• OSHA requires employers to comply with either manufacturer procedures or employer procedures for crane assembly and disassembly.
• Before beginning A/D, crew members must know their tasks, the associated hazards, and the hazardous locations to avoid on the jobsite.

Some mobile crane accidents happen because of improper assembly and disassembly of the crane on the jobsite. Most of these accidents could be avoided by following the crane manufacturer’s requirements for assembly/disassembly (A/D). That’s why the Occupational Safety & Health Association (OSHA) requires the employer to comply with all manufacturer prohibitions applicable to assembly and disassembly, and use either:

• Manufacturer procedures for assembly and disassembly, or
• Employer procedures for assembly and disassembly.

Manufacturer procedures are generally the first choice. Employer procedures may be used only where the employer can demonstrate that the procedures used do the following:

• Prevent unintended dangerous movement and collapse of any part of the equipment,
• Provide adequate support and stability of all parts of the equipment, and
• Position employees involved in the A/D operation so that their exposure to unintended movement or collapse of part or all of the equipment is minimized.

Employer procedures must be developed by a qualified person.

Synthetic slings are an exception. Employer procedures can’t be used during rigging if the employer uses synthetic slings. Rather, the synthetic sling manufacturer’s instructions, limitations, specifications, and recommendations must be followed.

Proper assembly procedures

Accidents during A/D are often caused by:

• Misunderstanding or confusion by employees as to their tasks and how they are to be performed, or
• Failure to recognize potentially dangerous areas in and around the equipment.

The details of these tasks, and the location of danger areas that workers need to keep out of, often vary from one machine to another. The A/D director is responsible for making sure that the crew members know this essential information before starting the A/D process.

Crew instructions

Before beginning A/D operations, the A/D director must make sure that the crew members understand:

• Their tasks,
• The hazards associated with their tasks, and
• The hazardous positions and locations that they need to avoid.

Before a crew member takes on a different task, or when adding new personnel during the A/D operations, the crew instruction requirements listed above must be met. Crew instructions must be given first.

Capacity limits

Rated capacity limits must not be exceeded for loads imposed on the equipment, equipment components (including rigging), lifting lugs, and equipment accessories. This prohibition applies during all phases of A/D.

In some cases, the crane being assembled is used to install its own counterweights (which can create a capacity limit risk). Early in this process, when few counterweights are in place, the crane’s capacity will be so limited that swinging beyond a certain point, or booming out beyond a certain point, may cause it to overturn.

Note that where an assist crane is being used during the A/D of another crane/derrick, the requirements for rated capacity during operations must be met.