According to the security situation in the pressure vessel is divided into five levels . Security level should be assessed according to the test results to assess the project level which is the lowest rating level. 1 : Pressure vessel factory complete information ; design , manufacturing quality compliance with the relevant regulations and standards ; safe to use in the design conditions . 2 : Factory data basically complete ; design , manufacturing quality basic compliance with relevant regulations and standards ; according to inspection reports, there are some not compromise , do not fix general defect ; periodic inspection cycle in the regulations , the provisions of can be used safely under operating conditions. 3 : Factory data is not complete ; main material , strength, structure basically meet the requirements of the relevant regulations and standards , there are some do not comply with the relevant regulations or standards issues or defects , according to the inspection report , recognized as a regular inspection cycle and regulations in inside , under specified operating conditions , can be used safely . 4 : Factory data is not complete ; main material is unknown or does not comply with the relevant provisions ; structure and strength does not meet the requirements of the relevant regulations and standards ; seriously flawed ; according to inspection reports, is recognized in the laws and regulations of the inspection cycle , require two operations under condition monitoring use . 5 : serious defects , it is difficult or impossible to repair after repair value or no repair is still difficult to ensure the safe use ; inspection report concluded that the sentence of waste . It should be noted that: security level of the defect , refers to the existence of the state of ultimate pressure vessel , such defects have been eliminated , then the condition is removed to determine the security level of the pressure vessel .