ISO 9927-4:2016 Jib Crane Inspection Procedure Explained
ISO 9927-4:2016, "Cranes — Inspections — Part 4: Inspection procedures for jib cranes," is the dedicated standard governing inspections of jib cranes. It defines the scope, methods, and acceptance criteria for daily, periodic, thorough, and special inspections of jib cranes, including portal cranes, mast cranes, deck cranes, and floating cranes.
Jib Crane Inspection Classification
ISO 9927-4:2016 establishes a four-tier inspection system: Daily inspections (performed by the operator before each shift; a visual check of the overall machine condition and functionality, taking roughly 15–30 minutes), periodic inspections (conducted monthly by qualified maintenance personnel, involving a detailed examination of structures, mechanisms, and safety devices, typically taking half a day to a full day), thorough examinations (carried out annually by a certified inspector, including non-destructive testing and load tests, spanning 1–3 days), and special inspections (performed after installation, overhaul, retrofit, or an incident, focusing on in-depth evaluation of specific components).
Daily inspection scope: boom condition (deformation, cracks, corrosion), wire ropes (wire breaks, wear, lubrication), hooks (throat opening, hook latch), abnormal noise and temperature in all mechanisms, safety devices (load moment limiter self-test alarm, limit switch functionality), and the foundation/rails (settlement, inclination, rail displacement). Operations may only commence once the daily inspection is passed. Results are recorded in the operation log, and any abnormality requires immediate shutdown and reporting for maintenance.
Key Points of Periodic Inspection
Boom structure: Magnetic Particle Inspection (MPI) of critical weld seams — focusing on welds at the boom root, luffing hinge points, and wire rope connection lugs, using a portable MPI flaw detector. Deformation measurement of boom members — straightness deviation measured with a theodolite or total station must not exceed 1/1000.
Slewing bearing: Tooth flank wear — tooth thickness reduction must not exceed 10% of the original tooth thickness. Bolt pretightening torque — verified with a torque wrench and calibrated to the design value ±5%. Raceway clearance — radial and axial clearances measured and must not exceed 0.1% of the bearing diameter.
Mechanisms: Hoisting mechanism gearbox oil analysis (contamination level per NAS ≤ 9, moisture content ≤ 0.05%). Brake lining wear (≤ 50% of original thickness) and brake wheel surface condition (no cracks, no groove depth exceeding 0.5 mm). Luffing mechanism brake and wire rope end fastening inspection.
Crane rail: Rail head wear ≤ 5 mm, rail span deviation ±5 mm, and rail joint gap between 1–2 mm. For mast cranes, cable system tension testing and anchor bolt torque inspection.
| Inspection Location | daily inspection | monthly inspection | Annual Inspection | Inspection Method |
|---|---|---|---|---|
| Boom Structure | Appearance Deformation | Weld Seam MPI | Ultrasonic Testing (UT) | MPI/UT |
| Slewing Bearing | Abnormal noise/Sway | Tooth Surface/Bolt/Clearance | Comprehensive Detection | torque wrench/feeler gauge |
| Wire Rope | wire break/Lubrication | Full Lengthdiameter measurement | electromagnetic testing EMT | Caliper/EMT |
| Brake | functional check | Friction lining/Brake wheel | Comprehensive Test | Thickness Measurement/Visual Inspection |
| rail foundation | Appearance | Rail Top/Span/Joint | Full-Line Leveling | Level Instrument/Steel Ruler |
| cable system | Appearance | Cable Tension | Cable Tension Detection | Tensiometer |
Thorough Examination and Load Testing
Annual thorough examination scope — full structural non-destructive testing (ultrasonic testing (UT) covering all major load-bearing weld seams — critical welds on the boom, portal base, slewing platform, and balance arm; magnetic particle inspection (MPI) of all connecting lug plates and pin hole surfaces; radiographic testing (RT) applied to critical butt welds where necessary). Load testing — single and combined motion tests for hoisting, luffing, and slewing at 100% and 110% of rated load to verify overall structural integrity, mechanism performance, and safety device functionality.
Comprehensive slewing bearing inspection — disassembly inspection every 5 years or after 10,000 operating hours, including measurement of raceway surface hardness and wear depth, plus inspection of seal rings and grease condition. Full control system examination — load moment limiter (LML) calibration (verified using standard test weights or force sensors, accuracy ±5%), electrical system insulation testing (insulation resistance ≥1MΩ), and PLC and variable-frequency drive (VFD) parameter verification. All inspection results must be documented and archived, with the inspection report signed by a certified inspector.
Special Inspections and Record Retention
Triggers for special inspections — after installation or major overhaul (full verification following structural modifications, mechanism replacement, or safety device upgrades), after overload or collision incidents (checking structural integrity and mechanism function of affected areas), after severe wind or earthquake events (inspecting foundation and structural damage), and after changes in operating conditions or retrofits (such as boom extensions, additional tie-ins, or lifting capacity increases). Special inspection procedures should be developed based on the specific circumstances.
Record retention requirements — daily inspection logs retained for ≥3 months, monthly inspection reports retained for ≥3 years, and annual and special inspection reports retained for ≥3 years after equipment decommissioning. Kelude Heavy Industry provides inspection services for jib crane users in accordance with ISO 9927-4:2016 (staffed by certified inspectors, equipped with professional testing tools and standardized inspection forms), issuing nationally recognized inspection reports.
| Record Type | Frequency | retention period | content requirements |
|---|---|---|---|
| operation log | Daily | ≥3Monthly | Abnormality/maintenance record |
| monthly inspection Report | Monthly | ≥3Yearly | inspection item/Data |
| Annual Inspection Report | Annually | Scrapping+3Yearly | Non-destructive testing/Load test |
| Special Report | On-Demand | Scrapping+5Yearly | Specific Detection Procedure |
| maintenance record | On-Demand | Scrapping+3Yearly | Replacement/Repair Record |
Frequently Asked Questions
Q: How many inspection levels are there for jib cranes?
A: Four levels — daily inspection (performed by the operator before each shift), monthly inspection (carried out by maintenance personnel), thorough examination (conducted annually by a certified inspector), and special inspection (performed as needed after installation, retrofit, or an incident). Each level increases in depth and scope.
Q: What are the key focus areas during a monthly inspection?
A: Magnetic Particle Inspection (MPI) of critical weld seams on the boom, slewing bearing gear surfaces and bolt pretightening torque, brake friction lining wear, full-length wire rope diameter measurement, crane rail top wear and span, and guy cable tension (for mast cranes). Monthly inspection reports must be retained for at least 3 years.
Q: What does the annual thorough examination cover?
A: Comprehensive Non-destructive testing of the structure (UT + MPI), combined load test at 110% of rated load, slewing bearing disassembly inspection (every 5 years or 10,000 hours), Load moment limiter (LML) calibration (accuracy within ±5%), and electrical insulation test. Annual inspection reports must be kept for at least 3 years after the crane is decommissioned.
Q: When is a special inspection required?
A: After equipment installation or overhaul, after an overload or collision incident, after exposure to severe wind or an earthquake, or after boom extension or modification. The inspection plan is tailored to the specific situation. Kelude offers comprehensive jib crane inspection services and issues nationally recognized inspection reports.
