In modern construction, construction hoists have been increasingly widely used due to their advantages such as smooth transmission, fast lifting, simple structure, and ease of use. However, due to construction companies' negligence regarding hoist safety issues and unscientific usage management, various safety accidents involving construction hoists are continuously increasing, drawing social attention. Therefore, relevant units must pay attention and actively take preventive measures for improvement and resolution.

1. Cause Analysis of Construction Hoist Accidents

1.1 Malfunction of the Safety Anti-Drop Device. The safety anti-drop device is a crucial safety component ensuring smooth lifting and preventing the cage from falling during operation. Its safety performance is closely related to the Life Safety of occupants. Therefore, when adopting a safety anti-drop device, it must first be strictly checked for qualified factory test certificates. Secondly, since the qualification inspection of the safety anti-drop device is only valid for one year, it must be sent for inspection promptly during use. However, in practice, most domestic construction companies pay little attention to sending the safety device for inspection, basically failing to do so as required, and even failing to perform the performance test every three months, only realizing the severity of the problem after an accident occurs. Therefore, to effectively prevent construction hoist accidents, attention must be paid to testing and regularly sending the safety anti-drop device for inspection.

1.2 Failure of Safety Switches. Safety switches on construction hoists include the top door limit switch, cage door limit switch, final limit switch, fence door limit switch, upper and lower limit switches, and counterweight anti-rope-break protection switch. Failure of any one safety switch constitutes a safety hazard and may lead to near-miss incidents or safety accidents.

1.3 Safety Accidents Caused by Failure of Wall Tie and Mast Section Connections. Generally, the working and construction environment of building projects is quite harsh. If installation personnel are not conscientious, missing the installation of connecting bolts between wall ties and mast sections, installing them loosely, or failing to detect loose bolts can all lead to safety accidents.

1.4 Safety Accidents Caused by Frequent Operation. At construction sites, to meet construction Progress requirements, hoists are generally in a state of frequent operation. This prolonged, uninterrupted use often leads to motor heating and eventual failure, resulting in safety accidents. Therefore, hoist management staff and operators must consider the intermittent duty design of the motor, reasonably schedule hoist usage, ensure safety, and maximize the equipment's role.

1.5 Failure to Install Safety Doors at Landing Floors Easily Causes Accidents. Installing safety doors at landing floors is very necessary. Relevant construction regulations require the door height to be at least 1.8 meters and equipped with effective interlocking devices. However, judging from current actual construction situations, many construction companies do not pay much attention to the installation and use of protective doors at hoist landing floors. Safety doors can be opened arbitrarily, leading to frequent safety incidents.

1.6 Accidents Caused by Not Installing Interlocking Devices on the Base Enclosure. Some construction companies, to save costs, do not strictly follow construction regulations to install interlocking devices on the base enclosure where the hoist operates. Therefore, during operation, if someone suddenly appears directly under the hoist cage, serious impact safety accidents can occur with even slight carelessness. Additionally, exceeding the set free-standing height of the hoist also easily leads to accidents.

2. Effective Management Measures for Construction Hoists

2.1 Selecting the Hoist Construction and Installation Unit. First, before the hoist enters the site, a comprehensive inspection should be carried out to ensure its safety devices are complete and performance is qualified. Second, an experienced installation unit with appropriate qualifications should be chosen to be responsible for installation, requiring installation and  personnel to hold certificates and work accordingly.

2.2 Strict Supervision for Initially Installed Hoists. After hoist installation is complete, application should be made to the supervision unit for qualified acceptance, strengthening supervision over the construction situation.

2.3 Strengthening Management of Hoist Usage. Require hoist operators to hold certificates. Simultaneously, set up a full-time hoist management staff position to conduct comprehensive daily inspections of the construction hoist and carefully fill in true and complete inspection records. If equipment undergoes repairs, detailed maintenance records must also be kept.

3. Preventive Measures for Construction Hoist Accidents

3.1 Inspection of the Frame Structure. Inspection of the frame structure should focus on the following points: First, check the tightness of connecting bolts between mast sections and the foundation, and whether nuts are loose. Second, check the welding quality of various components. Third, check whether attaching rods are installed strictly according to instructions, and verify the correctness of their fastening methods and connection types. During daily inspections, a relatively serious phenomenon that can easily lead to safety accidents is when pins and bolts intended for and connection are replaced by construction companies with reinforcing steel bars and iron wire.

3.2 Inspection of the Enclosure Gate. During daily inspections, check whether the enclosure gate is equipped with a mechanical interlock and whether the interlock's performance is effective. Only with the interlock installed can it be ensured that the hoist cage opens the enclosure gate in time at the specified bottom position and that the cage remains stationary and does not restart after the door is opened.

3.3 Inspection of Landing Floors. Construction companies should, according to relevant requirements, reasonably set up effective safety doors at each hoist landing floor and strengthen the management of these safety doors.

3.4 Inspection of Wire Rope End Fastening Quality. During daily inspections, the phenomenon of unqualified fastening quality of wire rope ends at many construction sites appears. The reason is that when using rope clips for fixing, standards for the number of clips, clip spacing, and tail length are not strictly followed, reducing the joint's fastening strength, thus increasing the probability of safety incidents.

3.5 Inspection of the Equipment's Transmission System. First, check the gearbox for oil leakage. Second, check the transmission belt gap, ensuring it is controlled within the range of 0.2-0.5 mm. Third, check the meshing clearance; the optimal clearance is approximately 2 mm. Fourth, check the wear level of gears and racks to avoid excessive axial misalignment, which reduces transmission strength and leads to gear tooth breakage accidents. In summary, during operation, the hoist must remain stable, with no obvious vibration and no abnormal noise.

3.6 Inspection of Hoist Safety Switches. Although most current construction hoists are scientifically equipped with necessary safety switches according to regulations before leaving the factory, during actual use, many units choose to manually cancel safety switches for convenience. For example, when transporting long items needed for construction, due to insufficient cage space, they directly disable the top door limit switch. Or, some units ignore and fail to repair safety switches after they are damaged. These situations subtly bury serious safety hazards. Therefore, during daily inspections, management of hoist safety switches must be emphasized. Strict inspection systems and equipment maintenance systems should be established to ensure the effectiveness of safety switches. Using the hoist to carry people or materials when safety facilities are incomplete is strictly prohibited to prevent safety incidents.

3.7 Inspection of the Cage Top Control Box. When dismantling or inspecting the control box on top of the cage, the hoist can only operate at low speed. Pay attention to checking whether the control box has an emergency stop switch correctly installed; if not, install one immediately.

3.8 Inspection of Circuit Protection. Operating a construction hoist without protective devices or with failed protective devices easily leads to safety incidents. However, most maintenance personnel, when the hoist's protective device malfunctions, their first reaction is not to inspect and repair it as soon as possible but rather  or cancel the protective device directly, greatly increasing the equipment's safety risks. During daily inspections, the occurrence of this situation must be resolutely prevented.

3.9 Inspection of Safety Anti-Drop Device Performance. The safety anti-drop device plays an important safety protection role in construction hoists. Therefore, before leaving the factory, it must undergo strict testing, and a qualified test report must be issued by a statutory testing institution before it can be put into use. Additionally, relevant regulations require a drop test every three months for construction hoists in use. After the one-year validity period of the safety anti-drop device inspection expires, it must be sent for inspection promptly.

4. Conclusion

In summary, strengthening the research and analysis of construction hoist usage management and accident prevention has important practical significance. Due to the wide and frequent use of hoists in modern construction, management must be strengthened during equipment use. Operations must strictly follow regulations, and regular equipment inspections must be carried out to prevent safety accidents.

Source: Zhihu, Construction Hoist Manufacturer