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Subchapter 6. Elevator Safety Orders
Article 18. Design Data, Formulas, Tests on Approved Devices, and Electrical Regulations

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§3106. Car and Counterweight Safety Stopping Distances and Approval Data.

(a) Stopping Distances, Type B Safeties.

(1) The following formulas shall be used to determine the maximum and minimum stopping distances for Type B car and counterweight safeties:

                         (V)2
                  S = --------- + 0.84					  
                        81,144				  
						
                         (V)2
                  S' = --------
                       231,840				  						 						

Where:

S = Maximum stopping distance in feet.

S' = Minimum stopping distance in feet.

V = Governor tripping speed in feet per minute.

(2) Figures 3106 A1 to 3106 A7 show the maximum and minimum stopping distances from various governor tripping speeds.

Design Data and Formulas

FIG. 3106 A-1 - STOPPING DISTANCE IN FEET
Stopping Distances for Type B Car and Counterweight Safeties

FIG. 3106 A-2 - STOPPING DISTANCE IN FEET
Stopping Distances for Type B Car and Counterweight Safeties

FIG. 3106 A-3

FIG. 3106 A-4

FIG. 3106 A-5 - Stopping Distances for Type B Car and Counterweight Safeties

FIG. 3106 A-6

FIG. 3106 A-7 - Stopping Distances for Type B Car and Counterweight Safeties

(b) Data Required for Approval.

(1) Two complete sets of assembly and detail drawings of the safety device shall be submitted to the division and shall show the following:

(A) The construction of the safety device and the dimensions of major parts for identification.

(B) The adjustment range and valves of the data as marked on the safety marking plate required by Section 3035(n).

(C) The design and operational details indicating that the safety device complies with Sections 3035(g), 3035(i), 3035(j), 3035(k), 3035(l), 3035(o), and 3035(p).

(2) The results of performance tests conducted by the manufacturer or an approved testing laboratory. These tests shall be conducted to demonstrate that the safety device will function satisfactorily within the range of loads and speeds for which the safety is to be approved.

(c) Performance Tests Required for Safety Approval.

(1) On Type B safeties in which the maximum retarding force does not depend on the pull in the governor rope, the tests shall be of the drop-test type or of the overspeed type. On such tests the governor tripping speed need not exceed 280 feet per minute.

(2) On Type B safeties in which the maximum retarding force depends on the pull in the governor rope and the car speed at which the safety is applied, the tests shall be of the drop-test type.

(3) On Type A safeties the tests shall be:

(A) A test shall be made of the inertia application of the safety by attaching the proper weight, as determined by the manufacturer, to the return run of the governor rope. This weight shall be that necessary to reproduce inertia operation of the safety at not to exceed 9/10 gravity. The inertia application shall be made with the car stationary, and the weight when released shall move the safety pats into contact with the rails, and

(B) A runaway test made from governor tripping speed with the safety device applied by the governor mechanism.

(4) On Type C safeties, the tests shall be of the overspeed type. The inertia application of the safety is not required.

(d) Factor of Safety. Parts of safeties, except springs, shall have a factor of safety of not less than 3.5, and the materials used shall have an elongation of not less than 15 percent in a length of 2 inches. Forged, cast, or welded parts shall be stress relieved.

EXCEPTION: Safety-rope drums, leading sheaves, and their supporting brackets and safety jaw gibs may be made of cast iron and other metals, provided such parts have a factor of safety of not less than 10.

(1) Rope used as a connection from the safety to the governor rope, including rope wound on the safety rope drum, shall be not less than 3/8 inch in diameter and shall be made of a corrosion-resistant metal. Tiller rope construction shall not be used. The factor of safety of the rope shall be not less than 5.

(2) The factors of safety shall be based upon the maximum stresses developed in the parts during the operation of the safety when stopping rated load from governor tripping speed.

(3) Springs may be used in the operation of car or counterweights safeties. Where used, and where partially loaded prior to safety operation, the loading on the spring shall not produce a fiber stress exceeding 1/2 the elastic limit of the material. During operation of the safety, the fiber stress shall not exceed 85 percent of the elastic limit of the material. Helical springs, where used, shall be in compression.

(4) Safety-rope leading-sheave brackets and other safety operating parts shall not be attached to or supported by wood platform members.

HISTORY

1. Editorial correction of subsections (a)(1) formula and (c)(3)(A) (Register 95, No. 34).

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