1、Designation: E546 14Standard Test Method forFrost/Dew Point of Sealed Insulating Glass Units1This standard is issued under the fixed designation E546; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A num
2、ber in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This test method describes a laboratory procedure fo
3、rdetermining the frost/dew point within the air space(s) ofsealed insulating glass units, and establishes the criteria fordetermining whether that point is below or above a given orspecified temperature.1.2 This test method also describes the apparatus to be usedfor these determinations.1.3 The valu
4、es stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with
5、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. For specific hazardstatements, see 9.1.3.2. Referenced Documents2.1 ASTM Standards:2C1036 Specification for Fla
6、t GlassE77 Test Method for Inspection and Verification of Ther-mometersE576 Test Method for Frost/Dew Point of Sealed InsulatingGlass Units in the Vertical PositionE631 Terminology of Building Constructions3. Terminology3.1 DefinitionsFor definitions of general terms used in thistest method, refer t
7、o Terminology E631.3.2 Definitions of Terms Specific to This Standard:3.2.1 frost/dew point, nthe temperature at which water,organic vapor, or other chemicals begin to appear on theinterior glass surface of a sealed insulating glass unit in contactwith the measuring surface of the frost/dew-point ap
8、paratus.3.2.2 frost statethe case where the frost/dew point of asealed insulating glass unit is above the test temperaturespecified by the purchaser or user.3.2.3 no-frost statethe case where the frost/dew point of asealed insulating glass unit is below the temperature specifiedby the purchaser or u
9、ser.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 exposed flatcircular surface, 1 in. (25 mm
10、) 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 109F (78C) by dry ice. The test specimenis placed in contact with this chilled flat circular surface of theupper block for specified
11、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 primarily for sealed insulating glass
12、 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 E576.1This test method is under the jurisdiction of ASTM Committee E06 onPerformance
13、 of Buildings and is the direct responsibility of Subcommittee E06.22on Durability Performance of Building Constructions.Current edition approved Dec. 1, 2014. Published December 2014. Originallyapproved in 1975. Last previous edition approved in 2008 as E546 08. DOI:10.1520/E0546-14.2For referenced
14、 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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consh
15、ohocken, PA 19428-2959. United States16. Apparatus6.1 Test Apparatus3(see Fig. 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 cyl
16、inder fitted with a retainer spring assembly.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 1 in. (25 mm)in diameter; has a ground or lapped finish; and, when placed incontact wi
17、th the glass test specimen, forms the frost/dew 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 dry3The sole source of supply of the apparatus known to the committe
18、e at this timeis Dennis Industries, 20032 Waynegarden Court, Germantown, MD 20874, http:/. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee
19、,1whichyou may attend.Parts ListPart No. Nomenclature Part No. Nomenclature1 upper metal block 12 supporting ring, bottom of inner 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 blo
20、ck 17 main spring7 supporting plate, top of inner tube 18 spacer8 outer tube 19 bearing9 inner tube 20 bimetallic dial thermometer10 disk, dry ice pushing 21 dial indicator11 clamp, dial gage 22 heat source blockFIG. 1 Schematic Diagram of Frost/Dew-Point ApparatusE546 142ice (109F (78C). Because th
21、e solid metal blocks arehighly conductive, the temperature of each is 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 th
22、e desired temperature while in contactwith the test specimen. The circular measuring surface diam-eter specified is suitable for frost/dew point measurement ofglass up to14 in. (6.0 mm) thick.6.1.1 Upper and Lower Metal Blocks, aluminum alloy thatmay be anodized, conforming to the dimensions shown i
23、n Fig.1. Other parts of the apparatus may be fabricated from anyappropriate materials.6.1.2 Calibrated Temperature-Measuring Device; such as athermocouple, thermistor, or bimetallic thermometer; having asuitable range graduated in 2F (1C) or smaller units; and anaccuracy of 61F (60.5C) over the full
24、 scale. A suggestedcalibration of the bimetallic thermometer is described inAppendix X1.6.1.3 The size of the temperature measuring probe shallmatch the bore size drilled into the aluminum head in order toensure proper temperature measurements.7. Test Specimen7.1 The specimen to be tested shall be r
25、epresentative 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 75 6 5F (24 6 3C) for not less than 24 h.9. Procedure9.1 Preparation of Apparatus:9.1.1 Disassemble the apparatus by taking ou
26、t 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 container and turn the c
27、ontrolring so that the air gap distance between upper and lower metalblocks is about 0.5 in. (13 mm). Invert the apparatus onto a softcloth.9.1.3 Spray alcohol or acetone (WarningBoth alcoholand acetone are flammable.) on the fin of the dry ice containerto ensure good contact with the dry ice. Compa
28、ctly charge thecontainer with the crushed or pulverized dry ice up to the “full”mark. Compress the dry ice with the spring assembly and lockthe cover lid.9.1.4 Return the apparatus to an upright position and secureit onto a horizontal surface. Allow sufficient time for thetemperature of the lower me
29、tal 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 outthe retainer spring assembly, and repeat
30、ing steps 9.1.3 and9.1.4.9.3 Determination of Frost State and No-Frost State:9.3.1 Charge the frost/dew 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 Due to the changes in the cold plate design the use ofthe aluminized polyester film
31、is no longer a requirement.However it is still recommended in order to ensure a pristineviewing surface.9.3.4 If the reflective film is used, use the following proce-dure: Place a piece of silver-colored aluminized polyester film3(highly reflective mirror surface, not thicker than 0.003 in.(0.08 mm)
32、 and 1 in. (25 mm) in diameter or 1 by 1 in. (25 by25 mm) on the measuring surface by wetting both surfaces ofthe film with acetone or alcohol (WarningSee 9.1.3). Centerthe specimen on the apparatus. Examine the lower air spaceglass surface in the region where frost is to be deposited, to beaware of
33、 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 be deposited (see Fig. 2).9.3.5 Slowly reduce the air gap distance between upper andlo
34、wer metal blocks by turning the control ring while watchingthe temperature of the upper metal block.9.3.6 Bring the temperature of the upper metal block to thetemperature to be checked for frost and stabilize it by fineadjustment of the control ring. Temperature fluctuation shouldnot exceed 2F (61C)
35、.FIG. 2 Cross Section of Sealed Insulating Glass Unit for Frost/Dew Point MeasurementE546 1439.3.7 Maintain the stabilized temperature for a duration asfollows:Glass Thickness Designation,in. (mm )Stabilized TemperatureDuration,min18 (2.5) 316 (3.0) 3316 (5.0) 414 (6.0) 5NOTE 2See Specification C103
36、6 for glass thickness tolerances.9.3.8 Wipe off the condensation that may have occurred onthe upper exterior surface of glass, or spray the upper surfacewith clear water.9.3.9 Examine the lower air space glass surface in contactwith the measuring surface for frost. Illuminate this surfacewith a fluo
37、rescent desk lamp (two 15-W daylight bulbs), orequivalent for better detection of frost (see Fig. 3).9.3.10 If a clearly visible frost deposit appears on the lowerair space glass surface during or after the temperature stabili-zation period, the frost/dew point of the specimen is above thisstabilize
38、d temperature (frost 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 the
39、temperature of the measuring surface by 2F (1C) and holdthis value for the duration given in 9.3.7. Reexamine thesuspected particles. If the deposit is frost, its size or populationwill grow or get heavier.9.3.10.1 Frost/dew point determination as described in9.3.10 is difficult to observe on reflec
40、tive glass. It is acceptableto lift the specimen off the tester and observe for frost byviewing the unit when held up to light.The observation shall bemade within5sofremoval from the tester.9.3.11 If frost does not appear after the temperature stabili-zation period, the frost/dew point of the specim
41、en is below thisstabilized temperature (no-frost state).9.3.12 To check at other temperatures, repeat the testprocedure described in 9.3.4 9.3.11 for the temperaturesdesired.9.4 Determination of Approximate Frost/Dew-Point Range:9.4.1 Perform a series of measurements as described in 9.3at successive
42、ly lower temperatures until frost state is proven.Temperature intervals of 20F (10C) are preferable: forexample, 20F (10C), 0F (20C), 20F (30C), 40F( 40C), 60F (50C), and 80F ( 60C) as described in9.3. Other temperature levels can be checked as desired. Thefrost/dew point will be between the tempera
43、ture at which frostappeared and the next higher temperature.9.4.2 When the frost/dew-point range can be predicted byexperience (newly fabricated specimen, and so forth), only thetemperatures bracketing the predicted frost/dew point need bechecked.9.4.3 Estimate the frost/dew point of the specimen wi
44、thinthe temperature range between frost and no-frost found in 9.4.1by comparing the frost at the lower temperature limit (froststate) with the reference photograph (see Fig. 4) of similartemperature range.9.5 Final Measurement of Frost/Dew Point:9.5.1 Perform a series of no-frost, frost state measur
45、ementsdescribed in 9.4 by starting at a few degrees Celsius above theestimated frost/dew point. Lower the temperature by intervalsof less than 3F (2C) (preferably 2F (1C). If frost appearsat the first starting temperature, reestimate the frost/dew pointusing Fig. 4 and repeat the test.9.5.2 The fros
46、t/dew point is the temperature at which visiblefrost first appears, or between this temperature and the nexthigher temperature that was checked.9.5.3 Record the frost/dew point as the temperature of theupper metal block when the visible frost first appears.FIG. 3 Frost/Dew-Point Test Apparatus in Us
47、eE546 1449.5.4 For repeated measurements of frost/dew point on thesame specimen, allow the frost to evaporate completely, orchoose another spot at least 2 in. (50 mm) away from theprevious measuring spot. Use a counterweight to balance thespecimen. The heat source block (see Fig. 1, Part No. 22) may
48、be warmed and placed in momentary contact with the uppermetal block to raise its temperature before proceeding with arepeated measurement.10. Report10.1 Report the following information:10.1.1 Complete description of the test specimen, includingsize, glass thickness, air space(s) thickness, desiccan
49、t type andquantity, and sealant type.10.1.2 Specimen conditioning temperature, if other than thatspecified in 8.1.10.1.3 Frost/dew point temperature.11. Precision and Bias11.1 The precision and bias of the test method were deter-mined after assembling various laboratory personnel in onecommon laboratory with their respective test equipment. Alltests were performed on the same set of specially prepared testspecimens.11.2 When the temperature measuring device is calibratedin accordance with 6.1.2 and
