The scope of product certification under the PED Directive covers pressure equipment. The term "pressure equipment" refers to equipment whose primary design parameter is pressure, including vessels, heat exchangers, pressure piping, safety accessories, pressure accessories, as well as assembled pressure equipment with specific functions composed of the above types of equipment (such as buffer tanks, forgings, pipe fittings, boilers, thermal power stations, etc.). Its scope covers products ranging from small pressure cookers to large thermal power stations, amounting to approximately more than 10,000 types in Europe.

PED certification is fully known as Pressure Equipment Directive certification. It is mandatory legislation issued by EU Member States reaching consensus on the safety of pressure equipment. Formulated for the purposes of eliminating trade barriers, ensuring the free movement of products, and safeguarding safety, health and environmental protection, it is a binding technical regulation. The CE marking is a typical symbol of EU PED certification, indicating compliance with the requirements of relevant directives and allowing products to circulate freely and be put into service within the European market.

The EU Pressure Equipment Directive has been updated from the old Directive 97/23/EC to 2014/68/EU, with the new directive entering into mandatory force in July 2016.

• Module A1 is replaced by Module A2, adding requirements for random inspections by notified bodies. The notified body may conduct sampling tests at any stage of the production process.

• Under the old directive, Module B and Module B1 corresponded to type-examination and design assessment respectively; these two modules are merged into a single Module B under the new directive.

• Module C1 is replaced by Module C2, which also strengthens the supervision authority of notified bodies.

Accordingly, the available module selection for products is as follows: