GB/T 23723.2-2008 Mobile Crane Safe Use Requirements

GB/T 23723.2-2008 is Part 2 of the crane safe use standard series, specifically addressing safe use and operational management requirements for mobile cranes. Mobile cranes combine travel and lifting functions, and their safe use requirements cover outrigger operation, luffing control, lifting capability tables, and more. This article provides a detailed interpretation of the standard's core provisions.

Standard Scope and Safety Responsibilities

GB/T 23723.2-2008 is Part 2 of the GB/T 23723 "Cranes — Safe Use" series and is one of the most important technical documents for mobile crane operational safety management. The standard defines the safety responsibilities of all parties involved in mobile crane use: the equipment owner is responsible for providing equipment and operation manuals that meet safety requirements; the equipment user (lessee) is responsible for inspecting the equipment's safety condition and ensuring operators are certified; operators are responsible for following the operation manual and safety regulations; the crane operator in charge (signaller) is responsible for developing the lifting plan and directing operations on site; and maintenance personnel are responsible for periodic maintenance and fault repair. Safety management for mobile crane use should cover the entire workflow — from selection, site entry, installation, and operation through to dismantling and removal from site.

Site and Ground Bearing Requirements

Mobile cranes impose far stricter demands on the working site than fixed base cranes: the ground must be firm and level, with sufficient bearing capacity to support the crane's ground pressure (truck crane outrigger ground bearing pressure is approximately 0.5–1.5 MPa; crawler crane ground bearing pressure is approximately 0.05–0.15 MPa). Obstacles must be cleared from the ground beneath outriggers, and soft ground should be reinforced with crane mats or steel plates (crane mat dimensions ≥ 2 m × 2 m, thickness ≥ 20 mm). Site slope — the crane must be level during operation, with inclination not exceeding 1% (0.5°). When outriggers are positioned near the edge of a slope or trench, the distance from the outrigger center to the slope crest must be at least twice the trench depth.

Outrigger Operation Safety

The standard sets out detailed safety requirements for outrigger operation: lifting operations may only begin after outriggers are fully extended and properly set. When outriggers are not fully extended (partial outrigger extension), the rated lifting capacity must be taken from the load capacity chart's partial-extension column — it is strictly prohibited to use the full-extension rated capacity for lifts performed with partially extended outriggers. After outriggers are extended, the outrigger hydraulic cylinders must have the hydraulic lock valve closed to prevent accidental retraction caused by a hydraulic pipeline failure. Crawler crane tracks must be tensioned to the specified value and locked.

Safe Lifting Operation Rules

The standard establishes the "Ten No-Lift Rules" for mobile crane lifting operations: no lift if overloaded or if the load weight is unknown; no lift if hand signals are unclear or multiple people are giving directions; no lift if the load is not properly secured or the center of gravity is offset; no lift if people are standing on the load or beneath the load; no lift for diagonally pulled loads or objects buried in the ground; no lift in poor lighting or obstructed visibility; no lift in winds of Force 6 or above (wind speed ≥ 13.8 m/s) — Force 7 for tower cranes; no lift if there is a mechanical fault or safety device failure; no lift if the operator lacks a valid operator certificate; no lift if the load has sharp edges without proper guards.

Before the actual lift, a trial lift must be performed — raise the load to a height of 200 mm above the ground and hold for approximately 2 minutes to check brake reliability, crane stability, and the condition of outriggers and ground. Only after confirming no abnormalities should the load be raised further. The lifting process should be slow and steady, avoiding sudden stops or starts (lifting acceleration ≤ 0.5 m/s²). During the lifting operation, the operator must continuously monitor the load, outrigger condition, and site environment, and must not leave the operating position.

Operating Limits and Special Environments

The standard specifies safe operating limits for mobile cranes in special environments: working near high-voltage lines — the safety distance between the crane and high-voltage lines must comply with DL 5009: ≥ 1.5 m for lines below 1 kV, ≥ 2 m for 1–10 kV, ≥ 3 m for 35 kV, ≥ 4 m for 110 kV, ≥ 6 m for 220 kV, and ≥ 8.5 m for 500 kV. If these distances cannot be maintained, a power outage must be arranged or work must be carried out under insulation supervision. Multiple cranes working together — a detailed lifting plan must be developed with a designated overall commander. The load on each crane must not exceed 75% of its rated lifting capacity, and lifting speeds must be synchronized. Night operations — adequate lighting must be provided, with illuminance of no less than 50 lx at the load and hook. High-temperature or extreme-cold environments — when temperatures exceed 40 °C or fall below −20 °C, targeted protective measures must be taken. Kelude Heavy Industry offers mobile crane safe operation training for users, covering all key points of this standard.

Mobile Crane Safe Use Quick Reference Table

The comparison table below outlines the key parameters and configurations for the safe use and operation of mobile cranes, serving as a reference for selection and operational personnel.

Frequently Asked Questions