Design changes for in-service pressure vessels
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The original designed service life of the pressure vessel in use was 10 years; upon reaching that lifespan, an application was submitted by the party using it to the original design agency, which then changed the service life to 15 years. It just feels wrong in some way; the regulations don’t specify any inspections for such situations. The design unit should bear responsibility for any signatures and seals it provides, but is such a way of bypassing supervision and inspection really feasible?
It shall be handled in accordance with the regulations for the use and management of pressure vessels. The design agency cannot issue design changes.
If it is used beyond its service life, it must pass inspection before it can be used; design specifications alone are not sufficient in this regard
According to the regulatory requirements, it’s not necessary to discard the device at the end of its design life; supervision and inspection as required by the regulations are sufficient. There is no need to change the design life, and the tolerance specifications do not allow it either.
Upon reaching the design life, supervision and inspection by a specialized inspection agency are required. They will issue a report recommending how many years to use it.
Upon reaching the design life, the user unit should engage an evaluation agency to assess whether the equipment can still be used and to determine the interval for further inspections, before deciding whether to continue using it. It has nothing to do with the original design agency anymore.
I can’t find which tolerance specification prohibits it.
It is incorrect for the design agency to make design changes; this practice does not comply with the regulatory requirements. In accordance with relevant regulations, after reaching the design service life, if pressure vessels are to be continued in use, the entity using them must commission a special equipment inspection agency with the appropriate qualifications to conduct inspections in line with the provisions for regular inspections. If they meet the requirements, approval from the person in charge of the using entity is also necessary; only after obtaining an updated registration certificate can the vessels continue to be used.
It is certainly not feasible to change the design service life of pressure vessels that have reached their designed service life in order to avoid inspections and safety assessments by having the design agency do so; although the regulations do not specify this, it should be something on which consensus can be reached without any need for explicit provisions. It’s better to follow clause 7.1.7 of the capacity regulations.
According to the pressure vessel regulations, a pressure vessel that has not reached its design life cannot be used. It must pass inspection in accordance with these regulations before it can be re-applied for use; only upon approval can it continue to be used.
The design life is determined at the time of design; who would agree to change it after it has been in use for ten years?