1st Digit: Resistance to compression
Conduit samples, (200±5) mm long, are placed on a fl at metallic base and an intermediate steel piece is placed in the middle of the sample (Figure 1); a steadily increasing compressive force is applied on the steel piece over a period of 30 sec, reaching the values given in the above table. Once applied for (60±2) sec, the external diameter of the sample must be measured without removing the force.
The difference between the initial diameter of the conduit before the test and the compressed diameter must not exceed 25% of the initial external diameter.
The force and the intermediate piece are removed and 60 sec after removal, the external diameter of the compressed sample must not exceed 10% of its initial external diameter. The samples must not have cracks that are visible with the naked eye.
2nd Digit: Resistance to impact ( ΕΝ 61386-1 )
Twelve samples of conduits, (200±5) mm long, or twelve conduit fi ttings are submitted to an impact test by the apparatus shown in (Figure 2).
When the samples reach the specified temperature (minimum operating temperature) they are placed on the steel base of the apparatus.
The hammer must be left to fall once on each sample. The hammer’s mass and the fall height must be those shown in the above table.
After the test, at least 9 samples must not have cracks that are visible with the naked eye, or distortions that prevent their normal use.