ASTM C693-93(2019)

Standard Test Method for Density of Glass by Buoyancy

SIGNIFICANCE AND USE
4.1 Density as a fundamental property of glass has basic significance. It is useful in the physical description of the glass and as essential data for research, development, engineering, and production.
SCOPE
1.1 This test method covers the determination of the density of glasses at or near 25 °C, by buoyancy.  
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Jul-2019
• ICS: 17.060 - Measurement of volume, mass, density, viscosity
• ICS: 81.040.30 - Glass products
• Technical Committee: C14 - Glass and Glass Products
• Drafting Committee: C14.04 - Physical and Mechanical Properties

Relations

• Replaces: ASTM C693-93(2013) - Standard Test Method for Density of Glass by Buoyancy
• Effective Date: 01-Aug-2019
• Referred By: ASTM F1538-03(2017) - Standard Specification for Glass and Glass Ceramic Biomaterials for Implantation
• Effective Date: 01-Aug-2019
• Referred By: ASTM A901-19 - Standard Specification for Amorphous Magnetic Core Alloys, Semi-Processed Types
• Effective Date: 01-Aug-2019
• Referred By: ASTM C1926-23 - Standard Test Method for Measurement of Glass Dissolution Rate Using Stirred Dilute Reactor Conditions on Monolithic Samples
• Effective Date: 01-Aug-2019
• Referred By: ASTM F3078-15 - Standard Test Method for Identification and Quantification of Lead in Paint and Similar Coating Materials using Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF)
• Effective Date: 01-Aug-2019
• Referred By: ASTM C1285-21 - Standard Test Methods for Determining Chemical Durability of Nuclear, Hazardous, and Mixed Waste Glasses and Multiphase Glass Ceramics: The Product Consistency Test (PCT)
• Effective Date: 01-Aug-2019
• Referred By: ASTM A912/A912M-11(2019) - Standard Test Method for Alternating-Current Magnetic Properties of Amorphous Materials at Power Frequencies Using Wattmeter-Ammeter-Voltmeter Method with Toroidal Specimens
• Effective Date: 01-Aug-2019
• Referred By: ASTM C1662-18 - Standard Practice for Measurement of the Glass Dissolution Rate Using the Single-Pass Flow-Through Test Method
• Effective Date: 01-Aug-2019

Overview

ASTM C693-93(2019): Standard Test Method for Density of Glass by Buoyancy is an internationally recognized standard developed by ASTM International. This document outlines a precise method to determine the density of glass at or near 25°C using buoyancy techniques. Accurate glass density measurement is fundamental in the physical characterization of glass and supports research, development, engineering, and production processes in the glass industry.

This test method provides standardized procedures to achieve reliable and accurate density results, offering significant value for material verification, quality control, and scientific studies. Developed in alignment with international standardization principles, ASTM C693 ensures global compatibility and best practices in glass measurement.

Key Topics

• Scope: The method covers the determination of density for glass materials at or near 25°C using the principle of buoyancy. It highlights the need for users to address specific safety, health, and environmental practices.
• Apparatus: Key equipment includes an analytical balance with 0.1 mg sensitivity, a beaker (250-750 cm³), calibrated thermometers, precision wire for suspending specimens, and weights with high accuracy. The procedure may also use a barometer for precise air density measurements.
• Test Procedure: The test involves cleaning the glass specimen, weighing it in air and then in distilled water, and recording the temperatures and barometric pressure. Water used for immersion must be distilled, boiled, and temperature-stabilized.
• Calculations: The glass density is calculated based on the weight difference in air and water, accounting for air and water densities at the observed temperature and barometric pressure. Corrections for temperature and void inclusions are also part of the final reporting.
• Reporting: Results should include specimen identification, measured density, temperature, thermal history, and estimates of void content.

Applications

ASTM C693 is widely applied in:

• Quality Control: Manufacturers use this standard to verify the consistency and quality of glass products, ensuring that specifications are met for construction, container, and specialty glass.
• Research and Development: Laboratories utilize the method to characterize new glass formulations or to benchmark properties against industry standards.
• Material Verification: Density measurements help in differentiating glass types and detecting impurities or inclusions, vital for both manufacturers and buyers.
• Engineering Data: Accurate density values are essential for engineering calculations, physical modeling, and performance evaluations in glass product design.

Regular use of ASTM C693 in these areas helps ensure that glass products meet physical property requirements essential for safety, durability, and performance.

Related Standards

Relevant standards linked to glass density and measurement include:

• ASTM E12: Terminology Relating to Density and Specific Gravity of Solids, Liquids, and Gases (Withdrawn, but referenced for definitions in C693).
• ISO 4883: Glass - Density Measurement Methods (International approaches to glass density).
• ASTM C162: Terminology of Glass and Glass Products (Relates to definitions and properties used in ASTM C693).
• ISO/IEC Guides for general laboratory procedures and best practices in material testing.

ASTM C693-93(2019) is an essential document for anyone involved in the measurement and qualification of glass density, providing a consistent and accurate methodology in compliance with globally recognized standards.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C693 − 93 (Reapproved 2019)
Standard Test Method for
Density of Glass by Buoyancy
This standard is issued under the fixed designation C693; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 5.2 Beaker, of convenient capacity (250 to 750 cm)tofit
inside the balance chamber and allow immersion of the basket
1.1 This test method covers the determination of the density
or wire loop specimen holder in distilled water.
of glasses at or near 25 °C, by buoyancy.
5.3 Thermometers, calibrated (20 to 30 °C), sensitive to
1.2 This standard does not purport to address all of the
0.1 °C for determining air and water temperatures.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5.4 Nickel-Chromium-Iron or Platinum-Alloy Wire, less
priate safety, health, and environmental practices and deter- than 0.2-mm diameter for suspending the specimen either in a
mine the applicability of regulatory limitations prior to use.
basket or a loop made of the same wire. The suspension wire
1.3 This international standard was developed in accor- shall be cleaned by degreasing or heating in a vacuum. An
dance with internationally recognized principles on standard-
acceptable alternative method of cleaning the platinum-alloy
ization established in the Decision on Principles for the wire is to heat in an oxidizing gas flame until there is no longer
Development of International Standards, Guides and Recom-
any color emitted from the gases passing around the wire.
mendations issued by the World Trade Organization Technical
5.5 Weights, with accuracy of 0.1 mg.
Barriers to Trade (TBT) Committee.
5.6 Barometer, with sensitivity of 1-mm Hg (optional, see
Note 3).
2. Referenced Documents
2.1 ASTM Standards:
6. Reagent
E12 Terminology Relating to Density and Specific Gravity
6.1 Distilled Water, fresh, boiled, and used within 24 h,
of Solids, Liquids, and Gases (Withdrawn 1996)
allowed to stabilize at balance air temperature for at least 2 h
in the beaker.
3. Terminology
7. Test Specimen
3.1 Definitions:
3.1.1 density of solids—the mass of a unit volume of a 7.1 Specimens weighing about 20 g, with a minimum of
material at a specified temperature. The units shall be stated as
seeds or other inclusions (Note 1), shall be taken or cut from
grams per cubic centimetre (see Terminology E12). the sample object, preferably in cylindrical or rectangular bar
form with smooth, slightly rounded surfaces having no cracks
4. Significance and Use
or sharp edges.
4.1 Density as a fundamental property of glass has basic
NOTE 1—For a specimen of 20 g with a density of approximately 2.5
significance. It is useful in the physical description of the glass
g/cm , a gaseous void of diameter 2 mm will cause an error in measured
density of 0.05 %.
and as essential data for research, development, engineering,
and production.
7.2 The specimens shall be cleaned, handling them with
tweezers throughout subsequent operations, by immersion
5. Apparatus
preferably in an ultrasonic bath of hot nitric acid, chromic-
5.1 Analytical Balance, with sensitivity and accuracy of 0.1 sulfuric acid, or organic degreasing solvent, followed by a
mg. rinsing in alcohol and distilled water. For samples only soiled
by ordinary handling or exposure, adequate cleaning may be
obtained using a warm 2 % volume MICRO-brand detergent,
This test method is under the jurisdiction of ASTM Committee C14 on Glass
followed by a deionized or distilled water rinse.
and Glass Products and is the direct responsibility of Subcommittee C14.04 on
Physical and Mechanical Properties.
Current edition approved Aug. 1, 2019. Published August 2019. Originally Bowman,H.A.,andSchoonover,R.M.,“ProcedureforHighPrecisionDensity
approved in 1971. Last previous edition approved in 2013 as C693 – 93 (2013). Determinations by HydrostaticWeighing.” Journal of Research, National Bureau of
DOI: 10.1520/C0693-93R19. Standards, Vol 71C, No. 3, July–August 1967, pp. 179–198.
2 4
The last approved version of this historical standard is referenced on Manufactured by International Products Corporation, PO Box 70, Burlington,
www.astm.org. NJ 08016.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C693 − 93 (2019)
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
8. Procedure 9. Calculation
8.1 Hold the specimens and covered beaker of boiled
9.1 Calculate the weight of the specimen in water, W ,as
W
distilled water near the laboratory balance until the water has
follows:
cooled to ambient temperature before weighing.
W 5 W 2 W (1)
W T O
8.2 Read the laboratory air temperature to the nearest 1 °C.
9.2 Calculate the glass density, ρ, at the average air-water
Read the barometric pressure to the nearest 1-mm Hg. A fixed
laboratory tempera
...