Reprint--Damage to the grille caused a fall from a height and a fatal accident

Source: Thermosphere

On December 4, 2011, unit #2 of a power plant was put into operation, #1机组停运备用. Taking advantage of the shutdown of the unit, a power plant arranges for the maintenance and elimination of auxiliary equipment and utility system equipment. This includes the inspection of the #1 desulfurization system and the #1 absorption tower.

On November 30, the person in charge of the work, Yang, handled: #1 desulfurization system #1 absorption tower overall shutdown and maintenance work ticket, and the planned work period: 11:45 on November 30 to 17:00 on December 05. The work ticket was completed at 15:10 on November 30 and the work permit procedures were completed. On December 2, the washing and inspection of the mist eliminator was completed, and the manhole door was closed.

At about 9:10 on December 4, the person in charge of the work, Yang, led Yin, Liu, Zhang, and Shen to work to the #1 desulfurization system #1 to absorb the tower gate (1 each on the first to fifth floors, and only 1 on the first, third, fourth, and fifth floors will be opened in this work). At around 9:40, the manhole door on the fifth floor of the #1 absorption tower was closed, and the manhole door on the right side of the fourth floor was turned to the overhauled manhole door (23 meters above the ground). Because the manhole door bolt needs to be tightened with an air wrench during the work process, but the length of the air wrench trachea is not enough, in the process of transferring the work site, it is necessary to reconnect the air pipe from zero meters. Yang arranged for Liu to go to the ground air source valve to close the gas source, and arranged for Zhang to go to the second layer to help sort out the leather pipe. Shen was not at the scene because he went to the toilet. Yin and Yang went down to the fourth floor to prepare to close the mist eliminator and repair the manhole door. Yin first went to the manhole door, put down the tool, and inspected the manhole door of the mist eliminator, and Yang released the pneumatic wrench air source leather tube downward on the annular aisle near the manhole door of the mist eliminator. At 9:55, Yang fell with a fan-shaped grille plate under his feet, and after Yin heard the sound, he looked back and found that Yang was not on the circular aisle, and a fan-shaped grille plate on the annular aisle had fallen off. Yin immediately went down to the ground to check the situation and saw Yang lying on the ground between the slurry circulation pumps of #1 and #1 absorption tower #1 and 2, the pneumatic wrench fell to one side, and the grille plate fell on the ground on the other side. Yang suffered multiple injuries to his head and body, and there was blood on his face, and the injuries were serious, but he was still conscious.

Yin immediately ran to the desulfurization control room for help, and the operation staff on duty called to report to the relevant leaders on duty. At about 10:05, the on-duty leaders and relevant personnel of a company rushed to the scene, organized personnel to rescue, and dialed the 120 emergency number to send the injured to the town health center 1.5 kilometers away from the accident site for first aid. At 10:40, the city's 120 ambulance rushed to the town health center to transfer the injured to the city's people's hospital for rescue. At around 11:20, the injured were sent to the Municipal People's Hospital for first aid. At 11:55, the Municipal People's Hospital failed to rescue and confirmed that Yang was dead.

【Case Analysis】

(1) Direct causes

In the process of infrastructure construction and installation, the railing of the #1 absorption tower platform of the #1 desulfurization system of a company did not comply with the requirements of "the platform shall be welded in accordance with the "fixed industrial steel platform" (GB4053.4-1983) on "the platform shall be welded, and the welding requirements shall comply with the "steel structure welding specification" and the "technical regulations for the design of escalators of steel platforms for thermal power plants" (DLGJ158-2001) on "the platform shall be installed on a firm support structure, fixedly connected with it, and must have sufficient stability" and other provisions for construction and installation. The steel grating plate of the platform is not fixed and welded and installed, and there is a gap of 100~150mm left on the inside of the absorption tower, and when Yang casts the air source leather pipe downward, the steel grating plate under his feet slides to the inner side of the absorption tower to cause displacement, and after sliding out of the outer support frame, he is unstable and falls downward, and Yang himself fell to the ground with the steel grating plate, and was injured in many places on his head and body, and finally died due to compound injuries.

(2) Indirect causes

As the person in charge of the work, Yang did not have a strong sense of safety precautions and self-protection, ignored the possible dangers of the airport annular platform, and failed to conscientiously perform the safety work conditions of the maintenance site after the transfer, confirm whether the safety measures were perfect, and there should be no factors affecting the safety of people and equipment, so that the safety duties of the maintenance operation could be carried out, which eventually led to the accident.

3. Other reasons

1. The desulfurization system #1 and 2 of the power plant absorption tower ladder platform are designed with a total of four layers, which are the channels for the operators to check the equipment and maintenance personnel to carry out maintenance work, and the general contractor of a company is responsible for the design and construction. During the installation process, each layer of steel grating plate is not fixed and installed and welded firmly in accordance with the relevant requirements of the "Fixed Industrial Steel Platform" (GB4053.4-1983) and the "Technical Regulations for the Design of Steel Platforms and Escalators for Thermal Power Plants" (DLGJ158-2001). After on-site investigation and confirmation, the maximum spacing of the platform railing column is 1600mm, which greatly exceeds the requirement that the column clearance should be 1000mm specified in the "Safety Technical Conditions for Fixed Industrial Protective Railings" (GB4053.3-1993), and the construction and installation are not carried out according to the requirements of 860mm column spacing on the design and construction drawings, and there are serious safety hazards.

2. When the infrastructure is handed over for production, the supervision and the owner unit do not carefully inspect and accept the infrastructure project in accordance with the relevant regulations, and fail to discover and eliminate the unsafe hidden dangers of the platform railing of the absorption tower in time.

3. Although the power plant organizes seasonal safety inspections and special hidden danger investigations in accordance with the regulations every year, it fails to discover and eliminate the hidden dangers in the railings of the absorption tower platform in time, reflecting the weak awareness of safety production of personnel at all levels, and the insufficient intensity and depth of safety inspections.

4. The safety awareness of on-site maintenance operators is weak, the self-safety protection skills are not high, and the safety training and job training of a company are not in place. The potential safety hazards in the on-site operating environment are not discovered in time, and the self-protection safety awareness of aerial workers is not strong.

【Case Warning】

1. Safety warning education should be carried out for all employees, and safety education and self-protection skills training should be strengthened for employees with fresh accident cases around them, so that the majority of employees can receive profound education from this accident and improve the ability of "four non-harm".

2. In view of the potential safety hazards of unfixed locking of the steel grille in the annular passage of the #1 and 2 absorption towers, the unit completed the investigation and remediation of similar hidden dangers of all on-site stairs, platforms and high-altitude corridors within the specified time.

3. The power plant should carry out the special work of "checking two votes and three systems, anti-illegal operations, anti-installation violations, and hidden danger investigation and management", formulate specific implementation measures, and reverse the passive situation of safety production as soon as possible.

(1) Carry out in-depth supervision and inspection of the "two votes and three systems", strictly implement the "two votes and three systems" management system, strictly assess, strengthen the supervision and inspection of the implementation of the two votes on the spot, and strengthen the standardization of the implementation of the two votes;

(2) Strengthen anti-violation management, continue to seriously investigate and deal with habitual violations such as ticketless operations, and ensure personal safety.

(3) Strengthen the study and implementation of the intrinsic safety management regulations of the operating environment of power generation enterprises, strictly implement the requirements of "unsafe and no work", strengthen the identification and elimination of various risk factors in the operating environment, do a good job in safety disclosure and self-safety protection, improve various safety measures to prevent personal injury, and ensure operation safety.

(4) Deepen the investigation and management of potential safety hazards, increase the safety management of the operating environment such as installation violations, eliminate potential accidents, and regularly organize and carry out the investigation and management of potential safety hazards in accordance with the relevant requirements of the unit's "Anti-Violation Management Implementation Standards" on anti-installation violations, strengthen the inspection of on-site installation violations, strengthen process management and supervision, and take effective measures to ensure personal safety. Closed-loop management should be achieved in the management of hidden dangers and anti-device violations, improve the level of intrinsic safety, and form a long-term mechanism for anti-device violations.

4. Strengthen the construction quality acceptance management of infrastructure projects under construction. Relevant companies should strictly control the quality of project acceptance according to the relevant engineering design standards and construction process requirements. All infrastructure projects with potential safety hazards must be rectified, otherwise they will not be allowed to be put into production and operation.

5. It is necessary to conscientiously learn the lessons of this accident, actively take practical measures, and conduct special safety inspections on all high-altitude walkways, working platforms, escalator aisles, cable covers and manhole covers, and immediately arrange for treatment if problems are found. During the holidays, it is necessary to reduce the operation and maintenance operations, and the relevant leaders and management personnel must be present to guide and supervise the major operation operations and maintenance operations.

6. It is necessary to conscientiously carry out the construction of safety production standardization, pay close attention to anti-habitual violations, and take this opportunity to do a good job in publicizing, learning, and tracking the implementation of the intrinsic safety management regulations of the operating environment of power generation enterprises, so that they will not work if they are not safe. Strengthen the management of safety production and take effective measures to ensure the personal safety of employees and the stable operation of equipment.