BS EN ISO 4672:1999 pdf free.Rubber and plastics hoses – Sub-ambient temperature flexibility tests.
BS EN ISO 4672d specifies two methods for assessing whether a rubber or plastics hose retains adequate flexibility at sub-ambient temperatures.
Method A is applicable to non-collapsible hose with a nominal bore up to and including 25. It measures the increase in stiffness compared to the flexibility at a standard laboratory temperature.
Method B is a simpler, qualitative method suitable for control testing and is applicable to hose with a nominal bore up to and including 100.
2 Normative references
ISO 471: 1995 Rubber – Temperatures, humidities and times for conditioning and testing. ISO 1402: 1994 Rubber and plastics hoses and hose assemblies – Hydrostatic testing.
ISO 3383 : 1985 Rubber – General directions for achieving elevated or subnormal temperatures for test purposes.
3 Method A – Sub-ambient temperature stiffness test
3.1 Apparatus (see figure 1)
3.1.1 Torque wheel, having a diameter equal to twice the minimum bend radius specified for the hose, provided with equipment for holding the hose tangential to the wheel, a suitable device to bend the hose around the wheel, and a strain gauge and graphical recorder to measure the torque with an accuracy of ± 3 %. If the minimum bend radius is not specified the torque wheel shall have a diameter equal to 12 times the nominal bore of the hose.
3.1.2 Cooling container, equipped with an agitator, a temperature-measuring device and a roller having a diameter of 50 mm for guiding the hose.
The coolant shall not affect the hose to be tested and shall be used as prescribed in ISO 3383.
A suitable coolant liquid is methanol or ethanol with crushed dry ice (solid carbon dioxide) added. Gaseous coolants may be employed when the design of the apparatus is such that tests using such coolants give results equivalent to those obtained with liquid coolants.
4 Method B Cold bend test
4.1 Apparatus
4.1.1 Mandrel, having an outside diameter equal to twice the minimum bend radius specified for the hose, or a former, with an arc of at least 1800. If the minimum bend radius is not specified, the mandrel or former shall have an outside diameter equal to 12 times the nominal bore of the hose.
4.1.2 Conditioning chamber, capable of being maintained at the specified temperature (see 4.3).
4.2 Test syecimen
The test specimen shall be cut from the hose under test and shall have a length adequate to provide a grip at each end in addition to a section which can be bent round the periphery of the mandrel.BS EN ISO 4672 pdf download.