3.4 Definitions for the normative design of polypropylene pipes
Service Pressure: The maximun pressure that can be handled by pipes intended to
conduct liquids in constant use.
Nominal pressure (NP): Alfanumeric designation related to the mechanical
characteristics of a piping system components. It is used for reference purposes and its
denomination is normalized according to ISO 161-1:1996.
Safety Coefficient (SC): Specified according to the material and the aplication area.
IPS applies the DIN 8077:99 Norm service conditions.
For cold and hot water calculation, the safety coefficient used is 1.25; for heating, the
coefficient is 1.5.
SDR (Standard Dimensional Relation): Value that relates the dimensions of the pipe
and it is obtained by calculating of the quotinet between the pipe’s external diameter
and its thikness.
SDR=
External D
Thikness
Series (S): Adimentional number used to name the different types of pipes. It is set
according to the ISO 4065:1996 Norm.
S=
SDR - 1
2
Design Stress: Of 6.3 MPa. for random polypropilene copolymer ( type 3 ) according
to 13470:2005 IRAM EA1 standards.
Comparison between Series (S) and Nominal Pressure (NP) EA1 13470:2005
S
SDR
PN ( bar )
8.3
17
8.3
5
11
12.5
3.2
7.4
20
2.5
6
25
2
5
32
Nominal pressure and continual service during 50 years
IPS Product
Service Pressure
and Working
temperature
Maximum
resistance
to pressure
120 Kgf/cm2
PN
S
32
2
IPS Fusion Fittings
32.3 Kgf/cm2 at 20ºC
Strengthened Fusion
Multilayer
30.9 Kgf/cm2 at 20ºC
120 Kgf/cm2
25
2.5
IPS Fusion Multilayer
24.5 Kgf/cm2 at 20ºC
100 Kgf/cm2
20
3.2
15.5 Kgf/cm2 at 20ºC
80 Kgf/cm2
12.5
5
S3.2 and Maxum S3.2
IPS Fusion Pipe
(Cold water)
17