Washington Administrative Code › Title 296 - Labor and Industries, Department of › Chapter 296-155 - Safety standards for construction work › Part L - CRANES, RIGGING, AND PERSONNEL LIFTING › Section 296-155-56430 - Assembly/disassembly - Working under the boom, jib or other components - Sample procedures for minimizing the risk of unintended dangerous boom movement

Current through Register Vol. 24-14, July 15, 2024
(1) WAC
				296-155-53402(7)(a)
				 provides that when pins (or similar devices)
				are being removed, employees must not be under the boom, jib, or other
				components, except where the requirements of WAC
				296-155-53402(7)(b)
				are met. The exception in WAC
				296-155-53402(7)(b)
				 applies when the employer demonstrates that
				site constraints require one or more employees to be under the boom, jib, or
				other components when pins (or similar devices) are being removed. In such a
				situation, the assembly/disassembly supervisor must implement procedures that
				minimize the risk of unintended dangerous movement and minimize the duration
				and extent of exposure under the boom.
The following scenario is an example of how the exception
				  applies: A boom cannot be disassembled on the ground because of an aboveground
				  structure (as might be found, for example, at some construction sites) that
				  precludes lowering the boom to the ground. The boom must therefore be
				  disassembled in the air, and the employees who remove the pins must perform
				  that work from an aerial lift whose base is positioned on one side (the near
				  side) of the boom. To gain access to the pins on the far side, the aerial lift
				  basket must move under the boom, since, due to lack of room, the aerial lift
				  cannot be repositioned on the far side. Due to lack of room, the aerial lift
				  cannot be repositioned on the far side, so the aerial basket must move under
				  the boom to gain access to the pins on the far side.
To minimize the risk of unintended dangerous movement while
				  the pins are removed, the assembly/disassembly director uses an assist crane
				  that is rigged to support the boom section that is being detached, using
				  particular care to ensure that the section end that is near the employee(s)
				  removing the pins is well supported. The duration and extent of exposure is
				  minimized by removing the far side pins first, moving the aerial lift basket as
				  soon as possible to the near side so that the employees are no longer under the
				  boom, and then removing the near side pins.
(2) WAC
				296-155-53402(9)(f)(i)
				 provides that, during assembly/disassembly,
				the center of gravity of the load must be identified if that is necessary for
				the method used for maintaining stability. WAC
				296-155-53402(9)(f)(ii)
				 states that, where there is insufficient
				information to accurately identify the center of gravity, measures designed to
				prevent unintended dangerous movement resulting from an inaccurate
				identification of the center of gravity must be used.
An example of the application of WAC
				  296-155-53402(9)(f)(ii)
				  is as follows. The boom is assembled by lowering boom sections sequentially
				  into place using an assist crane. The assembly/disassembly director's plan is
				  to keep the boom sections stable while they are lowered into place by attaching
				  the assist crane hoist line above the center of gravity of each section.
				  However, in assembling the nonsymmetrical top section of the boom, the
				  assembly/disassembly director is not able to determine where to attach the
				  assist crane hoist line so that it is above the center of gravity. In this
				  situation, before raising the section, all personnel are kept clear of the
				  section and the section is first raised a few inches to determine whether it
				  tips when raised (if it did tip, it would indicate it is not rigged over the
				  center of gravity). If this occurs, the hoist line is repositioned and the
				  procedure repeated (with employees kept clear of the section while it is
				  raised) until the assembly/disassembly director determines that it is rigged
				  over the center of gravity and can be moved into place without dangerous
				  movement.
Statutory Authority:
					 RCW
					 49.17.010,
					 49.17.040,
					 49.17.050,
					 49.17.440,
					 49.17.060, and 29 C.F.R. 1926,
					 Subpart CC. 12-01-086, § 296-155-56430, filed 12/20/11, effective
					 2/1/12.