What is the safety relief pressure of the rupture disc?

• A. 30 psi
• B. 10 psi
• C. 15 psi
• D. 20 psi

Answer: (C)

Rupture discs are safety devices that vent when the system pressure reaches a set relief pressure. That relief pressure is the exact point at which the disc will rupture and start releasing pressure to prevent damage or danger. It’s chosen to be higher than normal operating pressure but below the equipment’s maximum allowable pressure, so it doesn’t vent during normal use but activates promptly if pressure rises. In this scenario, normal operation is around 10 psi, so a 15 psi relief setting ensures the disc stays intact during regular use but will open if pressure climbs to 15 psi, providing protection before reaching unsafe levels. Values like 30 psi would allow too much buildup before relief, while 10 psi would vent during normal operation; 20 psi could be acceptable in some designs, but 15 psi fits the intended protection for this case.