I. Operation Procedure

　　1. The setting of the electric power switch for the blind flange valve during actual operation should, as far as possible, prevent the valve from being left unattended. When personnel are operating the valve, they should stand in a favorable position and carefully monitor the surrounding environment for any changes.

　　2. Before performing any operational procedures on blind flange valves, it is mandatory to complete and submit an application for a liquefied gas equipment operating permit. Only after passing step-by-step inspections and obtaining on-site safety confirmation can the next operational step be carried out.

　　3. At least two personnel must be involved in the actual operation of blind flange valves, and all operators must hold the required certifications. Prior to starting work, ensure thorough communication and coordination with colleagues on both sides. Before commencing operations, verify that air respirators, combustible gas detection and alarm systems, and communication equipment are all in good working order and fully functional. During operations, wear air respirators at all times; dedicated personnel shall be responsible for operating and monitoring the equipment. For high-altitude work, obtain the necessary high-altitude work permit. All workers must wear safety belts properly, ensuring that the belt is secured at a higher point and used at a lower position.

　　4. Before operating the blind flange valve, the person responsible for the task must inspect the sealing ring of the blind flange valve for signs of embrittlement and damage deformation. If any damage is found, it must be replaced immediately. The valve can only be operated once a replacement has been completed and confirmed to be in good condition.

　　5. During the operation of blind flange valves, the supervisor shall establish a safety perimeter, remove any flammable or explosive materials from the site, and strictly prohibit unauthorized personnel from entering the operational area or performing other tasks.

　　II. In actual operation

　　1. Personnel performing actual operations must thoroughly understand the safety operating procedures for this position. When operating butterfly valves or blind flange valves, be sure to confirm the position of the gate valve’s power switch to prevent reverse operation.

　　2. Before operating the blind flange valve in practice, first completely release its clamping device. Then, adjust the valve flap to the correct position. It is strictly prohibited to operate the valve flap while the clamping device remains partially or fully engaged.

　　3. No personnel are allowed to stand in the operational area of the blind flange valve during actual operation. When manually operating the blind flange valve, to prevent the valve disc from moving freely, you must first secure the valve disc before releasing the clamping device. Only after the clamping device has been completely released should you then proceed to operate the valve disc promptly.

　　4. Butterfly valves and blind flange valves should be equipped with interlocking safety devices. If the butterfly valve fails to close in time, the blind flange valve cannot be operated effectively. At the current production site, there is no interlocking equipment yet, or the butterfly valve before the blind flange valve is not tightly closed. When operating the blind flange valve, first open the vent valve located between the two valves to relieve pressure. Then, depending on the leakage situation, proceed with operating the blind flange valve to prevent excessive pressure from causing liquefied gas to leak and spread around.

　　III. After Actual Operation

　　1. After the blind flange valve has been operated successfully, the electrolysis line must be shut down, a tag must be hung to indicate that it is out of service, and the power switch control cabinet must be locked to prevent operational errors.

　　2. After completing the actual operation of the blind flange valve, check whether there is any steam leakage at the flange connection to prevent safety accidents caused by gas leakage due to an improperly closed valve.

　　IV. Other

　　1. Blind flange valves should, whenever possible, be operated during daylight hours to prevent gas leaks from going unnoticed at night. If operations must be carried out at night due to maintenance requirements, it is essential to ensure adequate lighting. The floodlights must be positioned at least 10 meters away from the work area, and a designated line manager or full-time safety officer must be present on-site to provide unified command and assign personnel for monitoring.

　　2. If the electric power switch for the blind flange valve is malfunctioning, when manually operating the blind flange valve, you must wear an air respirator. The tools used for the job—such as wrenches and pipe wrenches—must be explosion-proof to ensure reliability.

　　3. When actually operating the blind flange valve, avoid handling liquefied gas whenever possible. First, close the butterfly valve upstream of the valve, then open the vent valve between the valves before proceeding with the actual operation.

　　4. To address emergency situations in the operation procedures of blind flange valves, each enterprise must develop and clearly define a comprehensive emergency management plan specifically tailored to handle critical valve malfunctions. This plan should ensure that, in cases of valve failure, improper operation, abnormal leakage of liquefied gas, or other unexpected incidents, immediate and effective responses can be implemented.

　　Training on Practical Operating Procedures for the Safety of Liquefied Gas Blind Flange Valves

　　1. Utilize the production base’s safety WeChat platform account to publish “Safety Operating Requirements for Gas Blind Flange Valves,” providing employees with convenient access to learning and training materials.

　　2. Boiler operators, electric welders, equipment maintenance workers, chief controllers, full-time safety officers, production and manufacturing team leaders, electrical equipment supervisors, and machinery equipment supervisors shall receive training on the “Safety Operating Requirements for Gas Blind Flange Valves” and participate in a discussion. The content of the discussion shall be recorded in the safety education logbook.

　　3. The following personnel—boiler operators, electric welders, equipment maintenance workers, chief controllers, full-time safety officers, production and manufacturing team leaders, electrical equipment supervisors, and machinery and equipment supervisors—will take an exam on the safety operating procedures for liquefied gas blind flange valves.