Hidden Danger Investigation and Countermeasures for Construction Hoisting Machinery and Equipment

Abstract: Construction hoisting machinery and equipment (tower cranes, construction hoists, etc.) are key equipment in high-rise building construction due to their high working height, large span, wide service range and strong applicability. They are also critical parts prone to mass casualty accidents. We should standardize and strengthen the management of hoisting equipment in installation, use, disassembly and other links to eliminate potential accident hazards. Only in this way can the safety of the lives and property of the country and the people be ensured.

Key words: Lifting machinery Hidden danger; Countermeasures

1. Preface

With the rapid development of modern urban construction, construction hoisting machinery and equipment (tower cranes, construction hoists, etc.) have become the main construction machinery in modern industrial and civil buildings. Its main features are high working height, large amplitude, wide service range and strong applicability. Through hook and cage lifting devices, it can lift, lower or move heavy objects horizontally It is a key piece of equipment for high-rise building construction. The extensive use of construction hoisting machinery and equipment has also exposed many safety management issues and planted potential accident hazards. Even the slightest carelessness in installation, use, disassembly and other management aspects may lead to the occurrence of safety accidents, causing serious losses to the country and people's lives and property.

2. Problems existing in lifting machinery and equipment

2.1 The safety management system of the responsible entity is not in place

2.1.1 Although the leasing, installation, dismantling and usage units of construction hoisting machinery and equipment have established corresponding responsibility systems, the safety responsibilities are not clear enough. They only remain on paper and hung on the wall, and have not been truly assigned to the relevant responsible persons. Although some enterprises have set up dedicated mechanical equipment management departments, they have not established corresponding supervision mechanisms, and the work has not been implemented.

2.1.2 The installation, operation and maintenance ledger materials of on-site lifting machinery and equipment are incomplete. The compilation and review of special plans for installation and dismantling are not given due attention. The content of the plans is not targeted and there are no substantive measures. Some of the plans still have obvious errors and cannot guide on-site installation and disassembly. The operators merely rely on "experience" for installation and disassembly. The acceptance and commissioning of lifting machinery and equipment were merely formalities, and potential accident hazards were not identified.

2.1.3 Due to the relatively small number of installation and dismantling units with professional contracting qualifications for construction hoisting machinery and equipment, some construction sites borrow or rely on qualified installation and dismantling units, resulting in the actual installation and dismantling process involving crane operators, installation fitters, mechanical technicians, electrical technicians, and safety officers not matching the personnel recorded in the installation and dismantling filing.

2.1.4 After installation and before use, the construction hoisting machinery and equipment were not inspected and tested in a timely manner in accordance with the requirements of the "Regulations on Safety Production in Construction Projects" and the "Regulations on Safety Supervision of Special Equipment". As a result, a considerable number of hoisting machinery and equipment on the construction site have varying degrees of safety hazards during use. In addition, the installation units and user units apply for inspection late, and the special equipment inspection units take a long time from inspection to the issuance of the inspection qualification report. The lifting machinery and equipment operate based on the "feeling" of the operators.

2.2 The on-site supervision by the supervisory unit was inadequate

2.2.1 Due to the promulgation of the "Regulations on Safety Production in Construction Projects", the responsibility of supervision units has objectively increased. However, although the supervisory units have participated in the supervision of work safety, their initiative in urging construction enterprises to rectify safety issues is insufficient. Most supervisors are not familiar with the "standards and norms" of safety management and have a low level of professional skills. Especially for highly specialized lifting machinery and equipment, the on-site inspection of lifting machinery and equipment is merely a formality and fails to identify potential accident hazards.

2.2.2 The review of the special safety plans for the installation and dismantling of lifting machinery and equipment submitted by the installation and dismantling units and the user units was not conducted in detail in accordance with the actual usage conditions at the construction site, the performance of the machinery and equipment, and the requirements of the mandatory standards for engineering construction. There was no focused supervision over key and important parts, and no timely measures were taken when potential hazards were discovered.

2.3 The safety management work at the construction site is inadequate

2.3.1 Before the construction hoisting machinery and equipment entered the site, their safety performance was not effectively tested. After installation, self-inspection was not strict, and during use, inspection, testing and debugging were not carried out carefully. There is a lack of understanding of the safety distances stipulated in the "Safety Technical Code for the Use of Construction Machinery (JGJ33-2001)" regarding the strength of the foundation concrete, the travel limit, amplitude limit, lifting height limit, rotation limit of mechanical equipment, and the rope breakage protection device of the trolley. The limited safety distances are arbitrary. The lifting capacity limiter and lifting moment limiter are not debugged correctly, and overloading occurs from time to time. The damage to the safety devices of lifting hooks and other safety protection equipment has not received sufficient attention either.

2.3.2 The cantilever platform for the lifted object of the tower crane was not set up in a standardized manner, the design calculation was sloppy, and the erection handover was not taken seriously. Some projects are still using steel pipe cantilever platforms. Some lifting machinery is not equipped with equipment command signals, command personnel and riggers, resulting in the situation where whoever uses it, ties it up and commands it, leading to unsafe behaviors such as illegal command and illegal operation.

2.3.3 When the floor stop device, anti-fall device, over-height limit device, hoist basket protective door and self-dropping door of the material hoist are incomplete or malfunctioning during operation, they are not repaired or debugged in time. The unloading platform is not set up in a standardized manner, and some are not independently established. The protection on both sides and the base plate are not tightly laid. In addition, the overall stability and the setting of rigid connections of high-rise material hoists over 31 meters have not received sufficient attention.

2.3.4 The speed limiter of the passenger-cargo dual-purpose elevator is not detected in a timely manner, and the up and down communication signals are not fully set, etc.

2.3.5 The electrical components in the dedicated distribution box for lifting machinery and equipment are not set up in a standardized manner, the TN-S zero connection protection system is incorrect, the repeated grounding is set up randomly, and the grounding resistance value is greater than the specification requirements.

3. Countermeasures and Measures

3.1 Strengthen the main safety responsibility of construction enterprises and improve the quality of practitioners

3.1.1 Implement the enterprise's responsibility for production safety. In accordance with the requirements of the signed "Work Safety Target Responsibility Agreement", during the implementation process, the implementation of the safety responsibility system at all levels should be strengthened in the assessment, and enterprises are required to shift their focus of work to the specific management of work safety in project departments. Strengthen the job responsibilities of full-time project safety personnel, enhance the three-level safety education for construction workers, and strictly prohibit untrained and unlicensed personnel from taking up their posts. Emphasize that 100% of special operation personnel and operators of lifting machinery must hold valid certificates to be on duty. And conscientiously carry out daily safety supervision and inspection, promptly eliminate potential hazards, and ensure safe construction.

3.1.2 Improve the working and living conditions of migrant workers. In response to the changes in seasonal climate and environmental conditions, construction enterprises should formulate relevant safety technical measures and implement safety protection measures for on-site workers. Emphasis should be placed on improving the living environment and food hygiene of migrant workers to ensure the physical health of front-line workers.

3.1.3 Establish a pre-control system for major hazard sources at the construction site. Construction enterprises and supervision enterprises are required to list major hazard sources based on the actual situation of ongoing projects, formulate corresponding pre-control measures and assign relevant responsible persons. Pre-control boards for major hazard sources should be hung in prominent positions on the construction site to facilitate supervision by all parties.

3.2 Strengthen the safety responsibility of supervision enterprises and standardize safety supervision behaviors

3.2.1 Supervision enterprises should strictly follow the requirements of the "Regulations on Safety Production in Construction Projects", carefully review and confirm the special safety construction plans submitted by construction units in accordance with the norms, standards, mandatory provisions and the actual situation of the construction site. Urge construction enterprises to strictly implement the special plan.

3.2.2 On-site supervision must be implemented for key parts, dangerous points and critical procedures at the construction site. Carefully organize safety inspections, identify potential safety hazards, urge construction units to rectify in accordance with the requirements of "designated personnel, designated time, and designated measures", and earnestly implement the re-examination work.

3.2.3 During the implementation of supervision, if the engineering supervision unit discovers major safety hazards in the safety protection facilities and equipment at the construction site, it shall notify the construction unit to suspend construction activities, and supervise the construction unit to rectify and report to the construction unit. If the construction unit refuses to rectify or does not stop construction, it shall promptly report to the local industry administrative department. After the construction unit has completed the rectification, the chief supervising engineer should organize relevant personnel to conduct a re-examination in accordance with the relevant "standards and norms" for construction safety. Only after confirming that the safety hazards have been truly rectified can work resume.

3.3 Strengthen safety supervision and management, with a focus on addressing prominent issues

3.3.1 Organize business training courses. Organize relevant personnel from construction and supervision units to study laws, regulations, standards and norms, enhance their legal awareness and safety responsibility consciousness, and urge enterprises to voluntarily do a good job in safety protection and civilized construction at the construction site.

3.3.2 Carefully organize re-examinations and implement rectification work. In response to the problems identified during the inspection, the construction industry administrative department of the project location is required to earnestly urge the construction unit and the supervision unit to make rectifications. For projects with major accident hazards in on-site lifting machinery and equipment, a re-examination should be conducted, and the rectification work should be earnestly implemented to effectively eliminate the accident hazards.

3.3.3 Strengthen the special governance and management of weak links in safety at construction sites. Conduct a thorough investigation of potential hazards and dangerous points at the construction site, and focus on the management of the formulation, review and approval of special construction plans. It is necessary to urge construction enterprises and supervision units to implement the plan in accordance with the regulations. At the same time, the management of temporary construction electricity usage should also be strengthened to ensure safe electricity usage.

3.3.4 We must earnestly carry out the activities of creating standardized construction sites for safe and civilized building construction. By setting up exemplary models and taking the form of leading by example, the creation of standardized construction sites for safety and civilized construction in buildings and the implementation of safety and quality standardization work in construction enterprises are combined to promote the in-depth development of safety and quality standardization work and comprehensively enhance the overall level of safety production and civilized construction at construction sites.

4. Conclusion

Life is above all else. Safety must be jointly managed and a synergy formed. Under the premise of adhering to the principle of "safety first, prevention foremost, and comprehensive governance", the competent authorities of each construction industry should carry out more special inspections, especially on the dangerous points and sources of danger in projects. They should urge construction enterprises and supervision units to earnestly fulfill their safety responsibilities, take a highly responsible attitude towards life, do a good job in production safety, and eliminate unsafe behaviors such as illegal command and illegal operation. Only in this way can the lifting machinery and equipment at the construction site operate safely, play their due role in economic construction, and contribute to building a harmonious society.