The European powerful online platform with manufacturers and suppliers of pressure equipments​

pressure equipments plant

Pressure Equipment Manufacturer and Supplier Directory

PED classification: Piping

Pipings are classified into categories according to increasing hazard potential in accordance with PED Annex II (see tables 6, 7, 8 and 9 below). The category is determined according to the procedure listed below. The determined category determines the permissible conformity assessment procedures.

Piping with only a low risk are not assigned to any category (see tables below). Sound engineering practice (SEP) applies to them.

Definition of piping

Piping are piping components intended for the transport of fluids, when connected together for integration into a pressure system; piping includes in particular a pipe or system of pipes, tubing, fittings, expansion joints, hoses, or other pressure-bearing components as appropriate;

Procedure for determining the category for pipings

The piping is classified on the basis of:

  • Fluid type (gas or liquid)
  • their maximum allowable pressure PS [bar],
  • their nominal size DN1,
  • the group of fluids for which they are intended.

1 For non-circular piping a comparative diameter must be determined from the existing cross-section. This comparative diameter must be used as the basis for classification.

Note 1: Unheated piping for super-heated water (temperature > 110° C is covered by table 7 below.

Note 2: Heat exchangers which consist of straight or bent pipes which may be connected by common circular header(s) made also from pipe are classified as piping, and only if, the three following conditions are met:
– air is the secondary fluid,
– they are used in refrigeration systems, in air conditioning systems or
– in heat pumps,
– the piping aspects are predominant.

Note 3: Half-pipe coil or a similar “jacket” construction that heat or cool a vessel or Pipe coil that is inside a vessel to heat or cool its content are to be classified as vessels.

Note 4: If a “piping” comprising pipes with different DNs, the maximum DN used for that item of pressure equipment shall be the basis for the classification. The term a “piping” as used above means an item of pressure equipment, and not an “assembly”. 

Note 5: Heat exchangers consisting of pipes for the purpose of cooling or heating air shall be considered as piping.

Classification flow chart for piping

Fluid group

Fluid group 1: Consisting of substances and mixtures, that are classified as hazardous

Fluid group 2: Fluids not falling into fluid group 1

Read more details about the allocation of fluids to the fluid groups

Tables for gaseous fluidsTables for liquid fluids
Gaseous fluid:
Means gases, liquefied gases, gases dissolved under pressure, vapours and also those liquids whose vapour pressure at the maximum allowable temperature is greater than 0,5 bar above normal atmospheric pressure (1013 mbar) 

Exceptionally, piping intended for unstable gases and falling within categories I or II on the basis of Table 6 shall be classified in category III.
Liquids fluid:
Means liquids having a vapour pressure at the maximum allowable temperature of not more than 0,5 bar above normal atmospheric pressure (1013 mbar)
Exceptionally, all piping containing fluids at a temperature TS > 350 °C and falling within category II on the basis of Table 7 shall be classified in category III.
PED -Table-9


Manufacturers & Suppliers
  • Link directly to your Website
  • Company type
  • Location
  • Brief description of your company
  • Products limits dia., length & weight
  • Main used mat'l groups ISO/TR 15608
  • Directory is supported by professional Engineers
1 entry for free

Simple registration in 3 steps:

  1. Registration only with name, e-mail, company name,
  2. Approval and sending login data by PED directory team
  3. The vendor sends the prepared form with the details for the vendor directory listing