ASTM C693-93(2003)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:C693–93 (Reapproved 2003)
Standard Test Method for
Density of Glass by Buoyancy
This standard is issued under the fixed designation C 693; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 5.3 Thermometers, calibrated (20 to 30°C), sensitive to
0.1°C for determining air and water temperatures.
1.1 This test method covers the determination of the density
5.4 Nickel-Chromium-Iron or Platinum-Alloy Wire, less
of glasses at or near 25°C, by buoyancy.
than 0.2-mm diameter for suspending the specimen either in a
1.2 This standard does not purport to address all of the
basket or a loop made of the same wire. The suspension wire
safety concerns, if any, associated with its use. It is the
shall be cleaned by degreasing or heating in a vacuum. An
responsibility of the user of this standard to establish apppro-
acceptable alternative method of cleaning the platinum-alloy
priate safety and health practices and determine the applica-
wire is to heat in an oxidizing gas flame until there is no longer
bility of regulatory limitations prior to use.
any color emitted from the gases passing around the wire.
2. Referenced Documents 5.5 Weights, with accuracy of 0.1 mg.
5.6 Barometer, with sensitivity of 1-mm Hg (optional, see
2.1 ASTM Standards:
Note 3).
E12 Terminology Relating to Density and Specific Gravity
of Solids, Liquids, and Gases
6. Reagent
3. Terminology 6.1 Distilled Water, fresh, boiled, and used within 24 h,
allowed to stabilize at balance air temperature for at least 2 h
3.1 Definition:
in the beaker.
3.1.1 density of solids—the mass of a unit volume of a
material at a specified temperature. The units shall be stated as
7. Test Specimen
grams per cubic centimetre (see TerminologyE12).
7.1 Specimens weighing about 20 g, with a minimum of
4. Significance and Use
seeds or other inclusions (Note 1), shall be taken or cut from
the sample object, preferably in cylindrical or rectangular bar
4.1 Density as a fundamental property of glass has basic
form with smooth, slightly rounded surfaces having no cracks
significance. It is useful in the physical description of the glass
or sharp edges.
and as essential data for research, development, engineering,
and production.
NOTE 1—For a specimen of 20 g with a density of approximately 2.5
g/cm , a gaseous void of diameter 2 mm will cause an error in measured
5. Apparatus
density of 0.05 %.
5.1 Analytical Balance, with sensitivity and accuracy of 0.1
7.2 The specimens shall be cleaned, handling them with
mg.
tweezers throughout subsequent operations, by immersion
5.2 Beaker, of convenient capacity (250 to 750 cm)tofit
preferably in an ultrasonic bath of hot nitric acid, chromic-
inside the balance chamber and allow immersion of the basket
sulfuric acid, or organic degreasing solvent, followed by a
or wire loop specimen holder in distilled water.
rinsing in alcohol and distilled water. For samples only soiled
by ordinary handling or exposure, adequate cleaning may be
This test method is under the jurisdiction of ASTM Committee C14 on Glass
and Glass Products and is the direct responsibility of Subcommittee C14.04 on
Physical and Mechanical Properties.
Current edition approved April 10, 2003. Published July 1993. Originally
e1 3
approved in 1971. Last previous edition approved in 1988 as C 693 – 84 (1988) . Bowman,H.A.,andSchoonover,R.M.,“ProcedureforHighPrecisionDensity
Discontinued—Replaced by E 1547, Annual Book of ASTM Standards,Vol Determinations by HydrostaticWeighing.” Journal of Research, National Bureau of
15.05. Standards, Vol 71C, No. 3, July–August 1967, pp. 179–198.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C693–93 (2003)
TABLE 1 Density of Dry Air, g/cm
Pressure, mm Hg
Temperature,
°C
720 730 740 750 760 770
20 0.001 141 0.001 157 0.001 173 0.001 189 0.001 205 0.001 221
21 137 153 169 185 201 216
22 134 149 165 181 197 212
23 130 145 161 177 193 208
24 126 142 157 173 189 204
25 122 138 153 169 185 200
26 118 134 149 165 181 196
27 115 130 146 161 177 192
28 111 126 142 157 173 188
29 107 123 138 153 169 184
30 104 119 134 150 165 180
obtained using a warm 2 % volume MICRO-brand detergent, 8.8 Readthedistilledwatertemperaturetothenearest0.1°C
followed by a deionized or distilled water rinse. and determine the water density from Table 2. Record this as
r .
W
8. Procedure
8.1 Hold the specimens and covered beaker of boiled 9. Calculation
distilled water near the laboratory balance until the water has
9.1 Calculate the weight of the specimen in water, W ,as
W
cooled to ambient temperature before weighing.
follows:
8.2 Read the laboratory air temperature to the nearest 1°C.
W 5 W 2 W (1)
W T O
Read the barometric pressure to the nearest 1-mm Hg. A fixed
9.2 Calculate the glass density, r, at the average air-water
laboratory average barometric pressure estimate is an accept-
laboratory temperature, T , as follows:
able alternative to the barometric pressure measurement (see L
Note 3). Det
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