Multiple Lift Rigging, what can you tree?

OSHA’s Final Rule for Safety Standards for Steel Erection was published in 2001, and paragraph (e), Multiple Lift Rigging Procedure, outlines OSHA’s standard for lifting multiple pieces of steel at one time. 

Multiple Lift Rigging (Christmas-Treeing), is allowed only for steel erectors and should only be done when the outlined criteria are met. Recently, I have seen erection companies perform multiple lifts with items not approved under OSHA’s final rule. For example, bundles of decking, pallets of CMU blocks and portable toilets are not permitted for multiple lift rigging because it unnecessarily exposes employees to overhead loads.

Multiple lifts should only be performed if the following criteria are met: 

1. A multiple lift rigging assembly is used;
2. No more than five members are hoisted per lift;
3. Only beams and similar structural members are lifted.

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It is important to understand the Steel Erection Negotiated Rulemaking Advisory Committees (SENRAC) original argument captured in the Federal Register persuaded OSHA to allow steel erection employees to work under the load by using multiple lift rigging. This is because multiple lift rigging, when done properly, is a safe and effective method for decreasing the number of total crane swings and employee exposure on the steel while connecting. To be in compliance with OSHA, steel erectors may “tree” steel beams, bar joists, and girders. 
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Other benefits of multiple lift rigging are:

• A reduction in the time connectors must spend out on the iron because tandem loading allows them to complete their tasks more quickly.
• Reduced stress on the crane operator because fewer mechanical operations are required.
• Further, the practice reduces the total number of swings the crane makes in each project, thus reducing the risk of exposing the workers located in the vicinity of the crane or in the path of travel of the load.​

Best Practices:
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• The total load must not exceed the rated capacity of the hoisting equipment specified in the load charts or the rigging capacity specified in the rigging rating chart.
• Bundles of decking are not permitted for multiple lift rigging. The best practice for lifting bundles of decking is one at a time. 
• Only structural members may be lifted during a multiple lift.
• A typical multiple lift member would be a wide flange beam section between 10 and 30 feet long, typically weighing less than 1,800 pounds.
• All employees engaged in the multiple lift have been trained in these procedures in accordance with § 1926.761(c)(1).
• No crane is permitted to be used for a multiple lift where such use is contrary to the manufacturer's specifications and limitations.
• Members must be attached at their center of gravity and maintained reasonably level
• Members must be rigged at least 7 ft apart
• The members on the multiple lift rigging assembly shall be set from the bottom up.​

Resources: 

OSHA’s Final Rule for Safety Standards for Steel Erection

OSHA’s Safety and Health Regulations for Construction Subpart R

This Safety Flash was contributed by Bryan McClure, Senior Safety Consultant, Trivent Safety Consulting in cooperation with SEAA’s Safety Committee. It is designed to keep members informed about ongoing safety issues and to provide suggestions for reducing risk. Best practices are gathered from a variety of sources. They may be more or less stringent than individual corporate policies and are not intended to be an official recommendation from SEAA. Always get approval and direction from your company officers on any new practice or procedure as these best practices may not work for all situations.   

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