OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

July 11, 1980

Mr. V.J. McNeill
Lexvin Industries
100 Amber Street, Unit 11
Markham, Ontario

Dear Mr. McNeill:

Assistant Secretary Eula Bingham has asked me to respond to your letter concerning the Occupational Safety and Health Administration's (OSHA) regulations for back-up alarms. We apologize for the delay of this response.

As you may be aware, OSHA has no requirements for back-up alarms in the general industry standards, 29 CFR Part 1910. However, the regulation you mentioned in your letter is 29 CFR Part 1926.601(b)(4) of the Construction Safety and Health Regulations.

The regulation you refer to reads:

"(4) No employer shall use any motor vehicle equipment having an obstructed view to the rear unless:

(i) The vehicle has a reverse signal alarm audible above surrounding noise level or;

(ii) The vehicle is backed up only when an observer signals that it is safe to do so."

As you can see, the alarm is only required when vision to the rear of the operator is obstructed and the operator lacks an observer to signal him.

It would be the employer's obligation to determine the noise level in his particular worksite and select an appropriate alarm if he chooses to use it.

A second regulation, 29 CFR Part 1926.602(a)(9), reads as follows:

"(9) Audible alarms

(i) All bidirectional machines, such as rollers, compactors, front-end loaders, bulldozers, and similar equipment, shall be equipped with a horn, distinguishable from the surrounding noise level, which shall be operated as needed when the machine is moving in either direction. The horn has to be maintained in operative condition.

(ii) No employer shall permit earthmoving or compacting equipment which has an obstructed view to the rear to be used in reverse gear unless the equipment has in operation a reverse signal alarm distinguishable from the surrounding noise level or an employer signals that it is safe to do so."

The second requirement may more closely relate to your inquiry in that it requires the alarm to be distinguishable from the surrounding noise level.

The regulations allow a 90 decibel (dba), 8-hour exposure for employees. Thus, it appears that your device (BUA-1) may meet the requirements in either case.

We trust that this provides you with the information you requested. Should you have further questions, please feel free to contact us.


Jerry L. Purswell, Ph.D., P.E.
Director, Directorate of Safety Standards Programs