AS-1180.5-1999.pdf
iAS 1180.51999 Australian Standard Methods of test for hose made from elastomeric materials Method 5: Hydrostatic pressure PREFACE This Standard was prepared by the Joint Standards Australia/Standards New Zealand Committee RU/1, Industrial Hose, to supersede AS 1180.51993, Methods of test for hose made from electrostatic materials, Method 5: Hydrostatic pressure. It is based on and reproduced from ISO 1402:1994, Rubber and plastic hoses and hose assembliesHydrostatic testing. This Standard is being produced as an Australian only Standard. The objective of this Standard is to provide safe methods of testing. In some parts of this Standard, the Australian requirements differ from the ISO Standard. To accommodate these differences, a marginal bar is placed alongside the ISO text, and Appendix ZZ details the Australian specifications for the deviations. The term normative has been used in this Standard to define the application of the Appendix to which it applies. A normative appendix is an integral part of a Standard. The differences between this edition and the 1993 edition are as follows: (a)The test assembly or test pieces are conditioned at a standard temperature of 23 ±2°C immediately prior to testing. (b)A warping requirement for hose has been included. As this Standard is reproduced from an International Standard, the following applies: (i)The number of this Standard appears on the cover and title page while the International Standard number appears only on the cover. (ii)In the source text, this International Standard should read this Australian Standard. (iii)A full point substitutes for a comma when referring to a decimal marker. (iv)The reference to International Standards should be replaced by the equivalent Australian Standards, as follows: ISO 471RubberTimes, temperatures and humidities for conditioning and testing AS 1683Methods of test for rubber 1683.20Method 20: Standard temperatures, humidities and times for conditioning and testing test pieces 4671 Rubber and plastic hose assemblies Methods of measurement of dimensions 1180Methods of test for hose made from elastomeric materials 1180.1Method 1: Dimensions Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 23 Jan 2008 ii NOTES Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 23 Jan 2008 1 METHOD Rubber and plastics hoses and hose assemblies Hydrostatic testing 1Scope This International Standard specified methods for the hydrostatic testing of rubber and plastics hoses and hose assemblies, including methods for the determi- nation of dimensional stability. 2Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investi- gate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 471:1)Rubber Times, temperatures and humidities for conditioning and testing. ISO 4671:1984,Rubber and plastics hose and hose assemblies Methods of measurement of dimensions. ISO 7751:1991,Rubber and plastics hoses and hose assemblies Ratios of proof and burst pressure to design working pressure. 3General Unless otherwise specified, all tests shall be carried out at standard temperature (see ISO 471). 4Apparatus 4.1Pressure source, capable of applying pressure at the rate specified in 6.2.2, up to the required test pressure. 4.2Calibrated pressure gauge or pressure trans- ducers with digital readouts, chosen for each test so that the test pressure is between 15 % and 85 % of the full-scale reading. In the interest of accuracy, calibrated pressure gauges or pressure transducers with digital readouts shall be checkedatfrequentintervalsandthefittingof restrictors; is recommended to minimize shock damage. 4.3Sliding vernier callipers or micrometer, and measuring tape. 5Test pieces 5.1Hose assemblies When hose assemblies are to be tested, the manu- factured assembly length shall be used for the test. 5.2Hoses The hydrostatic pressure and burst tests shall be carried out on a hose test piece with a minimum free length, excluding end fittings and end reinforcements, of 600 mm when deformation is to be measured and 300 mm when it is not. 1) To be published. (Combination and revision of ISO 471:1983 and ISO 1826:1981) COPYRIGHT Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 23 Jan 2008 2 5.3Number of test pieces At least two test pieces shall be tested. 6Application of hydrostatic pressure 6.1General Water or another liquid suitable for the hose under test shall be used as the test medium. WARNING Hoses and hose assemblies pres- surized by liquids can fail in a potentially danger- ous manner. For this reason, the test shall be performed in a suitable enclosure. Also the use of air and other gases as test media shall be avoided because of the risk to operators. In special cases, where such media are required for the tests, strict safety measures are imperative. Furthermore, it is stressed that, even when a liquid is used as the test medium, it is essential that all air is expelled from the test piece because of the risk of injury to the operator due to the sudden expansion of trapped air released when the hose bursts. 6.2Procedure 6.2.1Fill the test piece with test liquid, expelling all air, and connect to the test equipment. Close the valve and apply the hydrostatic pressure at a uniform rate of increase. Measure the pressure using a calibrated pressure gauge or pressure transducer with digital readout (4.2). NOTE 1It is important to allow unrestricted movement of the free or plugged end of the test piece during the test. 6.2.2The rate of pressure increase shall be constant and chosen to reach the final pressure after between 30 s and 60 s for hoses with nominal inside diameters up to 50 mm. For hoses with nominal inside diameters greater than 50 mm and less than or equal to 250 mm, the time needed to reach the final pressure shall be between 60 s and 240 s. For hoses with nominal inside diameters larger than 250 mm, the time needed to reach the final pressure shall be decided between the manufacturer and user. 7Hydrostatic pressure tests 7.1Proof pressure hold test When proof pressure tests are used to determine leakage of hoses or hose assemblies, apply the specified proof pressure in accordance with 6.2.2 and hold it for not less than 30 s or more than 60 s, unless otherwise specified in the product standard, examining the test pieces during this period for evidence of leakage, cracking, abrupt distortions indicating irreg- ularity in material or manufacture, or other signs of failure. Unless otherwise specified for the hose, the proof pressureshallberelatedtothedesignworking pressure by the ratio given in ISO 7751. NOTE 2The test is not applicable to curved hose. 7.2Measurement of deformation under pressure 7.2.1General procedure When tests for determining change in length, change in internal diameter and twisting are required, straighten the hose, lay it out horizontally for inspection and apply a hydrostatic pressure of 0,07 MPa when this is necessary to stabilize the hose. Make three reference marks (A, B and C) on the outer surface of the hose, the middle mark (B) being made approximately midway along the length of the hose, and the two outer marks (A and C) being 250 mm from B. Each mark shall consist of an arc on the circumference of the hose through which is drawn a straight line perpendicular to the arc, the three straight lines being colinear (see figure 1). Maintain the initial pressure of 0,07 MPa (if applied) and make the appropriate measurements (see 7.2.2, 7.2.3 and 7.2.4) at the reference marks. Apply the specified test pressure at the rate specified in 6.2.2 and maintain it for 1 min before making the test measurements, which shall then be made as quickly as possible to avoid prolonging the test period. NOTE 3The test pressure will be specified in the appro- priate hose product specification and could be the design working pressure, the proof pressure or any other pressure below the proof pressure at which the hose deformation characteristics are to be measured. 7.2.2Change in length Measure the length between the two outermost ref- erence marks (A and C) with an accuracy of ± 1 mm, using the measuring tape (4.3), at the initial pressure (0 or 0,07 MPa) and at the specified test pressure. Calculate the change in length, l, expressed as a percentage of the original length, from the equation l l1l0 l0 ×100 COPYRIGHT Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 23 Jan 2008 3 where l0is the distance between the two outermost reference marks (A and C) measured at the initial pressure; l1is the distance between the same two reference marks measured at the specified test pressure. 7.2.3Change in external diameter 7.2.3.1General The external diameter should preferably be determined from measurements of circumference made with an accuracy of 1 mm using the measuring tape (see ISO 4671). The measurements may, however, be made directly,usingslidingverniercallipershavinga minimum useful tip width of 5 mm. 7.2.3.2Determination by measuring the change in external circumference Using the measuring tape (4.3), measure the circum- ference at each of the three reference marks (A, B and C) at the initial pressure (0 or 0,07 MPa) and at the specified test pressure. Calculate the change in diameter D, expressed as a percentage of the original diameter, from the equation D C1C0 C0 ×100 where C0is the sum of the circumferences at the three reference marks measured at the initial pressure; C1is the sum of the circumferences at the three reference marks measured at the specified test pressure. 7.2.3.3Direct measurement of change in external diameter Using the sliding vernier callipers (4.3), measure two perpendicular diameters at each of the three reference marks at the initial pressure (0 or 0,07 MPa) and at the specified test pressure. Calculate the change in diameter D, expressed as a percentage of the original diameter, from the equation D D1D0 D0 ×100 where D0is the sum of the six diameters measured atthereferencemarksattheinitial pressure; D1is the sum of the six diameters measured at the reference marks at the specified test pressure. 7.2.4Twisting If twisting of the hose develops under pressure, the original lines forming the reference marks will take up a helical pattern (see figure 2). With the hose at the specified test pressure, project a straight line along the length of the hose from reference mark A until it intersects, at C, the circular arc at reference point C. Then measure the length s of the circular arc CC to the nearest millimetre, using the measuring tape (4.3). Calculatetheamountoftwistingpermetre,T, expressed in degrees, from the equation T s × 360 Cc× l0 where Ccis the circumference at reference mark C, measured as described in 7.2.3.1; l0is the distance between A and C as measured in 7.2.2. 7.2.5Warping Warping in hose tests is the deviation from a straight line drawn from fitting to fitting in a plane parallel to the surface on which the hose rests at the initial pressure (0 or 0,07 M Pa). A tightly stretched cord may be used to establish the straight line from centre to centre of the fittings. The amount of warping at the specified test pressure is the maximum deviation of any portion of the hose from the straight line drawn from centre to centre of the fittings at the initial pressure. Express warping as the distance from this line to the centreline of the hose at the point of maximum deviation. Report the result to the nearest 5 mm. 7.3Burst pressure test Increase the pressure at a rate in accordance with 6.2.2 until the hose or hose assembly fails. The position COPYRIGHT Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 23 Jan 2008 4 and mode of failure shall be recorded in the test report. Any failure caused by blowing off of fittings, leakage or bursts within 25 mm of a fitting or within a distance equal to the external diameter of the hose, whichever is greater, shall not be interpreted as a true hose burst. 7.4Leakage test 7.4.1Test pieces The test pieces for the leakage test shall comprise unaged hose assemblies on which the end fittings have been attached for not more than 30 days and not less than 1 day. 7.4.2Procedure Subject the test assemblies to a specified hydrostatic pressure equal to 70 % of the specified minimum burst pressure. Maintain this specified test pressure for 5 min ± 0,5 min and then reduce it to zero. Reapply the specified test pressure and maintain it for a further period of 5 min ± 0,5 min. This is considered to be a destructive test and the test assemblies shall be destroyed after test. 7.4.3Criteria for failure There shall be no leakage or evidence of failure. Leakage at the end fitting, fitting blow-off or rupture of the hose adjacent to the fitting shall be considered as failures in the performance of the assembly. NOTE 4Such failures do not necessarily demonstrate an inability of the hose to meet the specified requirements with an alternative fitting. 8Test report The test report shall include the following particulars for each test undertaken: a)a full description of the hose and, where applica- ble, hose assembly tested; b)a reference to this International Standard, i.e. ISO 1402; c)the method used; d)the number of test pieces tested and the length of each test piece; e)the test pressure and rate of pressure increase; f)the test medium (if other than water); (g)the results obtained for each test piece; (h)if the test piece fails, the position and mode of failure; (i)any unusual features noted during the test; (j)the date of the test. COPYRIGHT Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 23 Jan 2008 5 Figure 1 Measurement of dimensional stability Figure 2 Measurement of amount of twisting COPYRIGHT Accessed by UNIVERSITY OF SOUTH AUSTRALIA on 23 Jan 2008 6 APPENDIXZZ VARIATIONS TO ISO 1402 FOR APPLICATION IN AUSTRALIA (Normative) ZZ1SCOPEThis Appendix sets out variations to ISO 1402 for application in Australia. ZZ2VARIATIONS Clause 2Delete the footnote relating to ISO 471. Delete the reference to ISO 7751:1991. Clause 3Delete the existing text and insert the following text: The text assembly or test pieces shall be conditioned at a temperature of 23 ±2°C immediately prior to testing in accordance with AS 1683.20, except that, the conditioning time shall be at least 15 min if conditioned in air, or at least 5 min if conditioned in water. Clause 6.1Delete the words Water or another liquid suitable for the hose under test shall be used as the test medium and insert the following text: Water or another liquid suitable for the hose under test shall be used as the test medium, and shall be maintai
