Which of the following is NOT an example of overfill protection?

Which of the following is NOT an example of overfill protection?

• A. Drop Tube With An Automatic Shut Off Device
• B. Audible And Visual Alarm
• C. Expandable Bladder In Manway
• D. Vent Restricting Device

Answer: (C)

Overfill protection is about preventing a tank from being filled beyond its capacity or warning when that risk occurs. Devices that fit this idea include systems that automatically stop the fill (drop tube with an automatic shut-off), alert operators with alarms (audible and visual alarm), or manage venting to control pressure and fill rate (vent restricting device). The expandable bladder in the manway, however, is used as a sealing element during tank tightness testing. It’s a tooling component that helps isolate or pressurize parts of the system for a test, not a mechanism that prevents or warns about overfilling during normal filling operations. Because of its purpose, it does not serve as an overfill protection device.

Overfill protection is about preventing a tank from being filled beyond its capacity or warning when that risk occurs. Devices that fit this idea include systems that automatically stop the fill (drop tube with an automatic shut-off), alert operators with alarms (audible and visual alarm), or manage venting to control pressure and fill rate (vent restricting device).

The expandable bladder in the manway, however, is used as a sealing element during tank tightness testing. It’s a tooling component that helps isolate or pressurize parts of the system for a test, not a mechanism that prevents or warns about overfilling during normal filling operations. Because of its purpose, it does not serve as an overfill protection device.