Case analysis and preventive measures of the hotte

2022-10-22
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Limited space accident case analysis and preventive measures

limited space refers to a space that is closed or partially closed, with narrow inlet and outlet, not designed as a fixed workplace, with poor natural ventilation, which is easy to cause the accumulation of toxic and harmful, flammable and explosive substances or insufficient oxygen content (compiled by the publicity and education center of the State Administration of work safety, safety training materials for limited space operation, Tuanjie press, 2010). Limited space operation involves a wide range of industries, such as service industry, public facilities management industry, power, gas, water production and supply industry, manufacturing industry, construction industry, catering and accommodation, etc. The working environment in limited space is complex and there are many uncertain risk factors. If the preventive measures are not in place, poisoning, suffocation, drowning, burning and explosion and other accidents may occur

according to the statistics of the State Administration of work safety, from 2001 to August 2009, there were 668 accidents in which 3 or more people died at one time due to poisoning and asphyxiation during confined space operations in China, with a total number of 2699 deaths, with an average of more than 300 per year. In 2011, 15 major accidents occurred in limited space operation in industrial and trade enterprises such as metallurgy, nonferrous metals, building materials and machinery, with a total of 57 deaths, accounting for 37.5% and 35% of the number of major accidents and deaths in industrial and trade enterprises respectively. Since 2012, there have been 10 major accidents and 37 deaths, accounting for 37% of the number of major accidents and deaths in industrial and trade enterprises, respectively, with a year-on-year increase of 66.7% and 76.2% respectively (notice of the State Administration of work safety on the special treatment of limited space operations in industrial and trade enterprises (ajzgs4 C2012) No. 93)

1 typical case of limited space

1.1 "2.20" water sealed tank hypoxia asphyxiation accident

(1) accident process

on February 20, 2006, Ma, the manager, Yu, the deputy manager, Zhao, the technician, and Shi, the worker of a spherical tank branch of China National Petroleum Corporation in Daqing City, Heilongjiang Province, went to the flare system of the synthetic ammonia plant to check the freezing and blocking of the steam heat tracing system according to the arrangement of the alcohol branch of the chemical industry group A of the Petroleum Administration Bureau in the whole process of petroleum exploration, drilling, oil production, gathering and transportation, water injection, storage and transportation, oil refining and so on, When checking whether there is a leak in the horizontal water sealed tank (? 2.4mx 8.9m), Yu and Zhao removed the manhole cover (480mm in the middle) on the top of the tank, Yu went down to the tank for inspection first, and fainted in the tank because the tank was full of nitrogen (not put into production). After Zhao found it, he got into the tank to save people and fainted in the tank. Ma then tied a rope and went into the tank to save people again. He also fainted in the tank. Shi, the worker who accompanied him on the scene, immediately called for help. Two drivers near the construction site rushed to the construction site to drag Ma out and called the police at the same time. The hospital and firefighters arrived at the scene one after another, lifted Yu and Zhao out, so that the piston rod did not accept additional load, and the parallel length of the sample should be long enough. The on-site rescue was invalid, and all three people died

(2) accident cause analysis

direct cause: the gas was not detected and ventilated before operation, and entered the high concentration nitrogen tank without taking effective protective measures. Blindly entering the rescue without taking effective safety measures, resulting in the expansion of the accident

indirect cause: the production and business units do not pay attention to the emergency rescue work, the system is not perfect, and the main body is not implemented. Safety training is not in place, and employees lack basic emergency knowledge and self rescue and mutual rescue ability. There is no rescue organization, and there is a lack of necessary safety facilities and emergency rescue equipment and equipment

1.2 "10.8" anoxia asphyxia accident in an iron and Steel Group Company

(1) accident process

at 9:00 on October 8, 2006, Lu and painters long and Ma from a Zhejiang anti-corrosion engineering company in Hangzhou measured the painted surface area of the liquid nitrogen cooling tower of the air separation plant that had been completed and put into production. When Ma was measuring the top of the cooling tower, he fell into the tower due to hypoxia and asphyxiation due to excessive nitrogen inhalation. Long and Lu entered the tower for rescue without wearing any protective measures, and collapsed in the tower one after another. The accident caused a total of three deaths

(2) accident cause analysis

direct cause: the equipment that has been put into production contains a lot of nitrogen, and the operators operate against rules without gas detection and safety protection measures. Without any protective measures, the operators blindly entered the tower for rescue, resulting in further expansion of the accident

indirect cause: the anti-corrosion engineering company failed to correctly identify the hazard sources in the limited space, did not formulate or strictly implement the safety management system and operating procedures in the limited space, did not provide labor protection articles, did not do a good job in relevant monitoring work, blindly rescued after the accident, and the operators lacked self-protection awareness and safety prevention skills. No safety education and training for operators

1.3 "7.3" sewage well hydrogen sulfide poisoning accident

(1) accident process

on July 3, 2009, a property company in Tongzhou District, Beijing, was carrying out maintenance work on the sewage lift pump in the sewage well on the west side of the community. Three workers fainted due to hydrogen sulfide poisoning, and another seven people went down the well to carry out rescue, causing a total of 10 people to be poisoned. Six of them died, and the other four were rescued from life-threatening. Another public security firefighter died during the rescue

(2) accident cause analysis

direct cause: the operators lack basic safety knowledge, fail to measure the concentration of oxygen or harmful gas and ventilate before entering the dangerous environment for construction according to the requirements of safety regulations for operation in limited space. Rescuers rushed to rescue without wearing protective equipment

indirect cause: the safety supervision and inspection work on the construction site is not in place, and no special supervisor is arranged to monitor the operation on the well. The property management company did not carry out targeted safety education for the construction personnel, and the operators were indifferent to safety production and lacked self-protection awareness

2 preventive measures

2.1 the government should strengthen the supervision of the employment units

because the operation in limited space is a high-risk operation, and it is hidden, which is prone to acute poisoning, hypoxia and asphyxia accidents, the relevant government departments should further strengthen the supervision and management. The suggested measures are as follows:

(1) strict market access. For the production and business operation units that want to engage in limited space operations, first obtain the corresponding operation qualification, entrust the safety evaluation organization to evaluate their safety production conditions, review whether the operators have been trained, whether the unit is equipped with safety equipment and facilities for limited space operations, and whether the safety management system for limited space operations is established. Only when the safety production conditions are met can they engage in limited space operations. Normalize and standardize the operation in limited space and make it a regular army. In this way, the randomness of temporary employment and some work units can be banned

(2) serious handling of accidents. Once a limited space accident occurs, the unit shall be seriously dealt with, the qualification level shall be reduced, and the work permit shall be revoked if the circumstances are serious. For enterprises that violate the requirements of laws and regulations, in addition to economic punishment, they shall also be investigated for criminal responsibility in accordance with the relevant provisions of the criminal law

(3) irregularly carry out law enforcement inspection, irregularly supervise and inspect the production and business units engaged in operations, check the employment licenses of employees, work approval procedures, work safety protective equipment, etc., and rectify the workplaces with hidden dangers within a time limit

2.2 enterprises implement the main body

(1) establish and improve the safety management system. In accordance with the requirements of the work safety law, the occupational disease prevention law and other laws and regulations, the approval system for work in limited space shall be formulated. According to the requirements of various levels, the safety subject shall be clarified, the safety disclosure shall be done, the employees shall be informed of the risk factors of work in limited space, the safe operation procedures shall be strictly enforced, and the operators shall be prompted to use the correct labor protection articles and strictly follow the safe operation procedures

(2) safety investment should be strengthened. Units engaged in confined space operations shall be equipped with equipment and facilities necessary for confined space operations, including safety protection equipment such as pump suction gas detection alarm, explosion-proof fan, explosion-proof lighting and communication equipment, as well as personal protective equipment such as air respirators and full body safety belts. At the same time, the operation site should also be equipped with a certain number of life-saving facilities that continue to expand the scope of industrialization and meet the requirements, such as safety ropes, life ropes, rescue tripods, first-aid kits and other equipment, and ensure that they can be used effectively

(3) operators should strictly follow the operation procedures and work in accordance with the relevant technical standards. The current technical specifications include the safety regulations for painting operations, safety technical requirements for work in confined space (GB), code for protection against occupational hazards of work in confined space (GBZ/T), guide to the selection of direct reading gas detectors in confined space (GBZ/T), safety specifications for work in confined space of chemical production units (AQ) The operators shall strictly follow the safety requirements in the confined space entry guide for oil tankers in the petroleum industry (SY/T), the technical code for monitoring and protection of oxygen deficient hazardous operations in the power industry (DL/T), the safety code for preventing oxygen deficient hazardous operations in ship cargo holds and enclosed spaces (GB), and the safety code for oxygen deficient hazardous operations (GB), so as to avoid poisoning and suffocation accidents

(4) do a good job in three-level safety education and training. Do a good job in the safety education of management, middle level and post safety education, especially the education and training of safety production in limited space for new employees, and the safety education of new posts and new operation methods for those who change new types of work and adopt new technologies, new processes, new equipment and new materials. The educated can only work after passing the examination. The contents of the training shall include the dangerous characteristics of work in limited space, the use and maintenance of personal protective equipment in limited space, the safety production management in limited space, the emergency rescue and on-site first aid of safety accidents in limited space. Beijing has included the monitoring personnel of underground limited space into the assessment scope of special operations. According to the requirements of article 5.2.4 of the technical code for safety of underground confined space operation, the supervisor can judge whether the material is suitable for some specific processing or terminal use by using UTM test materials. The guardian should hold a valid special operation certificate for underground confined space operation. The person in charge of the operation, the supervisor and the operator shall pass the safety production education and training of underground confined space operation

(5) carry out emergency drills regularly. For units that have been engaged in limited space operations for a long time, they should comprehensively identify the dangerous and harmful factors that may be encountered in their limited space operations and possible emergencies, prepare scientific, reasonable, feasible and effective accident emergency rescue plans, and ensure that drills are organized at least once a year

analyze relevant data and cases to reveal the harmfulness of limited space accidents. For limited space operations, we should strengthen safety management, strict market access, implement the main body of production and business units, equip safety protection equipment, do a good job in three-level safety education and training, master the ability to respond to first aid and other measures, so as to reduce limited space accidents, ensure personnel safety and reduce property losses

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