🔍 Key Concepts

• Safety valve operation: popping (set) pressure vs. reseating (closing) pressure • Maximum Allowable Working Pressure (MAWP) and how it relates to set pressure • Purpose of blow down: preventing chattering and ensuring stable valve operation

💭 Think About

• Which pressures are involved at the exact moment the valve opens, and which when it closes again? • Is blow down about how far the valve pressure is from MAWP, or about how much the pressure drops between opening and closing? • Look at each choice and ask: does this describe a pressure DIFFERENCE, or a mechanical drain/feature?

✅ Before You Answer

• Confirm that blow down is defined as a PRESSURE DIFFERENCE, not a drain or piping feature. • Identify which answer choices use the popping (set) pressure and the reseating (closing) pressure in their definition. • Check if MAWP is directly part of the blow down definition, or just used to decide what the set pressure should be.