R 408.10565 Roof cars; carriages; suspension methods.

Rule 565. (1) A roof car shall be used when it is necessary to move a working platform horizontally to a work or storage position. (2) Movements of a roof car shall be restricted to a designated path of travel. Mechanical stops shall be provided and shall prevent the roof car from traversing outside the intended path of travel. The stops shall be capable of withstanding a force equal to 100% of the inertial effect of the roof car under power and shall be designed to prevent a crushing or shearing hazard. (3) Elevated building maintenance equipment shall be suspended by a roof car, carriage, outrigger, davits, or an equivalent method. (4) Carriages or roof cars shall be in compliance with all of the following provisions: (a) The horizontal movement of a carriage shall be controlled to ensure its safe movement and allow accurate positioning of the platform for vertical travel or storage. (b) Powered carriages shall not exceed a traversing speed of 50 feet per minute (0.3 ms). (c) The initiation of a traversing movement for a manually propelled carriage on a smooth level surface shall not require a person to exert a horizontal force of more than 40 pounds (444.8 n). (d) Structural stops and curbs shall be provided to prevent the traversing of the carriage beyond its designed limits of travel. (e) Traversing controls for a powered carriage shall be of a continuous pressure weatherproof type. Multiple controls, when provided, shall be arranged to permit operation from only 1 control station at a time. An emergency stop device shall be provided on each end of a powered carriage for interrupting power to the carriage drive motors. (f) The operating control or controls shall be connected so that, in the case of suspended equipment, traversing of a carriage is not possible until the suspended portion of the equipment is located at its uppermost designed position for traversing and is free of contact with the face of the building or building guides. All protective devices and interlocks shall be in the proper position to allow traversing of the carriage. (g) Stability for underfoot supported carriages shall be obtained by gravity, by an attachment to a structural support, or by a combination of gravity and a structural support. The use of flowing counterweights to achieve stability is prohibited. (h) The stability factor against overturning shall not be less than 5 for horizontal traversing of the carriage, including the effects of impact and wind. (i) The carriages and their anchorages shall be capable of resisting accidental over-tensioning of the wire ropes that suspend the working platform, and this calculated value shall include the effect of 1-1/2 times the stall capacity of the hoist motor. The forces that result from the stall load of the hoist and 1/2 of the wind load shall not cause damage to any part of the installation. (j) Roof carriages that rely on having tie-down devices secured to the building to develop the required stability against overturning shall be provided with an interlock that will prevent vertical platform movement unless the tie-down is engaged. (k) An automatically applied braking or locking system, or an equivalent, shall be provided that will prevent the unintentional traversing of power-traversed or power-assisted carriages. (l) A manual or automatic braking or locking system, or an equivalent, shall be provided that will prevent the unintentional traversing of manually propelled carriages. (m) A means to lock out the power supply for the carriage shall be provided. (n) Safe access to, and egress from, the carriage shall be provided from a safe surface. If the carriage traverses an elevated area, any operating area on the carriage shall be protected by a guardrail system in compliance with General Industry Safety and Health Standard Part 2 “Walking-Working Surfaces,” as referenced in R 408.10509. Any access gate shall be self-closing and self-latching or shall be provided with an interlock. (o) Each carriage work station position shall be identified by location markings or position indicators, or both. (p) A motor shall stall if the load on the hoist motor is at any time more than 3 times that necessary for lifting the working platform with its rated load.