1、Designation: E 546 88 (Reapproved 1999)e1Standard Test Method forFrost Point of Sealed Insulating Glass Units1This standard is issued under the fixed designation E 546; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.e1NOTEKeywords were added in October 1999.1. Scope
3、1.1 This test method describes a laboratory procedure fordetermining the frost point within the air space(s) of sealedinsulating glass units, and establishes the criteria for determin-ing whether that point is below or above a given or specifiedtemperature.1.2 This test method also describes the app
4、aratus to be usedfor these determinations.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of
5、the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specific hazardstatements, see Notes 2 and X1.1.2. Referenced Documents2.1 ASTM Standards:C 1036 Specification for Flat Glass2E 77 Test Method
6、for Inspection and Verification of Ther-mometers3E 576 Test Method for Frost Point of Sealed InsulatingGlass Units in Vertical Position43. Terminology3.1 frost pointthe temperature at which visible frostbegins to deposit on the lower air space glass surface of asealed insulating glass unit in contac
7、t with the measuringsurface of the frost point apparatus.3.2 frost statethe case where the frost point of a sealedinsulating glass unit is above the test temperature specified bythe purchaser or user.3.3 no-frost statethe case where the frost point of a sealedinsulating glass unit is below the tempe
8、rature specified by thepurchaser or user.4. Summary of Test Method4.1 This test method is conducted by the use of a specialapparatus, consisting basically of two chilled cylindrical metalblocks positioned one over the other and separated by a gap ofcontrollable distance. The upper block has an expos
9、ed flatcircular surface, 25 mm (1 in.) in diameter, and can be chilledto far below the ice point by regulating the air-gap distancebetween it and the lower metal block which is maintained atapproximately 78C (109F) by dry ice. The test specimenis placed in contact with this chilled flat circular sur
10、face of theupper block for specified short periods of time, with the metalsurface at successively lower temperatures, to determine atwhat temperature frost appears on the corresponding lower airspace glass surface.5. Significance and Use5.1 This test method and the apparatus described are in-tended
11、primarily for sealed insulating glass units positionedhorizontally. If the procedure is applied to such units in otherthan a horizontal position, the results may not be comparable tothose obtained by this procedure.NOTE 1A similar method is Test Method E 576.6. Apparatus6.1 Test Apparatus5(see Fig.
12、1), consisting of upper andlower cylindrical metal blocks, with a thermocouple, bimetallicthermometer, or other suitable temperature sensors beinginserted in the upper block; a control ring; and an insulatedcontainment cylinder fitted with a retainer spring assembly.1This test method is under the ju
13、risdiction of ASTM Committee E-6 onPerformance of Buildings and is the direct responsibility of Subcommittee E06.22on Durability Performance of Building Constructions.Current edition approved March 25, 1988. Published September 1988. Originallypublished as E 546 75. Last previous edition E 546 83.2A
14、nnual Book of ASTM Standards, Vol 15.02.3Annual Book of ASTM Standards, Vol 14.03.4Annual Book of ASTM Standards, Vol 04.07.5Available from Dennis Industries, 20032 Waynegarden Court, Germantown,MD 20874.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2
15、959, United States.The two metal blocks are separated by a small air gap, thedistance of which can be regulated by the control ring. Theexposed flat circular surface of the upper block is 25 mm (1 in.)in diameter, has a ground or lapped finish, and when placed incontact with the glass test specimen,
16、 forms the frost pointmeasuring surface. The lower block is chilled by a dry ice packkept in contact with it by the retainer spring assembly,maintaining it at a temperature near to that of sublimating dryice (78C (109F). Because the solid metal blocks arehighly conductive, the temperature of each is
17、 virtually uniform.Use of the control ring adjusts the air gap distance between thetwo blocks to give the desired thermal resistance across the airgap. The circular measuring surface of the upper block is thusreadily adjusted to the desired temperature while in contactwith the test specimen. The cir
18、cular measuring surface diam-eter specified is suitable for frost point measurement of glassup to 6.0 mm (14 in.) thick.6.1.1 Upper and Lower Metal Blocks, aluminum alloy thatmay be anodized, conforming to the dimensions shown in Fig.1. Other parts of the apparatus may be fabricated from anyappropri
19、ate materials.6.1.2 Calibrated Temperature-Measuring Device, such as athermocouple, thermistor, or bimetallic thermometer, having asuitable range graduated in 1C (2F) or smaller units, and anParts ListPart No. Nomenclature Part No. Nomenclature1 upper metal block 12 supporting ring, bottom of inner
20、tube2 lower metal block 13 control ring3 top cover 14 cover lid, inner tube4 supporting plate, upper metal block 15 elbow5 spacer 16 tube, nylon6 spring, upper metal block 17 main spring7 supporting plate, top of inner tube 18 spacer8 outer tube 19 bearing9 inner tube 20 bimetallic dial thermometer1
21、0 disk, dry ice pushing 21 dial indicator11 clamp, dial gage 22 heat source blockFIG. 1 Schematic Diagram of Frost Point ApparatusE 5462accuracy of 60.5C (61F) over the full scale. A suggestedcalibration of the bimetallic thermometer is described inAppendix X1.7. Test Specimen7.1 The specimen to be
22、tested shall be representative of theunits to be evaluated and capable of being positioned horizon-tally.8. Conditioning8.1 Prior to testing, condition the test specimen at a tem-perature of 24 6 3C (75 6 5F) for not less than 24 h.9. Procedure9.1 Preparation of Apparatus:9.1.1 Disassemble the appar
23、atus by taking out the dry icecontainer and retainer spring assembly. Carefully clean themeasuring surface with a soft cloth or paper. Do not scratch themeasuring surface. Wipe and clean the apparatus thoroughly ifany moisture is condensed on the surfaces and walls.9.1.2 Assemble the dry ice contain
24、er and turn the controlring so that the air gap distance between upper and lower metalblocks is about 13 mm (0.5 in.). Invert the apparatus onto a softcloth.9.1.3 Spray alcohol or acetone (WarningSee Note 2) onthe fin of the dry ice container to ensure good contact with thedry ice. Compactly charge
25、the container with the crushed orpulverized dry ice up to the “full mark. Compress the dry icewith the spring assembly and lock the cover lid.NOTE 2Warning: Both alcohol and acetone are flammable.9.1.4 Return the apparatus to an upright position and secureit onto a horizontal surface. Allow sufficie
26、nt time for thetemperature of the lower metal block to approach that of thedry ice temperature.9.2 Recharging of Apparatus:9.2.1 During the test procedure, replenish the supply of dryice whenever it becomes depleted by turning the apparatusupside down on a soft cloth, opening the cover lid, taking o
27、utthe retainer spring assembly, and repeating steps 9.1.3 and9.1.4.9.3 Determination of Frost State and No-Frost State:9.3.1 Charge the frost point apparatus with dry ice asdescribed in 9.1 or 9.2.9.3.2 Clean both exterior surfaces of the specimen.9.3.3 Place a piece of silver-colored aluminumized p
28、olyes-ter film5(highly reflective mirror surface, not thicker than 0.08mm (0.003 in.) and 25 mm (1 in.) in diameter or 25 by 25 mm(1 by 1 in.) on the measuring surface by wetting both surfacesof the film with acetone or alcohol (WarningSee Note 2).Center the specimen on the apparatus. Examine the lo
29、wer airspace glass surface in the region where frost is to be deposited,to be aware of any dirt or other foreign particles that might bemistaken for frost. Note, however, that a small foreign particleon the lower air space glass surface may be helpful in focusingon the surface where the frost is to
30、be deposited (see Fig. 2).9.3.4 Slowly reduce the air gap distance between upper andlower metal blocks by turning the control ring while watchingthe temperature of the upper metal block.9.3.5 Bring the temperature of the upper metal block to thetemperature to be checked for frost and stabilize it by
31、 fineadjustment of the control ring. Temperature fluctuation shouldnot exceed 61C (2F).9.3.6 Maintain the stabilized temperature for a duration asfollows:Glass Thickness Designation,mm (in.)Stabilized TemperatureDuration,min2.5 (332)33.0 (185.0 (316)46.0 (14)5NOTE 3See Specification C 1036 for glass
32、 thickness tolerances.9.3.7 Wipe off the condensation that may have occurred onthe upper exterior surface of glass, or spray the upper surfacewith clear water.9.3.8 Examine the lower air space glass surface in contactwith the measuring surface for frost. Illuminate this surfacewith a fluorescent des
33、k lamp (two 15-W daylight bulbs), orequivalent for better detection of frost (see Fig. 3).9.3.9 If a clearly visible frost deposit appears on the lowerair space glass surface during or after the temperature stabili-zation period, the frost point of the specimen is above thisstabilized temperature (f
34、rost state) (see Fig. 4 for frost forma-tion). Check for double image of the frost to assure that thefrost lies on the lower air space glass surface (see Fig. 4B). Ifthe frost deposit is so small and faint that it cannot bedistinguished from dirt or other foreign particles, lower thetemperature of t
35、he measuring surface by 1C (2F) and holdthis value for the duration given in 9.3.6. Reexamine thesuspected particles. If the deposit is frost, its size or populationwill grow or get heavier.FIG. 2 Cross Section of Sealed Insulating Glass Unit for FrostPoint MeasurementE 54639.3.9.1 Frost point deter
36、mination as described in 9.3.9 isdifficult to observe on reflective glass. It is acceptable to lift thespecimen off the tester and observe for frost by viewing theunit when held up to light. The observation shall be madewithin5sofremoval from the tester.9.3.10 If frost does not appear after the temp
37、erature stabi-lization period, the frost point of the specimen is below thisstabilized temperature (no-frost state).9.3.11 To check at other temperatures, repeat the test pro-cedure described in 9.3.3-9.3.10 for the temperatures desired.9.4 Determination of Approximate Frost Point Range:9.4.1 Perfor
38、m a series of measurements as described in 9.3at successively lower temperatures until frost state is proven.Temperature intervals of 10C (20F) are preferable: forexample, 10C (20F), 20C (0F), 30C (20F), 40C (40F), 50C (60F), and 60C (80F) as de-scribed in 9.3. Other temperature levels can be checke
39、d asdesired. The frost point will be between the temperature atwhich frost appeared and the next higher temperature.9.4.2 When the frost point range can be predicted byexperience (newly fabricated specimen, etc.), only the tem-peratures bracketing the predicted frost point need be checked.9.4.3 Esti
40、mate the frost point of the specimen within thetemperature range between frost and no-frost found in 9.4.1 bycomparing the frost at the lower temperature limit (frost state)with the reference photograph (see Fig. 4) of similar tempera-ture range.9.5 Final Measurement of Frost Point:9.5.1 Perform a s
41、eries of no-frost, frost state measurementsdescribed in 9.4 by starting at a few degrees Celsius above theestimated frost point. Lower the temperature by intervals ofless than 2C (3F) (preferably 1C (2F). If frost appears atFIG. 3 Frost Point Test Apparatus in UseNOTE 1Number X means XC below frost
42、point.NOTE 2Size of frost deposit varies with the thickness of glass.FIG. 4 References of Frost Deposit at a Glass Thickness of 5.0 mm (316 in.)E 5464the first starting temperature, reestimate the frost point usingFig. 4 and repeat the test.9.5.2 The frost point is the temperature at which visible f
43、rostfirst appears, or between this temperature and the next highertemperature that was checked.9.5.3 Record the frost point as the temperature of the uppermetal block when the visible frost first appears.9.5.4 For repeated measurements of frost point on the samespecimen, allow the frost to evaporate
44、 completely, or chooseanother spot at least 50 mm (2 in.) away from the previousmeasuring spot. Use a counterweight to balance the specimen.The heat source block (see Fig. 1, Part No. 22) may be warmedand placed in momentary contact with the upper metal block toraise its temperature before proceedin
45、g with a repeated mea-surement.10. Report10.1 Report the following information:10.1.1 Complete description of the test specimen, includingsize, glass thickness, air space(s) thickness, desiccant type andquantity, and sealant type.10.1.2 Specimen conditioning temperature, if other than thatspecified
46、in 8.1.10.1.3 Frost point temperature.11. Precision and Bias11.1 The precision and bias of the test method weredeter-mined after assembling various laboratory personnel in onecommon laboratory with their respective test equipment. Alltests were performed on the same set of specially prepared testspe
47、cimens.11.2 When the temperature measuring device is calibratedin accordance with 6.3 and Appendix X1, the frost pointdifferential measured was within 2C (4F).12. Keywords12.1 building; frost point; insulating glass; sealed insulatingglass unitsAPPENDIX(Nonmandatory Information)X1. CALIBRATION OF BI
48、METALLIC THERMOMETERX1.1 Required EquipmentX1.1.1 Secondary Standard ThermometerASTM Thermometer 99F or equivalent (50 to + 10C (55to + 40F), maximum scale error 0.2C (0.4F). Anothercalibrated secondary standard (thermocouple, resistance ther-mometer, etc.) can be used.X1.1.2 Dewar flask or well-ins
49、ulated liquid container.X1.1.3 Acetone or alcohol.X1.1.4 Dry ice.X1.2 ProcedureX1.2.1 Pour a sufficient amount of acetone or alcohol intothe Dewar flask.NOTE X1.1Warning: Both acetone and alcohol are flammable.X1.2.2 Insert both the secondary standard thermometer andthe bimetallic thermometer in the liquid bath to specifieddepths of the thermometer.X1.2.3 Slowly drop the small pieces of dry ice into theliquid bath to cool it while continuously stirring it.X1.2.4 Bring the temperature of the liquid ba
