ASTM E438-92(1996)
(Specification)Standard Specification for Glasses in Laboratory Apparatus
Standard Specification for Glasses in Laboratory Apparatus
SCOPE
1.1 This specification covers the glasses commonly used to manufacture laboratory glass apparatus.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 438 – 92 (Reapproved 1996)
Standard Specification for
Glasses in Laboratory Apparatus
This standard is issued under the fixed designation E 438; 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.
TABLE 1 Chemical Requirements of Type I Glasses
1. Scope
Type I, Class A, Type I, Class B,
1.1 This specification covers the glasses commonly used to
weight % weight %
manufacture laboratory glass apparatus.
Major constituents, approximate:
SiO 81 73
2. Referenced Documents
B O 13 10
2 3
Al O 27
2.1 ASTM Standards: 2 3
BaO see below 0–2
C 225 Test Methods for Resistance of Glass Containers to
CaO see below 1
Chemical Attack
NaO4 6
K O see below 1
C 338 Test Method for Softening Point of Glass 2
Trace constituents, max:
C 598 Test Method for Annealing Point and Strain Point of
As O plus Sb O 0.005 0.1
2 2 2 3
Glass by Beam Bending
PbO 0.1 0.1
MgO 0.1 0.3
C 693 Test Method for Density of Glass by Buoyancy
ZnO 0.1 0.1
C 729 Test Method for Density of Glass by the Sink-Float
CaO 0.1 see above
A
Comparator
K O 0.75 see above
All other constituents, max 0.2 1.0
E 228 Test Method for Linear Thermal Expansion of Solid
3 A
Materials with a Vitreous Silica Dilatometer Each manufacturer must publish the maximum percentage in his glass
because certain limited applications require a level under 0.1 %.
3. Classification
3.1 Three types are included, as follows:
5. Physical Requirements
3.1.1 Type I, Class A—A low-expansion borosilicate glass.
3.1.2 Type I, Class B—An alumino-borosilicate glass.
5.1 The physical requirements for glasses shall be as pre-
3.1.3 Type II—A soda-lime glass. scribed in Table 3. The tolerances listed in Table 3 must be on
the published values of the manufacturer’s specific glass
4. Chemical Requirements
compositions.
4.1 The Type I, Class A and B glasses shall have the major
constituents and comply with the restrictions on trace constitu-
ents given in Table 1. The major constituents will be varied to TABLE 2 Chemical Requirements of Type II Glasses
maintain the physical requirements as shown.
Composition A, Composition B,
weight % weight %
4.2 Suitable Type II glasses may vary somewhat in chemical
composition and still meet essential physical requirements.
Major constituents, approximate:
SiO 68 72
Two such compositions are shown in Table 2; both are readily 2
B O 2 .
2 3
available and are used for laboratory apparatus.
Al O 32
2 3
BaO 2 .
CaO 5 5
MgO 4 4
...
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