How to Operate a Bridge Crane Safely: Essential Precautions

Bridge cranes are commonly used heavy-duty lifting equipment in manufacturing, warehousing, factories and engineering fields. They have high heavy-duty handling efficiency, but they are high-risk special equipment.Its structure is complex, the load is large, the operation is wrong, the inspection is not in place or the maintenance is missing, and it is prone to falling objects, equipment damage, casualties and shutdown accidents.

Based on international safety standards such as OSHA and ASME B30 and original factory specifications, this article combs the main safety risks of bridge cranes, pre-shift inspections, operating specifications, maintenance, emergency response, common violations, and equipment safety design points to provide practical guidance for enterprise lifting safety management.

Understand the Main Safety Risks of Bridge Cranes

Most of the safety accidents of bridge cranes originate from predictable and unavoidable risks and hidden dangers, which are mainly concentrated in the four dimensions of improper load operation, material swing and fall, mechanical and electrical equipment failure, personnel operation and on-site environment. Accurate identification of risks is the basis for safe production.

Overload and load risk

Overload is the most important safety hazard of bridge cranes.Exceeding the rated safe working load (SWL) and exceeding the working level will cause deformation of the main beam, overload of the mechanism, derailment, and structural fracture and collapse in severe cases.

The center of gravity of the load is skewed and the binding is not strong, which will produce additional dynamic loads and damage the equipment.The selection of the spreader rigging is wrong or damaged, and the spreader is prone to fracture and material slippage.The total weight of materials and spreaders must be calculated before hoisting, and it is forbidden to estimate the load empirically.

Load swing and falling object risk

The load swing is mostly due to emergency start and stop, cable-stayed crane, unbalanced load, strong wind, and excessive operating speed.Swinging cargo will hit the plant and equipment, threaten the safety of personnel, and cause the crane to capsize and the track to be damaged in severe cases.During operation, it should be operated smoothly, the load attitude should be controlled, and the traction rope should be used if necessary.

Risk of electromechanical failure

Wear and failure of core components such as hoists, brakes, wire ropes, hooks, limit switches, etc. can cause rushing, falling objects, and slipping cars.Electrical faults such as aging of the line, failure of the remote control, and abnormal voltage can cause the equipment to get out of control.Most mechanical and electrical failures gradually deteriorate, and preventive maintenance can investigate hidden dangers in advance.

Personnel environmental risk

Undocumented induction, insufficient training, and illegal operation are the main human-caused causes of the accident.Poor vision, insufficient light, and confusion in command and communication can easily lead to operational errors.There are many obstacles on the scene, the area is crowded, and unrelated personnel enter the hoisting area, which is prone to collisions and injuries.High temperature, dust, and corrosive environments will also accelerate the aging of components.。

Pre-Operation Safety Inspection

Before each start-up operation and before the start of each shift, all-round inspections of bridge cranes must be strictly implemented, and the four modules of structure, lifting components, safety devices, and operating environment must be investigated one by one, and inspection records must be made. If defects are found, immediately stop for rectification, and the equipment is strictly prohibited from operating with faults.

Main structure inspection

Focus on inspecting the main beam, end beam, operating track, connecting bolts, welding parts and support structure of the crane.Carefully investigate whether there are cracks, deformation, bending, corrosion and aging problems in the main structure, and confirm that all connecting fasteners are not loose or missing, and the track is not offset, worn, deformed, or damaged by bumps.At the same time, check the connection parts of the equipment to ensure that the overall structure is stable and there are no structural safety risks.

Inspection of lifting accessories

The lifting parts are the core of the carrying material, and they need to be refined one by one: check whether the hook has cracking, distortion, and excessive wear, and whether the anti-release buckle of the hook is intact and tightly closed; check whether the wire rope/chain has broken wires, kinks, deformation, corrosion, tensile wear, etc., and replace it immediately if it meets the scrap standard.

At the same time, check the working conditions of the reel and pulley, and confirm that the wire rope is arranged in a regular manner, no slotting, and no blocking; test the braking performance of the brake to ensure that the braking is sensitive and the locking is stable.；

Finally, check all lifting accessories such as slings, beams, shackles, etc. To confirm that the rated bearing capacity of the accessories is up to standard, the appearance is intact, and the specifications match, so as to prevent the use of damaged, unmarked, and non-standard accessories.

Safety device test

Start the no-load test of all control devices to verify that the handle, wireless remote control, and cab control system are responsive and accurate in action, without caton, delay, or loss of control.Focus on testing the emergency stop device to ensure that the operating power of the equipment can be cut off instantly and emergency braking can be achieved.

Verify the upper and lower stroke limit switches and operating limit devices one by one to ensure that the limit is accurate and effective, and to prevent topping and over-range accidents; test the safety warning equipment such as alarm horns, warning lights, and anti-collision devices to ensure normal operation; and finally test the walking brake and lifting motion system to confirm that there is no offset, no slippage, and no abnormal lag in braking.

Operating environment inspection

Clean up all obstacles in the crane operation track and ground operation area in advance to ensure that the operation path of the cart and trolley is smooth throughout the process.Strictly delineate the isolation area for hoisting operations, set up a no-entry area under the floating operation path of the material, place warning signs and protective fences, and strictly prohibit unrelated personnel from entering the scope of the operation.

Confirm that the work site is well-lit and has a clear field of vision. Outdoor operations need to investigate the effects of severe weather such as wind, rain and high winds; confirm in advance that the on-site command and operator communication channels are smooth, the operator's position is safe, and the safety line of defense for on-site operations is fully strengthened.

Safe Operating Practices for Bridge Cranes

Load control

All operations must strictly follow the rated safety load of the equipment, and overloading operations and over-working conditions are strictly prohibited.When calculating the hoisting load, all the material weight, lifting accessories weight, and dynamic shaking load must be included in the calculation, and the equipment nameplate and load parameter table must be accurately checked.Under special and complex working conditions, the equipment load needs to be derated to eliminate all lucky operations and avoid the risk of overload from the source.

Standard lifting

Before lifting, the hook must be accurately aligned directly above the center of gravity of the material to ensure vertical force, and illegal operations such as cable-stayed, diagonal hoisting, dragging materials, and violent hoisting must be resolutely eliminated.

When lifting, slowly tighten the sling to eliminate the slack of the rope. After the material is slightly off the ground, the attitude is stable, and the force is balanced, the height will be steadily raised and the transfer operation will be carried out.Standard binding and hoisting processes are used throughout the process to ensure that the material is evenly forced and firmly bound.

Control pendulum load

During the operation of the equipment, sudden acceleration, emergency braking, and instantaneous reversing are prohibited to avoid the material swinging violently due to inertia.The whole process adopts a smooth and gradual control method, and the equipment equipped with a frequency conversion drive device can use the characteristics of the equipment to achieve uniform speed operation and minimize material shaking.

Plan the transfer path in advance before the operation, and maintain a safe distance from the plant structure, peripheral equipment, and pipelines during operation. Large-scale material hoisting can be assisted by traction ropes to stabilize, completely avoiding the risk of material swing and collision.

Regional control

Operating principle: It is strictly forbidden for floating materials to pass above the personnel, and the path must be adjusted in advance if it can be avoided.The personnel in the operation area are controlled through warning lights, alarm sound effects, protective fences, and special supervision throughout the process.

Strictly implement the principle of “No standing under the material”, and under any circumstances, operators are prohibited from standing, operating, and passing under the floating material.If you need to enter the work area, you must first land the material safely and fix it firmly.

Communication management

On-site operations must adopt national standard standardized gesture signals or special radio communication equipment to ensure that the instructions of the operator and the command staff are unified and transmitted accurately.When the field of vision of the operation is limited and there is a visual blind spot, it is necessary to set up a unique and exclusive command staff to eliminate the problem of multiple people commanding and confusing instructions.

The instruction information is confirmed in real time throughout the operation. Once the communication is interrupted and the instruction is blurred, the operation will be stopped and suspended immediately, and the construction can continue after it is restored unobstructed.

Safety Precautions for Different Crane Movements

Lifting operation

The material lifting process should start and stop smoothly, rapid lifting and instantaneous braking are strictly prohibited, and the attitude of the crane and the operating status of the wire rope should be observed in real time, and abnormal conditions such as offset and stuck resistance should be dealt with in time.

During the operation, the operator shall not leave the post without authorization, and the load shall not be allowed to hang in the air for a long time.Rely on the limit switch to control the lifting limit, prevent accidents such as rushing to the top and taking off the rope, and avoid dangerous areas such as equipment clamping points during operation.

Cart operation

Before the cart starts, make sure that the whole line of the track is unobstructed, and the limit stop at the end of the track is intact, and investigate the personnel, vehicles and obstacles along the track.The operation process remains low-speed and stable, and decelerates in advance near the end of the track and in densely populated areas, and high-speed sprinting is prohibited.At the same time, pay attention to the deformation of the equipment caused by the track slope and load, and adjust the operating speed in a timely manner to prevent derailment and collision accidents.

Trolley operation

When the trolley is moving, maintain a sufficient safe distance from the end of the main beam and other equipment to prevent collision.Try to avoid operations such as emergency stops, sharp turns, and rapid movement as much as possible to reduce the load and swing significantly.When the cart and trolley need to work together, the two movements cooperate smoothly and run at a uniform speed, and the trajectory and attitude of the crane are continuously paid attention to throughout the process, so as to eliminate safety hazards in a timely manner.

Operator Safety and Training Requirements

Bridge cranes are special equipment. Only authorized personnel who are licensed and professionally trained can operate the equipment. It is strictly forbidden to start operations without witnesses and personnel who have not been assessed.

Operators must fully master the core knowledge and practical skills of the equipment, including: equipment rated load parameters, load chart interpretation, equipment control logic, fault emergency response process, standardized command signals, equipment inspection specifications, safe hoisting and bundling technology, on-site risk identification and prevention and control methods.

Enterprises need to establish a normalized training mechanism. After safety accidents, dangerous situations, equipment transformation, and long-term downtime and reuse, they must organize retraining and assessment to ensure that the skills of operators meet the standards.

At the same time, the operators are given the right to stop work safely. When the equipment is abnormal or the site is unsafe, the operation can be stopped immediately to prevent risky construction in violation of regulations.All operators must strictly abide by local special equipment safety regulations, hold a certificate to take up the post, and review on time.

Regular Inspection and Preventive Maintenance

The core of the long-term safe operation of equipment lies in “prevention as the main and prevention as the combination”. It is necessary to strictly follow the original equipment specifications, ASME B30.2 industry standards and national special equipment management requirements, and formulate hierarchical inspection and maintenance plans according to the frequency of equipment use and operating load.

• Daily pre-shift inspection: complete visual inspection and functional testing before each shift starts, focusing on verifying the main structure, wire rope, hook, brake, limit, emergency stop device, control system and operating environment, test safety warning devices and keep inspection records.
• Periodic in-depth inspections: in-depth inspections are carried out on a monthly, quarterly, and annual basis, including structural nondestructive testing, electrical system testing, wear inspection of transmission and hoist components, track calibration, safety protection device verification, synchronous lubrication debugging, and load testing of heavy-duty equipment as needed.
• Inspection and maintenance file records: establish an equipment ledger, register inspection results, hidden dangers, rectification plans, replacement of accessories and running time.Rely on the ledger for predictive maintenance and replace aging parts in advance; perform locking and listing during maintenance to cut off power to ensure safety.

What to Do When a Bridge Crane Problem Occurs

Once abnormal conditions such as abnormal equipment noise, abnormal vibration, control failure, material offset, and component caton are found during the operation, the following procedures shall be handled strictly in accordance with the following procedures to prevent panic operations and illegal handling.：

• Immediate shutdown: Once the equipment is found to be abnormal, all lifting operations will be stopped as soon as possible, and the control of the equipment will be terminated to prevent the failure from further expanding, and to avoid secondary safety accidents such as falling objects and collisions.
• Safe blanking: If the hoisting material is in a floating state, under the premise of fully evaluating the safety, slowly and smoothly lower the load to the ground or a stable and reliable support position. It is not allowed to hang the material in the air for a long time, let alone leave without authorization when the hanging object is floating.
• Equipment isolation: strictly abide by the safety management specifications of the factory, cut off the power supply of the equipment and implement the locking and listing (LOTO) process, isolate and protect the faulty crane, and strictly prohibit unrelated personnel from trying to start and test the equipment.
• Report and prepare: report fault information to on-site management personnel and equipment maintenance departments in a timely manner, and clearly describe the phenomenon, equipment status and operating conditions at the time of the failure, so as to facilitate rapid judgment of the problem.
• Re-inspection and reuse: Faulty equipment must be tested and repaired by professional maintenance personnel, and after passing the acceptance, it can be put back into lifting operations.At the same time, it is necessary to dig deep into the root cause of the failure and implement corresponding prevention plans to prevent similar failures from happening again.

Common Bridge Crane Safety Mistakes to Avoid

Most lifting safety accidents are caused by habitual illegal operations. The following high-frequency misunderstandings need to be resolutely avoided during operation.：

• Overload operation: Ignoring the rated load limit of the bridge crane, blindly carrying out overload hoisting, overestimating the carrying capacity of the equipment, so that the equipment can withstand loads that exceed the design standards.
• Illegal use of spreaders: the use of damaged, deformed, lack of rated load identification or non-standard specifications of spreaders and rigging, the safety performance of the spreader itself cannot be guaranteed.
• Illegal hoisting operations: implement dangerous behaviors such as cable-stayed slanting, dragging heavy objects, and violently lifting and falling, which will form an impact load on the load, which can easily cause the spreader to break or the equipment to be damaged.
• People standing under the crane: Tacitly allow personnel to stand, pass or operate under the floating crane. Once the load falls, it will directly cause serious personal injury.
• Operation with faults: ignoring abnormal signals such as abnormal noise, abnormal vibration, slippage, and caton of equipment, and continuing to carry out lifting operations knowing that there are hidden dangers.
• Destruction of safety devices: artificially shield, remove, short-connect safety protection devices such as limit switches and brakes, and remove the safety protection barriers of the equipment.
• Illegal on-duty operations: operators are on-duty without a license, tired or distracted during operations, and operate the crane without receiving complete professional training.
• Omit the pre-shift inspection: simplify or even skip the pre-shift safety inspection directly. The inspection work is perfunctory, resulting in missed inspection of equipment hidden dangers, and the risks cannot be investigated in advance.
• Hanging objects are placed in the air: the materials are hung in the air for a long time after the operation is over, and the site is unattended, which greatly increases the safety risk of the load falling.
• Forced operation with illness: After discovering that the equipment failed, it did not stop in time, and was lucky enough to continue to operate with illness, and forced to make do with the operation.
• Lack of on-site management: The command and communication mechanism of the hoisting site is chaotic, and the safety isolation operation area is not delineated, which is prone to situations where unrelated personnel strayed into the dangerous area.
• Lack of maintenance work: failure to comply with the equipment maintenance cycle, long-term failure to arrange inspections and repairs, failure to replace worn and aging parts in time, accelerate the aging and failure of equipment.

How Crane Design Can Improve Workplace Safety

The safety and security of modern bridge cranes not only rely on standardized operation and maintenance, but also rely on scientific equipment design to reduce the risk of accidents from the hardware level. The mainstream safety design configuration is as follows：

• Matching selection of load and working conditions: In accordance with CMAA, FEM, and ISO related standards, cranes with rated load and working level adapted to on-site working conditions are selected to meet the needs of different working loads.
• Multiple load safety protection: equipped with dual braking system, overload protection and load monitoring device to effectively prevent dangerous situations such as overload and car slip.
• Travel limit protection device: configure the upper and lower lifting limits, operating limits, and anti-collision devices to avoid accidents caused by over-range operations from the hardware level.
• Multi-point emergency stop system: Set up a multi-point emergency stop mechanism, which can quickly cut off the power source of the equipment, and realize shutdown and risk avoidance in emergency situations.
• Frequency conversion drive control system: equipped with a frequency conversion drive system, it realizes smooth start-stop and uniform speed operation, which significantly reduces the load swing during hoisting.
• Diversified control methods: equipped with a handheld operation box and a wireless remote control device to optimize the standing position of the operator and reduce the safety risks caused by blind spots in the field of vision.
• Sound and light early warning device: standard warning lights and sound and light alarms are equipped to continuously issue safety warnings during the operation of the crane and actively warn of risks.
• Multi-machine anti-collision protection: In scenarios where multiple cranes work together on the same track, an anti-collision system is installed to avoid collisions between equipment.
• Track end protection structure: strengthen the track end buffer and limit stop to enhance the overall stability of the cart during operation.
• Automated auxiliary system: For repetitive hoisting operations, automatic positioning and anti-swing system are optional to reduce human operation errors.
• Optimized design of structure and maintenance: adopt an anticorrosive and wear-resistant structure design, and reserve a channel for convenient inspection and maintenance to facilitate daily investigation of hidden dangers.

Conclusion

Bridge crane safety management is a system engineering that includes equipment design, installation, inspection, operation, training, maintenance and emergency management.Enterprises need to comply with OSHA 1910.179, ASME B30 and local special equipment regulations, implement pre-shift inspections, licensed induction, regular maintenance and investigation of hidden dangers, and formulate safety operating procedures based on working conditions.

Take into account risk prevention and standardized operation during operation, rely on various safety protection devices to reduce risks, and carry out personnel training and emergency drills.Henan Mine Crane can provide safety configuration and technical support for bridge cranes based on plant conditions, loads, operating frequencies and environments, and assist enterprises in building safety operation and maintenance plans adapted to the site.