What Are the Different Types of Construction Hoists?

Construction elevator (English: Construction elevator), also known as construction elevator, construction elevator. In Hong Kong and Southeast Asia, it is commonly referred to as "" (transliteration of lift), which generally refers to a means of transportation for vertically transporting pedestrians or building materials on construction sites. The total number of construction elevators in the world exceeds 8 million, and it is the most vertical type of people and goods transportation used by the contemporary construction industry.

Ancient China and European countries had used people to transport people and goods vertically. Modern

Building lifts are also called freight lifts, which are generally larger and carry more loads than passenger lifts, ranging from 2,000 to 5,000 kg, most of which are traction. Freight elevators are generally not well-decorated to avoid damage during shipment. Many elevator door switches are manually controlled. There is a very small freight elevator, called dumb waiter in English, which is specially used to transport food, cups and plates in multi-storey restaurants. Such debris lifts are also used to transport books in multi-story libraries. Gear rack and pinion lifts (commonly known as "cages" in Hong Kong) are sometimes used at construction sites, warehouses, and other places to transport goods and let workers ride. This type of lift has no lift shaft and uses racks to support and move the car. ^[1]

In the construction of high-rise buildings, vertical transport often uses machinery such as building elevators. Due to the use of machinery or improper management, major safety accidents often occur, and often it is a group of injuries and deaths, which has a serious impact on society and a harmonious society. Significant negative impacts. Through analysis of multiple accident cases, this article proposes specific reasons and countermeasures for the use and management of construction elevators and other machinery. ^[2]

Construction elevator accident cases and analysis

Case 1: In December 2008, a 33-storey high-rise building construction site in Changsha City, Hunan Province suffered a construction elevator drop accident, which killed 18 people. The lift has a rated capacity of 12 people, but actually carried 23 passengers on the day of the accident. When it reached the 17th floor, 5 people were downloaded. When rising from the 17th floor, the trailer suddenly fell, that is, from a height of 49.3 meters. , 18 people died. The direct cause of fatal accidents is overloading in violation of regulations. The anti-fall safety lock of the elevator has not been regularly inspected, which violates Article 8.1 of the national standard "Safety Regulations for Construction Lifts" (GB10055-2007), resulting in a serious lack of elevator safety. Case 2: At 10:00 on November 14, 2007, a major accident occurred at a construction site in Wuxi City, Jiangsu Province. The west side of a SCD200 / 200 construction elevator suddenly fell from an 11-story building, and 17 operators ( (Including the lift operator) fell to the ground with the cage, resulting in 11 deaths and 6 injuries. After analysis, the accident was caused by mechanical and electrical failure of the lifting equipment and failure of the safety device. Case 3: In April 2003, a project in Ningbo had a total height of 32 floors, and the SC100 / 100J construction elevator had been demolished to the 12th floor. During the operation of the hanging cage, the roof fell and 3 people died when the hanging cage fell to the ground. The hanging cage was severely damaged. The main cause of the accident: the analysis was that the height limit and three-phase limit failure failed. After the punching, the elevator drive and the gear of the fall arrester slipped out of the rack, causing the suspension cage to tilt outward, and the safety hook plate bolts above the suspension cage were loosened and broken. The electromagnetic brake and the fall arrester both pushed and fell. On the surface, the accident was caused by careless operation of the operator, careless operation, and the lifting of the cage. However, further analysis shows that this type of elevator has serious hidden safety hazards because it has no counterweight device and no capping device at the top of the standard section. In addition, although the disassembly personnel and operators are certified, they have not been trained in the system. After the partial disassembly of the construction elevator, the upper limit and three-phase limit must be installed as required, and tested and effective. During the operation, the operator must carefully observe the floor position and the operating conditions of the mechanical appliances. Do not use the upper and lower limits as automatic stops. Case 4: On June 2, 2003, in the process of installing a material hoist in a project in Hangzhou Xiaoshan, a major accident that caused the material hoist to collapse due to serious violations of rules and regulations and violation of operating procedures, resulting in 3 deaths. The main reasons after analysis are: the installer has not obtained special equipment manufacturing and installation permits, and has not prepared a special construction plan for installation; the installers have not been certified to work and have seriously violated regulations, and have not erected in time a temporary cable wind rope and other fixed facilities. . At the same time, the construction unit failed to supervise the safety of the installation process. Case 5: On September 9, 2002, in a certain project in Hangzhou, during the demolition and demolition of the human-goods construction lift of the building, the installation lifter cage was caused by the installer's undocumented employment and serious violations of regulations and rules. A major accident involving the fall resulted in three deaths and one serious injury. ^[2]

Main causes of accidents in construction lift construction lifting machinery

Based on a brief analysis of the causes of the five major safety accidents mentioned above, combined with the major hidden safety hazards that often occur at the construction site, the main reasons for various types of accidents in construction elevators are summarized as follows. ^[2]

elevator

2.1 The safety management system of each participating party is not perfect

The specific performance is that the construction general contractor is managed by the contractor, the project department is not equipped with professional management personnel, and regular or irregular safety inspections are not carried out; the installation unit pays attention to the initial installation and disassembly, and does not pay attention to the lifting operation of the construction elevator, and sometimes it Completed by non-professionals of the general contractor or rental unit, or delivered without prior experience after the operation. In addition, engineering supervision does not have the professional knowledge of lifting equipment, which makes safety supervision work impossible. ^[2]

2.2 Mechanical installation team is not standardized

In order to save costs, some installation teams arbitrarily call on the qualifications of regular units and commission undocumented migrant workers to perform installation and disassembly. Because the installers did not have professional system training, there was no process plan and safety technical measures for the assembly and disassembly, and the equipment installation, elevation and disassembly did not operate in accordance with the requirements of the operating procedures and product descriptions. As a result, it was extremely easy to occur during the installation and disassembly. Security incident. ^[2]

2.3 Safety protection device management is not in place

The elevator fence boarding door and the cage entrance door should be equipped with electromechanical interlocking according to the requirements of the code, but some machinery is missing or fails after frequent use; some elevators are equipped with mechanical door interlocking devices, which works well. The elevator brake is not strengthened for maintenance and is prone to malfunction, and the automatic adjustment gap mechanism is not cleaned properly. ^[2]

2.4 The routine maintenance management of the elevator is not standardized

Who is responsible for the daily maintenance of the machine is not clearly stated in the contract, which causes the poor management of the machine on the site and the equipment rental, management, and use are disconnected. The hanging cage is badly damaged and it is not repaired in time; there are unlimited cards and operating rules in the hanging cage. The wire rope was not inspected in time, and the broken wire was severely not replaced in time. The guide wheels and pulleys were severely worn, and the brake and electrical components were not repaired in time. ^[2]

Preventive measures for major accidents in building elevators

3.1 Strengthen the safety management of all construction parties

Building construction is a field of high-risk operations. Therefore, the control of building safety construction must not only be in the form of slogans and slogans. A project leadership team with all-round functions should be established, and various potential safety hazards are being implemented. Under surveillance. In all aspects of construction elevator installation, lifting, disassembly, etc., the construction general contractor, rental, and installation units have carefully strengthened the safety management of the equipment, established a safety responsibility system, and should have emergency rescue plans for safety incidents. The supervision unit should strictly perform the duties of safety supervision In particular, we must emphasize program control and standardize operating procedures. ^[2]

3.2 Strengthen the management of construction machinery installation and disassembly units

The installation and disassembly unit shall have the corresponding qualifications and production safety licenses issued by the competent department of the Ministry of Construction, and shall undertake the installation and disassembly of machinery within the scope of its qualifications. Regarding the phenomenon of selling brands and engaging in the construction market, the competent government department should resolutely investigate and deal with it. For some projects, the simple and extensive management mode of the project manager's responsibility should be fundamentally rectified. For those who do not have qualifications, Yes, we should resolutely clear the construction market, otherwise construction safety accidents will still happen. In addition, after the installation and disassembly units have completed their tasks, they should pass the inspection and inspection of the relevant local competent inspection and testing institutions before inspection and acceptance, and then they should be leased, installed, supervised, and other relevant units by the user to conduct acceptance inspections, or they must be commissioned to carry out inspections The organization conducts inspection and acceptance, and can be put into use after passing the acceptance. ^[2]

3.3 Strengthening the management of machinery and equipment by machinery users

Set up a special person to manage, conduct regular inspections and maintenance, and perform routine operation and maintenance of elevators and other machinery; long-term training of operator safety operation skills to prevent operators from operating in violation of regulations. ^[2]

3.5 Supervision units strengthen supervision and inspection

Strictly review manufacturing licenses for building elevators and other machinery and equipment, product qualification certificates, manufacturing supervision and inspection certifications, and record certification documents; review the qualification certificates of installation units, users, production safety licenses, and special operation qualification certificates of special operators; audit Installation and disassembly engineering special construction plan; supervise whether the installation unit carefully implements the installation and disassembly engineering special construction plan and safety operation regulations; supervise and inspect the use of machinery such as building elevators; ^[2]

Building elevators and material elevators are the main vertical transportation equipment in building construction. Due to the dangers and management problems, they have been included in the special inspection content requirements in the "Building Construction Safety Inspection Standard" (JGJ59-99). The unit is carefully managed. However, accidents still occur from time to time in various places, and the laws and regulations are not followed, which is the root cause of casualties in construction elevators. In this series of accidents, it is prominently reflected that the construction industry's production safety supervision and management mechanism is not complete, the safety production responsibility system has not been implemented, and the managers and operators of the production safety responsibility subjects have weak production safety awareness during the construction process. Therefore, to establish a system of accountability, it is necessary to investigate the criminal responsibility of those responsible for violations of the law in accordance with the law, and to investigate the administrative responsibility of the leaders of the companies responsible for management responsibility. Only through serious regulations and implementation of responsibilities can casualties be effectively controlled. In addition, construction elevators are stereotyped equipment. How to use them and how to verify that the country has the "Construction Lift Standards." If all units comply with the implementation, most accidents can be avoided. Finally, the safety awareness and skills education and training and various inspections of construction machinery managers and operators must not be in the form, and it is necessary to strengthen the management. ^[2]