Independent Overfill Protection System is to prevent the hazardous, toxic, or flammable substance to discharge the fluid to the atmosphere for reasons of fire, danger to personnel safety and health or its environmental impact. According to API 2350, tanks are classified into three main categories based on the features for overfill prevention: Category 1 system: manual operation for tank gaging and stopping/diversion of filling operation; Category 2 system: automatic and continuous tank level information is transmitted to the control room; Category 3 system: uses one independent sensor for automatic continuous tank gaging.
Reference Definition by hse.gov.uk: Independent Overfill Protection System is a system that detects when the liquid in a storage tank has reached a level where continued further filling will result in loss of containment and acts to prevent further filling in time to prevent such loss of containment. Where such systems are automatic, they do not rely on any human operator action.
Related Definitions in the Project: The Process Safety Engineering
