From the first start-up of olefin alkylation plant, we are faced with very frequent plugging and bursting of fresh H2SO4 dozing lines, which causes severe process upsets.

This situation is that my proposed subdivision will be served by an 8" city water main that will not meet fire protection (20psi). The county has a 16" main across the street.

Based on API 589 closure test requirements, some passing (leakage) is permitted during manufacturer shop closure test.

Sharing philosophy of Automatic Block Valve and emergency block valve.Many plants use gate valves for isolating units at the battery limits etc.

Application of double block & bleed valves,single block & bleed valves ; where and for what working classes these are necessary ?

It appears the general trend of this thread is going in the right direction, but I will add my 2-cent's worth (after adjusting for inflation) Gate valves were invented many years ago.

Looking for the proper type of valve to install to bleed pressure off water mains when they have to be taken down for maintenance

Bubble-tight is a relevant term if applied to a certain set of conditions. It must be explained that way.