Problem: Safety valve cannot be removed for inspection
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In the new chemical plant, there is one electrically heated heat transfer oil boiler along with two safety valves. It seems that the issue of calibration wasn’t given sufficient consideration during the design phase; now the boiler cannot be stopped while it’s in operation, and the safety valves are approaching their calibration deadline. What should be done? Can a valve be installed between the safety valve and the boiler? If it can be installed, what type of valve should be chosen? Is it necessary to inform the Quality Supervision Bureau if it is installed? Has anyone with the expertise to carry out delayed calibration of safety valves? Please ask the experts for guidance, thank you
A valve should be installed in front of the safety valve for long-term continuous operation, to facilitate online monitoring. Choose a globe valve whose material is in compliance with safety regulations and whose pressure and temperature operating ranges meet the requirements. It’s best to discuss this with the testing department to avoid disrupting production; online testing is an option.
Except for those newly installed, all our safety valves are calibrated on-site. You can communicate well with the inspectors; they can come to the site for verification.
What types of valves can be installed? Can stop valves, gate valves, etc. be used?
I just saw it in the online front end and brought it up, but the manager had never heard of online and rejected it. How is it usually charged online?
The regular calibration of spring-loaded direct-load safety valves should, in principle, be carried out in a calibration laboratory. When it is difficult to disassemble the valve for calibration, one laboratory calibration and one on-line calibration can be performed every two calibration cycles. However, safety valves installed on pressure vessels with toxic, hazardous, flammable, or explosive media are not allowed to be calibrated online. Online verification must be carried out while ensuring the safety of personnel and production ； Lever-type safety valves and gravity-type safety valves are generally not suitable for calibration in a laboratory. Online verification is often not a solution either; the vulnerable components of the valve need to be replaced as they age. . . It is not possible to determine the reseating pressure. . . Built-in spring safety valves – pilot-operated safety valves are also difficult to handle. The RBI test is still widely used today to streamline risk-based classification and supervision. . . After identifying the risks, they still need to be verified. . . Doing these things is not just about making money; it’s about creating a concept. . . It really can’t solve practical problems. My personal opinion is to stop it if necessary; one has to bear the risks themselves. . . I hope nothing goes wrong. . . With MDB, the enforceability of regulatory requirements is very poor; experts write in a vague manner and show no sense of responsibility. . . If something goes wrong, it’s entirely your own fault.:Q:shutup::dizzy:.
When the boiler stops, the pipes get clogged. Without any special exceptions, the boss won’t allow a stop. Even though the pipeline is lacking materials and the boiler’s temperature and pressure need to be reduced, it still cannot be shut down. I agree that the regulations are indeed rather vague and lack enforceability
A valve can be installed in front of the safety valve; however, when the equipment is put into use, this valve needs to be fully open and sealed with a lead seal – generally, a gate valve is sufficient for this purpose； Two safety valves can be installed on critical equipment; if their calibration intervals differ, this ensures that at least one safety valve remains functional.