Dear Nirav,

I did work for 20 years for DSM, a chemical company in the Netherlands, first in an ethylene plant, than for Stamicarbon (urea licensing).

In my experience, it is good practice that a HAZOP is done for each modification, even small ones like a control valve. Sometimes the capacity of a safety valve is determined by the size of a control valve for example.

DSM does not work with a permanent committee but DSM had regulations which disciplines should be part of a HAZOP committee

Mark Brouwer, UreaKnowHow.com