Interpretation of the ISO 12480-2:2008 Standard, “Cranes—Safe Use—Part 2: Mobile Cranes”

General Safety Guidelines and Responsibilities

ISO 12480-2:2008 specifies the responsibilities of all parties involved in the safe use of mobile cranes: Employer (crane owner) responsibilities—Ensure the crane complies with safety standards and holds a valid inspection certificate—Provide a safe working environment for operators—Establish safe operating procedures and oversee their implementation—Provide qualified lifting gear and rigging—Train operators and signalers and ensure they hold valid certifications. Operator Responsibilities—Inspect all crane mechanisms and safety devices before operation—Confirm that the outriggers are fully extended and provide reliable support—Operate within the limits specified in the lifting characteristics table and avoid overloading—Pay close attention to the surrounding environment during operation—Prohibit anyone from standing beneath the load—Immediately stop work and report any safety hazards upon discovery. Responsibilities of Signalers — Be familiar with the crane’s performance parameters and operational limits — Use standard signals for direction (hand signals, flag signals, or walkie-talkie) — Stand in a safe location visible to the operator — Coordinate teamwork among multiple personnel. Responsibilities of Maintenance Personnel — Perform regular maintenance and servicing according to the manufacturer’s requirements — Record maintenance details and replaced parts — Calibrate safety devices periodically — Repair any issues promptly. The standard specifies ten prohibitions for the safe use of mobile cranes: Do not overload; do not perform oblique pulls or oblique lifts; do not allow people to stand beneath the load; do not extend the telescoping boom while under load (unless permitted by the manufacturer); prohibiting lifting when outriggers are not fully extended; prohibiting operation on ground with a slope greater than 3°; prohibiting operation when wind speeds exceed 13.8 m/s (Force 6 winds); prohibiting operation within the safety distance of high-voltage power lines; prohibiting the use of lifting slings to drag objects on the ground; and prohibiting the operator from leaving the site while the load is suspended.

Outrigger Operation and Stability

Detailed specifications in the standard regarding outrigger operation and stability: Outrigger deployment—The operator must fully extend the outriggers to their maximum span (partial extension is not permitted)—After deploying the outriggers, check the chassis level using a spirit level—Forward/backward direction: ≤1°—Left/right direction: ≤1°. Ground Conditions—Sleeper timbers or base plates should be placed under the outrigger pads (to distribute pressure)—The point load of the outrigger pads on the ground should not exceed the ground’s bearing capacity (generally required to be ≥150 kPa). When operating on muddy or soft ground, steel plates or base boxes must be laid down—increasing the contact area to 2–3 times the original size. When operating near excavation pits or backfilled areas, verify the stability of the foundation—perform foundation reinforcement as necessary—and confirm that the foundation bearing capacity meets requirements. Slope Limits—When operating on non-level ground, the crane’s operating slope should be ≤3° (approximately 5.21 TP3T)—when the slope is between 1° and 3°, the rated lifting capacity should be reduced according to the manufacturer’s specified slope reduction factor (reduction range: 5%–15%). Outrigger Pressure Monitoring—Large mobile cranes must be equipped with an outrigger pressure indication system—which displays the ground pressure of each outrigger in real time—and issues an alarm when the pressure of any outrigger falls below the set value (approaching the point of lifting off the ground)—alerting the operator to take corrective action. Outrigger Interlock — When the outriggers are not fully extended, the system locks the slewing and boom movements, preventing operation, to ensure operators do not begin lifting operations before fully extending the outriggers. The standard specifically emphasizes that lifting operations are prohibited when outriggers are not deployed or are only partially deployed—this is one of the primary causes of mobile crane overturn accidents.

Safety in Lifting Operations

Safety Regulations for Lifting Operations: Test Lift—A test lift must be performed before each lift (slowly raise the load to 200 mm above the ground and pause). During the test lift, check: whether the load is balanced (if tilted, adjust the lifting points); whether the brakes are reliable (no slippage after stopping); whether there are any abnormalities with the outriggers or the ground (such as subsidence or cracks); and whether the torque limiter is displaying normally. Continue lifting only after confirming that everything is in order during the test lift. Lifting Path—The load’s travel height must be at least 0.5 m above any ground obstacles. No personnel are allowed beneath the load—a safety zone must be established beneath the load’s travel path (cordoned off with warning tape or barriers). Avoid sudden stops and starts during lifting operations (to minimize load sway). If the load sways significantly, suspend operations—wait until the load stabilizes naturally before continuing. Wind Speed Limits—Suspend lifting operations when wind speeds reach or exceed 11 m/s (Force 6 winds). When wind speeds reach or exceed 8 m/s—take wind loads into account when lifting large, thin-walled components (such as steel plates or wall panels). Boom Safety—It is prohibited to rotate or adjust the boom’s reach while personnel are on the boom; the danger zone beneath the boom must be cordoned off with barriers. The safety distance when the boom approaches overhead high-voltage power lines must comply with the provisions of ISO 12480-2; if the safety distance is insufficient, a request must be made to de-energize and ground the line. Night Operations—During nighttime lifting operations, the illuminance in the work area must be ≥30 lux—The load must be equipped with width-indicating lights or reflective markers. The standard also stipulates that operators should not work continuously for more than 4 hours—a 30-minute rest period is required after 4 hours of operation—Fatigue is a major cause of operational errors with mobile cranes.

Changing Lanes and Driving Safety

Standards for Site Relocation and Safe Operation: Pre-operation preparations—the boom must be fully retracted and locked in the boom support—the hook must be raised to its highest position and secured—all outriggers must be retracted and locked—the slewing platform must be locked in the transport position. Travel Speed—The speed of a truck-mounted crane on public roads must not exceed the maximum speed limit for that model (generally ≤70 km/h)—The travel speed of an all-terrain tire crane within a construction site must be ≤15 km/h. For long-distance transport of crawler cranes, a flatbed trailer must be used—crawler cranes are prohibited from traveling long distances under their own power (travel speed ≤ 5 km/h—long-distance travel causes severe wear on the tracks and travel mechanisms). When traveling up or down slopes—the boom should be oriented toward the top of the slope (to prevent the boom from tilting forward due to inertia). The standard also specifies travel requirements for mobile cranes under various road conditions—on wet or slippery surfaces (during rain or snow), reduce speed and increase the safety distance—when crossing bridges, verify that the bridge’s load-bearing capacity exceeds the crane’s curb weight— —when passing through tunnels or under height-restricted structures, verify that the crane’s travel height meets clearance requirements. Upon arriving at a new job site—operators should first survey the site environment (ground conditions, high-voltage power line locations, layout of other equipment, etc.)—confirm the ground conditions at the outrigger positions—and then deploy the outriggers before commencing lifting operations. Krud Heavy Industry can provide users with safety training on the operation of mobile cranes.

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