The triangular relationship between nominal pressure, design pressure, and operating pressure
Thread Content
I. What is nominal pressure PN (MPa)? The reference values related to the pressure resistance of pipeline system components refer to the design-specific pressures associated with the mechanical strength of the pipeline elements. The nominal pressure is generally denoted by PN. (1) Nominal pressure – the pressure resistance strength of the product at a reference temperature, denoted as PN, with the unit being MPa. (2) Reference temperature: The reference temperature varies depending on the material. For example, the reference temperature for steel is 250°C. The nominal pressure is 1.0 Mpa, denoted as: PN 1.0 Mpa. II. What is working pressure? It refers to the maximum pressure specified based on the highest operating temperatures at various levels for the medium being transported, in order to ensure the safe operation of the piping system. Work stress is generally denoted by Pt. III. What is the design pressure? It refers to the maximum instantaneous pressure acting on the inner wall of the water supply pipeline system. Generally, the sum of the operating pressure and the residual water hammer pressure is used. The design pressure is generally denoted by Pe. IV. Test pressure: The pressure required to be achieved when testing pipes, containers, or equipment for pressure resistance and airtightness. The test pressure is generally denoted by Ps. V. The relationship among nominal pressure, working pressure, and design pressure: Nominal pressure is a nominal pressure value that is artificially specified for the convenience of design, manufacturing, and use. The unit of this nominal pressure is actually pressure intensity; \"pressure\" is just a common term in Chinese, and its unit is \"Pa\" rather than \"N\". The English term for nominal pressure is nominal pressure; nominal means in name or form but not in reality (something that exists only in name, without actual substance). The nominal pressure of a pressure vessel refers to the nominal pressure of its flange. The nominal pressures of pressure vessel flanges are generally divided into 7 grades, namely 0.25, 0.60, 1.00, 1.60, 2.50, 4.00, and 6.40 MPa. Design pressure = 1.5 × operating pressure. The working pressure is determined through hydraulic calculations of the pipe network. VI. Relationships: Test pressure > Nominal pressure > Design pressure > Operating pressure
There is also the maximum operating pressure and the maximum allowable operating pressure
Why is there no source? You can’t just talk nonsense.
GBT1048 Nominal pressure is a designation consisting of a combination of letters and numbers related to the mechanical properties and dimensional characteristics of pipeline system components; it is composed of the letter PN or Class, followed by a dimensionless number. Note 1: Unless otherwise specified in the relevant standards, dimensionless numbers do not represent measured values and should not be used in calculations. Note 2: Apart from their association with relevant pipeline component standards, the letters PN or Class have no meaning. Note 3: The maximum allowable operating pressure of a piping element depends on its PN value or Class value, material, design of the element, and maximum allowable operating temperature, among other factors. Note 4: Pipe components with the same PN or Class and DN values, along with their corresponding flanges, have the same connection dimensions.
For the last line, I’ve copied it for you: “Design pressure = 1.5 × operating pressure (usually)””
This is the copy from the official account, of a basic introductory nature; there are indeed many mistakes in it, but these flaws don’t overshadow its overall value. For example, the design pressure is 1.05 to 1.1 times the operating pressure
I can only say that this is roughly how things are, but the source isn’t an official account; there are relevant technical specifications and standards to consider. You all have heard it from others, and those others might have gotten it wrong or might have just heard nonsense themselves.
The test pressure does not necessarily have to be greater than the nominal pressure.