Where is the design service life of the pressure vessel specified

The provisions on the design service life of pressure vessels mainly come from national standards, industry norms and the agreement between the design client and the design unit. Specifically, it can be summarized in the following aspects:

1. national standards and industry norms

"Safety Technical Supervision Regulations for Fixed Pressure Vessels" (such as TSG 21-2016 and other versions): This is one of the safety technical specifications for special equipment in my country, which covers the design, manufacture, installation, use, transformation, repair, inspection and testing of pressure vessels. Comprehensive regulations have been made in other links. Among them, it is clearly required that the design service life should be indicated on the general design plan of the pressure vessel (for fatigue vessels, the number of cycles should be indicated). This provision ensures that the designer must consider the expected service life of the pressure vessel when designing it and clearly indicate it in the design document.

Other relevant national standards and industry standards: such as GB/T 150, these standards also provide a reference for the design life of pressure vessels. For example, GB/T 150.1-2011 clearly states that the designer should consider the design life of the container and the corrosion rate of the medium to determine the corrosion allowance.

Agreement between the 2. design client and the design unit

in the actual design process, the design client (user) usually proposes the design conditions of the pressure vessel to the design unit in writing, including the expected service life. The designer determines the design service life based on these conditions and the expected service conditions of the pressure vessel (such as operating parameters, media components and characteristics, use environment, etc.).

It should be noted that the design service life is not equivalent to the actual service life. It is only an estimate given by the designer according to the expected use conditions of the container, and its function is to remind the user that when the design service life is exceeded, necessary measures should be taken to ensure the safe operation of the pressure vessel, such as measuring the thickness frequently and shortening the inspection cycle.

Considerations in 3. Practice

when determining the service life of the pressure vessel design, the designer also needs to consider a variety of factors, such as the mechanical properties of the material, the design of the structure and size of the vessel, the corrosion allowance, the dependence of high temperature creep and high temperature fracture on time, wear and local corrosion factors, the cost of vessel construction and the replacement cycle of the load.

In addition, with the continuous progress of technology and the accumulation of experience, designers will adjust the estimation method of design service life according to the latest research results and engineering practice to ensure the safety and economy of pressure vessels.

In summary, the provisions of the design service life of pressure vessels mainly come from national standards, industry norms and the agreement between the design client and the design unit. These regulations and agreements together constitute the basis for determining the design life of the pressure vessel and ensure the safe use of the pressure vessel.