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The power transmission apparatus includes all components of a mechanical system that transmit energy to the part of the machine performing the work. These components include flywheels, pulleys, belts, connecting rods, couplings, cams, spindles, chains, cranks, and gears. If not guarded properly, these parts of the machines can be just as dangerous as the point of operation.
Scope
OSHA’s standard applies to all employers who have mechanical power transmission apparatus. Note however that some equipment is not covered by the standard because of belt speed or height. And, there is a modified guarding requirement for the textiles industry.
Regulatory citations
- 29 CFR 1910.219 — Mechanical power transmission apparatus
Key definitions
- Belts: Include all power transmission belts, such as flat belts, round belts, V-belts, etc., unless otherwise specified.
- Exposed to contact: The location of an object is such that a person is likely to come into contact with it and be injured.
- Flywheels: Include flywheels, balance wheels, and flywheel pulleys mounted and revolving on crankshaft of engine or other shafting.
- Maintenance runway: Any permanent runway or platform used for oiling, maintenance, running adjustment, or repair work, but not for passageway.
- Nip-point belt and pulley guard: A device which encloses the pulley and is provided with rounded or rolled edge slots through which the belt passes.
- Point of operation: That point at which cutting, shaping, or forming is accomplished upon the stock and shall include such other points as may offer a hazard to the operator in inserting or manipulating the stock in the operation of the machine.
- Prime movers: Include steam, gas, oil, and air engines, motors, steam and hydraulic turbines, and other equipment used as a source of power.
- Sheaves: Grooved pulleys, and shall be so classified unless used as flywheels.
Summary of requirements
Employers must:
- Ensure all belts, pulleys, shafts, etc., are guarded properly, unless meeting the height exception. (The height exception is only for certain equipment at certain speeds; see the full text of 1910.219.)
- Ensure shaft ends present a smooth edge and end and do not project more than one-half the diameter of the shaft unless guarded by nonrotating caps or safety sleeves.
- Fill or cover unused keyways.
- Establish a program for regular inspection of the equipment.
- Perform maintenance under a lockout/tagout program per 1910.147.
Did you know?
In some instances the application of “enclosed” and “fully enclosed” as applying to power transmission belts has been interpreted to mean that all four sides of a power transmission belt must be covered by an enclosure. However, that is not always required. According to OSHA Instruction STD 1-12.14 dated October 30, 1978:
- When there is no employee exposure to power transmission belts because they are naturally guarded by location, then no enclosure or guarding is required. Guarding by location has been accomplished by the belts running close enough to walls and other objects to present no exposure to employees.
- “Enclosure,” as used in 1910.219(e)(3)(ii), for vertical and inclined belts is intended to mean that only the portion of a belt seven feet or less from the floor is required to be enclosed by a guard.
- “Fully enclosed” applies to the sides of a power transmission system not guarded by location as described in 1910.219(e)(1)(i), which includes both runs of a horizontal belt, pulley, and flywheel (small units with slightly inclined belts are included in this category.)