PALADEX pipes
Ring stiffness
The ring stiffness classes of PALADEX pipes are calculated to EN ISO 9969 and extend beyond the values set out in UNI 11434.
The classes
- Class A = 8 kN/m², equivalent to SN 8
- Class B = 12 kN/m², equivalent to SN 12
- Class C = 16 kN/m², equivalent to SN 16
- 20 kN/m², equivalent to SN 20, on request
A class A PALADEX pipe has a ring stiffness equivalent to that of a structured-wall pipe in polyethylene only, SN 8 to EN 13476, and of a series 5, SR24 32 pipe to DIN 16961.
On request, and subject to verification by the technical department, pipe lengths from 1.00 to 13.40 m are available.
Calculation method
Ring stiffness is a pipe's resistance to vertical deformation under an external load along a diametral plane. For solid-wall pipes it is calculated as S = E·I / D³, where E is the flexural modulus of elasticity, I the moment of inertia of the wall per unit length (s³/12) and D the diameter of the neutral axis.
For structured-wall pipes such as PALADEX, the test method of EN ISO 9969 applies. Actual in-service deformation depends greatly on the quality of the side fill material, which supports the pipe laterally and counteracts ovalisation.
Tables
