Heat resistance. Test
Samples of conduits, (100±5)mmlong, are kept in a hot chamber together with the test apparatus (Figure 4) for 4h±5min at the highest operating temperature stated.
Then, each sample is placed in the apparatus together with the corresponding mass weight and they remain in the hot chamber for 24h±15min. The sample together with the load must be left to cool-off at room temperature.
Then, the load is removed. Immediately after removal, it must be possible to pass a suitable calibrator through the conduit with the same load and without initial speed, with the sample in vertical position.