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Subchapter 4. Construction Safety Orders
Article 14. Construction Hoists

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§1604.20. Governors.

(a) Requirement for Governors and Location.

Car safeties, and counterweight safeties, where furnished, shall be actuated by a speed governor.

The governor shall be located where it cannot be struck by the car or the counterweight in case of over-travel and where there is adequate space for full movement of governor parts.

(b) Tripping Speeds.

(1) Car Governors.

Governors for car safeties shall be set to trip at overspeeds as follows:

(A) At not less than 115% of rated speed.

(B) At not more than the tripping speed listed opposite the applicable rated speed in Table 3. Maximum tripping speeds for intermediate rated speeds shall be determined from Figure 3.

(2) Counterweight Governors.

Governors for counterweight safeties, where provided, shall be set to trip at an overspeed greater than, but not more than 10% above, that at which the car speed governor is set to trip.

(c) Sealing and Painting.

Governors shall have their means of speed adjustment sealed after test. If speed governors are painted after sealing, all bearing and rubbing surfaces shall be freed of, or kept free from, paint and a hand test made to determine that all parts operate freely as intended. Seals shall be of a type which will prevent readjustment of the governor-tripping speed without breaking the seal.

(d) Governor Overspeed and Safety Switches.

(1) A switch shall be provided on the governor and operated by the overspeed action of the governor. A switch shall be provided on the governor when used with a counterweight safety. Every car safety shall be provided with a switch operated by the car safety mechanism when the safety is applied. These switches shall, when operated, remove power from the driving-machine motor and brake before, or at the time of, application of the safety. The governor overspeed switch and the safety switch may be the same switch on rack and pinion safeties.

EXCEPTION: A period of five years from the effective date of these orders will be allowed during which the overspeed switch on existing governors may be omitted where the governor is of a type not designed to operate a switch.

(2) The setting of the car governor overspeed switch shall conform to the following requirements:

(A) The car governor overspeed switch shall open in the down direction of the hoist at not more than 100% of the speed at which the governor is set to trip in the down direction.

(B) The switch, when set as specified in Section 1604.20(d)(2)(A), shall open in the up direction at not more than 100% of the speed at which the governor is set to trip in the down direction.

EXCEPTION: Rack and pinion safeties.

(3) Switches used to perform the functions specified shall be positively opened and shall remain in the open position until manually reset. Switches operated by the car safety mechanism shall be of a type which will not reset unless the car safety mechanism has been returned to the "off" position.

(e) Governor Ropes and Tripping Mechanisms.

(1) Material and Factor of Safety.

Governor ropes shall be of iron, steel, nickel-copper alloys (Monel Metal, or the equivalent), phosphor bronze, or stainless steel, of regular lay construction, and shall be not less than 3/8-inch in diameter. Tiller rope construction shall not be used.

The factor of safety of governor ropes or governor-tripping mechanisms shall be not less than five.

(2) Replacement of Existing Governor Ropes.

Replacement governor ropes shall be of the same size, material, and construction as the rope originally furnished by the hoist manufacturer, except that a rope of the same size but of either different material or construction may be employed provided there is conformance with the requirements of Section 1604.20(g) and a test is made of the car or counterweight safety and speed governor with the new rope to demonstrate that the safety will function as required by Section 1604.19(b).

(3) Governor Rope Clearance.

During normal operation of the hoist, the governor rope shall run free and clear of the governor jaws, rope guards, or other stationary parts.

(4) Splicing Governor Ropes.

Governor ropes shall not be lengthened or repaired by splicing.

(f) Design of Governor Jaws.

Type B and C car and counterweight safeties shall be actuated by a governor equipped with rope-grip jaws which will permit the governor rope to pull through the jaws. The maximum tension in the governor rope to cause it to slip through the governor jaws shall not exceed 1/5 of the rated ultimate strength of the rope.

Governor jaws shall be of such shape and minimum length that no appreciable damage to, or deformation of, the rope shall result from the stopping action of the jaws in operating the car or counterweight safety.

(g) Design of Speed Governor Sheaves and Traction Between the Speed Governor Rope and Sheaves.

The arc of contact between the governor rope and the governor sheaves shall, in conjunction with a governor-rope tension device, provide sufficient traction to cause proper functioning of the governor.

Governor-sheave grooves shall have machine-finished surfaces. Governor tension sheaves shall have machine-finished grooves for rated car speeds of more than 200 feet per minute. Machined governor-sheave grooves shall have a groove diameter of not more than 1 1/8 times the diameter of the governor rope.

The pitch diameter of governor sheaves and governor tension sheaves shall be not less than the product of the diameter of the rope and the applicable multiplier in the following list, based on the rated speed and the number of strands in the rope:


                                No. of 
            Rated Speed         Strands          Multiplier 
200 feet per minute or less       6                 42 
200 feet per minute or less       8                 30 
Over 200 feet per minute          6                 46 
Over 200 feet per minute          8                 32 

(h) Governor Marking Plate.

A plate shall be securely attached to each governor and shall be marked in a legible and permanent manner with letters and figures not less than 1/4-inch in height, indicating the following:

(1) The speed, in feet per minute, at which the governor is set and sealed to trip the governor rope-grip jaws.

(2) The size, material and construction of the governor rope on which the governor jaws were designed to operate.

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