Current through Register Vol. 54, No. 50, December 14, 2024
Section 7.155 - Suspension means(a) Suspension means shall be wire ropes or suspension chains. There shall not be less than two such ropes or chains.(b) Steel tapes or tiller rope as suspension means is prohibited.(c) On elevators having a contract load of less than 450 pounds and operating at a contract speed of less than 30 feet per minute, ropes shall not be less than 1/4 inch in diameter. When the contract load exceeds 450 pounds, or the contract speed exceeds 30 feet per minute, ropes shall not be less than 3/8 inch diameter.(d) The factor of safety of the suspension means shall not be less than seven. When the car and counterweight are suspended by wire ropes and the driving means between the machine and counterweight is an endless chain, the factor of safety of such chain with the rated load in the car shall be not less than eight.(e) The arc of contact of a wire rope on a traction sheave shall be sufficient to produce adequate traction under all load conditions. The arc of contact of a chain on a driving sprocket shall not be less than 140°.(f) Wire ropes anchored to a winding drum shall have not less than one full turn of rope on the drum when the car or counterweight has reached its extreme limit of possible overtravel.(g) No car or counterweight wire rope shall be lengthened or repaired by splicing. Broken or worn suspension chains shall not be repaired but the entire chain shall be replaced.(h) The winding drum ends of car and counterweight wire ropes shall be secured by clamps on the inside of the drum or by one of the methods specified in subsection (i) for fastening wire ropes to car or counterweight.(i) The car or counterweight ends of wire ropes shall be fastened by return loop, properly made individual, tapered, babbitted sockets, or attached fittings as recommended by wire rope manufacturers. Clamps of the U-bolt type shall not be used.(j) A metal tag shall be placed on all wire ropes or chain fastenings, or be permanently fixed on the car frame, upon which shall be stamped the size, the material, the ultimate strength of the rope or chain, as rated by the manufacturer, and the date of installation or renewal.