1、Designation:F207214Standard Test Method forHosedown of a Membrane Switch1This standard is issued under the fixed designation F2072;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 indi
2、cates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method establishes procedures for the hose-down of a membrane switch to verify adequate protection fromingress of water from a high-volume water spray.1.2
3、This test method can also be used to verify the ability ofa membrane switch or graphics layer to act as a liquid seal fora finished product.1.3 Additional test methods or practices can be incorporatedto investigate specific results or capabilities.1.4 This test method is a modification of NEMAPublic
4、ationNumber 250-2008 Section 6.7 which is a test for hosedown ofa finished product housing.2.Referenced Documents2.1 ASTM Standards:2F1595 Practice for Viewing Conditions for Visual Inspectionof Membrane SwitchesF1680 Test Method for Determining Circuit Resistance of aMembrane SwitchF1689 Test Metho
5、d for Determining the Insulation Resis-tance of a Membrane Switch2.2 NEMA Publication:250-200833.Terminology3.1 Symbols:3.1.1 membrane switch,na momentary switching devicein which at least one contact is on,or made of,a flexiblesubstrate.3.1.2 specified resistance,nmaximum allowable resis-tance as m
6、easured between two terminations whose internalswitch contacts,when held closed,complete a circuit.4.Significance and Use4.1 The presence of water inside a membrane switch canaffect its mechanical operation or electrical functionality,orboth.4.2 This practice establishes a procedure to verify the ab
7、ilityof a membrane switch to resist the entry of liquid into itself ora finished product,or both.It is useful in identifying designdeficiencies.4.3 Hosedown testing may be destructive,therefore anysamples tested should be considered unfit for future use.5.Interferences5.1 External Venting Any delibe
8、rate external venting ofthe switch will allow liquid to enter.5.2 Atmospheric PressureSignificant changes in atmo-spheric pressure during the test or at different facilities mayalter the time in which leakage might occur.5.3 Duration of Test Longer exposure time increases thepossibility of leakage.5
9、.4 Dye ColoringChoose a dye coloring that will notchemically attack the materials.6.Apparatus6.1 Water Supply,capable of delivering a stream of water ata rate of at least 65 gal/min through a 1 in.(25 mm)internaldiameter nozzle for the specified duration,6.2 An appropriate device or fixture to hold
10、the switch in afixed position,6.3 Any additional equipment as required by other testmethods employed,and6.4 Nozzle with 1 in.(25 mm)internal diameter.7.Test Specimen7.1 The test specimen will be a membrane switch with orwithout graphics laminated to a rigid material or the finalintended mounting con
11、figuration(using a clear material willfacilitate visual inspection).8.Conditioning8.1 Condition specimens by exposure to ambient conditionsfor 72 h prior to hosedown to allow full cure of adhesives.1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct resp
12、onsibility of Subcommittee F01.18 on MembraneSwitches.Current edition approved Jan.1,2014.Published January 2014.Originallyapproved in 2000.Last previous edition approved in 2007 as F207201(2007).DOI:10.1520/F2072-14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM C
13、ustomer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3National Electrical Manufacturers Association(NEMA),1300 North 17thStreet,Suite 1847,Rosslyn,VA 22209.Copyright ASTM International,100 Barr Harbor D
14、rive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 9.Procedure9.1 Pre-Test Setup:9.1.1 Fixture Unit Under Test(UUT)as specified.9.2 In-Process Test:9.2.1 Test switch for proper function if required.9.2.1.1 Visually inspect in accordance with Practice F1595and note anything that could af
15、fect results or of interest tocompare after test.Pictures of UUT may be useful as well butnot required.9.2.1.2 Measure circuit resistance in accordance with TestMethod F1680 of preselected(or all switches).9.2.1.3 Measure insulation resistance in accordance withTest Method F1689 of preselected(or al
16、l)conductive points.9.2.2 Direct water flow at test specimen at all angles ofpotential water entry such as seams,joints,external operatingmechanisms,etc.from a distance of 10 to 12 ft(3.0 to 3.5 m)for a total of 5 min or as specified.9.2.3 Measure and observe the characteristics of the switchas in 9.2.1 and if liquid has penetrated the UUT record as muchdetail as possible the extent of penetration seen by visualinspection.Pictures of UUT may be useful as well but notrequired.10.Report10.1 Report