Derating for Process Safety Reasons
Why would anyone de-rate a pressure vessel or heat exchanger? What is the point of formally accepting less out of your equipment than it was designed for?
The simple answer is to reduce the operational risk at your facility by ensuring that pressurizing to the original Maximum Allowable Working Pressure (MAWP) is never attempted. The most common scenario I observe is when a design with no corrosion allowance does not align with measured in-service corrosion.
Many times pressure vessels and heat exchangers operate much lower than their ratings so de-rating causes no operational disruptions. Is there any equipment in your facility that could use a de-rate?
