ASTM D1458-01(2007)
(Test Method)Standard Test Methods for Fully Cured Silicone Rubber-Coated Glass Fabric and Tapes for Electrical Insulation
Standard Test Methods for Fully Cured Silicone Rubber-Coated Glass Fabric and Tapes for Electrical Insulation
ABSTRACT
These test methods cover procedures for testing fully cured silicone rubber-coated glass fabric and tapes to be used for electrical insulation. The test procedures for the following test methods are detailed: (1) breaking strength, (2) breaking strength after creasing, (3) dielectric breakdown voltage, (4) dielectric proof voltage, (5) dissipation factor and relative permittivity, (6) thermal endurance, (7) thickness, (8) thread count, (9) volume resistivity, and (10) weight. The procedures for sampling of fabric rolls, fabric sheets, tapes and strips, and test specimen preparation and conditioning are given. The test apparatus, report requirements, and precision and bias for each test are provided. The drum type gripping device and creasing apparatus for breaking strength test are illustrated. Voltage stress test shall be done for dissipation factor and relative permittivity and volume resistivity tests.
SCOPE
1.1 These test methods cover procedures for testing fully cured silicone rubber-coated glass fabric and tapes to be used for electrical insulation.
1.2 The procedures appear in the following order:
1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
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 and health practices and determine the applicability of regulatory limitations prior to use. See 9.5.1 for a specific warning statement.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D1458 − 01(Reapproved 2007) An American National Standard
Standard Test Methods for
Fully Cured Silicone Rubber-Coated Glass Fabric and Tapes
for Electrical Insulation
This standard is issued under the fixed designation D1458; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope DielectricStrengthofSolidElectricalInsulatingMaterials
at Commercial Power Frequencies
1.1 These test methods cover procedures for testing fully
D150 Test Methods forAC Loss Characteristics and Permit-
cured silicone rubber-coated glass fabric and tapes to be used
tivity (Dielectric Constant) of Solid Electrical Insulation
for electrical insulation.
D202 Test Methods for Sampling and Testing Untreated
1.2 The procedures appear in the following order:
Paper Used for Electrical Insulation
ASTM
D257 Test Methods for DC Resistance or Conductance of
Procedure Sections References
Insulating Materials
D295 Test Methods for Varnished Cotton Fabrics Used for
Breaking Strength 7 D828
Breaking Strength After Creasing 8 .
Electrical Insulation
Conditioning 5 .
D374 Test Methods for Thickness of Solid Electrical Insu-
Dielectric Breakdown Voltage 9 D149, D295,
lation
D6054
Dielectric Proof-Voltage 10 D1389
D828 Test Method for Tensile Properties of Paper and
Dissipation Factor and Relative Permittivity 11 D150
PaperboardUsingConstant-Rate-of-ElongationApparatus
Sampling 4 .
Thermal Endurance 15 D1830 (Withdrawn 2009)
Thickness 6 D374
D1389 Test Method for Proof-Voltage Testing of Thin Solid
Thread Count 14 .
Electrical Insulating Materials
Volume Resistivity 12 D257
D1711 Terminology Relating to Electrical Insulation
Weight 13 .
D1830 Test Method for Thermal Endurance of Flexible
1.3 The values stated in inch-pound units are to be regarded
Sheet Materials Used for Electrical Insulation by the
as the standard. The values given in parentheses are for
Curved Electrode Method
information only.
D5032 Practice for Maintaining Constant Relative Humidity
1.4 This standard does not purport to address all of the
by Means of Aqueous Glycerin Solutions
safety concerns, if any, associated with its use. It is the
D6054 Practice for Conditioning Electrical Insulating Mate-
responsibility of the user of this standard to establish appro-
rials for Testing
priate safety and health practices and determine the applica-
E104 Practice for Maintaining Constant Relative Humidity
bility of regulatory limitations prior to use. See 9.5.1 for a
by Means of Aqueous Solutions
specific warning statement.
3. Terminology
2. Referenced Documents
3.1 Definitions—For definitions of terms used in these test
2.1 ASTM Standards:
methods, see Terminology D1711.
D149 Test Method for Dielectric Breakdown Voltage and
4. Sampling
4.1 Sample shipments of material as specified below, and
These test methods are under the jurisdiction of ASTM Committee D09 on
where possible take only one sample from any package.
Electrical and Electronic Insulating Materials and are the direct responsibility of
Subcommittee D09.07 on Flexible and Rigid Insulating Materials.
4.1.1 Fabric—Over 3 in. (75 mm) in width.
Current edition approved May 1, 2007. Published June 2007. Originally
4.1.1.1 Rolls—Select one roll from each ten rolls or fraction
approved in 1957. Last previous edition approved in 2001 as D1458 – 01. DOI:
thereof in a shipment of full-width fabric. Cut off not less than
10.1520/D1458-01R07.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1458 − 01 (2007)
two turns of fabric from each roll selected from sampling, and certain properties, such as thermal conductivity and dielectric
select sample material for the preparation of test specimens constant, cannot be determined without a knowledge of thick-
from the remaining layers of the roll. ness.
4.1.1.2 Sheets—Select one sheet from each 50 sheets or
6.2 Test Specimens—Cut specimens prepared from fabric
fraction thereof in a shipment of sheeted fabric. Remove not
samples 1 in. (25 mm) wide across the entire width of the
less than six sheets from the outer layers of each package of
fabric, while specimens prepared from tape and strip samples
sheets selected from sampling, and then select sample material
shall be the width of the sample and 36 in. (910 mm) long.
for the preparation of test specimens from the remaining
Where the specimen is 36 in. or longer (full-width fabric 36 in.
sheets.
or more in width, or where the length of a strip is 36 in. or
4.1.2 Tapes and Strips—3 in. (75 mm) and less in width.
longer), only one specimen will be required unless otherwise
4.1.2.1 Tapes—Cut off not less than six turns of tape from specified. Where the specimen is less than 36 in. (full-width
eachrollselectedforsampling,andthenselectsamplematerial fabric less than 36 in. wide, or strips less than 36 in. long), as
for the preparation of test specimens from the remaining layers many specimens as are needed to obtain the equivalent 36 in.
oftheroll.Selectrollsoftapeinaccordancewiththefollowing linear measure will be required.
schedule:
6.3 Conditioning—It is not necessary to condition the speci-
Minimum Number of Sample
mens for this test. Conduct tests at the Standard Laboratory
Number of Rolls in Shipment Rolls
Temperature of 23 6 1 °C (73.4 6 1.8 °F).
Over 10 000 1 per 1000
6.4 Procedure—Make ten measurements, equally spaced
5001 to 10 000 10
along 36 in. (910 mm) of the specimen or specimens in
2001 to 5000 5
Less than 2000 2
accordance with Method C of Test Methods D374 modified as
follows:
4.1.2.2 Strips—Select three strips from each 100 strips or
6.4.1 Allow the presser foot to remain on the test specimen
fraction thereof in a shipment of strips. Remove not less than
for 2 s, at the end of which read the dial gage.
six strips from the outer layers of each package of strips
6.4.2 Use a presser foot 0.250 in. (6.35 mm) in diameter,
selected for sampling, and then select sample material for the
and an anvil surface upon which the specimen rests at least 2
preparation of test specimens from the remaining strips.
in. (51 mm) in diameter. The force exerted on the specimen
4.2 Prepare the test specimens from samples selected as
shall be 3 ozf (85 g).
specified in 4.1, and as provided for in the individual test
6.4.3 Method C is not considered interchangeable with
methods.
Method A.
6.5 Report—Report the average, maximum, and minimum
5. Conditioning
thickness to the nearest 0.0001 in. (0.003 mm).
5.1 Significance and Use—The properties of the material
described in these test methods are affected by the temperature
7. Breaking Strength
and moisture content of the material to a greater or lesser
7.1 Significance and Use—Thebreakingstrengthoffinished
extent, depending on the specific property.
fabric or tape is of importance as a measure of the tension it
5.2 Conditioning—Unless otherwise specified in the indi-
will withstand without failure while being applied in service.
vidual test method, condition test specimens as described in
7.2 Apparatus—Use a power-driven tensile testing machine
5.2.1 or 5.2.2, and in matters of dispute, consider 5.2.1 as the
meeting the requirements specified for Tensile Properties in
referee method.
Test Methods D202, except that the means for determining
5.2.1 Condition the test specimens for 48 h in the Standard
elongation and for recording applied load and elongation are
Laboratory Atmosphere of 50 6 2 % relative humidity at a
not required. The machine shall be equipped with specimen-
temperatureof23 61°C(73.4 61.8°F),andconductthetests
gripping devices as described in 7.2.1 or 7.2.2.
under these conditions.
7.2.1 Provide two flat-jawed clamps, in which case crocus
5.2.2 Condition the test specimens for 48 h in the Standard
cloth will be required for holding specimens between the jaws,
Laboratory Atmosphere of 50 6 2 % relative humidity at a
or
temperatureof23 61°C(73.4 61.8°F),andconductthetests
7.2.2 Provide two gripping devices of the drum type as
immediately upon removal of the specimens from the condi-
described in Fig. 1, in which case pins as indicated will be
tioning room or chamber.
required for securing specimens on the cylinders.
7.3 Test Specimens—The test specimen shall be of sufficient
6. Thickness
length to provide positive gripping in the jaws with a separa-
6.1 Significance and Use:
tion of approximately 6 in. (150 mm). In the case of the
6.1.1 The importance of space factor in the design of
flat-jawed clamps, this will require a minimum specimen
electrical equipment makes proper determination of thickness
length of 8 in. (200 mm) and a desirable length of 10 in. (250
essential.
mm). Where drum-type gripping devices are used, a specimen
6.1.2 Some properties, such as dielectric strength and di- no less than 20 in. (500 mm) long will be required. Prepare the
electricbreakdown,varywiththethicknessofthematerial,and specimens from each sample as follows:
D1458 − 01 (2007)
7.5.3 Adjust the speed of the machine in accordance with
the requirements for Tensile Properties in Test Methods D202.
7.5.4 Disregard values for breaks in or at the jaws. In these
cases, continue tests so that there are five reportable breaking
strength values per sample.
7.6 Report:
7.6.1 Report the average, maximum, and minimum break-
ing strength in pounds per inch of width (or kilograms per
millimetre of width), together with the width and nominal
thickness.
7.6.2 In the case of fabrics, report the breaking strength in
the warp and fill directions separately.
7.7 Precision and Bias:
7.7.1 Theprecision(repeatabilitywithinasinglelaboratory)
of this test method has been demonstrated to be approximately
17 %, expressed as a coefficient of variation of a series of
replicate measurements on different specimens of the same
sample.
7.7.2 This test method has no bias because the value for
breaking strength is determined solely in terms of this test
method itself.
8. Breaking Strength After Creasing
FIG. 1 Drum-Type Gripping Devices
8.1 Significance and Use—Creasing of silicone rubber-
coated glass fabric is accompanied by breaking of some of the
7.3.1 Fabrics—Cut five specimens, 1 in. (25.4 mm) wide
glass fibers at the crease and a consequent reduction in
(Note 1), with sides parallel to the warp threads, and cut five
breaking strength. The extent of this damage is related to the
specimens of similar width with sides perpendicular to the
thickness and weave of the glass fabric and the nature and
warp threads (Note 2).
thicknessofthesiliconerubbercoating.Thecreasingsimulates
to a degree the pinching action resulting from several succes-
NOTE 1—Where specimens 1 in. (25.4 mm) in width have ultimate
breaking loads exceeding the capacity of the machine, it is permissible to sive layers of tape moving relative to one another while in
reduce the width of the specimen to not less than 0.5 in. (13 mm).
confined position, such as in cables.
NOTE2—Frequentlythefillthreadsofglassfabricsusedtomanufacture
siliconerubber-coatedglassfabricsdonotruninastraightlineandarenot 8.2 Apparatus:
perpendicular to the warp threads. Breaking strength from specimens cut
8.2.1 Use a metal weight adjustable between 2.25 and 4.50
perpendicular to the warp threads may, therefore, be highly variable.
lbf (10 and 20 N). Mount it suitably through guides over a
7.3.2 Tapes and Strips—Cutfivespecimens,1in.(25.4mm)
metal horizontal plane so that the weight may be lowered at a
wide (see Note 2), from each sample. Where tapes or strips are
uniform speed perpendicular to the horizontal plane. The
manufactured in widths less than 1 in. (25.4 mm), use the
bottom of the weight shall be parallel to the top surface of the
specimen width as manufactured.
horizontalplaneatalltimes.Thecreasingsurfaceoftheweight
7.4 Conditioning—It is not necessary to condition speci- is a rectangle of such dimensions that the side which is
mens for this test. Conduct tests at the Standard Laboratory
perpendicular to the crease made on the specimen is 1.5 in. (40
Temperature of 23 6 1 °C (73.4 6 1.8 °F). mm). Suitable apparatus is shown in Fig. 2.
8.2.2 Provide suitable means for lowering the weight at a
7.5 Procedure:
uniform rate of 12 in. (300 mm)/min and of raising the weight
7.5.1 Clamp the ends of the specimen in the jaws between
at the end of a 2-s dwell. This may be accomplished by
two pieces of crocus cloth, the abrasive side of the cloth facing
utilizing the breaking strength machine, described in 7.2,in
the metal jaws. Carefully align the specimen so that the
combination with a system of pulleys. It may also be achieved
breakingforceisparalleltothelengthofthespecimenbetween
by using a motor fitted with reducing gears and a cam, or by
the jaws.Adjust the clearance between jaws to 6 in. (150 mm).
other devices that accomplish the purpose.
7.5.2 Alternatively, loop the specimen around a binding pin
of suitable diameter so that the specimen fits neither too tightly
8.3 Test Specimens—Prepare ten specimens as described in
nor too loosely in the hole provided. Insert the looped
7.3 except that specimens shall be taken from samples of tape
specimen and pin in the hole provided in the drum-type
or rolls of fabric only. In the case of fabric, cut the specimens
gripping device. Carefully align the specimen so that the
in the warp direction only.
breaking force will be parallel to the length of the specimen.
Adjust the clearance between jaws to 6 in. (150 mm). 8.4 Conditioning:
D1458 − 01 (2007)
FIG. 2 Creasing Apparatus for Breaking Strength Test
8.4.1 It is usually not necessary to condition specimens for 8.5.3 Allow the creased specimen to support the weight for
this test. When specimens are not especially conditioned, test a period of 2 s, at the end of which period lift the weight from
them at the Standard Laboratory Temperature of 23 61°C the specimen.
(73.4 6 1.8 °F).
8.5.4 Determine the breaking strength of the creased speci-
8.4.2 Where it is desired to obtain the greatest degree of
men in accordance with 7.5.
reproducibility, condition specimens in a
...
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