main reason I was asking is that I am running a new 6″ line into an existing 14″ gate valve attached to a tank nozzle. The p&id shows a ROSOV (remotely operated shut off valve) then the check valve, reducer and then the 14″ gate valve. Why is the check valve not before the ROSOV? Is the ROSOV not classed as a block valve?