BS EN ISO 8031:2009 pdf free.Rubber And Plastics Hoses And Hose Assemblies – Determination Of Electrical Resistance And Conductivity.
This edition of Iso 8031 addresses the problems encountered in field testing and during product acceptance tests in a production facility in following the test procedures specified in the previous edition (ISO 8031:1993) and a more practical approach is suggested. Also, a test procedure for determining electrical continuity between the end fittings of a hose assembly without actually measuring the resistance has been introduced. This test is frequently carried out in the field and in the factory when the product standard does not require the exact electrical resistance to be measured, but only requires verification of electric conductivity between both metal end fittings.
Special test methods to determine the electrical resistance through the hose wall (now required in some product standards for hoses used in explosive atmospheres) have been added.
Some test methods which have been standard practice in the hose industry for some time have now been included, as have several new methods to determine the ability of a hose assembly (with metal end fittings) to dissipate static electric charges when the metal end fitting is connected to earth. A total of four new explanatory sketches are included. The hose and hose assembly product standard applicable will have to specify which method is most suitable for the purpose of verification of the required property.
Annex A, an amended version of informative Annex A, “Recommended terminology and limits for electrical resistance”, in ISO 8330:2007, has been included.
This International Standard specifies electrical test methods for rubber and plastics hoses, tubing and hose assemblies to determine the resistance of conductive, antistatic and non-conductive hoses and the electrical continuity or discontinuity between metal end fittings.
NOTE All the test methods described for rubber hoses in this International Standard can also be applied to plastics hoses.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 2878, Rubber — Antistatic and conductive products — Determination of electrical resistance
ISO 8330, Rubber and plastics hoses and hose assemblies — Vocabulary
ISO 23529, Rubber — General procedure for preparing and conditioning test pieces for physical test methods
4 Measurement of resistance of conductive, antistatic and non-conductive hoses
4.1 General
Rubber hoses may have a conducting lining only or a conducting cover only, or may be manufactured from conducting rubber compounds throughout. A method of test is specified for each of the three possible types of construction.
4.2 Apparatus
The following apparatus is required and shall be basically as described in Iso 2878.
4.2.1 Test instruments
4.2.1.1 To determine the resistance of conductive, antistatic and non-conductive hose1), the test should preferably be made with an instrument specifically designed for measuring insulation resistance, having a nominal open-circuit voltage of 500 V d.c., or with any other instrument known to give comparable results. The instrument shall be sufficiently accurate to determine the resistance to within ± 10 % unless specified otherwise. During the test, not more than 3 W shall be dissipated in the specimen, to prevent erroneous results due to effects of temperature. The power dissipated shall be determined by the square of the open- circuit voltage divided by the measured resistance.
The resistance values obtained will vary with the applied voltage, and errors may occur when low test voltages are involved. In cases of dispute, the voltage applied to the test piece shall be not less than 40 V. except where this conflicts with the requirement not to dissipate more than 3 W in the test piece.
4.2.1.2 For tests requiring the measurement of the electrical continuity between end fittings or through continuous internal or external bonded wires, the instrument used shall be an ohmmeter sufficiently accurate to determine the resistance to within ± 10 %.