Withdrawn from 02.05.2019
This European Standard specifies rules for design, calculation and installation for preinsulated bonded pipe
systems for buried hot water distribution and transmission networks (cf. Figure 2) with pipe assemblies in
accordance with EN 253, for continuous operation with hot water at various temperatures up to 120ºC and
occasionally with peak temperatures up to 140ºC and maximum internal pressure 25 bar (overpressure).
For larger pipe dimensions and pressures below 25 bar wall thickness bigger than specified in EN 253 can be required for straight pipes, bends
The principles of the standard can be applied to preinsulated pipe systems with pressures higher than 25 bar, provided that special attention is
paid to the effects of pressure. Adjacent pipes belonging to the network (e.g. pipes in ducts, valve chambers, road crossings above ground etc.)
can be designed and installed according to this standard.
The standard assumes use of treated water, which by softening, demineralisation, deaeration, adding of chemicals,
or otherwise has been treated to prevent internal corrosion and deposits in the pipes.
This standard is not applicable for such units as:
c) boiler installations, tank installations,
d) consumer installations.
However, the full functional ability and durability of such units should be ensured in consideration of the impacts
from the district heating system and other impacts occurring from the conditions under which they have been
Guidelines for product quality inspection and in situ tests of joints are given in Annex A of EN 448:2009, Annex D of
EN 253:2009, Annex A of EN 488:2009 and Annex B of EN 489:2009.
Guidelines for welding of polyethylene casing are given in Annex B of EN 448:2009.
The estimation of expected life with continuous operation at various temperatures is outlined in Annex B of