Key points of safety technology for working in confined spaces

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1. A \"confined space\" refers to enclosed or semi-enclosed facilities and areas in production or living areas, such as furnaces, towers, kettles, tanks, warehouses, tank trucks, pipelines, flues, tunnels, sewers, ditches, pits, wells, ponds, and culverts. When entering a confined space for work, the following safety and technical measures must be taken. 2. Safety technical measures for working in confined spaces: ① Before entering a confined space for work, hazard identification and risk assessment of the confined space should be carried out based on the nature of the work, and corresponding operating procedures and safety measures should be established. The construction unit must clarify the responsibilities of the job supervisor, the workers, and the external supervisors ； Construction projects that involve entering underground areas, ditches, pipelines, and other locations where toxic gases may be present must not be assigned to entities or individuals that do not meet the required conditions. ②To carry out work in a confined space, a “Permit for Work in Confined Spaces” must be obtained, and the approval procedures must be strictly followed. The person in charge of the construction site shall provide the workers with instructions on the work procedures and safety measures, and assign a supervisor for the work. Work in confined spaces is prohibited in the absence of a \"Confined Space Entry Permit\" and a supervisor. ③Before entering a confined space for work, it is necessary to safely isolate the confined space from other areas (by installing blind flanges or removing a section of pipeline), and to clean and purge it thoroughly. Closing valves shall not be used as a substitute for installing blind flanges, and signs should be placed at the locations of the blind flanges. ④Sampling and analysis must be conducted 30 minutes before entering a confined space, with strict control to keep the concentrations of flammable gases, toxic gases, and oxygen within safe limits (when the lower explosive limit of a flammable gas is greater than 4%, a concentration of no more than 0.5% is considered acceptable) ； When the lower explosion limit of the combustible gas is less than 4%, a measured concentration of no more than 0.2% is considered acceptable ； An oxygen content of 19.5%–23.5% is considered acceptable ； The levels of toxic and harmful substances must not exceed the **specified maximum allowable concentrations of toxic substances in workshop air**; work in confined spaces is only permitted after the analysis shows that these levels are within acceptable limits. If work is carried out in a confined space for an extended period, testing should be conducted at least every 2 hours. If levels exceed the allowable limits, work must be stopped immediately and personnel evacuated promptly. ⑤Implement appropriate ventilation measures to ensure good air circulation in confined spaces. Natural ventilation can be used; forced ventilation may be employed if necessary, but it is strictly prohibited to introduce oxygen inside. The working time for personnel entering confined spaces should not be too long; shift work or breaks should be arranged. ⑥When working in confined spaces, there must be sufficient lighting, and safe voltage as well as safety lamps should be used. The lighting voltage in confined spaces should not exceed 36V. When working in humid or confined spaces, the voltage should be less than 12V; all lighting fixtures and power tools must meet the requirements for moisture resistance and explosion prevention. ⑦When entering confined spaces containing corrosive, asphyxiating, flammable, explosive, or toxic materials to carry out work, it is necessary to wear the appropriate personal protective equipment and devices as required. In special circumstances, workers may wear long-tube masks or air respirators. When using a long-tube mask, it is essential to carefully check its airtightness and prevent the ventilation tube from being compressed; the air intake should be positioned at the upwind side of fresh air, and there must be someone to supervise the use of such masks. ⑧When performing welding work in a confined space, it is necessary to obtain a welding permit in accordance with regulations and go through the required procedures at the same time. ⑨When working inside a confined space, it is necessary to assign a dedicated person to supervise and maintain effective communication with the workers inside the confined space. In case of emergencies such as poisoning or suffocation, rescue personnel must wear isolation protective equipment to enter the confined space, with at least one person remaining outside to handle communications. Blind rescue attempts without the necessary conditions are prohibited to prevent an increase in casualties. ⑩When the working conditions in a confined space change and pose a risk to the safety of the workers, they must be evacuated immediately ； If work needs to continue, the approval process for working in a confined space must be obtained again. ⑾After the work is completed, the confined space must be inspected together by the workers, the supervisor, and the person in charge of the department using it. Only after it is confirmed that there are no people, tools, or debris inside the confined space can it be sealed and left. 3. Requirements related to confined space operations as stipulated in other regulations, standards, and codes. Do different companies have any other distinct security requirements?