ASTM E1066-1995(2006) Standard Test Method for Ammonia Colorimetric Leak Testing《氨比色泄漏检验的测试方法》.pdf

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1、Designation: E 1066 95 (Reapproved 2006)Standard Test Method forAmmonia Colorimetric Leak Testing1This standard is issued under the fixed designation E 1066; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision

2、. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the testing of large single- anddouble-walled tanks, pressure and vacuum vessels, laminated,lined- or doub

3、le-walled parts, complex piping systems, flexiblecontainers (such as aircraft fuel tanks), glass-to-metal seals inhybrid packages, and systems that inherently contain or willcontain ammonia (such as large tonnage refrigeration systemsand fertilizer storage systems).1.2 This method can be used on pip

4、ing, valves and contain-ers with welded, fitted, or laminated sections that can be sealedat their ends or between their outer and inner walls and that aredesigned for internal pressures of 34.5 kPa (5 psig) or greater.1.3 Basic procedures are described based on the type ofinspection used. These proc

5、edures should be limited to findingleakage indications of 4.5 3 1012mol/s (1 3 107Std cm3/s)2or larger.1.4 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 h

6、ealth practices and determine the applica-bility of regulatory limitations prior to use. (For more specificsafety precautionary information see 7.4, 8.2, 9.4.1, and10.3.1).2. Referenced Documents2.1 ASTM Standards:3E 1002 Test Method for Leaks Using UltrasonicsE 1316 Terminology for Nondestructive E

7、xaminations2.2 Other Documents:SNT-TC-1A Recommended Practice for Personnel Qualifi-cation and Certification in Nondestructive Testing4ANSI/ASNT CP-189 ASNT Standard for Qualification andCertification of Nondestructive Testing Personnel43. Terminology3.1 DefinitionsFor definitions of terms used in t

8、his stan-dard, see Terminology E 1316, Section E.4. Summary of Test Method4.1 This test method consists of testing a container alreadyfilled with ammonia or of introducing an anhydrous ammoniaor an ammonia-nitrogen mixture into a container or system sothat the final ammonia percentage achieved is be

9、tween 1 and100 % by volume at a gage pressure between 34.5 and 689.5kPa (5 and 100 psig). The ammonia flows through leaksexisting in welds and connections and reacts with a developerthat is applied outside of the container producing a visibleindication.4.2 Two basic developer procedures are describe

10、d:4.2.1 Smoke-producing developers.4.2.2 Color-change developers.4.3 Methods of introducing ammonia into unfilled systemsare described, together with methods of estimating the concen-tration and pressure needed to achieve specific detectable leakrates.4.4 Procedures for testing large tanks and syste

11、ms aredescribed.4.5 Ultrasonic pretesting for gross leaks is described.5. Personnel Qualification5.1 It is recommended that personnel performing leak test-ing attend a dedicated training course on the subject and passa written examination. The training course should be appropri-ate for NDT level II

12、qualification according to RecommendedPractice No. SNT-TC-1A of the American Society for Nonde-structive Testing or ANSI/ASNT Standard CP-189.1This test method is under the jurisdiction of ASTM Committee E07 onNondestructive Testing and is the direct responsibility of Subcommittee E07.08 onLeak Test

13、ing Method.Current edition approved Dec. 1, 2006. Published January 2007. Originallyapproved in 1985. Last previous edition approved in 2000 as E 1066 - 95(2000).2The gas temperature is referenced to 0C. To convert to another gas referencetemperature, Tref, multiply the leak rate by (Tref+ 273)/273.

14、3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available fromAmerican Society for NondestructiveTesting (AS

15、NT), P.O. Box28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Significance and Use6.1 This method is useful for locating and measuring thesize of gas leaks eith

16、er as a quality-control test or as afield-inspection procedure. It can be used to test critical parts orcontainers that will hold toxic or explosive gases or liquids oras a quick test for other containers.7. Interferences7.1 The interior and exterior welds and joints where leaksare often found must

17、be free of oil, grease, flux, slag, paint, orother contaminants that might temporarily block or maskleakage. New containers should not be painted prior to test.Smoking during the test may cause false indications.7.2 Pure ammonia gas is likely to attack brass or coppermetals in a humid environment. I

18、t will not if there is no watervapor present.7.3 Ammonia gas attacks wood fibers when the woodcontains a high moisture content. Dry wood tolerates ammoniaconcentrations below 30 %.7.4 Ammonia in high concentrations can be hazardous.When working with ammonia it is recommended that anammonia-sensitive

19、 badge be worn for safety.7.4.1 The lower explosive limit (LEL) for ammonia and airis 15 %. The upper explosive limit (UEL) is 28 %.7.4.2 The ceiling for limited exposure to ammonia (1 h) isabout 500 ppm.7.5 If the container to be tested has parts made of stainlesssteel, nickel, or chromium alloys,

20、the color-change developerresidue should have a sulfur and halogen content of under 500ppm of each.8. Apparatus8.1 Apparatus for Precleaning:8.1.1 Gloves.8.1.2 Vacuum Pump or Heat Gun, if necessary to drycontainer.8.1.3 Spray Gun, if aerosol cleaner not used.8.1.4 Ammonia-Sensitive Monitor, to test

21、area contamina-tion.8.2 Safety Apparatus:8.2.1 Mask, covering mouth and nose.8.2.2 Ammonia Monitors.8.2.3 Gas Mask, if personnel work inside the tank or withhigh concentrations of ammonia during a test.8.3 Apparatus for Injecting Ammonia Gas:8.3.1 Pressure GageThe gage must be able to withstandnorma

22、l test pressures. The gage must be accurate to within 1 %of full scale. The gage must read at least 1.53 but not morethan 43 the maximum test pressure to be used. The gage mustbe in current calibration.8.3.2 Pressure-Relief Valve, if high pressures are to be used.8.3.3 Pressure-Reducing, -Control, a

23、nd -Mixing Valves, forthe ammonia and nitrogen circuits if not already mixed.8.3.4 High-Conductance Injection Line and Exhaust Line.8.4 Apparatus for Applying Colorimetric Developer:8.4.1 Spray Gun, if an aerosol is not used.8.4.2 Temperature-Controlled Heat Gun, if a water-baseddeveloper is used.8.

24、5 Apparatus for Post Cleaning and Inspection:8.5.1 Brush or Vacuum Sweeper, for developer powder.8.5.2 Tape, for marking and sealing leaks.9. General Procedures for Test Objects not AlreadyContaining Ammonia9.1 Openings:9.1.1 Seal all openings using plugs or covers that canwithstand the test pressur

25、e and can be completely removedafter the test.9.1.2 Locate the test gas inlet on the bottom of the testobject with the trapped air vent at the highest point.9.1.3 Components rated at pressures below the test pressuremust be isolated.9.2 GagesOne or more test gages must be connected tothe system. If

26、more than one gage is used, one may be arecording gage. All gages must have been calibrated within aspecified time period. One indicating gage must be easilyvisible to the operator controlling the pressure throughout thepressurizing cycle.9.3 Pre-Test Inspection:9.3.1 Before pressurizing is begun, i

27、nspect the outside (andinside if possible) of the test object to verify that it is dry, freeof oils, greases, smoke deposits, or slag and that all welds andconnectors are exposed.9.3.2 An ultrasonic pretest (Section 12) can be used tolocate gross leaks.9.4 Vacuum Drying:9.4.1 If the test object cont

28、ains wood or copper parts thatwill be exposed to ammonia, and if the vessel is designed to besafe under vaccum, it may be necessary to vacuum-dry theinside of the object.9.4.2 Moisture begins to evaporate at a pressure of about 3kPa (25 torr). Bring the test object down to a pressure of 250Pa (20 to

29、rr). At this point water will boil off, indicated by asudden halt in the vacuum gage needle. When the needle startsto go down indicating a lower pressure it can be assumed thatall but trace mounts of water have been eliminated.9.5 PressurizingGradually increase the pressure in thesystem to 50 % of t

30、est pressure during which time frequentchecks should be made for leakage. Thereafter, slowly increasethe pressure to the final test pressure. The test pressure usuallyis between 75 and 150 % of design pressure and should notviolate any applicable codes. If large leaks are expected and anultrasonic p

31、retest has not been conducted, stop the pressuriza-tion at 6.9 kPa (1 psig) and repair any leaks found beforecontinuing.9.6 Leak Test:9.6.1 At the completion of test pressure holding time,examine the system for leakage. Examination of leakage shallbe made of all welds, joints, and connections.9.6.2

32、The inspector shall mark all accessible leaks found onthe equipment using a nondeleterious distinctive tape. Themagnitude of leak shall be described in terms of the diameterof the color-change indication or the apparent density of thesmoke produced.9.7 DepressurizingAfter inspection, slowly release

33、thepressure by venting the ammonia-nitrogen mixture to atmo-sphere or into water.Ammonia is very soluble; 1 Lof water canE 1066 95 (2006)2absorb between 800 and 2000 L of gaseous ammonia. Avacuum pump may be used to help exhaust the remainingammonia or the tank may be purged with nitrogen or com-pre

34、ssed air.9.8 Removing the Color-Change DeveloperRemove thetest developer from the test object by brushing it from thesurface and cleaning with a dust-remover.10. Smoke-Developer Method10.1 SensitivityThis test is the least sensitive and leastcalibratable of the developer methods. Its sensitivity wit

35、h pureammonia at 6.9 kPa (1 psig) is approximately 4.5 3 108mol/s (1 3 103Std cm3/s).210.2 Application:10.2.1 This test is used primarily on systems that alreadycontain ammonia or as a quick pre-test before applying thecolor-change developer.10.2.2 Where small volumes need to be pressurized andpure

36、ammonia may be used, this method can provide rapid leaklocation.10.3 Smoke-Developer Types:10.3.1 Sulfur candles produce a hazardous gas (sulfur diox-ide) and for this reason are not recommended. This gasproduces a visible smoke upon contact with ammonia.10.3.2 Some dilute acid vapors produce a visi

37、ble smokewith ammonia. The liquids that give rise to these vapors can beapplied by wet swab or by aerosol. An aerosol spray is thepreferred technique.10.4 Process:10.4.1 If the test object does not contain ammonia, it shouldbe pressurized slowly to between 6.9 and 69 kPa (1 and 10psig) with pure amm

38、onia. If leak location rather than theleakage rate is desired, a cloth saturated with ammoniumhydroxide can be placed in the pressurized space. Move thedeveloper vapor slowly over areas of possible leaks. A whitecloud will be produced at the leak location.10.4.2 Mark and seal leak locations with tap

39、e wheneverpossible.11. Color-Change Method11.1 Sensitivity:11.1.1 By varying the ammonia concentration, the testpressure and the development time, any leakage rate from4.5 3 1011to 4.5 3 1012mol/s (1 to 1 3 107Std cm3/s)2can be detected. The equation in 11.1.2 is usually applied byspecifying the sma

40、llest leakage rate required (MDLR), as wellas the maximum test pressure allowable. Depending on whichis the more important remaining variable, test time or ammoniaconcentration, the less critical variable is solved for.11.1.2 Leakage Rate CalculationThe following equationallows precise calculation o

41、f the test time in seconds ( t),percentage of ammonia tracer (c), and absolute pressure inpounds per square inch (psia) within the test vessel (p) for anyminimum detectable leakage rate (MDLR). This equation isbased on laboratory data using the time in seconds required togenerate a 1-mm reaction spo

42、t as the diameter of the minimumdevelopment area. Leakage rates are expressed in atmcm3/s.MDLR 52.53415p22 3241!c2/3!t!(1)where:t = time in seconds,c = % ammonia,p = psia, andMDLR = atmcm3/s.11.1.3 The equation can be recast to solve for any of thevariables. For example, a company wishing to test fo

43、r leakageof 4.5 3 1011mol/s (1 3 106Std cm3/s)2could proceed asfollows: Assuming that 345 kPa (50 psia) was the maximumpressure their system could tolerate, it would take 4 min and 30s to develop a reaction spot of 1 mm using a 50 % concentra-tion of ammonia.This result is calculated as follows:t 52

44、.534p15p22 3241!c2/3!MDLR!(2)ort 52.534 50!15 3 5022 3241!502/3!1 3 1026!(3)11.1.4 It has been determined experimentally for wall thick-nesses of 1 to 50 mm that for any given pressure differential,the observed leakage rate varies inversely with the thickness ofthe wall being tested. Although the re

45、lationship is not linear,the decrease in observed leakage can be approximated byadding the following numbers to the exponents of the theoreti-cal MDLR you wish to detect.11.1.4.1 For wall thicknesses of 2 to 10 mm (0.08 to 0.4 in.)add nothing.11.1.4.2 For wall thicknesses between 10 and 25 mm (0.4 t

46、o1 in.) add 1.11.1.4.3 For wall thicknesses between 25 and 50 mm (1 to2 in.) add 2.11.2 ApplicationThis method can be used on containersor systems that are filled or unfilled with ammonia as long asthe atmosphere surrounding the test area is not contaminatedwith ammonia vapors.11.3 Process Steps:11.

47、3.1 Pre-clean and Dry:11.3.1.1 Welds and test connections must be clean of smoke,soil, weld slag, grease, etc., that could block access of thetracer or contaminate the developer. Even water vapor canobscure leaks smaller than 4.5 3 1010mol/s (1 3 105Stdcm3/s).2Wear gloves to avoid contaminating the

48、surface withskin oils especially where the developer is to be applied.11.3.1.2 Test the color-change developer on the surface ofthe test object to verify that the developer dries to the correctcolor.11.3.1.3 If the developer color is not correct, check theatmosphere in the test area with an ammonia-

49、sensitive monitorto see if it is contaminated with excessive ammonia vapors. Ifthe atmosphere is contaminated, it must be cleared or a smokedeveloper used. If the atmosphere is not contaminated, passi-vate or more thoroughly clean the developer side of the testobject.E 1066 95 (2006)311.3.1.4 Use a low-residue volatile cleaner. If some weldscause a slight discoloration of the developer, an acidic cleanercan be used to clean and passivate the weld. If the cleaner iswater based it should be dried at a low temperature of less than200F with a heat g