Machine Design

Don’t make these conveyor safety mistakes, part 2 of 3

A contractor was found dead of suffocation and a broken neck behind the guard of a conveyor’s tail pulley. As in the incident discussed last month (“Analyzing conveyor designs for safety,” Sept. 23, 2010) the person who turned the conveyor back on after a shutdown couldn’t see the entire conveyor. The fact that these machines can stretch through doorways is another one of their hidden safety hazards.

The victim in this case was a contractor employed to move boxes from the conveyor to pallets and keep the area swept up. When the boxes on the conveyor were small, as on the day of the accident, a person could crawl between the housing covering the tail pulley and the conveyor.

The supervisor stopped the conveyor during a production lull, and the contractor started sweeping up. But the contractor was nowhere to be found when the supervisor restarted the conveyor. Blood on the conveyor belt led searchers under the guard of the tail pulley where they found the contractor dead with his broom, a soft drink, and his cell phone on which he’d called his girlfriend during his impromptu break.

Investigators identified several underlying problems, each of which resulted in an OSHA citation.

The contractor had not been trained in lockout/tagout procedures. He was not supposed to be performing conveyor maintenance, but because all his work activity was around the moving machinery and his sweeping might have led him into restricted parts of the conveyor, he should have received some level of lockout/tagout training. OSHA citation #1.

There was no warning that conveyor was starting. A warning light or siren indicating the belt was about to start and a time delay would have let the contractor take action to protect himself. OSHA citation #2.

The space between the conveyor and the tail-pulley guard was large enough for a person to crawl through. Because this is a dangerous area when the conveyor belt is moving, a fixed guard should have blocked entry into this space. OSHA citation #3.

If the area could not be properly guarded, an emergency stop cable or button would have let a person trapped in that area stop the conveyor before coming to harm. OSHA citation #4.

The contractor had been trained to alert his supervisor when leaving his work area, but he had not done so while the conveyor was off. Therefore, the supervisor should have assumed he was in the conveyor area and located him before turning on the conveyor. OSHA citation #5.

Each of these lapses points to a common attitude that views conveyors as infrastructure, not as moving machinery. A safety officer or supervisor looking at the conveyor as if it was a piece of production equipment would have easily identified each problem.

Stay tuned for another tale of conveyor woe next month.

Lanny Berke is a registered professional engineer and Certified Safety Professional involved in forensic engineering since 1972. Got a question about safety? You can reach Lanny at [email protected]

Edited by Jessica Shapiro

© 2010 Penton Media, Inc.

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