Pressure Equipment Sector
Overview / News
PED / Pressure Equipment Directive
PED: The Text
PED: The Annexes
PED: The Guidelines
SPVD/Simple Pressure Vessels Directive
SPVD: The Text
SPVD: The Guidelines
ADD/Aerosol Dispensers Directive
TPED/Transportable Pressure Equipment Directive
Conformity Assessment Bodies
||Which type of pressure equipment is a heat exchanger ?
||Heat exchangers are considered to be vessels.
As an exception, heat exchangers which consist of straight or bent pipes which may be connected by common circular header(s) made also from pipe are classified according to Article 1 paragraph 2.1.2 last sentence as piping if, and only if, the 3 following conditions are met:
For such heat exchangers with headers, the piping aspects are pre-dominant if Catp ≥ Catv where:
- air is the secondary fluid,
- they are used in refrigeration systems, in air conditioning systems or in heat pumps,
- the piping aspects are predominant.
Catp = Abstract category that would be applicable according to 97/23/EC if the heat exchanger were classified as piping using DN of the biggest header.
Catv = Abstract category that would be applicable according to 97/23/EC if the biggest header, without the connecting piping, were classified as a vessel (i.e. for determining Catv, not the total volume V of the heat exchanger is taken into account, but only the volume VH of the biggest header).
When the result is Catv>Catp, the appropriate vessel classification shall be determined by using the volume of the entire heat exchanger (headers plus connecting tubes).
Piping heat exchangers which do not meet the requirements of the exception are not to be classified according to the last sentence of Article 1 paragraph 2.1.2 as piping; they are to be classified as vessels. For example:
- Heat exchangers which are not used in refrigeration systems, in air conditioning systems or in heat pumps, and for which the main purpose is to heat or cool the contained fluid by using the surrounding air;
- Half-pipe coil or a similar « jacket » construction that heat or cool a vessel;
- Pipe coil that is inside a vessel to heat or cool its content.
| Accepted by WPG on: 14 May 2003
| Accepted by Working Group "pressure": 03 Nov 2003
||Swedish reservation on the determination of Catv based only on the biggest header and not on the sum of the header volumes, and on the inclusion "refrigeration systems" and condensers in the second indent of the answer.