Standard Test Method for Frost Point of Sealed Insulating Glass Units

SIGNIFICANCE AND USE
This test method and the apparatus described are intended primarily for sealed insulating glass units positioned horizontally. If the procedure is applied to such units in other than a horizontal position, the results may not be comparable to those obtained by this procedure.
Note 1—A similar method is Test Method E 576.
SCOPE
1.1 This test method describes a laboratory procedure for determining the frost point within the air space(s) of sealed insulating glass units, and establishes the criteria for determining whether that point is below or above a given or specified temperature.
1.2 This test method also describes the apparatus to be used for these determinations.
1.3 The values stated in metric (SI) units are to be regarded as the standard. The inch-pound units in parentheses are for information only.
1.4 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Notes 2 and X1.1.

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Publication Date
09-Oct-1999
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ASTM E546-88(1999)e1 - Standard Test Method for Frost Point of Sealed Insulating Glass Units
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
e1
Designation: E 546 – 88 (Reapproved 1999)
Standard Test Method for
Frost Point of Sealed Insulating Glass Units
This standard is issued under the fixed designation E546; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript 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.
e NOTE—Keywords were added in October 1999.
1. Scope 3.2 frost state—the case where the frost point of a sealed
insulating glass unit is above the test temperature specified by
1.1 This test method describes a laboratory procedure for
the purchaser or user.
determining the frost point within the air space(s) of sealed
3.3 no-froststate—thecasewherethefrostpointofasealed
insulating glass units, and establishes the criteria for determin-
insulating glass unit is below the temperature specified by the
ing whether that point is below or above a given or specified
purchaser or user.
temperature.
1.2 This test method also describes the apparatus to be used
4. Summary of Test Method
for these determinations.
4.1 This test method is conducted by the use of a special
1.3 The values stated in SI units are to be regarded as the
apparatus, consisting basically of two chilled cylindrical metal
standard. The values given in parentheses are for information
blocks positioned one over the other and separated by a gap of
only.
controllable distance. The upper block has an exposed flat
1.4 This standard does not purport to address all of the
circular surface, 25 mm (1 in.) in diameter, and can be chilled
safety concerns, if any, associated with its use. It is the
to far below the ice point by regulating the air-gap distance
responsibility of the user of this standard to establish appro-
between it and the lower metal block which is maintained at
priate safety and health practices and determine the applica-
approximately−78°C (−109°F) by dry ice. The test specimen
bility of regulatory limitations prior to use. For specific hazard
is placed in contact with this chilled flat circular surface of the
statements, see Notes 2 and X1.1.
upper block for specified short periods of time, with the metal
2. Referenced Documents surface at successively lower temperatures, to determine at
what temperature frost appears on the corresponding lower air
2.1 ASTM Standards:
space glass surface.
C1036 Specification for Flat Glass
E77 Test Method for Inspection and Verification of Ther-
5. Significance and Use
mometers
5.1 This test method and the apparatus described are in-
E576 Test Method for Frost Point of Sealed Insulating
4 tended primarily for sealed insulating glass units positioned
Glass Units in Vertical Position
horizontally. If the procedure is applied to such units in other
3. Terminology thanahorizontalposition,theresultsmaynotbecomparableto
those obtained by this procedure.
3.1 frost point—the temperature at which visible frost
begins to deposit on the lower air space glass surface of a
NOTE 1—A similar method is Test Method E576.
sealed insulating glass unit in contact with the measuring
6. Apparatus
surface of the frost point apparatus.
6.1 Test Apparatus (see Fig. 1), consisting of upper and
lowercylindricalmetalblocks,withathermocouple,bimetallic
This test method is under the jurisdiction of ASTM Committee E-6 on
thermometer, or other suitable temperature sensors being
Performance of Buildings and is the direct responsibility of Subcommittee E06.22
inserted in the upper block; a control ring; and an insulated
on Durability Performance of Building Constructions.
containment cylinder fitted with a retainer spring assembly.
CurrenteditionapprovedMarch25,1988.PublishedSeptember1988.Originally
published as E546–75. Last previous edition E546–83.
Annual Book of ASTM Standards, Vol 15.02.
3 5
Annual Book of ASTM Standards, Vol 14.03. Available from Dennis Industries, 20032 Waynegarden Court, Germantown,
Annual Book of ASTM Standards, Vol 04.07. MD 20874.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E 546
Parts List
Part No. Nomenclature Part No. Nomenclature
1 upper metal block 12 supporting ring, bottom of inner tube
2 lower metal block 13 control ring
3 top cover 14 cover lid, inner tube
4 supporting plate, upper metal block 15 elbow
5 spacer 16 tube, nylon
6 spring, upper metal block 17 main spring
7 supporting plate, top of inner tube 18 spacer
8 outer tube 19 bearing
9 inner tube 20 bimetallic dial thermometer
10 disk, dry ice pushing 21 dial indicator
11 clamp, dial gage 22 heat source block
FIG. 1 Schematic Diagram of Frost Point Apparatus
The two metal blocks are separated by a small air gap, the gap. The circular measuring surface of the upper block is thus
distance of which can be regulated by the control ring. The readily adjusted to the desired temperature while in contact
exposedflatcircularsurfaceoftheupperblockis25mm(1in.) with the test specimen. The circular measuring surface diam-
in diameter, has a ground or lapped finish, and when placed in eter specified is suitable for frost point measurement of glass
contact with the glass test specimen, forms the frost point up to 6.0 mm ( ⁄4 in.) thick.
measuringsurface.Thelowerblockischilledbyadryicepack 6.1.1 Upper and Lower Metal Blocks, aluminum alloy that
kept in contact with it by the retainer spring assembly, may be anodized, conforming to the dimensions shown in Fig.
maintaining it at a temperature near to that of sublimating dry 1. Other parts of the apparatus may be fabricated from any
ice (−78°C (−109°F)). Because the solid metal blocks are appropriate materials.
highlyconductive,thetemperatureofeachisvirtuallyuniform. 6.1.2 Calibrated Temperature-Measuring Device, such as a
Useofthecontrolringadjuststheairgapdistancebetweenthe thermocouple, thermistor, or bimetallic thermometer, having a
two blocks to give the desired thermal resistance across the air suitable range graduated in 1°C (2°F) or smaller units, and an
E 546
accuracy of 60.5°C (61°F) over the full scale. A suggested
calibration of the bimetallic thermometer is described in
Appendix X1.
7. Test Specimen
7.1 The specimen to be tested shall be representative of the
units to be evaluated and capable of being positioned horizon-
tally.
8. Conditioning
8.1 Prior to testing, condition the test specimen at a tem-
perature of 24 6 3°C (75 6 5°F) for not less than 24 h.
9. Procedure
9.1 Preparation of Apparatus:
9.1.1 Disassemble the apparatus by taking out the dry ice
container and retainer spring assembly. Carefully clean the
measuringsurfacewithasoftclothorpaper.Donotscratchthe
measuring surface.Wipe and clean the apparatus thoroughly if
any moisture is condensed on the surfaces and walls.
9.1.2 Assemble the dry ice container and turn the control
ringsothattheairgapdistancebetweenupperandlowermetal
blocksisabout13mm(0.5in.).Inverttheapparatusontoasoft
cloth.
9.1.3 Spray alcohol or acetone (Warning—See Note 2) on
FIG. 2 Cross Section of Sealed Insulating Glass Unit for Frost
the fin of the dry ice container to ensure good contact with the Point Measurement
dry ice. Compactly charge the container with the crushed or
pulverized dry ice up to the “full’’ mark. Compress the dry ice
9.3.5 Bring the temperature of the upper metal block to the
with the spring assembly and lock the cover lid.
temperature to be checked for frost and stabilize it by fine
adjustment of the control ring. Temperature fluctuation should
NOTE 2—Warning:Both alcohol and acetone are flammable.
not exceed 61°C (2°F).
9.1.4 Return the apparatus to an upright position and secure
9.3.6 Maintain the stabilized temperature for a duration as
it onto a horizontal surface. Allow sufficient time for the
follows:
temperature of the lower metal block to approach that of the
Glass Thickness Designation, Stabilized Temperature—Duration,
dry ice temperature.
mm (in.) min
9.2 Recharging of Apparatus: 3
2.5 ( ⁄32)3
3.0 ( ⁄8)3
9.2.1 During the test procedure, replenish the supply of dry
5.0 ( ⁄16)4
ice whenever it becomes depleted by turning the apparatus
6.0 ( ⁄4)5
upside down on a soft cloth, opening the cover lid, taking out
NOTE 3—See Specification C1036 for glass thickness tolerances.
the retainer spring assembly, and repeating steps 9.1.3 and
9.1.4. 9.3.7 Wipe off the condensation that may have occurred on
9.3 Determination of Frost State and No-Frost State: the upper exterior surface of glass, or spray the upper surface
9.3.1 Charge the frost point apparatus with dry ice as
with clear water.
described in 9.1 or 9.2. 9.3.8 Examine the lower air space glass surface in contact
9.3.2 Clean both exterior
...

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