BS ISO 10619-3 pdf download Rubber and plastics hoses and tubing — Measurement of flexibility and stiffness Part 3: Bending tests at high and low temperatures
4.1.1 Compression testing machine, with a rate of travel of the moving jaw of 100 mm/min, preferably provided with a chart recorder. A scale, graduated in millimetre divisions, may be attached to the moving jaw to enable the bend diameter to be measured or, preferably, this may be determined from a graphical record or other measuring device.
4.1.2 Pair of twin channel-shaped holders, fitted with end stops for the hose test pieces (see Figure 1).
4.1.3 Thermostatically controlled environmental chamber, which can be fitted to the testing machine with the provision for access to enable the external diameter of the hose to be measured.
4.2 Hose test pieces
4.2.1 Types and dimensions The test shall be carried out on two hose pieces (one set), of equal length, of the hose or tubing under test. The length of the hose test pieces depends on the dimensions of the hose test piece holders and shall be 2 G + 0,5 π(C+D), where G is the length of the hose test piece holders (see Figure 1) and C is twice the minimum bend radius specified in the appropriate specification. In no case shall the hose test pieces come into contact with the walls of the chamber and the length, L, shall always be less than the length of the enclosure.
4.2.2 Number of hose test pieces Unless otherwise specified, three sets of tests shall be carried out (one set being two hose test pieces).
4.3 Conditioning of hose test pieces No test shall be carried out within 24 h of manufacture. For evaluations which are intended to be comparable, the test shall, as far as possible, be carried out after the same time interval after manufacture. The time between sample manufacture and testing shall be in conformity with ISO 23529. Before testing, the hose test pieces shall be conditioned in the straight condition or conforming to their natural curvature for 5 h in the environmental chamber (4.1.3) at the specified temperature (see 4.4).
4.4 Test temperature The test temperature is specified in the appropriate hose specification.
4.5 Test procedure
4.5.1 Where testing is being done on samples conditioned to sub-ambient temperatures, the following test should be completed within 8 s to 12 s. Testing on samples conditioned at higher temperatures should be completed within 5 s and the test equipment should be conditioned to the same temperature as the test piece.
4.5.2 Measure the outside diameter, D, three times at the midpoint of the test pieces in the unstressed condition by means of a suitable measuring instrument as specified in ISO 4671. A total of three readings per set for each test piece shall be taken and the average of these should be used for the value of D i .
4.5.3 Install the test piece between the holders with a large bend radius and the ends of the test pieces against the end stops. The curvature shall follow the natural curvature, if any.