Introduction to PED

Official Notice of the European Parliament and the Council Directive 2014/68 / EU on the harmonization of the law on pressure equipment in Member States (adopted on 29 May 1997).

This directive applies to the design, manufacture and conformity assessment of the maximum allowable pressure greater than 0.5 bar pressure equipment and its components.

The concepts covered by this Directive:

Pressure equipment refers to the container, pipe, with safety features of the annex and pressure of the annex. Under certain conditions, the pressure bearing equipment also includes all the components on the bearing part, such as flange, branch pipe, pipe joints and so on.

• A container is a closed element that is designed and manufactured to withstand the presence of fluid under pressure, including direct parts to devices that connect to other equipment. A container can have multiple pressure spaces.

A pipe is a certain pipe element that conveys a fluid and is interconnected for the construction of a pressure system. Pipes include pipe or tube systems, pipe moldings, accessories, expansion joints, hoses, or other pressure parts under given conditions. A heat exchanger consisting of pipes for cooling or heating air is treated as a pipe.

An accessory with a safety function means a device that is determined to be used to protect the pressure bearing device when the permissible limits are exceeded. These devices include devices that directly regulate the pressure, such as safety valves, rupture discs, cracking rods, control safety devices, and critical devices , Or to open the adjustment device or from the closing and cutting effect. Such as pressure, temperature or fluid level switches, and safety devices for measuring and regulating technology.

The pressure bearing attachment means a device with a running function, which has a pressure impact space.

• Pressure units (systems) refer to multiple pressure devices, which are connected by a manufacturer as a unit (system) of related functions.

• Pressure refers to the pressure at atmospheric pressure, ie a positive pressure, so the pressure in the vacuum range is indicated by negative pressure.

• Maximum pressure is the highest pressure provided by the manufacturer and the pressure is designed to press the pressure. May be defined as a device location designated by the manufacturer. For this reason, consider the attachment of the safety function of the attachment or the highest point of the pressure equipment, if not specific, consider a given location.

• Allow the minimum / maximum temperature specified by the manufacturer for the minimum / maximum temperature (TS), and use it to design the pressure equipment.

The volume refers to the internal volume of a space, including the volume from the branch pipe to the first connection, but minus the volume of the internal fixed part.

• Nominal size refers to a standard numerical level representation, which is used for all components of the piping system, but is different from the parts marked with an outside diameter or thread value. It is a convenient reference to the integer, and only about the approximate manufacturing value. The nominal size is expressed by the number of DNs.

Flow refers to gas, liquid and steam as pure phase and mixed fluid. The fluid includes a suspension of solids.

A fixed (permanent) connection means a connection that can only be separated by a destructive method.

• The European material license is a technical document that specifies the characteristics of the reusable material specified in the uniform standard, not included pressure equipment manufacturing process.

The eligibility criteria used are as follows:

——Class I: Mode A

——Class II: Mode A1; Mode D1; Mode E1

——Class III: Mode B1 + D; Mode B1 + F; Mode B + E; Mode B + C1; Mode H;

——Class IV: Mode B + D; Mode B + F; Mode G; Mode H1