Regular inspection schedule for safety valves and pressure vessels (self-inspection)

The \"Regulations on Safety Inspection of Fixed Pressure Vessels\" TSG R0004—2009 stipulates in 6.3.5 that pressure vessels shall be inspected internally at least once a month； 7.3 Periodic inspection cycle: Periodic inspection refers to the inspections and safety condition assessments carried out when the pressure vessel is shut down. Pressure vessels should generally undergo their first regular inspection within 3 years of being put into use. For the next inspection cycle, the inspection agency shall determine it in accordance with the following requirements, based on the safety condition grade of the pressure vessel: (1) For vessels with a safety condition grade of 1 or 2, inspections are generally carried out every 6 years ； (2) For those with a safety status level of 3, inspections are generally carried out every 3 to 6 years ； (3) Those with a safety status rating of 4 shall be used under monitoring, the inspection interval to be determined by the inspection agency, and the cumulative period of monitored use shall not exceed 3 years ； (4) For those with a safety status level of 5, the defects must be addressed; otherwise, they shall not be used any further ； (5) The evaluation of the safety condition grade of pressure vessels is carried out in accordance with the \"Rules for Periodic Inspection of Pressure Vessels\"; if the specified conditions are met, the inspection interval may be appropriately shortened or extended ； (6) For pressure vessels employing risk-based inspection (RBI) technology, the inspection interval shall be determined in accordance with the requirements of 7.8.3 of these regulations. Safety valves should generally be calibrated at least once a year

Now, the safety valves are inspected every six months.

Are there any standards I can refer to?

The following is excerpted from TSG 21-2016 \"Regulations on Safety Technical Inspection of Fixed Pressure Vessels\", 7.1.5 Regular self-inspections: The self-inspections of pressure vessels include monthly inspections and annual inspections. …… 7.2.3.1.3 Calibration cycle for safety valves 7.2.3.1.3.1 Basic requirements Safety valves should generally be calibrated at least once a year; under the special conditions specified in paragraphs 7.2.3.1.3.2 and 7.2.3.1.3.3, the calibration cycle may be extended appropriately with the approval of the person in charge of safety management at the using unit. 7.2.3.1.3.2 Extension of the inspection period to 3 years: The inspection period for spring-loaded safety valves can be extended up to 3 years if they meet the following conditions: …… 7.2.3.1.3.3 Extension of the inspection period to 5 years: For spring-loaded safety valves, the inspection period can be extended up to 5 years if they meet the conditions specified in items (2), (3), (4), (6), and (7) of section 7.2.3.1.3.2, in addition to meeting the following conditions as well: ……

The regular inspection of safety valves is carried out once a year. For pressure vessels, it is initially 3 years, and then determined based on the classification.