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Guidelines for Limited Space Operations

(Summary description)Limitedspacereferstoaclosedorpartiallyclosedspacewithlimitedimportandexport,notdesignedasafixedworkplace,poornaturalventilation,easytocausetoxicandharmful,inflammableandexplosivesubstancesaccumulation

Guidelines for Limited Space Operations

(Summary description)Limitedspacereferstoaclosedorpartiallyclosedspacewithlimitedimportandexport,notdesignedasafixedworkplace,poornaturalventilation,easytocausetoxicandharmful,inflammableandexplosivesubstancesaccumulation

Information

Limited space refers to a closed or partially closed space with limited import and export, not designed as a fixed workplace, poor natural ventilation, easy to cause toxic and harmful, inflammable and explosive substances accumulation or insufficient oxygen content. Limited space operation refers to the operation activities carried out by operators in limited space.
[Classification]
One is the airtight equipment, such as cabin, storage tank, vehicle tank, reaction tower (kettle), refrigeration box, pressure vessel, pipeline, flue, boiler, etc.
Second, there are limited underground space, such as underground pipelines, basements, underground warehouses, underground works, underground ditches, tunnels, culverts, pits, waste wells, cellars, sewage tanks (wells), biogas tanks, septic tanks, sewers, etc.
Third, there are limited space on the ground, such as storage room, distiller's grains pond, fermentation pond, garbage station, greenhouse, cold storage, granary, silo and so on.
[Detection]
Production and business units should strictly implement the principle of "testing first, then operating". The detection indexes include oxygen concentration value, flammable and explosive substances (flammable gas, explosive dust) concentration value, toxic gas concentration value, etc. The following three items should be tested at the minimum: oxygen concentration (within the range), flammable and combustible gas concentration (within the minimum explosion limit), and carbon monoxide concentration (below 25 ppm). Operators are strictly forbidden to enter the limited space without being tested and qualified. When the working environment may change, the hazard factors in the workplace should be continuously or regularly detected. When testing, the inspector should be in a safe environment. When testing, the inspector should record the inspecting time, place, gas type and concentration.
[Hazard Assessment]
Before the implementation of limited space operations, production and business units should assess the hazards to the working environment according to the test results, formulate measures to eliminate and control hazards, and ensure that the whole operation period is in a safe and controlled state. Hazard assessment should be carried out according to GB8958 "Safety Regulations for Hypoxic Hazardous Operations" and GBZ2.1 "Occupational Contact Limits of Hazardous Factors in the Workplace Part 1: Chemical Hazardous Factors". And we should make good preparations for ventilation, protective equipment, respiratory protective equipment, emergency rescue equipment and so on.
[Operational procedures]
1. According to the principle of testing first and then operating, the limited space can not be accessed until it meets the safety requirements. It is strictly forbidden to enter the workplace until the concentration of oxygen, harmful gases, flammable gases and dust is accurately measured.
2. Ensure the air quality of dangerous work site in limited space. The oxygen content should be above 18% and below 23.5%. The permissible concentration of harmful and toxic gases, combustible gases and dust must meet the safety requirements of national standards.
3. In the process of dangerous operation in limited space, ventilation should be strengthened. In the dangerous operation where the concentration of oxygen, harmful gases, combustible gases and dust may change, necessary measuring times or continuous testing should be maintained.
4. All electrical equipment used in operation must conform to the relevant technical operating rules for electricity safety. Lighting should use safety miner's lamp or safety lamp under 36 volts. Hand-held electric tools that exceed safety voltage must be equipped with leakage protector according to regulations.
5. When harmful gases and combustible gases are found, the inspectors should use harmful gases detection instruments and combustible gas testing instruments at the same time.
6. Inspectors should wear isolation breathing apparatus and strictly prohibit the use of oxygen breathing apparatus.
7. Explosion-proof products that meet the requirements of the Code for the Design of Electric Power Devices in Explosive and Fire Hazardous Environments must be used on the site where combustible gas or combustible dust exists, all detection instruments, electric tools, lighting fixtures, etc.
8. Operators must equip and use isolating breathing protective devices such as air respirators or hose masks in places where ventilation and ventilation measures cannot be adopted due to explosion-proof and oxidation-proof, or where ventilation and ventilation are not sufficiently ventilated and ventilated due to limitations of operating environment.
9. Operators should accurately count the number of workers before entering and leaving dangerous workplaces in limited space.
10. When entering dangerous workplaces in limited space, workers and guardians should specify clear contact signals beforehand.
11. If the risk of hypoxia in the workplace may affect the safety of workers in nearby workplaces, the relevant personnel in these workplaces should be notified in time.
12. It is strictly forbidden for unrelated personnel to enter dangerous workplaces in limited space, and warning signs should be set up in striking places.
13. Rescue devices, such as breathing apparatus, ladders, ropes and other necessary devices and equipment, must be equipped in dangerous workplaces with limited space in order to rescue workers in exceptional circumstances.
14. When welding with carbon dioxide or helium in an airtight container, ventilation must be carried out during the operation to ensure that the air meets the safety requirements.
15. Operators must close valves, install blindboards and set up signs prohibiting start-up in conspicuous places when working inside the sealed equipment (such as oil tanks, reaction towers, tanks, boilers, etc.) connected with the pipeline.
16. When the operator works in the closed equipment, he usually opens the door or cover of the entrance and exit. If the equipment communicates with the pipeline under suction or negative pressure, it is strictly prohibited to close the door or cover of the entrance and exit.
17. In the underground compressed air operation, hypoxic air should be prevented from leaking into the work place. If there is hypoxic air in the facilities connected with the work place, it should be eliminated directly to prevent the hypoxic air from entering the work place.

[Personnel Responsibilities]
1. Responsibilities of Hazardous Operators Entering Limited Space
Work in strict accordance with the tasks, locations and time signed on the Safety Approval Form.
Before operation, the safety measures in the workplace should be checked to ensure that they meet the requirements.
Wear protective clothing, protective devices and tools according to regulations. Familiar with emergency plan, master alarm contact method.
2. Duties of job Guardians
The guardian must have a strong sense of responsibility, be familiar with the environment and circumstances, and be able to timely judge and deal with abnormal situations.
The guardian shall inspect the implementation of the safety measures and, if he finds any problems, has the right to put forward that he shall not carry out the operation for the time being.
The guardian shall draw up a contact signal with the operator. If abnormalities are found, relevant measures should be taken immediately.
The guardian should be familiar with the emergency plan, master and skillfully use the equipped emergency rescue equipment, facilities, alarm devices and so on, and stick to his post.
The guardian shall carry the "Safety Approval Form" and be responsible for keeping and recording relevant issues.
3. Prohibit the following operations
No "limited space operation" procedures. Operations inconsistent with the procedures for "limited space operations". No guardian's work. Overtime work. Blind rescue in unknown circumstances.
4. Emergency supplies
Respiratory apparatus, ladders, cables and other necessary apparatus and equipment.
[Responsibilities of Principal Officials]
The principal responsible persons of production and business operation units shall strengthen the safety management of limited space operations and perform their management responsibilities.
[Operational Approval]
No one is allowed to work in limited space without the approval of the operator. In order to prevent unauthorized personnel from entering the work site, striking warning signs should be set up near the entry points in limited space, and dangerous and harmful factors and preventive measures should be notified to operators.
[On-site supervision and management]
The person in charge, guardian and operator should be clearly defined on the limited space operation site, and they should not operate without guardian.
[Contracting Management]
Strict contracting management and standardized contracting behavior shall not be allowed to contract projects to units or individuals that do not meet the conditions for safe production. Sign special safety production management agreements, or agree on their respective safety production management responsibilities. When there are many contractors, the production and operation units shall coordinate and manage the safe production work of the contractors.
[Temporary work]
In strict compliance with the requirements of this Code, construction operations shall not be organized on their own without necessary inspection and protection conditions. They shall contact the relevant departments for assistance and cooperation or be carried out in the form of entrustment.
[Training]
To carry out safety education and training, the contents include: dangerous characteristics and requirements of safe operation in limited space; correct use of program testing instruments and personal protective equipment entering limited space; emergency rescue measures and emergency rescue plans, etc. Training should be documented. After the training, the contents and dates of the training should be recorded. Where a production and business operation entity is not in a position to carry out training, it shall entrust a qualified training institution to carry out training work.
[Emergency rescue]
To formulate emergency rescue plan for limited space operations, clarify rescue personnel and responsibilities, implement rescue equipment and equipment, master accident disposal procedures, and improve emergency disposal capabilities for emergencies. The plan will be rehearsed at least once a year and constantly revised and improved. When an accident occurs in limited space, the guardian should give an alarm in time. Rescue workers should protect themselves and equip with necessary breathing apparatus and rescue equipment. Blind rescue is strictly prohibited, leading to the expansion of the accident. (Zhang Yue)

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