What is the proof load for a crane test?
Typically 100% to 125% of rated capacity, as specified by the applicable ASME B30 volume and OSHA. New or repaired rigging hardware may be proof-tested to a higher multiple of its working load limit.
DEFINITION
A proof load test applies a known overload — typically 100% to 125% of rated capacity — to a crane, hoist, or rigging device to verify it can safely handle its rated load. It is required after major repairs, alterations, or initial commissioning, and is documented and retained.
ALSO KNOWN AS · load test · proof test · rated load test
A proof (or rated) load test demonstrates that a piece of lifting equipment can safely sustain a load at or modestly above its rated capacity. The test load is defined by the governing standard: ASME B30 volumes and OSHA generally specify a proof load in the range of 100% to 125% of rated capacity for cranes and below-the-hook devices, while new or repaired rigging hardware may be tested to a higher multiple of the working load limit.
Load testing is required at specific lifecycle points rather than on a routine cadence. OSHA 1926.1412(a) and ASME B30 require a load test after a crane is newly assembled or commissioned, and after any repair, alteration, or modification to a load-bearing or load-controlling component. The test confirms the structure, brakes, and hoisting system perform under load before the equipment carries production work or personnel.
During the test the equipment is loaded to the specified percentage, the load is hoisted, held, swung, and lowered through the range of motion, and the structure and components are inspected for permanent deformation, cracks, or malfunction. A successful test is documented with the test load, date, configuration, and the qualified person who certified it, and that record is retained.
Proof load testing is distinct from a routine inspection: an inspection looks for deficiencies in the existing equipment, while a load test actively proves capacity by applying force. The two work together — equipment is inspected before and after the test, and the certified test record becomes part of the equipment's compliance history.
AUTHORITATIVE · SOURCE
29 CFR 1926.1412(a) — Inspections (post-assembly / load test) (OSHA.gov)FREQUENTLY · ASKED
Typically 100% to 125% of rated capacity, as specified by the applicable ASME B30 volume and OSHA. New or repaired rigging hardware may be proof-tested to a higher multiple of its working load limit.
After initial assembly or commissioning, and after any repair, alteration, or modification to a load-bearing or load-controlling component. It is event-driven, not a fixed periodic cadence.
RELATED · TERMS
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.
OSHA 1926.1412 is the construction-crane inspection standard within Subpart CC. It mandates three inspection tiers: each-shift inspections by a competent person, monthly documented inspections, and a comprehensive annual or 12-month inspection by a qualified person.
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.
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.
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