Inspection, maintenance and records

Cranes and hoists wear out. Wire rope loses wires, hooks open, brakes wear, hydraulic hoses age, welds crack, and safety devices drift out of calibration. Inspection finds these problems before they cause a failure, maintenance fixes them, and records show that both happened. A crane with no inspection history is a crane nobody can vouch for.

This lesson describes the levels of inspection, what each covers and who does it, the removal criteria for crane wire rope and hooks, the events that call for a special inspection, and the records that should travel with every crane. It also covers maintenance practice and the special case of rented cranes.

Levels of inspection

Crane standards and regulations describe inspection in levels that increase in depth and decrease in frequency. The names differ between documents, but the pattern is consistent.

OSHA's 1926.1412 requires a shift inspection by a competent person before each shift, a monthly inspection that is documented, and an annual comprehensive inspection by a qualified person, as well as inspections after modifications, repairs and assembly. Wire rope has its own shift, monthly and annual inspection requirements in 1926.1413. In general industry, 1910.179 requires frequent inspections of overhead cranes, daily to monthly, and periodic inspections at intervals of 1 to 12 months, with certification records for hooks, chains and ropes.

The shift inspection

The shift inspection is the one supervisors are most likely to see. It does not need tools or disassembly, but it should be done carefully, not as a walk around while drinking coffee. A checklist helps make sure nothing is skipped, and a signed checklist shows it was done.

Any defect that affects safe operation must be reported immediately and the crane taken out of service until it is repaired and a competent or qualified person has confirmed it is safe. Defects that do not affect safety, such as a cracked mirror housing, are recorded and scheduled for repair.

Crane wire rope

The hoist rope and boom ropes on a crane are running ropes: they bend over sheaves and wind onto drums thousands of times. They fail by fatigue, wear, crushing and corrosion, and their removal criteria are stricter than those for slings because the rope passes over sheaves and failure drops the load.

Hooks

Hooks deform when they are overloaded, tip-loaded or side-loaded. A hook whose throat has opened has been stressed beyond its design and may fail at a lower load next time. Inspectors measure the throat opening against a reference mark or the original dimension, check for twist from the plane of the hook, look for cracks, wear and corrosion, and check that the latch works.

Many hooks carry two punch marks or a gauge reference so that inspectors can measure the throat opening quickly. Recording the measurement at each periodic inspection makes slow deformation visible over time.

Events that trigger an inspection

Some events can damage a crane in ways that a routine shift inspection will not reveal. After any of the following, the crane should be taken out of service and inspected by a qualified person before use:

• an overload, a load moment indicator overload event or a sudden shock load such as a dropped or snagged load;
• contact with or arcing from a power line, which can damage wire rope, bearings, hydraulics and electronics;
• exposure to winds above the manufacturer's out-of-service limit, or an earthquake or other severe event;
• a fire on or near the crane;
• repairs, modifications or replacement of load-bearing parts;
• assembly, erection, climbing or reconfiguration, especially for tower cranes and lattice boom cranes.

Modern load moment indicators and rated capacity limiters often record overload events and overrides in a data logger. Reviewing that log at each periodic inspection, and after any incident, shows whether the crane has been pushed past its limits even if nobody reported it.

Load testing

A load test lifts a known test load, usually more than the rated load by a set percentage, to prove the crane after erection, major repair or modification. Load tests must be planned and supervised by qualified people, follow the manufacturer's procedure and the applicable standard, and use certified test weights or calibrated water bags. A load test is not a routine check and is never done casually by lifting something heavier than usual to see what happens.

Maintenance

Maintenance keeps cranes in the condition inspections expect. It should follow the manufacturer's schedule and instructions, use manufacturer-approved parts and be done by trained technicians. Repairs to load-bearing parts, such as welding on a boom, need the manufacturer's approval or an engineer's design and must be followed by inspection and, where required, a load test.

Maintenance work on cranes brings its own hazards: falls from booms and runways, being struck by moving bridges or trolleys, stored energy in hydraulic systems and counterweights, and electrical hazards. Overhead cranes must be locked out, including adjacent cranes on the same runway that could run into the work area, and rail stops placed. Lockout procedures are covered in HSE-210 and fall protection in HSE-212.

Records

Records make inspection and maintenance visible. They let a new operator see the crane's history, let a supervisor confirm inspections are current and let an inspector check compliance.

Rented cranes and hoists

When a crane is rented with an operator, the rental company usually maintains it, but the user on site still needs to see that it is in good condition and properly documented. When a crane or hoist is rented without an operator, the user takes on more responsibility for daily inspection and safe use. On arrival, a supervisor should check the annual inspection certificate, the log book, the load chart for the configuration to be used, the operator's qualification and any open deficiencies. If the paperwork is missing or out of date, the crane does not work until it is sorted out.

Returning a crane to service

When a crane has been taken out of service, someone must decide that it is safe to use again, and that decision should be recorded. For minor defects found at the shift inspection, a competent person may confirm the repair and sign the crane back into service. For repairs to load-bearing parts, safety devices, wire rope, brakes or structure, and after any event-triggered inspection, the return to service should be signed by a qualified person, and in some cases by the manufacturer or an engineer, after any required testing. Tagging the controls with an out-of-service tag, and removing the key where practical, prevents someone from using the crane before that sign-off. A supervisor who finds a tagged crane in use should stop it immediately and find out who removed the tag and why.