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Standard Dimension Ratio (SDR)The pressure rating of a pipe (PN) is determined by
the diameter, wall thickness and material type and
is expressed as
PN - Pipe pressure rating at 20° C (MPa x 10)
The basic polyethylene (PE) material types used for
pipe production ar PE63, PE80 and PE100, the number
indicating the long term strength.
The pipe serie (S) is expressed as
outside diameter - wall thickness
S = --------------------------------------
2 x wall thickness
The Standard Dimension Ratio (SDR) is introduced
to describe the pipe, in combination with the material
type.
min. outside diameter
SDR = -------------------------- = 2S + 1
min. wall thickness
The higher the SDR, the thinner the pipe and the lower
the pressure rating.
HDPE pressure pipes according to EN 12201,
EN 13244 and DIN 8074/75
| Examples of relationship between PN, MRS, S and SDR
at 20° C with the value of C=1,25
| | SDR | S | PE63 | PE80 | PE100 | | 41 | 20
| PN 2,5 | PN 3,2 | PN 4
| | 33 | 16 | PN 3,2
| PN 4
| PN 5 | | 26 | 12,5 | PN 4
| PN 5 | PN 6(1)
| | 21 | 10 | PN 5
| PN 6(1) | PN 8
| | 17,6 | 8,3
| PN 6 | --
| -- | | 17 | 8 | --
| PN 8
| PN 10
| | 13,6 | 6,3 | PN 8
| PN 10
| PN 12,5
| | 11 | 5 | PN 10
| PN 12,5
| PN 16
| | 9 | 4 | --
| PN 16
| PN 20
| | 7,4 | 3,2 | --
| PN 20
| PN 25
| | 6 | 2,5 | -- | PN 25 | -- | (1) actual calculated values are 6,4 bar for PE 100
and 6,3 bar for PE 80
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