Sec. 8-1.50. [General.]

(a) Angle of inclination.

The angle of inclination of an escalator shall not exceed 30 degrees with the horizontal.

(b) Width.

(1) The width of an escalator shall be measured between the balustrading at a vertical height of 24 inches above the nose line of the treads.

(2) Escalators shall be not less than 22 inches nor more than 48 inches wide.

(3) Escalators greater than 29 inches in width shall have a horizontal tread formation.

(c) Balustrading.

(1) Escalators shall be provided on each side with “solid balustrading”. On the escalator side the “balustrading” shall be smooth, without depressed or raised paneling or molding. Glass panels in “balustrading” shall be prohibited.

(2) There shall be no abrupt changes in the width between the “balustrading” on the two sides of the escalator. Should any change in the width be necessary, the change shall be not more than eight per cent of the greatest width.

(3) In changing from the greater to the smaller width the change in the direction of the “balustrading” shall not exceed 15 degrees from the line of the escalator travel.

(4) “Balustrading” shall be equipped with a handrail moving at the same speed and in the same direction as the travel of the escalator.

(d) Tread guards.

(1) Stationary tread guards shall be provided on the escalator side of the “balustrading” along the whole length of, and immediately above the nose line of the escalator treads.

(2) Escalator treads and landings shall be of material affording secure foothold, such as wood or material used for “safety treads”. If the landing is of concrete, it shall have edge insertions of metal, wood or other anti-slip material.

(e) Strength of trusses or girders.

(1) Escalator trusses or girders shall be designed with a factor of safety not less than five based on the static loads.

(2) The escalator truss or girder shall be designed to safely retain the escalator treads in their runs if the tread chain breaks while supporting the maximum load.

(f) Track arrangement.

The track arrangement for guiding the escalator tread shall prevent the displacement of the upper line of treads if the tread chain breaks.

(g) Capacity and loading.

(1) The maximum load permitted on an escalator 24 inches or less in width shall be computed by the following formula: Maximum load—110A.

(2) The maximum load permitted on an escalator wider than 24 inches but not exceeding 36 inches shall be computed by the following formula: Maximum load—110+5 (W-24) XA.

(3) The maximum load permitted on an escalator wider than 36 inches but not exceeding 48 inches shall be computed by the following formula: Maximum load—160+5 (W-36) XA.

Note:

In these formulas, W is the width of the escalator in inches and A is the horizontal projected length in feet of the exposed treads. The maximum load is expressed in pounds.

(h) Limits of speed.

The speed of an escalator shall not exceed 100 feet per minute.

(i) Application of power.

(1) Escalators shall be driven by direct connected electric motors. Two or more escalators placed side by side and operated as a single unit may be driven by one motor.

(2) The chain or chains used for driving escalators shall have a factor of safety of not less than 10.

(3) Every escalator “drive” shall be provided with an electrically released, mechanically applied brake, which shall stop the escalator automatically when the power is cut off.

(4) There shall be an emergency “stop” button or other type of switch accessible to the public, conspicuously located at the top and the bottom of each escalator runway.

(5) The operation of either one of these buttons or switches shall cause the opening of the power circuit, application of the brake and stoppage of the escalator. It shall be impossible to start an escalator by means of these buttons or switches.

(6) These buttons or switches shall be marked “escalator stop button” or “escalator stop switch”.

(7) Escalators operated in the ascending direction shall be equipped with a safety mechanism to prevent accidental reversal of the escalator.

(8) On a reversible escalator the safety mechanism shall be arranged to be inoperative when the escalator is descending and operative when the escalator is ascending. The safety mechanism shall be provided with a contractor, the functioning of which will cause the opening of the power circuit and the application of the brake.

(9) Escalators operating in a descending direction shall be provided with a safety mechanism to prevent the escalator attaining excessive speed.

(10) Escalators operated by polyphase alternating current motors shall be provided with relays of the potential type which will prevent starting the motor while:

(i) the phase rotation is in the wrong direction, or

(ii) there is a failure in any phase.