What is a rigging plan?

A rigging plan addresses the connection between the crane and the load. Where a lift plan addresses crane configuration and capacity, the rigging plan addresses how the load is attached, how the slings are configured, and whether the rigging system as a whole is rated for the load. Rigging failures are a leading cause of dropped load incidents, and the majority of dropped load incidents are attributable to rigging plans that were not prepared, not followed, or never considered.

Components of a Rigging Plan

A complete rigging plan includes the following: sling type (wire rope, synthetic web, round sling, chain), the diameter and grade of wire rope or the rated capacity of synthetic slings, the rigging configuration (single vertical, choker, basket, or bridle), the attachment points on the load and their load-bearing capacity, the sling angle from vertical at each attachment point, the working load limit (WLL) of each sling de-rated for the actual rigging angle, the total rigging capacity as configured compared to the load weight, the tag line requirements, and any special considerations for load center of gravity or asymmetric loads. Each of these elements must be documented, not estimated.

ASME B30.9 and Rigging Standards

ASME B30.9 governs slings in the United States. It specifies the rated capacities for wire rope slings, alloy steel chain slings, synthetic web slings, and round slings at various configurations and angles. B30.9 includes the rigging angle de-rating factors that are central to rigging plan calculations. As the sling angle from vertical increases (meaning the sling becomes more horizontal), the effective load on each sling leg increases substantially. At a 30-degree angle from vertical, each sling leg carries twice the load it would carry in a vertical configuration. This is the most commonly misunderstood factor in field rigging, and it is the source of sling failures when riggers use WLL ratings without accounting for angle.

Who Qualifies as a Rigger Under OSHA

OSHA 29 CFR 1926.1425 requires that rigging be done by qualified riggers. A qualified rigger under OSHA's Subpart CC definition is a person who, by possession of a recognized degree, certificate, or professional standing, or by extensive knowledge, training, and experience, has successfully demonstrated the ability to solve or resolve problems relating to rigging loads. NCCCO offers a Rigger Level I and Rigger Level II certification program that satisfies the qualified rigger standard and is increasingly required by GCs on commercial projects.

Rigging Plans in Critical Lifts

For critical lifts, the rigging plan is not optional. A complete critical lift plan must include the rigging plan as a component. The combination of the crane's load chart verification and the rigging system's WLL calculation at actual rigging angles constitutes the capacity verification requirement for a critical lift. Neither is sufficient without the other. A lift that is within the crane's rated capacity can still result in a rigging failure if the sling angles were not calculated and the actual sling loads exceed WLL.

Integration with the Lift Plan

In practice, the rigging plan and the lift plan are often combined into a single document. The rigging plan section addresses the hook-to-load connection. The crane section addresses the crane configuration and load chart comparison. Both sections require review and signature by the operator, the qualified rigger, and the lift director before the lift proceeds. This combined approach is the standard recommended by ASME B30.5 and adopted by most safety-conscious crane companies and GC rigging programs.