Standard Interpretations - Table of Contents|
| Standard Number:||1910.179; 1910.179(a)(2); 1910.179(f)(1)(i); 1910.179(f)(1)(ii)|
|This letter constitutes OSHA's interpretation only of the requirements discussed and may not be applicable to any situation not delineated within the original correspondence.|
November 15, 2005
Mr. David Sams
Crane America Services
1000 Black Run Road
Chillicothe, OH 45601
Dear Mr. Sams:
Thank you for your October 27, 2004, letter to the Occupational Safety and Health Administration's (OSHA) Directorate of Enforcement Programs (DEP). Your letter was referred to DEP's Office of General Industry Enforcement for an answer to your question regarding OSHA's Overhead and Gantry Crane Standard, 29 CFR 1910.179. We apologize for the delay in this response; additional research was required to fully answer your question. Your question has been restated for clarity, followed by our reply.
Question: Is a worm drive gearbox considered a holding brake for a floor pendant controlled, top-running, double girder bridge crane with top-running trolley and without any other kind of braking system?
Reply: No, a worm drive gearbox would not be considered a holding brake for this type of crane. Paragraph (f)(1)(i) of OSHA's Overhead and Gantry Cranes Standard, 29 CFR 1910.179, requires that each independent hoisting unit of a crane shall be equipped with at least one self-setting brake applied to the motor shaft or some part of the gear train. The standard also goes on to state at §1910.179(f)(1)(ii) that each independent hoisting unit of a crane, except worm-geared hoists, the angle of whose worm is such as to prevent the load from accelerating in the lowering direction shall, in addition to a holding brake, be equipped with control braking means to prevent over-speeding.
In addition, 29 CFR 1910.179(a)(20) defines a holding brake as a brake that automatically prevents motion when power is off. A brake is defined as a device used for retarding or stopping motion by friction or power means. These definitions are also found in §1910.179's source standard, American National Standard Safety Code for Overhead and Gantry Cranes, ANSI B30.2.0-1967. The 2001 edition of the American Society of Mechanical Engineers' (ASME) Overhead and Gantry Cranes Standard, ASME B30.2-2001, defines a brake as a device, other than a motor, used for retarding or stopping motion by friction or power. Paragraph 2-1.12.2(b) of the ASME B30.2-2001 standard states: "Hoist Control braking means can be electrical, such as regenerative, dynamic, countertorque, or eddy-current; mechanical; hydraulic; or a worm-geared hoist (emphasis added) where the angle of the worm is such as to prevent the load from accelerating in the lowering direction." Therefore, a worm-geared hoist may be considered a control brake but not a holding brake.
Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA requirements are set by statute, standards, and regulations. Our interpretations letters explain the 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. In addition, 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 www.osha.gov. If you have any further questions, please feel free to contact the Office of General Industry Enforcement at (202) 693-1850.
Richard E. Fairfax, Director
Directorate of Enforcement Programs
|Standard Interpretations - Table of Contents|