Crane swing-radius barricades versus audible alarms

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

August 13, 1976

Mr. Robert I. Slaughter
Corporate Safety Supervisor
Chicago Bridge & Iron Company
[Recipient address omitted]
Dear Mr. Slaughter:

This is in response to your correspondence of June 22, 1976, addressed to Mr. Frank C. Memmott, regarding an alternate to the requirements of 29 CFR 1926.550(a)(9).

This standard states: "accessible areas within the swing radius of the rear of the rotating superstructure of the crane, either permanently or temporarily mounted, shall be barricaded in such a manner as to prevent an employee for being struck or crushed by the crane."

The question of frequent moving of cranes, both crawler and wheel-mounted, was reviewed thoroughly before this rule was promulgated and again approximately a year later. The use of audible alarms in lieu of physical barriers was determined to be unsatisfactory on several counts. First, there is no means of satisfactorily monitoring an employee's entrance into the hazardous location. Secondly, the degree of such a person's ability in time and effort to clear himself from the hazardous location in relation to an audible alarm is not mechanically (by electronics or otherwise) feasible. In addition to those problems, the person in the hazardous location be confused by other similar alarms either by tonal and activated frequency, the surrounding noises, or hearing loss. Since noise standards which are presently enforced call for significant efforts to reduce the ambient noise level, one more audible warning device which could be confused with others, would only raise the noise level unnecessarily and probably fail to accomplish its purpose.

A number of employers have found ways to satisfactorily attach the required barricades to their machines. These systems have apparently met their needs without undue hardship.

If I may be of any further assistance, please feel free to contact me.

Sincerely,

John K. Barto, Chief
Division of Occupational Safety Programming