Technical Note SB79: Recognising belt conveyor danger zones

In most applications, a conveyor belt moves at a relatively constant speed, commonly running somewhere between 0.5 and 10 metres per second. An Olympic sprinter has a reaction time of about 0.18 seconds (roughly one-fifth of a second) when poised at the starting line and totally focused on the race. If this athlete becomes tangled in a conveyor belt traveling 1.5 metres per second, the person would be carried 0.27 metres before even realizing what has happened.

A ‘regular’ worker would likely require a longer time to react. For simplicity’s sake, we can assume it would be twice the athlete’s reaction time, so the worker would be pulled twice as far, introducing the potential to strike many more components or to be pulled farther and harder into the first one. In addition, most conveyors are engineered with the ability to start remotely. The system may go from dormant to active at any time at the push of a button, and that ability can suddenly catch a worker unaware, leading to serious injury or death.