ASTM_D_3902_-_90_2012.pdf

Designation:D390290(Reapproved 2012)Standard Test Method forRubber Hose for Gas Diffusion of Liquefied Petroleum Gas1This standard is issued under the fixed designation D3902;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the volumeof liquefied petroleum gas diffusing through the wall of a hoseduring a specified period of time.1.2 The values stated in SI units are to be regarded asstandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.A specific precau-tionary statement is given in the note in Section 5.2.Significance and Use2.1 Rubber hose has an inherent characteristic of permittingdiffusion of a gas through the hose structure.This test methodquantitatively measures the loss of liquefied petroleum gas.3.Apparatus3.1 Water Bath,long enough to accommodate the gas-collecting apparatus and hose.3.2 Gas Supply,provided with a suitable pressure gage andemergency excess flow shutoff valve in case of hose failure.3.3 Set of Gas-Collecting Apparatus,consisting of a glasstube at least 10%longer than the hose being tested and with aninside diameter at least 10%larger than the outside diameter ofthe hose being tested,a conical funnel 25 mm in diameter,anda 500-cm3measuring cylinder graduated at 5.0-cm3intervals.3.4 Barometer,to record the barometric pressure during thetest.3.5 Thermometers,two,to record water and air temperatureat the gas-collection point.(For a schematic diagram of the testarrangement,see Fig.1.)3.6 LP-Gas,2having a minimum purity of 99 mol%propane,and a sulfur content less than 0.005 mass%.4.Test Hose4.1 The test hose shall have a 0.50-m(19.7-in.)free lengthbetween couplings and shall be coupled with suitablecouplings,that is,band-it-type couplings.If the test hose isrubber covered,then the cover should be thoroughly perforatedwith a pricker roll.5.Test Pressure5.1 Unless otherwise specified,conduct the test with theLP-gas in the liquid phase at a pressure of 1000 6 20 kPa(1456 3 psi).Regulate this pressure by keeping the LP-gas tank inthe water bath and adjusting the temperature of the water toobtain the desired pressure,approximately 28C.(WarningTake special precautions to ensure that the water bath tempera-ture cannot rise accidently,as this will increase the gas pressuresignificantly,creating a danger of explosion.Do the testing ina well-ventilated area.The system shall be equipped with asafety relief valve set at a gage pressure of 1200 6 35 kPa(1756 5 psi).)6.Procedure6.1 Cap or plug the hose coupling on one end of the testhose and connect the hose coupling on the other end to theLP-gas supply.(Invert the tank when testing in the liquid phaseor use a tank equipped with full-length dip tube.)6.2 Flush the inside surface of the test hose with LP-gas toremove air and seal the end.6.3 Locate the test hose in the center of the glass tube andmount in the water bath at an incline angle of approximately20.6.4 Adjust the water bath to the specified temperature.Apply the specified gas pressure to the test hose and maintainthis pressure and the water bath temperature for 14 days.At theend of the 14-day conditioning period,inspect the test appara-tus for leaks and,in particular,the area around the hosecouplings.Leaks will be evident by the formation of gasbubbles in the water bath.If none are found,insert the funnel1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.31 on Rubber Hose andBelting.Current edition approved May 1,2012.Published July 2012.Originally approvedin 1980.Last previous edition approved in 2004 as D3902 90(2004)1.DOI:10.1520/D3902-90R12.2CP Grade,available from Matheson Gas Products,has been found satisfactoryfor this purpose.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 into the measuring cylinder,fill the cylinder with water,andmount the funnel over the end of the glass tube.6.5 Collect the gas for a 6-h period or collect 450 to 500 cm3of gas,whichever occurs first,and record the time and thevolume of gas collected.Repeat this procedure every 24 h untiltwo successive gas volumes are within 5%of each other.Usethe average of two successive readings for calculation of gasdiffusion.6.6 If it is desired to determine gas diffusion at differentpressures,conduct the test at the lowest pressure first.7.Calculation7.1 Express the gas diffusion of the hose in cubic centime-tres of gas per second per square metre of inner hose su