Small pipe diameters as used for brake systems in automotive engineering can be tested to ISO 7628-2 using a pendulum impact tester in a modified Charpy arrangement with a 7.5J pendulum. A pendulum impact tester is used as the basic instrument for tests on plastics to ISO 179-1. The tup of the pendulum hammer is specifically designed in accordance with this standard, while the supports for the pipe sections consist of a metal section with a polymer insert to accommodate the pipe diameter.
This is a cold impact test performed at a temperature of -40°C. Following impact the sections of pipe are inspected for cracks and failure; no measured value in the form of impact strength is determined.
For scientific evaluation of raw materials where larger pipe diameters are involved, impact tests on complete sections of pipe, for example to ISO 3127, can be augmented by tests on pipe sections as per ISO 9854-1. This test method represents a special version of the Charpy method to ISO 179-1 . The pendulum hammer used is either a 15-joule or 50-joule version as in ISO 179-1. Standard supports as per ISO 179-1 are used; these are spaced at 70 mm for normal specimens and 40 mm for smaller specimens. Special supports are required for curved specimens removed perpendicularly to the pipe axis.
Tests to ISO 9854-1 can be performed at different temperatures. For this specimens are conditioned in a cool box. Testing must take place within ten seconds of the specimen being removed from the box. The result obtained is an assessment for cracks and breaks, which are calculated as a failure percentage within a test series consisting of thirty individual tests.
Part 2 of ISO 9854 sets out the exact test conditions for specimens made of various polymer materials.