DEFINITION
A critical lift is a crane lift that carries elevated risk and therefore requires extra planning, engineering review, and a written lift plan. Common triggers include lifts exceeding roughly 75% of the crane's rated capacity, multi-crane (tandem) picks, and any lift hoisting personnel.
ALSO KNOWN AS · critical lift plan · engineered lift · complex lift
There is no single OSHA definition that uses the exact phrase 'critical lift' for all construction cranes, but the concept is well established across ASME B30, ANSI, military and DOE standards, and most contractor safety programs. A critical lift is one where the consequences of failure are severe enough that the lift must be specifically engineered and planned rather than performed as a routine pick.
Typical triggers that classify a lift as critical include: a load that exceeds a set percentage of the crane's rated capacity (commonly 75%, sometimes 80% or 90% depending on the program); a tandem or multi-crane lift where two or more cranes share the load; lifting personnel in a suspended platform; lifts over occupied structures, live process equipment, or the public; lifts of unique, high-value, or irreplaceable loads; and lifts near power lines or in restricted clearances.
A critical lift plan documents the crane configuration, the load weight and center of gravity, the rigging and its rated capacity, ground bearing and outrigger or crawler positioning, the lift geometry (radius, boom length, swing), the percent of chart capacity at each point in the lift, and the personnel and their roles. The plan is typically reviewed and signed by a qualified person or engineer before the lift proceeds.
The critical-lift determination drives downstream inspection and rigging requirements: a lift at 90% of chart leaves no margin for a mis-rated sling or an unverified load chart, so the pre-lift inspection of the crane, the rigging gear, and the ground conditions becomes far less forgiving than for a routine pick.
AUTHORITATIVE · SOURCE
ASME B30.5 Mobile and Locomotive Cranes (asme.org)FREQUENTLY · ASKED
Many programs set the threshold at 75% of the crane's rated chart capacity, though 80% or 90% is used in some standards. The exact percentage is defined by the employer's lift program; any lift over the threshold typically requires a written, engineered lift plan.
Yes. Hoisting personnel in a suspended platform is treated as a critical lift in essentially every program because of the life-safety exposure, and it also triggers OSHA 1926.1431's specific personnel-platform requirements such as the 50% capacity derate.
RELATED · TERMS
A load chart is the manufacturer's table of a crane's rated lifting capacity for every combination of boom length, lift radius, and configuration. It defines the maximum weight the crane may safely hoist at each geometry and is the reference for determining percent-of-capacity on any lift.
A personnel basket is a platform suspended from a crane hook to hoist workers when no safer means of access exists. OSHA 1926.1431 permits it only as a last resort and requires the crane to be derated to 50% of its rated capacity for the lift, among other strict controls.
ASME B30 is the consensus safety standard series for cranes, derricks, hoists, hooks, slings, and rigging. Each volume addresses a class of equipment — B30.2 overhead and gantry cranes, B30.3 tower cranes, B30.5 mobile and locomotive cranes — and OSHA incorporates several volumes by reference.
An OSHA qualified person is one 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 the subject matter, work, or project.
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