How often should pressure vessels be inspected? What is the service life of pressure vessels?

Time2024-08-17

How often should pressure vessels be inspected?

Pressure vesselHow often is it inspected?

The first internal and external inspection cycle after the pressure vessel is put into use is generally 3 years. External inspection: regular online inspections during the operation of the pressure vessel, at least once a year. Internal and external inspection: inspection when the pressure vessel is shut down, with two types of inspection cycles: 1. For safety status levels 1 and 2, at least once every 6 years. 2. For safety status level 3, at least once every 3 years. Regular inspections of pressure vessels can generally be divided into external inspections, internal and external inspections, and comprehensive inspections. Inspections are conducted during the downtime of the vessel, and the cycle should be determined by the user unit based on the technical condition, usage conditions, and relevant regulations. However, at least one external inspection should be conducted each year, at least one internal and external inspection every three years, and at least one comprehensive inspection every six years.

What is the service life of a pressure vessel?

The service life of a pressure vessel is not determined by a specific regulation but is defined during the design and manufacturing process of the vessel. When designing a pressure vessel, the expected service life must be referenced, considering factors such as corrosion allowance to determine the service life of the vessel. According to multiple provisions in the relevant legal documents of TSG R0004, the design, manufacturing, and usage of pressure vessels should all consider the service life according to technical specifications. There should be clear records in the documentation of the pressure vessel. The 'Safety Technical Supervision Regulations for Simple Pressure Vessels' stipulates a recommended service life for simple pressure vessels (the service life is marked on the pressure vessel nameplate). According to HG/T20580-2011 'Basic Regulations for the Design of Steel Chemical Vessels', the design life of pressure vessels is around 8 to 10 years, with specific years determined by design specifications. General vessels and heat exchangers: 10 years; Distillation columns, reactors, high-pressure heat exchangers: 20 years; Spherical vessels: 25 years; Important reaction vessels (such as thick-walled hydrogen reactors, ammonia synthesis towers, etc.): 30 years. During the use of pressure vessels, there must be complete records of regular inspections and patrol inspections. Pressure vessels that exceed their designed service life must be reported to the competent authority and can only continue to be used after inspection by the authorized institution. It is essential to ensure usage within the designed service life to guarantee utilization.