Regarding pressure vessels that have reached the design service life or have been used for more than 20 years
Thread Content
In recent years, during the inspection of pressure-bearing special equipment, many companies lack understanding of the procedures and standards for pressure vessels that have reached the design service life or have been used for more than 20 years, especially in terms of handling changes to the registration certificate. In order to further serve enterprises, the Municipal Special Inspection Office organized the problems and helped enterprises resolve their doubts. Precautions for units using pressure vessels: 1. The concept of design service life. The design service life of a pressure vessel is determined by the designer taking into account the factors that affect the service life of the equipment during design, such as: The mechanical properties, corrosion allowance, load, operation, environment, etc. of the material are determined based on safety principles. 2. The relationship between the design service life and the actual service life. These factors are not constant during actual use, so the design life of the pressure vessel is not necessarily equal to the actual service life. It is only an estimate given by the designer based on the expected use conditions of the equipment. Its function is to remind the user that necessary safety measures should be taken when the design life of the pressure vessel is exceeded, such as: Strengthen monitoring during operation, shorten inspection cycles, etc. 3. How is the next inspection cycle determined? Periodic inspections are carried out by inspection agencies in accordance with the requirements of regulations and standards. Therefore, in order to comply with the provisions of Article 7.1.7 of the "Solid Capacity Regulations", the next inspection date will be determined before the inspection cycle is shortened in such pressure vessels, such as: The design service life of the equipment expires in January 2023, and the periodic inspection cycle is in January 2022, so the next inspection date will be: January 2023. The inspection cycle is determined not to shorten the inspection cycle, but to comply with the requirements of the inspection regulations. 4. Requirements before changing the use of registration certificate. After the equipment reaches the designed service life and is inspected (or fit for use) and "qualifies for use", it should be approved by the principal person in charge of the inspected unit (generally understood as the technical person in charge or the person in charge of production safety) (the approval understood by the inspection agency is: The person in charge shall submit a written request for the continued use of the equipment) and bring relevant technical information and inspection reports to the local special equipment safety supervision department to apply for a change of registration certificate. 5. Change of use registration certificate. After the change, the use registration certificate will be clearly marked with the words "exceeded the design service life", and the user will be reminded again that the equipment should be monitored during use and operation.
A thorny problem is that many third-party testing units are now unwilling to inspect and issue inspection reports for overage equipment.
If it has been used for more than 20 years, the calculation basis is the date of manufacture or the date of use?
What should I do if the special inspection office does not inspect the items beyond the design period?
The concepts of design service life and actual service life are inconsistent, and the two years are inconsistent. should be analyzed and treated separately.
study* , the actual service life is not necessarily equal to the design service life
The General Administration's reply is based on the trial production date, but it also requires the user to provide physical proof of the date of commissioning.
7.1.7 Pressure vessels that have reached their design service life. If pressure vessels that have reached their design service life (the design service life is not specified, but pressure vessels that have been used for more than 20 years are deemed to have reached their design service life), if they want to continue to be used, the user should entrust a special equipment inspection agency with inspection qualifications to inspect it in accordance with the relevant regulations on periodic inspection. If necessary, follow 8.9 of this regulation. Conduct a safety assessment (fitness for use evaluation) according to the requirements, and only after approval by the main person in charge of the user unit, the use registration certificate can be changed before it can continue to be used. The above is the original text of TSG 21-2016. Please pay attention to the "if" and "entrustment" in the original text. The meaning of "entrustment" is that the person being entrusted can accept your entrustment or not. After all, equipment design units, manufacturing units, and supervisory inspection agencies that have exceeded their design life will not be asked. All responsibilities will be borne by the entrusted unit. The entrusted unit will not easily accept over-limit inspections for insurance reasons. There are also many design drawings where the life span remarks are based on the factory date. Please study the as-built drawings in detail before making a decision.