Contraindications for plugging leaks under pressure

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Plugging a leak while the system is under pressure is an extremely dangerous practice. Prohibitions regarding this type of operation include: work must not be carried out when the nature of the leak is unknown; before attempting to plug the leak under pressure, it is necessary to determine the nature of the leak and develop a feasible technical plan. Operations are prohibited in the absence of a safety plan: A safety operation plan must be developed before carrying out leak sealing under pressure, and protective equipment must be worn. Environmental temperature and oxygen deficiency issues: When carrying out pressure-based leak sealing work in ducts and inspection wells, it is necessary to pay attention to the environmental temperature in order to avoid oxygen deficiency, the expansion of the leak area, or even situations that become uncontrollable. Leakage caused by thermal stress: For pipe leaks resulting from thermal stress, measures should be taken to eliminate or reduce thermal stress while sealing the leak, in order to prevent secondary leaks. Material temperature resistance: When selecting rubber gaskets, attention should be paid to the material’s temperature resistance. Different types of rubber have varying temperature resistance levels; for example, nitrile rubber has a temperature resistance of ≤120°C, EPDM rubber has a temperature resistance of ≤150°C, and fluororubber has a temperature resistance of ≤180°C. The design strength does not meet the requirements of operating pressure: The design strength of steel clamps, steel fixtures, and patch plates must meet the requirements of operating pressure. Equipment and pipelines handling extremely hazardous media: For equipment and pipelines dealing with media of extremely high toxicity, pressure-sealing operations must not be carried out. Leakage sites where the wall thickness of the sealed area cannot be measured, and where cracks in the material cannot be effectively prevented from spreading: pressure sealing operations must not be carried out at such sites. The strength and stiffness of the structure and materials do not meet the requirements for sealing operations under pressure; sealing operations under pressure are not permitted. For leak locations where the bolt strength does not meet the requirements for achieving the necessary sealing pressure and cannot be reinforced: sealing work under pressure is not permitted. Pressurized sealing systems outside the operating pressure and temperature ranges: Pressurized sealing operations shall not be carried out on systems that are outside the operating pressure range (400 Pa (absolute pressure) to 30 MPa (gauge pressure)) and temperature range (-180°C to 800°C). In the event of a leak in the pressure pipelines containing flammable and explosive materials in hazardous chemical facilities, the facility must be shut down immediately; it is not allowed to attempt to seal the leak while the pipeline is under pressure. Plugging leaks in a boiler while it is under pressure: Doing so is an extremely dangerous practice that can easily lead to boiler explosions; therefore, **strict prohibitions are in place against plugging leaks in boilers while they are under pressure.** The on-site safety measures do not comply with the company’s safety regulations: work to seal leaks under pressure is prohibited. Sealing leaky media containing particles has a low success rate: sealing operations under pressure must not be carried out.