GB/T 23723.4-2009 is Part 4 of the crane safe use standard series, specifically governing the safe use and operational management of jib cranes. Given the wide variety of jib crane types, the safe use requirements cover special working conditions such as wind resistance and anti-overturning protection. This article provides a detailed interpretation of the standard's core provisions.

Standard Scope and Key Safety Risks

GB/T 23723.4-2009 is identical to ISO 12480-4:2002 (IDT) and applies to the safe use of jib-type cranes — including portal, mast, floating, deck, cantilever, and railway cranes. The safety risks associated with jib cranes are characterized as follows: portal cranes — rail gnawing and overturning caused by rail foundation issues, plus wire rope wear and overload during grab operations; mast cranes — mast collapse resulting from guy rope failure; floating cranes — loss of load control due to vessel overturning and wave impact. The standard specifies safe use requirements across the entire lifecycle, from selection and installation through operation and dismantling.

Rail Foundation and Installation Requirements

For portal cranes, the rail foundation is the foundation of safe operation. The standard requires that the rail foundation be specifically designed according to the crane's design load, with a minimum bearing capacity of foundation of 200 kPa. Rails must be P38 or P43 and above. Installation tolerances for the crane rail include a gauge deviation of ≤±3 mm and a longitudinal height difference of ≤5 mm per 10 m. Buffer stops at both rail ends must be capable of withstanding the impact of the crane traveling at rated speed. After installation, portal cranes must undergo a No-Load Test, a Rated Load Test (100% SWL), and a Dynamic Load Test at 1.1 times the rated load. Test items include coordinated operation of the hoisting, slewing, luffing, and traveling mechanisms. The crane may only be put into operation after passing Installation Acceptance.

Special Requirements for Mast Cranes

Mast cranes — including lattice and tubular mast types — present the most complex safety management challenges of all crane types. The standard requires that the erection and lowering of the mast be carried out under a dedicated construction plan approved by the technical manager. The number and arrangement of guy ropes must comply with design requirements (generally no fewer than 4, evenly distributed). Guy ropes must be wire rope (diameter ≥16 mm) with wedge sockets or aluminum swaged terminations at the ends. Preload on guy ropes must be applied per the design value (typically 5%–10% of breaking force), and tension must be evenly distributed across all guy ropes (deviation ≤±5%). The load-bearing capacity of guy rope anchor points must be no less than twice the breaking force of the guy rope. The mast base foundation must be capable of withstanding the vertical and horizontal forces generated by the mast's dead weight and the suspended load. During hoisting operations, mast perpendicularity must be monitored in real time (inclination ≤1°).

Special Requirements for Floating Cranes

Safe use of floating cranes requires additional consideration of vessel stability and environmental conditions: a vessel stability verification must be performed before operations — under the combination of maximum suspended load and maximum working radius, the vessel's initial metacentric height GM must be ≥0.5 m (intact stability) or ≥0.15 m (damaged stability). Environmental operating limits — wind speed ≤7 on the Beaufort scale (≤17 m/s), significant wave height ≤1.5–2.5 m (depending on vessel type and lifting capacity), and current speed ≤2 knots (≤1 m/s). Floating cranes must cease operations and secure the boom in the stowed position when environmental limits are exceeded.

Operational Safety Management

Key points for operational safety management of jib cranes: operators must undergo specialized training and hold a special equipment operator certificate. Before each shift, the functionality of all limit switches, brakes, and safety devices must be checked. When traveling, portal cranes must be operated with attention to ensuring the crane rail is clear of obstructions. During grab operations, impact of the grab against the boom and portal frame must be avoided (anti-collision). Jib crane operations must be stopped immediately for troubleshooting under the following conditions: abnormal noise or vibration, abnormal hydraulic system pressure, abnormal limit switch actuation, or a sudden increase in wind speed approaching the limit. Kelude provides Safety Operating Procedures training and technical support to portal crane and floating crane users.

Jib Crane Safe Use Reference Table

The comparison table below summarizes the core parameters and configurations for the safe use of jib cranes, for reference by selection and operating personnel.

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