When purchasing a tower crane, it must be bought from a professional manufacturer with a valid production license. The manufacturer should provide technical documents such as the whole-machine certificate, quality guarantee for high-strength connecting bolts, quality guarantee for hoisting wire ropes, quality guarantees for other common components, and the tower crane operation manual.
2. Renting External Tower Cranes
Written Agreement: A written rental agreement must be signed. Both parties to the agreement must affix their official seals. Renting from private individuals or self-employed households is not permitted.
Crane Condition: The tower crane must be in good condition, without any unauthorized modifications. All safety devices should be complete, and its service life should not exceed five years.
Documentation: The lessor must provide the tower crane production license, the original factory certificate of this tower crane, the operation manual, and the inspection approval report from the relevant superior department.
3. Purchase of Second-hand Tower Cranes
When buying a second-hand tower crane, the following points should be confirmed:
Service Life: Its service life has not exceeded three years.
Safety Devices and Condition: All safety devices are complete, and the machine is in good condition.
Certificates and Data: The whole-machine certificate (original) and relevant technical materials are complete.
Manufacturer’s Status: The manufacturer has not ceased production or gone out of business.
4. Prohibited Purchases
It is forbidden to purchase tower cranes that have been officially phased out by the state due to backward technology, such as TQ60, TQ80 tower cranes, QT16, QT20, and QT25 derrick tower cranes, as well as tower cranes from manufacturers that have closed down or switched production lines.
II. Installation and Dismantling of Tower Cranes
1. Overhaul and Maintenance
Before the installation or after the dismantling of a tower crane, overhaul and maintenance must be carried out (and records should be kept).
Component Inspection: The machinery manager and safety officer shall organize the tower crane operator, driver, and mechanic to carefully inspect important components one by one, including high-strength connecting bolts, steel structure welds, pins, wire ropes, safety devices, and jacking devices. Any potential hazards found should be promptly repaired or replaced.
Anti-corrosion Treatment: After inspection and repair, the steel structure of the tower crane must be derusted and anti-corroded.
Lubrication: All pins and connecting bolts should be lubricated. Used cotter pins are not allowed to be reused.
2. Installation and Dismantling by External Units
Written Agreement: If an external unit is responsible for the installation or dismantling of a rented or newly purchased tower crane, a written installation and dismantling agreement must be signed, clearly defining the responsibilities of both parties and stamped with the official seals of both units.
License and Certificates: The installation and dismantling unit must provide the original or a copy of the valid tower crane installation and dismantling license. For copies, the installation location must be clearly stated and stamped with the enterprise’s official red seal. The original work permits of the installation and dismantling personnel must also be provided.
3. Use of High-strength Connecting Bolts for Standard Sections
Color-coding for Single-bolt-per-corner Cranes: For tower cranes with one connecting bolt at each corner of the standard section, during each installation, 12 new high-strength connecting bolts must be used for the base section and the two sections above it. These bolts should be marked with paint according to the number of uses. The first use is marked with green paint, the second with yellow paint, and the third with red paint. After the third use, the bolts must be scrapped.
Marking for New Bolts: All newly purchased high-strength connecting bolts for standard sections should be painted with color codes indicating the number of uses, and strict control should be exercised to prevent overuse.
Scrapping of Overused Bolts: Existing high-strength connecting bolts that have been confirmed to have been reused more than three times must be scrapped.
4. Inspection before Installation
Before the installation of a tower crane, if the steel structure (standard sections, jib, rear counter jib, climbing frame) is severely corroded (including welds in important parts), deformed, or in poor operating condition and cannot ensure normal and safe use, relevant technical personnel should be organized to conduct on-site measurement and verification. Installation and use under such risky conditions are strictly prohibited.
5. Written Plan
A written plan must be prepared in advance for the installation and dismantling of tower cranes. It can only be implemented after being approved by the technical supervisor at the next higher level.
6. Tower Crane Foundation
The tower crane foundation should be constructed strictly in accordance with the requirements of the manufacturer’s construction drawings. The pre-embedded bolts in the foundation should have a qualified material test report. Before the tower crane is installed, the acceptance record of concealed works and the inspection report of the concrete foundation should be provided. The counterweight of the tower crane must be made of precast concrete blocks. Bricks are prohibited. Concrete counterweights with damaged lifting points or cracked concrete should be discontinued.
7. Safety Education for Workers
All workers entering the construction site must receive safety and technical briefing education. They should wear safety helmets. For work at heights above 2 meters, a qualified safety belt must be worn, non-slip rubber shoes, and a tool bag should be carried.
8. Qualified Workers
Installation workers must hold relevant certificates to work, and working under the influence of alcohol is strictly prohibited.
9. Warning Zone
A warning zone should be set up in the installation work area, with warning signs hung, and special personnel should be assigned for supervision.
10. Preparatory Work
Before installation, the machinery manager must complete all preparatory work. In particular, the hydraulic jacking mechanism should be inspected and tested to ensure normal operation, and various tools such as slings, rigging, wrenches, and hammers should be checked.
11. Installation and Dismantling Procedures
The installation and dismantling should be carried out strictly in accordance with the procedures required by the tower crane construction manual. There should be sufficient personnel, with clear division of labor. A dedicated person (the machinery manager) should be responsible for commanding, and a dedicated person (the tower crane operator) should be responsible for operating the hydraulic jacking device.
12. Jacking Precautions
Before jacking the tower crane, the jib should be firmly fixed in the installation direction, and rotation is strictly prohibited. The weather forecast should be listened to in time. When the wind force reaches level 4 or above, the jacking operation must be stopped.
13. Bad Weather Conditions
When the wind force reaches level 6 or above, as well as during rainy and snowy weather, the hoisting operation should be stopped, and proper safety protection measures should be taken.
14. Tool Management at Heights
Tools must be placed in the tool bag during work at heights. Random placement is not allowed, and throwing objects downward is prohibited.
15. Mobile Crane Operation
The operation of the mobile crane should be carried out strictly in accordance with the 规范 requirements. The hoisting ropes and braking devices should be in good and effective condition, and overloading is strictly prohibited.
16. Hoisting Objects
Hoisting objects must be firmly tied and kept stable. Wind ropes should be attached to the front and rear jibs. Small and scattered items should be hoisted in cages.
17. Anti-corrosion Protection
All connecting bolts and ungalvanized pins of the tower crane must be protected against rust, especially in the foundation area, where strict anti-corrosion measures should be taken.
18. Inspection and Approval
After the installation of the tower crane, based on self-inspection, it should be reported to the relevant superior department for inspection. It can only be put into use after passing the inspection.
19. Storage after Dismantling
If a tower crane that has been inspected, overhauled, and maintained after dismantling is not installed immediately, it should be properly stacked and stored to avoid corrosion by water immersion.
III. Operation of Tower Cranes
1. Qualified Operators
Tower cranes should be operated by full-time drivers who must hold relevant certificates. There should also be full-time signalmen with certificates to give commands. Workers involved in hoisting operations must wear proper safety protection equipment.
2. Working Site Requirements
Tower crane operations require sufficient working space. There should be no obstacles within the lifting and slewing radius of the jib. Adequate lighting equipment is required at night.
3. Pre-operation Inspection
Before operation, a comprehensive understanding of the surrounding environment, driving roads, overhead lines, buildings, as well as the weight and distribution of components must be obtained.
4. Prohibited Attachments
Large promotional banners and other wind-blocking materials are prohibited from being hung on the tower crane standard sections and the front and rear jibs.
5. Unauthorized Modifications
Without the consent of the manufacturer, it is strictly prohibited to change the materials and facilities of the tower crane on one’s own or reduce any facilities on the tower crane.
6. Electrical Device Inspection
Maintenance electricians should check the tower crane’s electrical devices, luffing indicators, moment limiters, and various travel limit switches and other protection devices every day to ensure they are complete, in good condition, and sensitive and reliable. Using limit devices to replace the operating mechanism for shutdown is strictly prohibited.
7. Daily Inspection of Rigging
Every day before operation, the driver and the signalman should check the integrity of various slings, rigging, and hook latches. Any potential hazards found should be immediately rectified, and risky operations are prohibited.
8. Daily Inspection of Key Parts
Tower crane drivers should check important parts (components) such as high-strength connecting bolts (especially in the foundation area), steel structure welds, connecting pins (including cotter pins), moving pulleys, wire ropes, hoisting braking devices, and safety devices every day when going to and from work. Any potential hazards found should be reported or eliminated immediately. Using the tower crane in a faulty state is strictly prohibited. Records of daily inspections must be kept in the operation log.
9. Weekly Maintenance
Once a week, the connecting bolts of each standard section of the tower crane should be tightened, and the verticality of the tower crane should be measured.
10. Distance from Overhead Lines
Tower cranes should not operate close to overhead power transmission lines. When it is necessary to work beside the lines, the horizontal safety distance between the tower crane hook and the overhead lines must be greater than 6 meters. If this safety distance cannot be guaranteed, a safety protection barrier must be erected or the power supply must be cut off for construction. There should be no external high-voltage lines within the slewing range of the tower crane jib. Installing and using tower cranes under external high-voltage lines is prohibited.
11. Wire Rope Requirements
The specification and strength of the wire rope used in the tower crane must meet the requirements of the tower crane model. The technical documents provided by the manufacturer should be used as the basis for use.
12. Wire Rope Arrangement on Drum
The wire rope on the drum should be firmly connected and neatly arranged. When releasing the wire rope, at least three turns should be retained on the drum.
13. Wire Rope Splicing
When the wire rope is spliced, the splicing length should be no less than 20 times the diameter of the wire rope and not less than 0.3 meters. The spliced part should be bound with fine steel wire.
14. Wire Rope Clamping
When using clips to fix the wire rope, the number of clips shall not be less than 3. The distance from the last clip to the rope end shall not be less than 0.14 meters. The clip plates should be on the stressed side, and the “U” -shaped bolts must be at the end of the wire rope, without crosswise arrangement. The clips should be tightened until the two ropes are flattened by about one-third of their diameter. After the wire rope is stressed, the clips should be tightened again. The following is the wire rope clip matching table:
15. Warning Signals
Before performing actions such as raising and lowering, slewing, luffing, and traveling of the tower crane hook, a warning signal should be given.
16. Cooperation between Operators
During operation, the operator and the signalman must cooperate closely. The signalman must be familiar with the performance of the tower crane being commanded, and the operator should strictly execute the command signals. If the signals are unclear or incorrect, the operator can refuse to execute.
17. Safety below the Load
During operation, no personnel are allowed to stay or pass under the heavy object. Using the tower crane to hoist personnel is strictly prohibited.
18. Rated Load Operation
Operators must operate according to the specified hoisting capacity. It is prohibited to lift objects beyond the limit or lift objects of unknown weight.
19. Prohibited Lifting Operations
It is prohibited to use the tower crane to pull obliquely, lift obliquely, lift buried objects underground, or lift heavy objects that are adhered to the ground. For freshly cast concrete components or formworks, they must be completely loosened before hoisting.
20. Smooth Operation
The lifting and lowering speed of the tower crane should be uniform, and the slewing actions should be smooth. Sudden acceleration, deceleration, and sudden braking are strictly prohibited. When the slewing has not stopped steadily, the reverse action is not allowed.
21. Full-load Check
When the tower crane is lifting a full load or nearly a full load, the heavy object should be lifted 200 – 500 mm off the ground first, and then the machine should be stopped to check the stability of the tower crane, the reliability of the brakes, the stability of the heavy object, and the firmness of the binding. Only after verification can the hoisting continue.
22. Secure Lifting
Hoisting objects should be firmly bound to ensure stability. For heavy objects that may sway, guy ropes should be attached. Single-point lifting is not allowed. No scattered items should be stacked or hung on the hoisting object. For objects with marked binding positions or marks, they should be bound according to the positions or marks. The angle between the binding sling and the object should not be less than 30 degrees.
23. Separation of Materials
When hoisting, long and short materials should be separated, and small materials should be hoisted in cages.
24. Operation in Bad Weather
When working in rainy or snowy weather, a trial hoist should be carried out first. Only when it is proved that the brakes are sensitive and reliable can the operation proceed. In case of severe weather such as wind force above level 6, heavy rain, heavy snow, or thick fog, open-air tower crane operations should be stopped.
25. Wire Rope Inspection and Replacement
After each working day, all visible parts of the wire rope and its connection parts should be inspected. When the surface wear or corrosion of the wire rope causes its nominal diameter to decrease by 7%, or when the number of broken wires within the specified length reaches the following standards, the wire rope should be replaced in time:
26. Post-operation Procedures
After operation, the tower crane hook should be raised to the upper limit, the trolley should be retracted, the control lever should be set to zero, the power supply should be cut off, and the cab doors and windows should be closed. For rail-mounted tower cranes, they should be driven to the middle of the track and clamped to the track with rail clamps.
27. No Suspended Loads during Breaks
During breaks in the middle of the operation, it is not allowed to leave objects suspended in the air.
To further expand on these safety guidelines, in modern construction projects, with the continuous evolution of tower crane technology and the increasing complexity of construction sites, additional safety considerations are emerging. For instance, in large-scale urban construction projects where multiple tower cranes are operating simultaneously, a comprehensive crane management system has become essential. This system often utilizes advanced technologies such as the Internet of Things (IoT), GPS tracking, and real-time monitoring sensors. IoT sensors can be installed on various components of the tower crane, collecting data on factors like load, stress, vibration, and temperature. These data are then sent to a central server via wireless networks.
GPS tracking allows for precise positioning of each tower crane on the construction site, enabling better coordination between different cranes to avoid collisions. Real-time monitoring sensors for load and moment not only provide instant feedback to the operator but also trigger automatic safety alerts if the crane approaches its rated capacity or experiences abnormal load distribution. This way, potential accidents can be preempted long before they occur.
Moreover, in high-rise building construction, as building heights increase, tower cranes need to adapt to more challenging wind conditions. Specialized wind sensors can be added to tower cranes, which continuously measure wind speed, direction, and gust intensity. Based on this data, the crane’s operating system can adjust its movement speed, limit certain operations, or even initiate an emergency shutdown to safeguard against wind-induced instability.
In addition, with the growing emphasis on environmental protection, tower crane manufacturers are also exploring more energy-efficient designs. Hybrid power systems, combining diesel engines with electric motors, are being tested. These systems can switch between power sources depending on the crane’s operating mode, reducing fuel consumption and emissions. Electrically powered tower cranes are also becoming more prevalent, especially in urban areas where noise and air pollution are major concerns. They operate more quietly and produce zero emissions during use, contributing to a greener construction environment.
Furthermore, the training of tower crane operators and maintenance personnel is constantly being updated. Virtual reality (VR) and augmented reality (AR) technologies are being introduced into training programs. Through VR simulations, trainees can experience various complex operating scenarios and emergency situations in a virtual environment without any real risks. AR technology, on the other hand, can be used during on-site maintenance, providing technicians with real-time digital information, such as component diagrams, maintenance procedures, and troubleshooting guides, by overlaying them on the actual crane structure, improving the efficiency and accuracy of maintenance work.
The safety culture around tower crane use is also evolving. Construction companies are now more proactive in promoting safety awareness among all workers on the site, not just the crane operators.
