1、Designation: E576 08 E576 14Standard Test Method forFrost/Dew Point of Sealed Insulating Glass Units in theVertical Position1This standard is issued under the fixed designation E576; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This test method des
3、cribes a field or laboratory procedure for determining the frost/dew point within the air space(s) ofsealed insulating glass units and establishes the criteria for determining whether that point is below or above a given or specifiedtemperature.1.2 This test method also describes the apparatus to be
4、 used for these determinations.1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information only and are not considered standard.1.4 This standard does not purport to address all of
5、 the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For specific hazard statements, see 9.1.3 and 9.3.79.3.8.2. Referenc
6、ed Documents2.1 ASTM Standards:2C1036 Specification for Flat GlassE77 Test Method for Inspection and Verification of ThermometersE631 Terminology of Building ConstructionsE774 Specification for the Classification of the Durability of Sealed Insulating Glass Units (Withdrawn 2006)33. Terminology3.1 D
7、efinitionsFor definitions of general terms used in this test method, refer to Terminology E631.3.2 Definitions of Terms Specific to This Standard:3.2.1 frost statethe case where the frost/dew point of a sealed insulating glass unit is above the test temperature specified bythe purchaser or user.3.2.
8、1 frost/dew pointthe temperature at which water, organic vapor, or other chemicals begin to appear on the interior glasssurface of a sealed insulating glass unit in contact with the measuring surface of the frost/dew-point apparatus.3.2.2 frost statethe case where the frost/dew point of a sealed ins
9、ulating glass unit is above the test temperature specified bythe purchaser or user.3.2.3 no-frost statethe case where the frost/dew point of a sealed insulating glass unit is below the temperature specified bythe purchaser or user.4. Summary of Test Method4.1 This test method is conducted by the use
10、 of a special apparatus, consisting basically of two chilled cylindrical metal blockspositioned one over the other and separated by a gap of controllable distance. The upper block has an exposed flat circular surface,1 This test method is under the jurisdiction of ASTM Committee E06 on Performance o
11、f Buildings and is the direct responsibility of Subcommittee E06.22 on DurabilityPerformance of Building Constructions.Current edition approved April 1, 2008Dec. 1, 2014. Published May 2008February 2015. Originally approved in 1976. Last previous edition approved in 19992008 asE576 88 (1999)E576 08.
12、1 . DOI: 10.1520/E0576-08.10.1520/E0576-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approve
13、d version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict
14、all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-
15、2959. United States125 mm (1 in.)1 in. (25 mm) in diameter, and can be chilled to far below the ice point by regulating the air gap distance betweenit and the lower metal block which is maintained at approximately 78C (109F)109F (78C) by dry ice. The test specimenis placed in contact with this chill
16、ed flat circular surface of the upper block for specified short periods of time, with the metalsurface at successively lower temperatures, to determine at what temperature frost appears on the corresponding lower air spaceglass surface.5. Significance and Use5.1 This test method is suitable for use
17、under actual or simulated in-service conditions; that is, one side of the unit is exposedto room temperature, while the other side is exposed to natural or simulated weather conditions. Where the glazing conditions andthe 24-h history are different or changed from previous conditions, the frost/dew
18、point may not be comparable to a previousmeasurement.5.2 This test method is applicable for the uncoated or unfilmedun-filmed clear (transparent) glass panelite of sealed insulatingglass units. If this apparatus is used with coated or filmed glass pane,lite, the coating or film on the surface of gla
19、ss panelite maybe damaged.5.3 This test method may require minor modifications to keep the measuring surface of the frost/dew-point apparatus in contactwith the glass if the insulating glass unit is not in the true vertical position.Parts ListPart No. Nomenclature Part No. Nomenclature1 front metal
20、block 12 supporting ring, bottom ofinner tube2 rear metal block 13 control ring3 top cover 14 cover lid, inner tube4 supporting plate, front metalblock15 elbow5 spacer 16 tube, nylon6 spring front metal block 17 main spring7 supporting plate, top ofinner tube18 spacer8 outer tube 19 bearing9 inner t
21、ube 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 ApparatusE576 1426. Apparatus6.1 Test Apparatus4(see (see Fig. 1); consisting of upper and lower cylindrical metal blocks with a thermocoupl
22、e, bimetallicthermometer, or other suitable temperature sensors being inserted in the upper block; a control ring; and an insulated containmentcylinder fitted with a retainer spring assembly. The two metal blocks are separated by a small air gap, the distance of which canbe regulated by the control
23、ring. The exposed flat circular surface of the upper block is 25 mm (1 in.)1 in. (25 mm) in diameter,has a ground or lapped finish, and when placed in contact with the glass test specimen, forms the frost/dew point measuring surface.The lower block is chilled by a dry ice pack kept in contact with i
24、t by the retainer spring assembly, maintaining it at a temperaturenear to that of sublimating dry ice (78C (109F).(109F (78C). Because the solid metal blocks are highly conductive, thetemperature of each is virtually uniform. Use of the control ring adjusts the air gap distance between the two block
25、s to give thedesired thermal resistance across the air gap. The circular measuring surface of the upper block is thus readily adjusted to thedesired temperature while in contact with the test specimen. The circular measuring surface diameter specified is suitable forfrost/dew point measurement of gl
26、ass up to 6.0 mm (14 in.) in. (6.0 mm) thick.6.1.1 Upper and Lower Blocks, aluminum alloy that may be anodized, conforming to the dimensions shown in Fig. 1. Otherparts of the apparatus may be fabricated from any appropriate materials.6.1.2 Calibrated Temperature-Measuring Device; such as a thermoco
27、uple, thermistor, or bimetallic thermometer; having asuitable range graduated in 1C (2F)2F (1C) or smaller units; and an accuracy of 60.5C (61F)61F (60.5C) over the fullscale. A suggested calibration of the bimetallic thermometer is described in Appendix X1.6.1.3 The size of the temperature measurin
28、g probe shall match the bore size drilled into the aluminum head in order to ensureproper temperature measurements.6.2 Vertical Attachment Fixture4(see (see Fig. 2), consisting of a twin-grip vacuum cup holder, two parallel guide rods, two4 The sole source of supply of the apparatus known to the com
29、mittee at this time is Dennis Industries, 20032 Waynegarden Court, Germantown, MD 20874,http:/. If you are aware of alternative suppliers, please provide this information toASTM International Headquarters. Your comments will receive carefulconsideration at a meeting of the responsible technical comm
30、ittee,1 which you may attend.Parts ListPart No. Nomenclature1 rubber vacuum cup2 guide rod3 clamping spring4 vacuum hand lever5 hand grip6 spring postFIG. 2 Vertical AttachmentE576 143spring posts, and two clamping springs. The vacuum cup is made of rubber. When the vertical attachment fixture is pl
31、aced on thesurface of clean glass and the vacuum hand lever is pushed down, the vertical attachment fixture becomes firmly attached to theglass surface. Other equivalent attachment fixtures may be used.6.3 Glass Thickness Gage (see (see Fig. 3).7. Test Unit7.1 The sealed insulating glass unit to be
32、tested should have a clear glass panelite (see 5.2) in contact with the measuring sideof the test apparatus and shall be positioned vertically.8. Conditioning8.1 Condition the unit to be tested at room temperature on both unit sides by exposing to a temperature of 24 6 3C(75 6 5F)75 6 5F (24 6 3C) f
33、or not less than 24 h prior to the testing.8.2 Condition the unit to be tested under simulated in-service conditions by exposing to temperatures within63C (65F)65F(63C) of the desired simulated conditions for not less than 24 h 24 h prior to testing.8.3 For the unit to be tested under actual in-serv
34、ice conditions, record or obtain the ambient temperatures of both sides of theunit at the start and end of a particular measuring period, and the 24-h temperature history prior to testing.NOTE 1At the present time, there is insufficient information to compare the measured frost/dew point of the unit
35、 from the reported temperature historyto that implied in-service level of the unit. However, the temperature history will provide a valuable basis for evaluating the in-service level and life ofthe unit in the future.9. Procedure9.1 Preparation of Frost/Dew-Point Apparatus:9.1.1 Disassemble the appa
36、ratus by removing the dry ice container and retainer spring assembly. Carefully clean the measuringsurface with a soft cloth or paper. Do not scratch the measuring surface. Wipe and clean the apparatus thoroughly if any moisturehas condensed on the surfaces and walls.9.1.2 Assemble the dry ice conta
37、iner and turn the control ring so that the air gap distance between front and rear metal blocksis about 13 mm (0.5 in.).0.5 in. (13 mm). Invert the apparatus onto a soft cloth or a suitable mounting bracket.9.1.3 Spray alcohol or acetone (WarningBoth alcohol and acetone are flammable.) on the fin of
38、 the dry ice container toensure good contact with the dry ice. Compactly charge the container with the crushed or pulverized dry ice up to the “full” mark.Compress the dry ice with the spring assembly and lock the cover lid.9.1.4 Turn the apparatus to an upright position. Allow sufficient time for t
39、he temperature of the rear metal block to approachnear that of the dry ice temperature.9.2 Recharging of Frost/Dew-Point ApparatusDuring the test procedure, replenish the supply of dry ice whenever it becomesdepleted by inverting the apparatus onto a soft cloth, opening the cover lid, taking out the
40、 retainer spring assembly, and repeatingsteps 9.1.3 and 9.1.4.9.3 Determination of Frost State or No-Frost State:(a) Gage (b) Gage in UseFIG. 3 Glass Thickness GageE576 1449.3.1 Charge the frost/dew-point apparatus with dry ice as described in 9.1 or 9.2.9.3.2 Measure the thickness of glass in the m
41、easuring side as follows:9.3.2.1 Place the long side of the glass thickness gage (see Fig. 3) against the glass pane at a 45 angle.9.3.2.2 Observe the reflection in the glass.9.3.2.3 Note where the long line superimposes the short line.9.3.2.4 Read the minimum thickness of the glass above.9.3.3 Plac
42、e the frost/dew-point apparatus on top of the guide rods of the vertical attachment fixture, facing the measuring surfaceof the frost/dew-point apparatus toward the rubber vacuum cup, and slide both guide fins of the frost/dew-point apparatus inbetween the guide rods from the rear end.9.3.4 Hook eac
43、h clamping spring to the hooks of the frost/dew-point apparatus.9.3.5 Clean the exterior glass surface where the frost/dew-point apparatus and the vertical attachment fixtures are to be placed.Measure the frost/dew point within an area at least 250 mm (10 in.)10 in. (250 mm) away from the spacer or
44、at the center of theunit. Examine the interior air space glass surface in the region, where dew or frost is to be deposited, to be aware of any dirt orother foreign particles that might be mistaken for frost. However, a small foreign particle on the interior air space glass surfacemay be helpful in
45、focusing on the surface where the frost is to be deposited. Avoid the area where sunlight strikes directly on theunit or shade it from direct sunlight.9.3.6 Release both vacuum hand levers of the vertical attachment fixture.9.3.7 Due to the changes in the cold plate design, the use of the aluminized
46、 polyester film is no longer a requirement. However,it is still recommended in order to ensure a pristine viewing surface. If the reflective film is used then use the following procedure:9.3.8 Clean the surfaces of the rubber vacuum cups, and the measuring surface and front surface of the frost/dew-
47、pointapparatus. If there are any water vapor or frost deposits on the measuring surface of the frost/dew-point apparatus, clean themeasuring surface by wetting with alcohol (WarningAlcohol is flammable.). If the measuring surface is heavily scratched, thefront metal block should be replaced or repai
48、red. If the dew or frost deposit can be checked from the other side of the unit asdescribed in 9.3.159.3.16, a piece of silver-colored aluminized polyester film with a highly reflective surface, not thicker than 0.08mm (0.003 in.), and 25 mm (1 in.)0.003 in. (0.08 mm), and 1 in. (25 mm) in diameter,
49、 or 25 by 25 mm (1 by 1 in.)1 by 1 in. (25by 25 mm) can be placed on the measuring surface by wetting both surfaces with alcohol.9.3.9 To provide better thermal contact, wet the measuring surface of the frost/dew-point apparatus and exterior glass surfacewhere it is to be contacted with alcohol (WarningSee 9.3.79.3.8).9.3.10 Hold the hand grip of the vertical attachment fixture with one hand in a level position. Contact the measuring surfaceagainst the wetted glass surface and push the vertical attachment so th
