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Pressure and angular deviation at the joint

Technical solutions

   With the term “pressure”, a distinction needs to be drawn between terminology used by:
– the network designer (dependent on the hydraulic capacity),
– the manufacturer (dependent on the product performance),
– the network user (dependent on the service).


The terminology listed below is drawn from the draft European standard EN 805 – Water supply. Specification for external networks and components – applicable to all materials.

The product standard EN 545 - Ductile cast iron pipes and fittings - uses this terminology where the manufacturer is concerned.

designerdpDesign pressure
MdpMaximum design pressure
StpSystem test pressure
manufacturerpfAAllowable operating pressure
pMAAllowable maximum operating pressure
peAAllowable test pressure
useropOperating pressure
SpService pressure

Manufacturer’s definitions

PN - Nominal pressure (in compliance with Standard EN 545)

Numerical designation expressed by a number used for reference purposes. All flanged components with the same DN and designated by the same PN are compatible for interconnection.
Standard EN 545 sets out for flanged pipes and fittings, the following PN equivalents in PFA, PMA and PEA.

DNPN 10PN 16PN 25PN 40
40 to 50See PN 40See PN 40See PN 40404853
60 to 80See PN 16162025See PN 40404853
100 to 150See PN 16162025253035404853
200 to 300101217162025253035404853
350 to 1 200101217162025253035
1400 to 2000101217162025
For DN 80 flanged parts manufactured by PAM, use the following equivalents:
80See PN 40See PN 40See PN 40404853

Leaktightness test pressure (in the sense of Standard EN 545)

Pressure applied to a component during its manufacture to ensure its leaktightness.


Safety factor
Safety factor of ductile iron pipelines.
Water hammer
If protection devices have not been provided, ductile iron pipes have a safety coefficient which is often useful when faced with accidental pressure surges.
Joint deflection
The angular deflection allows negotiation of large radius bends.
Hydraulic thrust and anchoring
Hydraulic thrust in ductile cast iron pipelines
Allowable Operating Pressure
Discover how are Saint-Gobain PAM pipes designed to withstand high pressures.