Michigan Administrative Code › Department - Labor and Economic Opportunity › MIOSHA › General Industry and Construction Safety and Occupational Health Standards › General Industry Safety Standards › Part 5 - POWERED PLATFORMS FOR BUILDING MAINTENANCE › POWERED PLATFORM INSTALLATIONS - EQUIPMENT › Section R. 408.10565 - Roof cars; carriages; suspension methods

Current through Vol. 24-12, July 15, 2024
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.