ASTM D578/D578M-23

Standard Specification for Glass Fiber Strands

ABSTRACT
This specification covers the requirements for continuous fiber and staple fiber glass strands, including single, plied and multiple wound. It also covers textured glass fiber yarns. It is one of a series to provide a substitute for Military Specifications: MIL-Y-1140 Yarn, Cord, Sleeving, Cloth and Tape-Glass; and MIL-C-9084 Cloth, Glass Finished for Resin Laminates. The nominal twist in S and Z directions and breaking strength of the continuous filament yarns shall conform to the specified requirements. The fibers shall be free of any free alkali metal oxides, such as soda or potash, and from foreign particles, dirt, and other impurities. The direction of twist, twist level, filament diameter, breaking strength, and ignition loss (organic content) of the fiber shall be tested.
SCOPE
1.1 This specification covers the requirements for continuous fiber and staple fiber glass strands, including single, plied and multiple wound. It also covers textured glass fiber yarns. This specification is intended to assist ultimate users by designating the general nomenclature for the strand products that are generally manufactured in the glass fiber industry.  
1.2 Glass fibers are produced having various compositions. General applications are identified by means of a letter designation. The letter designation represents a family of glasses that have provided acceptable performance to the end-user in the intended application. For example, the composition limits stated for E-Glass in this specification representing the glass fiber family for general and most electrical applications is designated by the letter E. Military specifications, such as, MIL-R-60346, recognize the composition limits described in this specification as meeting the respective requirements for E-Glass strands used in reinforced plastic structure applications.  
1.3 Glass fiber strands have a variety of general uses under specific conditions, such as high physical or chemical stress, high moisture, high temperature, or electrical environments. Property requirements under specific conditions are agreed upon between the purchaser and the supplier. Electrical property requirements vary with specific end-use applications. For printed circuit board applications, other requirements may be needed such as the use of Institute for Interconnecting and Packaging Electronic Circuits (IPC) Specification EG 4412 A for finished fabric woven from E-Glass for printed circuit boards, or Specification MIL-P-13949 for printed wiring boards applicable to glass fabric base.  
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems will result in non-conformance with the standard.  
1.5 This specification is one of a series to provide a substitute for Military Specifications: MIL-Y-1140 Yarn, Cord, Sleeving, Cloth and Tape-Glass; and MIL-C-9084 Cloth, Glass Finished for Resin Laminates.  
1.6 Additional ASTM specifications in this series have been drafted and appear in current editions of the Annual Book of ASTM Standards. These include finished glass fabrics, unfinished glass fabrics, glass tapes, glass sleevings, glass cords, glass sewing threads, and finished laminates made from finished glass fabrics.  
1.7 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.  
1.8 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 ...

General Information

• Status: Published
• Publication Date: 31-May-2023
• ICS: 59.100.10 - Textile glass materials
• Technical Committee: D13 - Textiles
• Drafting Committee: D13.18 - Glass Fiber and its Products

Relations

• Refers: ASTM D1907/D1907M-12(2018) - Standard Test Method for Linear Density of Yarn (Yarn Number) by the Skein Method
• Effective Date: 01-Jul-2018
• Refers: ASTM D123-17 - Standard Terminology Relating to Textiles
• Effective Date: 01-Mar-2017
• Refers: ASTM D123-15b - Standard Terminology Relating to Textiles
• Effective Date: 15-Sep-2015
• Refers: ASTM D123-15a - Standard Terminology Relating to Textiles
• Effective Date: 01-Sep-2015
• Refers: ASTM D123-15 - Standard Terminology Relating to Textiles
• Effective Date: 01-Apr-2015
• Refers: ASTM D123-13a - Standard Terminology Relating to Textiles
• Effective Date: 15-Jun-2013
• Refers: ASTM D123-13ae1 - Standard Terminology Relating to Textiles
• Effective Date: 15-Jun-2013
• Refers: ASTM D123-13 - Standard Terminology Relating to Textiles
• Effective Date: 15-May-2013
• Refers: ASTM D1907/D1907M-12 - Standard Test Method for Linear Density of Yarn (Yarn Number) by the Skein Method
• Effective Date: 01-Jul-2012
• Refers: ASTM D123-12e1 - Standard Terminology Relating to Textiles
• Effective Date: 01-Feb-2012
• Refers: ASTM D123-12 - Standard Terminology Relating to Textiles
• Effective Date: 01-Feb-2012
• Refers: ASTM D7018/D7018M-11 - Standard Terminology Relating to Glass Fiber and Its Products
• Effective Date: 01-Jan-2011
• Refers: ASTM D2256/D2256M-10 - Standard Test Method for Tensile Properties of Yarns by the Single-Strand Method
• Effective Date: 01-Jun-2010
• Refers: ASTM D2256/D2256M-10e1 - Standard Test Method for Tensile Properties of Yarns by the Single-Strand Method
• Effective Date: 01-Jun-2010
• Refers: ASTM D2256/D2256M-09 - Standard Test Method for Tensile Properties of Yarns by the Single-Strand Method
• Effective Date: 01-Jul-2009

Overview

ASTM D578/D578M-23 is the international standard specification developed by ASTM International for glass fiber strands, including continuous fiber, staple fiber, single, plied, multiple wound strands, and textured glass fiber yarns. This specification provides essential requirements and nomenclature for glass fibers widely used in composite materials, electrical insulation, reinforced plastics, and a variety of industrial and military applications. Covering different glass families such as E-Glass, C-Glass, S-Glass, and R-Glass, ASTM D578/D578M-23 details product descriptions, physical property criteria, and test methods to ensure consistent quality and performance.

Key Topics

• Types of Glass Fiber Strands: The specification covers continuous filament yarns, staple (discontinuous) fiber yarns, rovings, and textured yarns.
• Nomenclature and Product Description: Provides a standard system for naming and describing glass fiber products, including segments for glass family, yarn number, construction, twist direction, and diameter.
• Physical and Chemical Requirements:
  • Free from alkali metal oxides (such as soda or potash), dirt, and other impurities.
  • Defines certified chemical composition for different glass families (e.g., E-Glass, S-Glass) to meet industry and military standards.
• Measurement Criteria: Standardizes how nominal twist in S and Z directions, breaking strength, filament diameter, ignition loss (organic content), and other physical attributes should be measured and reported.
• Units of Measurement: Details acceptance of both SI and inch-pound units; systems must not be mixed to maintain conformity.
• Substitution for Obsolete Military Standards: ASTM D578/D578M acts as a replacement for several legacy military specifications, aiding transition to modern international standards.

Applications

Glass fiber strands manufactured and specified according to ASTM D578/D578M-23 are essential in diverse industry sectors:

• Reinforced Plastics & Composites: Used in automotive, aerospace, and construction for achieving lightweight and high-strength materials.
• Electrical Insulation & Electronics: E-Glass is especially significant for electrical laminates, printed circuit boards, power distribution, and insulation components.
• Industrial Uses: Including filtration media, yarns for industrial textiles, and components for power generation and distribution.
• Military & Aerospace: Meets technical requirements for critical applications where performance and reliability are paramount.
• Resin Compatibility: Rovings and chopped strands can be specified for compatibility with various resins, such as epoxy or polyester, ensuring effective composite manufacturing.

Benefits of following ASTM D578/D578M-23:

• Guarantees uniform product quality and traceable nomenclature.
• Facilitates communication between manufacturers and end-users.
• Ensures material performance for demanding applications such as high temperature, moisture, physical, or chemical stress.

Related Standards

ASTM D578/D578M-23 references several important standards and guidelines to ensure comprehensive coverage and international compatibility:

• ASTM D123 - Terminology Relating to Textiles
• ASTM D1423/D1423M - Test Method for Twist in Yarns
• ASTM D2256/D2256M - Test Method for Tensile Properties of Yarns
• ASTM D4963/D4963M - Test Method for Ignition Loss of Glass Fiber
• MIL-Y-1140, MIL-C-9084, MIL-R-60346 - Obsolete military standards replaced by this specification
• IPC EG 4412 A - Finished Fabric Woven from E-Glass for Printed Circuit Boards

By adhering to ASTM D578/D578M-23, manufacturers and purchasers ensure the reliability and versatility of glass fiber products in advanced material applications. This standard serves as an indispensable reference for the glass fiber industry and its end-users worldwide.

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: D578/D578M − 23
Standard Specification for
Glass Fiber Strands
This standard is issued under the fixed designation D578/D578M; 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 U.S. Department of Defense.
1. Scope system shall be used independently of the other. Combining
values from the two systems will result in non-conformance
1.1 This specification covers the requirements for continu-
with the standard.
ous fiber and staple fiber glass strands, including single, plied
1.5 This specification is one of a series to provide a
and multiple wound. It also covers textured glass fiber yarns.
substitute for Military Specifications: MIL-Y-1140 Yarn, Cord,
This specification is intended to assist ultimate users by
Sleeving, Cloth and Tape-Glass; and MIL-C-9084 Cloth, Glass
designating the general nomenclature for the strand products
Finished for Resin Laminates.
that are generally manufactured in the glass fiber industry.
1.6 Additional ASTM specifications in this series have been
1.2 Glass fibers are produced having various compositions.
drafted and appear in current editions of the Annual Book of
General applications are identified by means of a letter
ASTM Standards. These include finished glass fabrics, unfin-
designation. The letter designation represents a family of
ished glass fabrics, glass tapes, glass sleevings, glass cords,
glasses that have provided acceptable performance to the
glass sewing threads, and finished laminates made from fin-
end-user in the intended application. For example, the compo-
ished glass fabrics.
sition limits stated for E-Glass in this specification representing
the glass fiber family for general and most electrical applica-
1.7 This standard does not purport to address all of the
tions is designated by the letter E. Military specifications, such
safety concerns, if any, associated with its use. It is the
as, MIL-R-60346, recognize the composition limits described
responsibility of the user of this standard to establish appro-
in this specification as meeting the respective requirements for
priate safety, health, and environmental practices and deter-
E-Glass strands used in reinforced plastic structure applica-
mine the applicability of regulatory limitations prior to use.
tions.
1.8 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.3 Glass fiber strands have a variety of general uses under
ization established in the Decision on Principles for the
specific conditions, such as high physical or chemical stress,
Development of International Standards, Guides and Recom-
high moisture, high temperature, or electrical environments.
mendations issued by the World Trade Organization Technical
Property requirements under specific conditions are agreed
Barriers to Trade (TBT) Committee.
upon between the purchaser and the supplier. Electrical prop-
erty requirements vary with specific end-use applications. For
2. Referenced Documents
printed circuit board applications, other requirements may be
needed such as the use of Institute for Interconnecting and
2.1 ASTM Standards:
Packaging Electronic Circuits (IPC) Specification EG 4412 A D123 Terminology Relating to Textiles
for finished fabric woven from E-Glass for printed circuit
D1423/D1423M Test Method for Twist in Yarns by Direct-
boards, or Specification MIL-P-13949 for printed wiring Counting
boards applicable to glass fabric base.
D1907/D1907M Test Method for Linear Density of Yarn
(Yarn Number) by the Skein Method
1.4 The values stated in either SI units or inch-pound units
D2256/D2256M Test Method for Tensile Properties of Yarns
are to be regarded separately as standard. The values stated in
by the Single-Strand Method
each system are not be exact equivalents; therefore, each
D2258/D2258M Practice for Sampling Yarn for Testing
D2904 Practice for Interlaboratory Testing of a Textile Test
This specification is under the jurisdiction of ASTM Committee D13 on
Textiles and is the direct responsibility of Subcommittee D13.18 on Glass Fiber and
its Products. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved June 1, 2023. Published August 2023. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1940. Last previous edition approved in 2018 as D578/D578M – 18. Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D0578_D0578M-23. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D578/D578M − 23
Method that Produces Normally Distributed Data (With- 4.2 “E” Glass—A family of glasses composed primarily of
drawn 2008) the oxides of calcium, aluminum, and silicon, which has the
D2906 Practice for Statements on Precision and Bias for following certified chemical compositions.
Textiles (Withdrawn 2008) 4.2.1 The following certified chemical composition applies
D4963/D4963M Test Method for Ignition Loss of Glass to E-glass fiber yarn products for printed circuit boards and
Fiber Strands and Fabrics aerospace.
D7018/D7018M Terminology Relating to Glass Fiber and
Chemical % by Weight
Its Products (Withdrawn 2021)
B O 5 to 10
2 3
2.2 ASTM Adjunct:
CaO 16 to 25
Al O 12 to 16
TEX-PAC 2 3
SiO 52 to 56
2.3 ANSI Standard: MgO 0 to 5
Na O and K O 0 to 2
2 2
ANSI/ASQC Z1.4 Sampling Procedures for Inspection by
TiO 0 to 0.8
5 2
Attributes
Fe O 0.05 to 0.4
2 3
Fluoride 0 to 1.0
2.4 Military Standards and Specifications:
4.2.2 The following certified chemical composition applies
MIL-P-13949 Specification for Plastic Sheet, Laminated,
to E-glass fiber products used in general applications.
Metal-Clad For Printed Wiring Board
MIL-R-60346 Roving, Glass Fibrous (for Prepreg Tape, Chemical % by Weight
Rovings, Filament Winding, and Pultrusion Applications)
B O 0 to 10
2 3
MIL-G-55636B Glass Cloth, Resin Preimpregnated (B-
CaO and MgO 16 to 30
STAGE) (For Multilayer Printed Wiring Boards) (Super- Al O 12 to 16
2 3
SiO 52 to 62
seded by MIL-P-13949 1981)
Total alkali metal oxides 0 to 2
MIL-Y-1140 Specification for Yarn, Cord, Sleeving, Cloth,
TiO 0 to 1.5
and Tape-Glass Fe O 0.05 to 0.8
2 3
Fluoride 0 to 1.0
MIL-C-9084 Specification for Cloth Finished for Resin
4.2.3 Electrical applications include a wide variety of uses.
Laminates (Cancelled 1999)
The composition in 4.2.1 is identical to IPC EG 4412 A for
2.5 Institute for Interconnecting and Packaging Circuits
printed circuit boards and to MIL-G-55636B. Additionally,
Standard:
such fiber glass products often are specified for aerospace
IPC EG 4412 A Specification for Finished Fabric Woven
applications. Products covered by the composition range in
from E-Glass for Printed Circuit Boards
4.2.2 are used in general applications, such as power company
equipment, high voltage devices, residential electric boxes,
3. Terminology
third rail covers, high voltage standoff rods, electrical pultru-
3.1 For all terminology related to D13.18, Glass Fiber and
sion products, light poles, electrical tool covers, and electrical
Its Products, see Terminology D7018/D7018M.
tape. Other applications include roofing, flooring, filtration,
3.1.1 The following terms are relevant to this standard:
panel rovings, gun rovings, smc rovings, chopped strand
atmosphere for testing textiles, chopped strand, continuous
reinforcements, paper yarns, and industrial yarns.
filament yarn, roving, staple glass yarn, strand, textured glass
4.2.4 The nomenclature “E-CR-Glass” is used for boron-
yarn.
free modified E-Glass compositions for improved resistance to
corrosion by most acids.
3.2 For all other terminology related to textiles, refer to
Terminology D123.
4.3 “S” Glass—A family of glasses composed primarily of
the oxides of magnesium, aluminum, and silicon with a
4. Classification of Glass Fiber
certified chemical composition which conforms to an appli-
cable material specification and which produces high mechani-
4.1 “C” Glass—A family of glasses composed primarily of
cal strength.
the oxides of sodium, calcium, boron, aluminum, and silicon
with a certified chemical composition which conforms to an
4.4 “R”Glass—A family of boron-free glasses composed
applicable material specification and which produces good acid
primarily of the oxides of silicon, aluminum, calcium and
resistance (excluding HF).
magnesium, such glasses possessing excellent acid and water
durability as well as specific strength and specific modulus
levels significantly greater than E glass.
The last approved version of this historical standard is referenced on
DESCRIPTION OF GLASS STRANDS
www.astm.org.
PC programs on floppy disk for analyzing Committee D13 interlaboratory data
5. General
are available through ASTM. Request ADJD2904.
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
5.1 The construction of glass strands is described in a series
4th Floor, New York, NY 10036.
of two to four segments of alphabetical or numerical charac-
Available from DLA Document Services, Building 4/D, 700 Robbins Ave.,
Philadelphia, PA 19111-5094, http://quicksearch.dla.mil.
ters.
Available from Institute for Interconnecting and Packaging Electronic Circuits,
7380 N. Lincoln Ave., Lincolnwood, IL 60646. NOTE 1—In glass fiber strand designations, and in the conversion of
D578/D578M − 23
yards per pound to tex units, the following rules are used: additional cabling step. The total single yarns in the final yarn will always
(1) less than 2.50 tex—round to nearest 0.01 tex be the product of all the counts in this segment. When 0 (zero) appears as
(2) 2.50 tex to less than 5.00 tex—round to nearest 0.05 tex a count it is considered as 1 (one) for multiplication purposes.
(3) 5.00 tex to less than 10.0 tex—round to nearest 0.1 tex
6.1.4 Segment Four—The fourth segment of the description
(4) 10.0 tex to less than 250 tex—round to nearest 1.0 tex
of continuous filament yarns specifies the twist level and
(5) 250 tex to less than 2000 tex—round to nearest 5.0 tex
(6) 2000 tex to less than 100 000 tex—round to nearest 100 tex
direction. For yarns described in SI units, the description
consists of an S or Z to show direction of twist immediately
5.1.1 For strands described in inch-pound units, the approxi-
followed by the twist level in turns per metre (tpm) to the
mate yards per pound of the final strand can be computed by
nearest 1 tpm. For yarns described in inch-pound units, the
multiplying the yarn number designation of the single yarn or
description consists of the twist level in turns per inch (tpi) to
strand by 100 to obtain yards per pound for the single yarn or
the nearest 0.1 tpi immediately followed by an S or Z to show
strand and then dividing by the total number of single yarns or
direction of twist.
strands in the final yarn. Actual yardage is less because of
organic content and twist take-up during plying.
NOTE 4—Twist in turns per metre (tpm) equals twist in turns per inch
(tpi) times 40. The exact factor 39.37 is rounded to 40 to obtain the twist
NOTE 2—Letter designations for filament diameter averages are shown
in turns per metre to the nearest 1 tpm when starting from turns per inch
in Table 1. The yards per pound stated in Table 2 is an approximate yarn
to the nearest 0.1 tpi.
number. The “As Received” yards per pound will be less than the bare
glass values stated. This may be contributed by twist take-up, sizing
6.2 Examples of Descriptions of Continuous Filament
percent, or purchaser agreement to produce to a lower yarn number to
Yarns:
meet other requirements for a further manufactured product, or both. For
6.2.1 Example 1a, Singles Yarn Using SI Units—The de-
example, EC9 66 1×0 (ECG 75 1/0) stated at approximately 66 tex [7500
yd/lb] will actually be about 68 tex [7300 yd/lb] in the delivered state for
scription of a singles continuous filament yarn using SI units
use in the electrical laminate industry.
might be:
6. Continuous Filament Yarns
EC6 33 1 × 0 Z40
6.1 Descriptions of Continuous Filament Yarns—The de-
where:
scription of continuous filament yarns consists of the following
E = symbol for glass family used in general and most
four segments:
electrical applications,
Segment 1 Segment 2 Segment 3 Segment 4
C = symbol for continuous filament yarn,
Glass family Yarn number Construction Twist level
6 = symbol for filament diameter average range 5.50 to
Fiber form Twist direction
6.49 μm,
Fiber diameter
33 = nominal yarn number of single yarn, tex,
6.1.1 Segment One—The parts of Segment one are respec-
1×0 = one single yarn twisted without plying or cabling,
tively the symbol for the glass family as directed in Section 4;
and
the symbol for fiber form, “C” for Continuous, and a symbol
Z40 = a twist level of 40 tpm in the “Z” direction.
for average filament diameter range as directed in Table 1.
The nominal yarn number in tex of the final yarn will be
6.1.2 Segment Two—The second segment of the description
approximately 33 since there is only one strand in the final
of continuous filament yarns specifies the yarn number of the
yarn.
single yarn. For yarns described in SI units, the yarn number is
6.2.2 Example 1b, Singles Yarn Using Inch-Pound Units—
specified in tex. For yarns described in inch-pound units, the
The description of a singles continuous filament yarn using
yarn number is specified in hundreds of yards per pound, that
inch-pound units might be:
is yards per pound divided by 100.
6.1.2.1 Some manufacturing processes are designed specifi-
ECDE 150 1/0 1.0Z
cally to produce yarns consisting of hollow filaments. For these
where:
yarns, the suffix HF is attached to the second segment of the
E = symbol for glass family used in general and most
yarn description. For example, 40 HF (125HF) represents a 40
electrical applications,
tex [125 × 100 yd ⁄lb] single yarn consisting of hollow fila-
C = symbol for continuous filament yarn,
ments.
DE = symbol for filament diameter average range 0.00023
6.1.3 Segment Three—The third segment of the description
to 0.000269 in.,
of continuous filament yarns specifies the number of single
150 = nominal yarn number of single yarns in hundreds of
yarns in the complete yarn. For yarn described in SI units, the
yards per pound [yd/lb],
description consists of a count of the single yarns twisted
1/0 = one single yarn twisted without plying or cabling,
together, a lower-case multiplication sign or x, and a count of
and
the twisted yarns plied together to form the final yarn. For
1.0Z = a twist level of 1.0 tpi in the “Z” direction.
yarns described in inch-pound units, the description consists of
The nominal yarn number in yards per pound of the final
a count of the singles yarns twisted together, a division sign or
“/”, and a count of the twisted yarns plied together to form the yarn will be approximately 15 000 since there is only one
strand in the final yarn.
final yarn.
6.2.3 Example 2a, Plied Yarn Using SI Units—The descrip-
NOTE 3—If additional stages of plying are involved, a lower-case
tion of a plied continuous filament yarn using SI units might
multiplication sign for SI units or a diagonal for inch-pound units,
followed by the count of plied yarns being cabled is added for each be:
D578/D578M − 23
EC9 33 2 × 2 S152 description of discontinuous filament yarns specifies the num-
ber of single yarns in the complete yarn. The description
where:
consists of the following with no intervening spaces: (1) a
E = symbol for glass family used in general and most
count of the singles yarns twisted together, (2) a lower case
electrical applications,
multiplication sign or x, (3) a count of the twisted yarns plied
C = symbol for continuous filament yarn,
together to form the final yarn, and (4) a symbol R when yarn
9 = symbol for filament diameter average range 8.50 to
is reinforced by a single continuous filament yarn (Note 3).
9.49 μm,
7.1.1.4 Segment Four—For yarns made from discontinuous
33 = nominal yarn number of single yarns, tex,
2×2 = two single yarns twisted together and two such filaments and described in SI units, the fourth segment of the
description of discontinuous filament yarns specifies the twist
yarns plied together, and
S152 = a twist level of 152 tpm in the “S” direction. level and direction. The description consists of an S or Z to
show direction of twist immediately followed by the twist level
The nominal yarn number in tex of the final yarn will be
in turns per metre (tpm) to the nearest 1 tpm (Note 4).
approximately 132 or four times 33 tex.
7.1.2 The three segments in a description of yarns made
6.2.4 Example 2b, Plied Yarn Using Inch-Pound Units—The
from staple fibers when using inch-pound units are:
description of a plied continuous filament yarn using inch-
pound units might be:
Segment 1 Segment 2 Segment 4
Glass family Yarn number ply count Twist level
ECG 150 2/2 3.8S
Fiber form Twist direction
Fiber diameter
where:
7.1.2.1 Segment One—For yarns made from staple filaments
E = symbol for glass family used in general and most
and described in inch-pound units, the parts of Segment one are
electrical applications,
respectively the symbol for the glass family as directed in
C = symbol for continuous filament yarn,
Section 4; the symbol for fiber form, S for staple; and a letter
G = symbol for filament diameter average range 0.00035
symbol for filament diameter average range as directed in
to 0.000399 in.,
150 = nominal yarn number of single yarns in hundreds of Table 1.
yards per pound,
7.1.2.2 Segment Two—For yarns made from staple filaments
2/2 = two single yarns twisted together and two such yarns
and described in inch-pound units, the second segment of the
plied together, and
description of staple filament yarns specifies the number of
3.8S = a twist level of 3.8 tpi in the “S” direction.
singles yarn in the complete yarn. The description consists of
The nominal yarn number in yards per pound of the final
the following with no intervening spaces: (1) the nominal yarn
yarn will be approximately 3750 or 150 hundreds of yards per
number of the single yarns in hundreds of yards per pound; that
pound divided by four.
is, yards per pound divided by 100, (2) the divisor sign or “/”
, (3) a count of the twisted yarns plied together in the final yarn,
7. Discontinuous or Staple Filament Yarns
and (4) a symbol R when yarn is reinforced by a single
continuous filament yarn. (Note 3)
7.1 Descriptions of Discontinuous or Staple Filament
7.1.2.3 Segment Three—For yarns made from staple fila-
Yarns—If SI units are used, the description of yarns made from
ments and described in inch-pound units, the third segment of
staple fibers contains four segments and the fiber form is
the description of staple filament yarns specifies the twist level
designated “D” for discontinuous. If inch-pound units are used,
and direction. The description consists of the twist level in
the description of yarns made from staple fibers contains three
turns per inch (tpi) to the nearest 0.1 tpi immediately followed
segments and the fiber form is designated “S” for staple.
by an S or Z to show direction of twist.
7.1.1 The four segments in a description of yarns made from
discontinuous fibers when using SI units are:
7.2 Examples of Descriptions of Staple or Discontinuous
Segment 1 Segment 2 Segment 3 Segment 4
Filament Yarns Using SI Units:
Glass family Yarn number Construction Twist level
7.2.1 Example 3a, Yarn from Discontinuous Filaments Us-
Fiber form Twist direction
Fiber diameter
ing SI Units—The description of a yarn made from discontinu-
7.1.1.1 Segment One—For yarns made from discontinuous ous filament might be:
filaments and described in SI units, the parts of Segment One
CD10 198 1 × 2 S260
are respectively the symbol for the glass family as directed in
where:
Section 4; the symbol for fiber form, “D” for discontinuous;
and a numeric symbol for filament diameter as directed in C = symbol for glass family used in acid resistant
Table 1. applications,
D = symbol for discontinuous filament yarn,
7.1.1.2 Segment Two—For yarns made from discontinuous
10 = symbol for filament diameter average range 6.50 to
filaments and described in SI units, the second segment of the
7.49 μm,
description of discontinuous filament yarns specifies the yarn
198 = nominal yarn number of single yarns, tex,
number of the single yarn in tex.
1×2 = two single yarns plied, and
7.1.1.3 Segment Three—For yarns made from discontinuous
S260 = a twist level of 260 tpm in the “S” direction.
filaments and described in SI units, the third segment of the
D578/D578M − 23
The nominal yarn number in tex of the final yarn will be 8.1.2.1 Segment One—For textured yarns the parts of seg-
approximately 396 since two strands of 198 tex are combined ment one are respectively the symbol for the glass family as
in the final yarn. directed in Section 4; the symbol for yarn type, T for textured;
and a symbol for filament diameter as directed in Table 2.
7.2.1.1 If the above yarn were reinforced by a single strand
of continuous filament yarn, R would be added to the second 8.1.2.2 Segment Two—The second segment of the descrip-
segment of the description to give: CD10 198R 1×2 S260 tion of textured yarns specifies the yarn number of the final
(Note 4).
yarn, not necessarily of the single yarns. For yarns described in
SI units, the yarn number is specified in tex (Note 2). For yarns
7.2.2 Example 3b, Yarn from Staple Filaments Using Inch-
described in inch-pound units, the yarn number is specified in
Pound Units—The description of a staple filament yarn using
hundreds of yards per pound, that is, yards per pound divided
inch-pound units might be:
by 100.
CSH 25/2 6.5S
8.1.2.3 Segment Three—The third segment of the descrip-
where:
tion of textured yarns specifies the number of single yarns in
C = symbol for glass family used in acid resistant the complete yarn. For yarn described in SI units, the descrip-
applications,
tion consists of a count of the singles yarns, a lower case
S = symbol for staple filament yarn,
multiplication sign or x, and a count of the single yarns
H = symbol for filament diameter average range 0.00040
fabricated together to form the final yarn. For yarns described
to 0.000449 in.,
in inch-pound units, the description consists of a count of the
25/2 = nominal yarn number of single yarns in hundreds of
single yarns, a division sign or “/”, and a count of the single
yards per pound and two such yarns plied together,
yarns fabricated together to form the final yarn.
and
8.1.2.4 Segment Four—The fourth segment of the descrip-
6.5S = a twist level of 6.5 tpi in the “S” direction.
tion of textured yarns specifies the manufacturer’s product
The nominal yarn number in yards per pound of the final code.
yarn will be approximately 1250 or 25 hundreds of yards per
8.2 Examples of Descriptions of Textured Yarns:
pound divided by two.
8.2.1 Examples 5a and 5b, Textured Yarns Using SI Units—
7.2.2.1 If the above yarn were reinforced by a single strand
The description of a textured yarn using SI units might be:
of continuous filament yarn, R would be added to the second
Three 2 segment description 2 ET 9 134 Manufacturer’s Code
~ ~ !!
segment of the description to give: CSH 25/2R 6.5S (Note 4).
Four 2 segment description
2 ET 9 134 1 × 2 Manufacturer’s Code
8. Textured Yarns ~ ~ !!
where:
8.1 The description of textured yarns consist of either three
or four segments.
E = symbol for glass family used in
8.1.1 Three Segment Description of Textured Yarns—The general and most electrical
segments in a three segment description of textured yarns are: applications,
T = symbol for textured yarn,
Segment 1 Segment 2 Segment 3
Glass family Yarn number Manufacturer’s code 9 = symbol for filament diameter aver-
Yarn type
age range 0.00035 to 0.000399 in.,
Fiber diameter
134 = nominal yarn number, tex,
8.1.1.1 Segment One—For textured yarns the parts of Seg- 1×2 = one singles yarn and two such yarns
ment One are respectively the symbol for the glass family as fabricated together, and
manufacturer’s code = further identification as necessary
directed in Section 4; the symbol for yarn type, T for textured;
by manufacturer to define process,
and a symbol for filament diameter as directed in Table 1.
sizing, etc.
8.1.1.2 Segment Two—The second segment of the descrip-
tion of textured yarns specifies the yarn number of the final
The actual tex of the final yarn may vary and result in a
yarn, not necessarily of the single yarns. For yarns described in
higher value. This is dependent upon the yarn number of the
SI units, the yarn number is specified in tex (Note 1). For yarns
input yarn and the degree of texture.
described in inch-pound units, the yarn number is specified in
8.2.2 Examples 5c and 5d, Textured Yarns Using Inch-
hundreds of yards per pound, that is, yards per pound divided
Pound Units—The description of a textured yarn using inch-
by 100.
pound units might be:
8.1.1.3 Segment Three—The third segment of the descrip-
Three 2 segment description 2 ETG 37 Manufacturer’s Code !
~ ~ !
tion of textured yarns specifies the manufacturer’s product
Four 2 segment description
code.
2 ~ETG 37 1 / 2 ~Manufacturer’s Code!!
8.1.2 Four Segment Description of Textured Yarns—The
segments in a four segment description of textured yarns are:
where:
Segment 1 Segment 2 Segment 3 Segment 4
E = symbol for glass family used in
Glass family Yarn number Construction Manufacturer’s code
general and most electrical
Yarn type
applications,
Fiber diameter
D578/D578M − 23
T = symbol for textured yarn, 526HT = manufacturer’s product type,
G = symbol for filament diameter aver- 4400 = nominal yarn number for total roving, tex,
3100 = nominal yarn number for total roving in tex,
age range 0.00035 to 0.000399 in.,
37 = nominal yarn number in hundreds of 2350 = nominal yarn number for total roving in tex,
and
yards per pound,
1/2 = one singles yarn and two such yarns 325864355 = manufacturer’s product code.
71B68820 = manufacturer’s product code
fabricated together, and
manufacturer’s code = further identification as necessary
9.2.2 Examples 6e, 6f, 6g and 6h, Rovings Using Inch-
by manufacturer to define process,
Pound Units—The description of rovings using inch-pound
sizing, etc.
units might be:
The actual yards per pound of the final yarn may vary and
Two 2 segment description 2 ~e! 988AB 113/~f! 998BA 113
result in a lower value. This is dependent upon the yarn number
Three 2 segment description 2 g 526HT 161 1325864355/ h
~ ! ~ !
of the input yarn and the degree of texture.
995AA 211 71B68820
where:
9. Rovings
988AB = manufacturer’s product type and manufac-
9.1 Descriptions of Rovings—The description of rovings
turer’s product code,
consists of either two or three segments.
988BA = manufacturer’s product type and manufac-
9.1.1 Two Segment Description for Rovings—The segments
turer’s product code,
in a two segment description of rovings are:
526HT = manufacturer’s product type,
Segment 1 Segment 2
113 = nominal yarn number for total roving, yd/lb,
Product type Yarn number
161 = nominal yarn number for total roving, yd/lb,
1325864355 = manufacturer’s product code, and
9.1.1.1 Segment One—For rovings, the first segment of the
71B68820 = manufacturer’s product code.
description of glass rovings represents the manufacturer’s
product type, which includes binder (sizing) and sliver (strand).
9.3 It is customary for producers of glass fiber rovings to
It consists of number or letter designations, or both letter and
indicate the compatibility of the binder (sizing) applied to the
number designations that reference the manufacturer’s code.
rovings to the matrix resins in which they can be used.
The designation for the manufacturer’s code may directly
9.3.1 The designation shall follow the form ”[matrix resin]
follow the product type or may be separated by a space.
compatible.”
9.1.1.2 Segment Two—For rovings, the second segment of
9.3.2 Examples of this designation would be “epoxy com-
the description specifies the yarn number of the total roving.
patible” or “polyester compatible.”
For rovings described in SI units, the yarn number is specified
9.3.3 The resin compatibility is not part of the three segment
in tex. For such rovings described in inch-pound units, the yarn
description outlined in 9.1.2, but is available upon request from
number is specified in yards per pound.
the manufacturer of the roving.
NOTE 5—Roving yield is synonymously used for yarn number of roving
NOTE 6—Discontinued MIL-R-60346 referred to the resin compatibility
products in the glass fiber industry. The term yarn number is used
by the term “Class 1” for epoxy compatible rovings and “Class 2” for
throughout Specification D578 to represent the more universal term.
polyester compatible rovings.
9.1.2 Three Segment Description for Rovings—The seg-
10. Chopped Strand from Continuous Filament Strands
ments in a three segment description of rovings are:
Segment 1 Segment 2 Segment 3
10.1 Descriptions of Chopped Strand from Continuous Fila-
Product type Yarn number Manufacturer’s
ment Strands—The description of chopped strand from con-
product code
tinuous filament strands consists of either two, three, or four
9.1.2.1 For rovings, the first and second segments of the
segments. For chopped strand used to reinforce thermoplastic
three segment description are as described in 9.1.1.1 and
and thermosetting plastic compounds, the description consists
9.1.1.2. The third segment references a manufacturer’s product
of two segments. For dry sized glass chopped strand, the
code and may be represented by letters or numbers, or both.
description consists of three segments. For wet sized glass
9.2 Examples of Descriptions of Rovings:
chopped strand, the description consists of four segments.
9.2.1 Examples 6a, 6b, 6c, and 6d, Rovings Using SI 10.1.1 Two Segment Description for Chopped Strand Used
Units—The description of rovings using SI units might be:
to Reinforce Thermoplastic and Thermosetting Compounds—
The segments in a description for chopped strand used to
Two 2 segment description 2 a 988AB 4400/ b 998 BA 4400
~ ! ~ !
reinforce thermoplastic and thermosetting compounds are:
Three 2 segment description 2 c 526HT 3100 1325864355/ d
~ ! ~ !
995AA 2350 71B68820 Segment 1 Segment 2
Product type Strand length
where:
10.1.1.1 Segment One—The first segment of the description
988AB = manufacturer’s product type and manufactur-
of chopped strand used to reinforce thermoplastic and thermo-
er’s code,
setting compounds represents the manufacturer’s product type.
988BA = manufacturer’s product type and manufactur-
It consists of numbers that are sometimes followed by letter
er’s code,
designations, or both, letter and number designations that
D578/D578M − 23
NOTE 7—Some manufacturers omit this segment when describing wet
reference the manufacturer’s code. The designation for the
sized chopped strand.
manufacturer’s code will directly follow the product type.
10.1.1.2 Segment Two—The second segment of the descrip-
10.1.3.4 Segment Four—The fourth segment of the descrip-
tion of chopped strand used to reinforce thermoplastic and tion of wet sized chopped strand specifies the length of the
thermosetting compounds specifies the length of the chopped
chopped strand. For chopped strands described in SI units, the
strand. For chopped strands described in SI units, the nominal nominal chopped length is specified in millimetres. For
chopped length is specified in millimetres. For chopped strands chopped strands described in inch-pound units the nominal
described in inch-pound units the nominal chopped length is chopped length is specified in inches.
specified in inches.
10.2 Examples of Descriptions of Chopped Strands:
10.1.2 Three Segment Description for Dry Sized Chopped
10.2.1 Example 7a, Chopped Strand Used to Reinforce
Strand—The segments in a description of dry chopped strand
Thermoplastic and Thermosetting Compounds Using SI
are:
Units—The description of chopped strand used to reinforce
Segment 1 Segment 2 Segment 3
thermoplastic and thermosetting compounds using SI units
Filament diameter Sizing or product type Strand length
might be:
10.1.2.1 Segment One—The first segment of the description
405AB 13 mm
of dry sized chopped strand represents the nominal filament
diameter range. When using SI units, this segment consists of
where:
a number specifying the nominal filament diameter range in
405AB = manufacturer’s product type and process code,
micrometers as directed in Table 1. When using inch pound
and
units, this segment consists of one or two letters as directed in
13 = length, mm.
Table 1.
10.2.2 Example 7b, Dry Sized Chopped Strand Using SI
10.1.2.2 Segment Two—The second segment of the descrip-
Units—The description of dry sized chopped strand using SI
tion of dry sized chopped strand represents the manufacturer’s
units might be:
sizing or product type. It consists of numbers that are some-
times followed by letter designations, or both, letter and
9 µm 685 13 mm
number designations that reference the manufacturer’s code.
where:
The designation for the manufacturer’s code will directly
9 = symbol for filament diameter average range 8.50 to
follow the sizing or product type.
9.49 μm,
10.1.2.3 Segment Three—The third segment of the descrip-
685 = manufacturer’s sizing code or process code, or both,
tion of dry sized chopped strand specifies the length of the
and
chopped strand. For chopped strands described in SI units, the
13 = length, mm.
nominal chopped length is specified in millimetres. For
chopped strands described in inch-pound units the nominal 10.2.3 Example 7c, Wet Sized Chopped Strand Using SI
Units—The description of wet sized chopped strand using SI
chopped length is specified in inches.
10.1.3 Four Segment Description for Wet Sized Chopped units might be:
Strand—The segments in a description of wet chopped strand
16 µm 775 14.5 32 mm
are:
where:
Segment 1 Segment 2 Segment 3 Segment 4
Filament Sizing or Moisture Strand 16 = symbol for filament diameter average range 15.5 to
diameter product type content length
16.49 μm,
10.1.3.1 Segment One—The first segment of the description 775 = manufacturer’s sizing code or process code, or both,
of wet sized chopped strand represents the nominal filament 14.5 = moisture content, wt % (Note 7), and
32 = length, mm.
diameter range. When using SI units, this segment consists of
a number specifying the nominal filament diameter range in
10.2.4 Example 7d, Chopped Strand Used to Reinforce
micrometres as directed in Table 1. When using inch-pound
Thermoplastic and Thermosetting Compounds Using Inch-
units, this segment consists of one or two letters as directed in
Pound Units—The description of chopped strand used to
Table 1.
reinforce thermoplastic and thermosetting compounds using
10.1.3.2 Segment Two—The second segment of the descrip-
inch-pound units might be:
tion of wet sized chopped strand represents the manufacturer’s
405AB ½ in.
sizing or product type. It consists of numbers that are some-
times followed by letter designations, or both, letter and
where:
number designations that reference the manufacturer’s code.
405AB = manufacturer’s product type and process code,
The designation for the manufacturer’s code will directly
and
follow the product type. 1
⁄2 = length, in.
10.1.3.3 Segment Three—The third segment of the descrip-
10.2.5 Example 7e, Dry Sized Chopped Strand Using Inch-
tion of wet sized chopped strand specifies the nominal percent
Pound Units—The description of dry chopped strand using
moisture content. This segment consists of a number represent-
inch-pound units might be:
ing the percent moisture content in both SI units and inch
pound units. G685 ½ in.
D578/D578M − 23
NOTE 8—Historically, it has been conventional practice to attenuate
where:
glass through bushings having 204 or 408 holes to produce strands
G = symbol for filament diameter average range 0.00035
containing those numbers of filaments. Then, rovings were made from
to 0.000399 in.,
those strands having 1, 12, 15, 20, 30, and 60 ends. Although this practice
685 = manufacturer’s sizing code or process code, or both,
is still used by some suppliers, others are attenuating fiber glass through
and bushings consisting of up to several thousand holes to make heavy rovings
1 containing only a single strand. Since the strands are not twisted, rovings
⁄2 = length, in.
made with the larger single strands are equivalent, for most purposes, to
10.2.6 Example 7f, Wet Sized Chopped Strand Using Inch-
those made with the smaller conventional made multiple strands. Since
Pound Units—The description of wet sized chopped strand many older material specifications specify in accordance with the older
multiple strand designation, a purchasing activity should review and agree
using inch-pound units might be:
upon with the supplier activity, the acceptability of the single strand
M 775 14.5 1¼ in.
roving having an equivalent yarn number.
14.1.1.1 The tex [yards per pound] as determined in Section
where:
23 and specified in Tables 2, 4, and 5 are the bare glass
M = symbol for filament diameter average range 0.00060
nominal. A commercial yarn normally has a size (binder)
to 0.000649 in.
treatment which will increase tex [decrease yards per pound] in
775 = manufacturer’s sizing code or process code, or both,
proportion to the amount of size.
14.5 = moisture content, wt %, and
14.1.2 Breaking Strength—No individual break shall be less
1 ⁄4 = length, in.
than the specified minimum requirement in Tables 2, 4, and 5.
11. Ordering Information
14.2 When required for roving and chopped strand, the
11.1 The purchase order or other agreement shall specify: nominal and physical properties shall be agreed upon between
specification conformance number, title, and year of issue; the purchaser and the supplier in an applicable material
designation of strand construction; product quantity; and any specification or other agreement, subject to the requirements of
special provisions. Table 2 and 14.1.1.
REQUIREMENTS
15. Ignition Loss (Organic Content)
15.1 The ignition loss (organic content) shall be within the
12. Material
tolerances as agreed upon between the purchaser and the
12.1 The fibers shall be free of any free alkali metal oxides,
supplier, or as specified in an applicable material specification
such as soda or potash, and from foreign particles, dirt, and
or other agreement.
other impurities. The glass classification shall be agreed upon
between the purchaser and the supplier in an applicable 16. Packaging
material specification or other agreement. The composition of
16.1 The glass fiber strand shall be put up on packages, and
the E-Glass classification of glass fiber shall be within the
in containers whose dimensions shall be agreed to between the
limits specified in 4.2.1 or 4.2.2 as agreed upon between the
purchaser and supplier.
purchaser and supplier.
16.2 Each package of strand, put up as specified, shall be
further packaged to afford adequate protection against physical
13. Workmanship
damage during shipment from the supply source to the receiv-
13.1 As agreed upon between the purchaser and the
ing activity. The supplier may use his standard practice when it
supplier, the defects listed in Table 3 shall be considered cause
meets this requirement.
for rejection of the package in which they occur. The allowable
16.3 For government procurement, the contracting instru-
quality level (AQL) shall be agreed upon between the pur-
ment shall specify the put up (see 11.1) and AQL (see 13.1).
chaser and the supplier.
17. Marking
14. Physical Properties
17.1 Each package of strand shall be marked to show the
14.1 The nominal and physical properties of glass fiber
construction designation of the glass fiber strand as specified in
strands shall conform to the requirements of Tables 1, 2, 4, and
Sections 5 – 10. Each container of packages shall be marked as
5, as applicable. The tolerances shall be subject to the toler-
agreed upon between the purchaser and supplier.
ances as agreed upon between the purchaser and the supplier.
However, the following maximum tolerances apply:
18. Sampling, Inspection, and Number of Specimens
14.1.1 Yarn Number, Tex [Yards per Pound), Individual
18.1 Lot Size—A lot shall consist of each shipment, date
Value—Plus or minus 10 % for continuous filament yarns. Plus
code, or consignment of a single strand designation. This may
or minus 20 % for discontinuous or staple yarns. Plus or minus
constitute all or part of any one customer order. The lot size is
15 % for textured yarns. Plus or minus 8.5 % for roving
the total number of packages of strand in the incoming
produced by either conventional or nonconventional roving
shipment date code, or consignment.
winding processes, except certain rovings produced by other
than conventional winding processes shall have a 613 %
NOTE 9—An adequate specification or other agreement between the
tolerance when agreed upon between the purchaser and the
purchaser and the supplier requires taking into account the variability
supplier. between packages of strand and between test specimens from a package of
D578/D578M − 23
strand to produce a sampling plan with meaningful producer’s risk,
23. Yarn Number
consumer’s risk, acceptable quality level, and limiting quality level.
23.1 Determine the yarn number of bare glass yards per
18.2 Lot Sample—As a lot sample for acceptance testing,
pound as directed in Test Method D1907/D1907M, Option 1,
take at random the number of shipping units specified in
excluding preconditioning.
Practice D2258/D2258M. Consider shipping cases or other
23.1.1 Prior to conditioning, place the skein in a muffle
shipping units to be the primary sampling units.
furnace and heat to 625 6 25°C [1157 6 45°F] for 15 min.
18.3 Laboratory Sample—As a laboratory sample for accep-
23.2 Calculations:
tance testing, take at random from each shipping unit in the lot
23.2.1 Calculate the yards per pound from the length and
sample the number of packages or ends directed in 18.3.1 and
average mass of the specimens using Eq 1 or Eq 2:
18.3.2. Preferably, the same number of packages should be
Y 5 453.6 × L /A (1)
~ !
taken from each shipping unit in the lot sample. If differing
Y 5 7000 × L /B (2)
numbers of packages are to be taken from shipping units in the ~ !
lot sample, determine at random which shipping units are to
where:
have each number of packages drawn.
Y = yarn number, yd/lb,
18.3.1 Workmanship—Take at random the number of pack-
L = specimen length, yd,
ages or ends of strand as directed in ANSI/ASQC Z1.4. Select
A = average mass of specimens, g, and
an acceptable quality level (AQL) that is agreeable to both the
B = average mass of specimens, grains.
purchaser and the supplier.
23.2.2 Calculate the tex equivalents using Eq 3 and 4:
18.3.2 Other Properties—Take at random the number of
bobbins or packages of strand specified in Table 6.
Tex 5 A/~0.0009144L! (3)
18.4 Test Specimens—Proceed as follows: Tex 5 496055/Y (4)
18.4.1 Workmanship—Use the packages of strand in the
where:
laboratory sample as the specimens. Evaluate the results of
A = average mass of specimens, g,
inspecting the specimens using ANSI/ASQC Z1.4, normal
L = specimen length, yd, and
inspection, and an acceptable quality level agreed upon be-
Y = yarn number, yd/lb.
tween the purchaser and the supplier.
23.2.3 Calculate the yarn construction designation using Eq
18.4.2 Other Properties—Take the number of specimens per
laboratory sampling unit specified in the applicable test 5:
method.
Y
YC 5 (5)
TEST METHODS
where:
19. Conditioning
YC = yarn number, hundreds of yd/lb, and
19.1 Condition the laboratory samples without precondi-
Y = yarn number, yd/lb.
tioning for a period of at least 5 hours in the atmosphere for
testing glass textiles, unless otherwise specified. 24. Direction of Twist
24.1 Verify the direction of twist in each laboratory sam-
20. Material
pling unit as directed in Test Method D1423/D1423M.
20.1 Upon prior agreement,
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D578/D578M − 18 D578/D578M − 23
Standard Specification for
Glass Fiber Strands
This standard is issued under the fixed designation D578/D578M; 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 U.S. Department of Defense.
1. Scope
1.1 This specification covers the requirements for continuous fiber and staple fiber glass strands, including single, plied and
multiple wound. It also covers textured glass fiber yarns. This specification is intended to assist ultimate users by designating the
general nomenclature for the strand products that ageare generally manufactured in the glass fiber industry.
1.2 Glass fibers are produced having various compositions. General applications are identified by means of a letter designation.
The letter designation represents a family of glasses that have provided acceptable performance to the end-user in the intended
application. For example, the composition limits stated for E-Glass in this specification representing the glass fiber family for
general and most electrical applications is designated by the letter E. Military specifications, such as, MIL-R-60346, recognize the
composition limits described in this specification as meeting the respective requirements for E-Glass strands used in reinforced
plastic structure applications.
1.3 Glass fiber strands have a variety of general uses under specific conditions, such as high physical or chemical stress, high
moisture, high temperature, or electrical environments. Property requirements under specific conditions are agreed upon between
the purchaser and the supplier. Electrical property requirements vary with specific end-use applications. For printed circuit board
applications, other requirements may be needed such as the use of Institute for Interconnecting and Packaging Electronic Circuits
(IPC) Specification EG 4412 A for finished fabric woven from E-Glass for printed circuit boards, or Specification MIL-P-13949
for printed wiring boards applicable to glass fabric base.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system mayare not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from
the two systems maywill result in non-conformance with the standard.
1.5 This specification is one of a series to provide a substitute for Military Specifications: MIL-Y-1140 Yarn, Cord, Sleeving, Cloth
and Tape-Glass; and MIL-C-9084 Cloth, Glass Finished for Resin Laminates.
1.6 Additional ASTM specifications in this series have been drafted and appear in current editions of the Annual Book of ASTM
Standards. These include finished glass fabrics, unfinished glass fabrics, glass tapes, glass sleevings, glass cords, glass sewing
threads, and finished laminates made from finished glass fabrics.
1.7 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.
This specification is under the jurisdiction of ASTM Committee D13 on Textiles and is the direct responsibility of Subcommittee D13.18 on Glass Fiber and its Products.
Current edition approved July 1, 2018June 1, 2023. Published August 2018August 2023. Originally approved in 1940. Last previous edition approved in 20112018 as
ɛ1
D578 – 05D578/D578M – 18.(2011) . DOI: 10.1520/D0578-18.10.1520/D0578_D0578M-23.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D578/D578M − 23
1.8 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.
2. Referenced Documents
2.1 ASTM Standards:
D123 Terminology Relating to Textiles
D1423/D1423M Test Method for Twist in Yarns by Direct-Counting
D1907/D1907M Test Method for Linear Density of Yarn (Yarn Number) by the Skein Method
D2256/D2256M Test Method for Tensile Properties of Yarns by the Single-Strand Method
D2258/D2258M Practice for Sampling Yarn for Testing
D2904 Practice for Interlaboratory Testing of a Textile Test Method that Produces Normally Distributed Data (Withdrawn 2008)
D2906 Practice for Statements on Precision and Bias for Textiles (Withdrawn 2008)
D4963/D4963M Test Method for Ignition Loss of Glass Fiber Strands and Fabrics
D7018/D7018M Terminology Relating to Glass Fiber and Its Products (Withdrawn 2021)
2.2 ASTM Adjunct:
TEX-PAC
2.3 ANSI Standard:
ANSI/ASQC Z1.4 Sampling Procedures for Inspection by Attributes
2.4 Military Standards and Specifications:
MIL-P-13949 Specification for Plastic Sheet, Laminated, Metal-Clad For Printed Wiring Board
MIL-R-60346 Roving, Glass Fibrous (for Prepreg Tape, Rovings, Filament Winding, and Pultrusion Applications)
MIL-G-55636B Glass Cloth, Resin PreimpreginatedPreimpregnated (B-STAGE) (For Multilayer Printed Wiring Boards)
(Superseded by MIL-P-13949 1981)
MIL-Y-1140 Specification for Yarn, Cord, Sleeving, Cloth, and Tape-Glass
MIL-C-9084 Specification for Cloth Finished for Resin Laminates (Cancelled 1999)
2.5 Institute for Interconnecting and Packaging Circuits Standard:
IPC EG 4412 A Specification for Finished Fabric Woven from E-Glass for Printed Circuit Boards
3. Terminology
3.1 For all terminology related to D13.18, Glass Fiber and Its Products, see Terminology D7018/D7018M.
3.1.1 The following terms are relevant to this standard: atmosphere for testing textiles, chopped strand, continuous filament yarn,
roving, staple glass yarn, strand, textured glass yarn.
3.2 For allother all other terminology related to textiles, refer to Terminology D123.
4. Classification of Glass Fiber
4.1 “C” Glass—A family of glasses composed primarily of the oxides of sodium, calcium, boron, aluminum, and silicon with a
certified chemical composition which conforms to an applicable material specification and which produces good acid resistance
(excluding HF).
4.2 “E” Glass—A family of glasses composed primarily of the oxides of calcium, aluminum, and silicon, which has the following
certified chemical compositions.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
PC programs on floppy disk for analyzing Committee D13 interlaboratory data are available through ASTM. Request ADJD2904.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.
Available from Standardization Documents Order Desk, Bldg. 4 Section D, DLA Document Services, Building 4/D, 700 Robbins Ave., Philadelphia, PA 19111-5094,
Attn: NPODS.http://quicksearch.dla.mil.
Available from Institute for Interconnecting and Packaging Electronic Circuits, 7380 N. Lincoln Ave., Lincolnwood, IL 60646.
D578/D578M − 23
4.2.1 The following certified chemical composition applies to glassE-glass fiber yarn products for printed circuit boards and
aerospace.
Chemical % by Weight
B O 5 to 10
2 3
CaO 16 to 25
Al O 12 to 16
2 3
SiO 52 to 56
MgO 0 to 5
Na O and K O 0 to 2
2 2
TiO 0 to 0.8
Fe O 0.05 to 0.4
2 3
Fluoride 0 to 1.0
4.2.2 The following certified chemical composition applies to glassE-glass fiber products used in general applications.
Chemical % by Weight
B O 0 to 10
2 3
CaO and MgO 16 to 30
Al O 12 to 16
2 3
SiO 52 to 62
Total alkali metal oxides 0 to 2
TiO 0 to 1.5
Fe O 0.05 to 0.8
2 3
Fluoride 0 to 1.0
4.2.3 Electrical applications include a wide variety of uses. The composition in 4.2.1 is identical to IPC EG 4412 A for printed
circuit boards and to MIL-G-55636B. Additionally, such fiber glass products often are specified for aerospace applications.
Products covered by the composition range in 4.2.2 are used in general applications, such as power company equipment, high
voltage devices, residential electric boxes, third rail covers, high voltage standoff rods, electrical pultrusion products, light poles,
electrical tool covers, and electrical tape. Other applications include roofing, flooring, filtration, panel rovings, gun rovings, smc
rovings, chopped strand reinforcements, paper yarns, and industrial yarns.
4.2.4 The nomenclature “E-CR-Glass” is used for boron-free modified E-Glass compositions for improved resistance to corrosion
by most acids.
4.3 “S” Glass—A family of glasses composed primarily of the oxides of magnesium, aluminum, and silicon with a certified
chemical composition which conforms to an applicable material specification and which produces high mechanical strength.
4.4 “R”Glass—A family of boron-free glasses composed primarily of the oxides of silicon, aluminum, calcium and magnesium,
such glasses possessing excellent acid and water durability as well as specific strength and specific modulus levels significantly
greater than E glass.
DESCRIPTION OF GLASS STRANDS
5. General
5.1 The construction of glass strands is described in a series of two to four segments of alphabetical or numerical characters.
NOTE 1—In glass fiber strand designations, and in the conversion of yards per pound to tex units, the following rules are used:
(1) less than 2.50 tex—round to nearest 0.01 tex
(2) 2.50 tex to less than 5.00 tex—round to nearest 0.05 tex
(3) 5.00 tex to less than 10.0 tex—round to nearest 0.1 tex
(4) 10.0 tex to less than 250 tex—round to nearest 1.0 tex
(5) 250 tex to less than 2000 tex—round to nearest 5.0 tex
(6) 2000 tex to less than 100 000 tex—round to nearest 100 tex
5.1.1 For strands described in inch-pound units, the approximate yards per pound of the final strand can be computed by
D578/D578M − 23
multiplying the yarn number designation of the single yarn or strand by 100 to obtain yards per pound for the single yarn or strand
and then dividing by the total number of single yarns or strands in the final yarn. Actual yardage is less because of organic content
and twist take-up during plying.
NOTE 2—Letter designations for filament diameter averages are shown in Table 1. The yards per pound stated in Table 2 is an approximate yarn number.
The “As Received” yards per pound will be less than the bare glass values stated. This may be contributed by twist take-up, sizing percent, or purchaser
agreement to produce to a lower yarn number to meet other requirements for a further manufactured product, or both. For example, EC9 66 1×0 (ECG
75 1/0) stated at approximately 66 tex [7500 yd/lb] will actually be about 68 tex [7300 yd/lb] in the delivered state for use in the electrical laminate
industry.”industry.
6. Continuous Filament Yarns
6.1 Descriptions of Continuous Filament Yarns—The description of continuous filament yarns consists of the following four
segments:
Segment 1 Segment 2 Segment 3 Segment 4
Glass family Yarn number Construction Twist level
Fiber form Twist direction
Fiber diameter
6.1.1 Segment One—The parts of Segment one are respectively the symbol for the glass family as directed in Section 4; the symbol
for fiber form, “C” for Continuous, and a symbol for average filament diameter range as directed in Table 1.
6.1.2 Segment Two—The second segment of the description of continuous filament yarns specifies the yarn number of the single
yarn. For yarns described in SI units, the yarn number is specified in tex. For yarns described in inch-pound units, the yarn number
is specified in hundreds of yards per pound, that is yards per pound divided by 100.
6.1.2.1 Some manufacturing processes are designed specifically to produce yarns consisting of hollow filaments. For these yarns,
the suffix HF is attached to the second segment of the yarn description. For example, 40 HF (125HF) represents a 40 tex [125 × 100
yd ⁄lb] single yarn consisting of hollow filaments.
6.1.3 Segment Three—The third segment of the description of continuous filament yarns specifies the number of single yarns in
the complete yarn. For yarn described in SI units, the description consists of a count of the single yarns twisted together, a lower
case lower-case multiplication sign or x, and a count of the twisted yarns plied together to form the final yarn. For yarns described
in inch-pound units, the description consists of a count of the singles yarns twisted together, a division sign or “/”, and a count
of the twisted yarns plied together to form the final yarn.
NOTE 3—If additional stages of plying are involved, a lower case lower-case multiplication sign for SI units or a diagonal for inch-pound units, followed
by the count of plied yarns being cabled is added for each additional cabling step. The total single yarns in the final yarn will always be the product of
all the counts in this segment. When 0 (zero) appears as a count it is considered as 1 (one) for multiplication purposes.
6.1.4 Segment Four—The fourth segment of the description of continuous filament yarns specifies the twist level and direction.
For yarns described in SI units, the description consists of an S or Z to show direction of twist immediately followed by the twist
level in turns per metre (tpm) to the nearest 1 tpm. For yarns described in inch-pound units, the description consists of the twist
level in turns per inch (tpi) to the nearest 0.1 tpi immediately followed by an S or Z to show direction of twist.
NOTE 4—Twist in turns per metre (tpm) equals twist in turns per inch (tpi) times 40. The exact factor 39.37 is rounded to 40 to obtain the twist in turns
per metre to the nearest 1 tpm when starting from turns per inch to the nearest 0.1 tpi.
6.2 Examples of Descriptions of Continuous Filament Yarns:
6.2.1 Example 1a, Singles Yarn Using SI Units—The description of a singles continuous filament yarn using SI units might be:
EC6 33 1×0 Z40
where:
where:
E = symbol for glass family used in general and most electrical applications,
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C = symbol for continuous filament yarn,
6 = symbol for filament diameter average range 5.50 to 6.49 μm,
33 = nominal yarn number of single yarn, tex,
1×0 = one single yarn twisted without plying or cabling, and
Z40 = a twist level of 40 tpm in the “Z” direction.
The nominal yarn number in tex of the final yarn will be approximately 33 since there is only one strand in the final yarn.
6.2.2 Example 1b, Singles Yarn Using Inch-Pound Units—The description of a singles continuous filament yarn using inch-pound
units might be:
ECDE 150 1/0 1.0Z
where:
where:
E = symbol for glass family used in general and most electrical applications,
C = symbol for continuous filament yarn,
DE = symbol for filament diameter average range 0.00023 to 0.000269 in.,
150 = nominal yarn number of single yarns in hundreds of yards per pound [yd/lb],
1/0 = one single yarn twisted without plying or cabling, and
1.0Z = a twist level of 1.0 tpi in the “Z” direction.
The nominal yarn number in yards per pound of the final yarn will be approximately 15 00015 000 since there is only one strand
in the final yarn.
6.2.3 Example 2a, Plied Yarn Using SI Units—The description of a plied continuous filament yarn using SI units might be:
EC9 33 2×2 S152
where:
where:
E = symbol for glass family used in general and most electrical applications,
C = symbol for continuous filament yarn,
9 = symbol for filament diameter average range 8.50 to 9.49 μm,
33 = nominal yarn number of single yarns, tex,
2×2 = two single yarns twisted together and two such yarns plied together, and
S152 = a twist level of 152 tpm in the “S” direction.
The nominal yarn number in tex of the final yarn will be approximately 132 or four times 33 tex.
6.2.4 Example 2b, Plied Yarn Using Inch-Pound Units—The description of a plied continuous filament yarn using inch-pound
units might be:
ECG 150 2/2 3.8S
where:
where:
E = symbol for glass family used in general and most electrical applications,
C = symbol for continuous filament yarn,
G = symbol for filament diameter average range 0.00035 to 0.000399 in.,
150 = nominal yarn number of single yarns in hundreds of yards per pound,
2/2 = two single yarns twisted together and two such yarns plied together, and
3.8S = a twist level of 3.8 tpi in the “S” direction.
The nominal yarn number in yards per pound of the final yarn will be approximately 3750 or 150 hundreds of yards per pound
divided by four.
7. Discontinuous or Staple Filament Yarns
7.1 Descriptions of Discontinuous or Staple Filament Yarns—If SI units are used, the description of yarns made from staple fibers
contains four segments and the fiber form is designated “D” for discontinuous. If inch-pound units are used, the description of
yarns made from staple fibers contains three segments and the fiber form is designated“ S”designated “S” for staple.
D578/D578M − 23
7.1.1 The four segments in a description of yarns made from discontinuous fibers when using SI units are:
Segment 1 Segment 2 Segment 3 Segment 4
Glass family Yarn number Construction Twist level
Fiber form Twist direction
Fiber diameter
7.1.1.1 Segment One—For yarns made from discontinuous filaments and described in SI units, the parts of Segment oneOne are
respectively the symbol for the glass family as directed in Section 4; the symbol for fiber form, “D” for discontinuous; and a
numeric symbol for filament diameter as directed in Table 1.
7.1.1.2 Segment Two—For yarns made from discontinuous filaments and described in SI units, the second segment of the
description of discontinuous filament yarns specifies the yarn number of the single yarn in tex.
7.1.1.3 Segment Three—For yarns made from discontinuous filaments and described in SI units, the third segment of the
description of discontinuous filament yarns specifies the number of single yarns in the complete yarn. The description consists of
the following with no intervening spaces: (1) a count of the singles yarns twisted together, (2) a lower case multiplication sign or
x, (3) a count of the twisted yarns plied together to form the final yarn, and (4) a symbol R when yarn is reinforced by a single
continuous filament yarn (Note 3).
7.1.1.4 Segment Four—For yarns made from discontinuous filaments and described in SI units, the fourth segment of the
description of discontinuous filament yarns specifies the twist level and direction. The description consists of an S or Z to show
direction of twist immediately followed by the twist level in turns per metre (tpm) to the nearest 1 tpm (Note 4).
7.1.2 The three segments in a description of yarns made from staple fibers when using inch-pound units are:
Segment 1 Segment 2 Segment 4
Glass family Yarn number ply count Twist level
Fiber form Twist direction
Fiber diameter
7.1.2.1 Segment One—For yarns made from staple filaments and described in inch-pound units, the parts of Segment one are
respectively the symbol for the glass family as directed in Section 4; the symbol for fiber form, S for staple; and a letter symbol
for filament diameter average range as directed in Table 1.
7.1.2.2 Segment Two—For yarns made from staple filaments and described in inch-pound units, the second segment of the
description of staple filament yarns specifies the number of singles yarn in the complete yarn. The description consists of the
following with no intervening spaces: (1) the nominal yarn number of the single yarns in hundreds of yards per pound; that is, yards
per pound divided by 100, (2) the divisor sign or “/” , (3) a count of the twisted yarns plied together in the final yarn, and (4) a
symbol R when yarn is reinforced by a single continuous filament yarn. (Note 3)
7.1.2.3 Segment Three—For yarns made from staple filaments and described in inch-pound units, the third segment of the
description of staple filament yarns specifies the twist level and direction. The description consists of the twist level in turns per
inch (tpi) to the nearest 0.1 tpi immediately followed by an S or Z to show direction of twist.
7.2 Examples of Descriptions of Staple or Discontinuous Filament Yarns Using SI Units:
7.2.1 Example 3a, Yarn from Discontinuous Filaments Using SI Units—The description of a yarn made from discontinuous
filament might be:
CD10 198 1×2 S260
where:
where:
C = symbol for glass family used in acid resistant applications,
D = symbol for discontinuous filament yarn,
D578/D578M − 23
10 = symbol for filament diameter average range 6.50 to 7.49 μm,
198 = nominal yarn number of single yarns, tex,
1×2 = two single yarns plied, and
S260 = a twist level of 260 tpm in the “S” direction.
The nominal yarn number in tex of the final yarn will be approximately 396 since two strands of 198 tex are combined in the
final yarn.
7.2.1.1 If the above yarn were reinforced by a single strand of continuous filament yarn, R would be added to the second segment
of the description to give: CD10 198R 1×2 S260 (Note 4).
7.2.2 Example 3b, Yarn from Staple Filaments Using Inch-Pound Units—The description of a staple filament yarn using
inch-pound units might be:
CSH 25/2 6.5S
where:where:
C = symbol for glass family used in acid resistant applications,
S = symbol for staple filament yarn,
H = symbol for filament diameter average range 0.00040 to 0.000449 in.,
25/2 = nominal yarn number of single yarns in hundreds of yards per pound and two such yarns plied together, and
6.5S = a twist level of 6.5 tpi in the “S” direction.
The nominal yarn number in yards per pound of the final yarn will be approximately 1250 or 25 hundreds of yards per pound
divided by two.
7.2.2.1 If the above yarn were reinforced by a single strand of continuous filament yarn, R would be added to the second segment
of the description to give: CSH 25/2R 6.5S (Note 4).
8. Textured Yarns
8.1 The description of textured yarns consist of either three or four segments.
8.1.1 Three Segment Description of Textured Yarns—The segments in a three segment description of textured yarns are:
Segment 1 Segment 2 Segment 3
Glass family Yarn number Manufacturer’s code
Yarn type
Fiber diameter
8.1.1.1 Segment One—For textured yarns the parts of Segment oneOne are respectively the symbol for the glass family as directed
in Section 4; the symbol for yarn type, T for textured; and a symbol for filament diameter as directed in Table 1.
8.1.1.2 Segment Two—The second segment of the description of textured yarns specifies the yarn number of the final yarn, not
necessarily of the single yarns. For yarns described in SI units, the yarn number is specified in tex (Note 1). For yarns described
in inch-pound units, the yarn number is specified in hundreds of yards per pound, that is, yards per pound divided by 100.
8.1.1.3 Segment Three—The third segment of the description of textured yarns specifies the manufacturer’s product code.
8.1.2 Four Segment Description of Textured Yarns—The segments in a four segment description of textured yarns are:
Segment 1 Segment 2 Segment 3 Segment 4
Glass family Yarn number Construction Manufacturer’s code
Yarn type code
Yarn type
Fiber diameter
8.1.2.1 Segment One—For textured yarns the parts of segment one are respectively the symbol for the glass family as directed in
Section 4; the symbol for yarn type, T for textured; and a symbol for filament diameter as directed in Table 2.
D578/D578M − 23
8.1.2.2 Segment Two—The second segment of the description of textured yarns specifies the yarn number of the final yarn, not
necessarily of the single yarns. For yarns described in SI units, the yarn number is specified in tex (Note 2). For yarns described
in inch-pound units, the yarn number is specified in hundreds of yards per pound, that is, yards per pound divided by 100.
8.1.2.3 Segment Three—The third segment of the description of textured yarns specifies the number of single yarns in the complete
yarn. For yarn described in SI units, the description consists of a count of the singles yarns, a lower case multiplication sign or
x, and a count of the single yarns fabricated together to form the final yarn. For yarns described in inch-pound units, the description
consists of a count of the single yarns, a division sign or “/”, and a count of the single yarns fabricated together to form the final
yarn.
8.1.2.4 Segment Four—The fourth segment of the description of textured yarns specifies the manufacturer’s product code.
8.2 Examples of Descriptions of Textured Yarns:
8.2.1 Examples 5a and 5b, Textured Yarns Using SI Units—The description of a textured yarn using SI units might be:
Three 2 segment description 2 ~ET 9 134 ~Manufacturer’s Code!!
Four 2 segment description 2 ~ET 9 134 1 × 2 ~Manufacturer’s Code!!
where:
where:
E = symbol for glass family used in general and most electrical applications,
T = symbol for textured yarn,
9 = symbol for filament diameter average range 0.00035 to 0.000399 in.,
134 = nominal yarn number, tex,
1×2 = one singles yarn and two such yarns fabricated together, and
manufacturer’s code = further identification as necessary by manufacturer to define process, sizing, etc.
The actual tex of the final yarn may vary and result in a higher value. This is dependent upon the yarn number of the input yarn
and the degree of texture.
8.2.2 Examples 5c and 5d, Textured Yarns Using Inch-Pound Units—The description of a textured yarn using inch-pound units
might be:
Three 2 segment description 2 ETG 37 Manufacturer’s Code !
~ ~ !
Four 2 segment description 2 ETG 37 1 / 2 Manufacturer’s Code
~ ~ !!
where:
where:
E = symbol for glass family used in general and most electrical applications,
T = symbol for textured yarn,
G = symbol for filament diameter average range 0.00035 to 0.000399 in.,
37 = nominal yarn number in hundreds of yards per pound,
1/2 = one singles yarn and two such yarns fabricated together, and
manufacturer’s code = further identification as necessary by manufacturer to define process, sizing, etc.
The actual yards per pound of the final yarn may vary and result in a lower value. This is dependent upon the yarn number of
the input yarn and the degree of texture.
9. Rovings
9.1 Descriptions of Rovings—The description of rovings consists of either two or three segments.
9.1.1 Two Segment Description for Rovings—The segments in a two segment description of rovings are:
Segment 1 Segment 2
Product type Yarn number
9.1.1.1 Segment One—For rovings, the first segment of the description of glass rovings represents the manufacturer’s product type,
D578/D578M − 23
which includes binder (sizing) and sliver (strand). It consists of number or letter designations, or both letter and number
designations that reference the manufacturer’s code. The designation for the manufacturer’s code may directly follow the product
type,type or may be separated by a space.
9.1.1.2 Segment Two—For rovings, the second segment of the description specifies the yarn number of the total roving. For rovings
described in SI units, the yarn number is specified in tex. For such rovings described in inch-pound units, the yarn number is
specified in yards per pound.
NOTE 5—Roving yield is synonymously used for yarn number of roving products in the glass fiber industry. The term yarn number is used throughout
Specification D578 to represent the more universal term.
9.1.2 Three Segment Description for Rovings—The segments in a three segment description of rovings are:
Segment 1 Segment 2 Segment 3
Product type Yarn number Manufacturer’s
product code
9.1.2.1 For rovings, the first and second segments of the three segment description are as described in 9.1.1.1 and 9.1.1.2. The third
segment references a manufacturer’s product code and may be represented by letters or numbers, or both.
9.2 Examples of Descriptions of Rovings:
9.2.1 Examples 6a, 6b, 6c, and 6d, Rovings Using SI Units—The description of rovings using SI units might be:
Two 2 segment description 2 a 988AB 4400/ b 998 BA 4400
~ ! ~ !
Three 2 segment description 2 ~c! 526HT 3100 1325864355/~d!
995AA 2350 71B68820
where:
988AB = manufacturer’s product type and manufacturer’s code,
988BA = manufacturer’s product type and manufacturer’s code,
526HT = manufacturer’s product type,
4400 = nominal yarn number for total roving, tex,
3100 = nominal yarn number for total roving in tex,
2350 = nominal yarn number for total roving in tex, and
1325864355 = manufacturer’s product code.
325864355 = manufacturer’s product code.
71B68820 = manufacturer’s product code
9.2.2 Examples 6e, 6f, 6g and 6h, Rovings Using Inch-Pound Units—The description of rovings using inch-pound units might be:
Two 2 segment description 2 e 988AB 113/ f 998BA 113
~ ! ~ !
Three 2 segment description 2 g 526HT 161 1325864355/ h
~ ! ~ !
995AA 211 71B68820
where:
where:
988AB = manufacturer’s product type and manufacturer’s product code,
988BA = manufacturer’s product type and manufacturer’s product code,
526HT = manufacturer’s product type,
113 = nominal yarn number for total roving, yd/lb,
161 = nominal yarn number for total roving, yd/lb,
1325864355 = manufacturer’s product code, and
71B68820 = manufacturer’s product code.
9.3 It is customary for producers of glass fiber rovings to indicate the compatibility of the binder (sizing) applied to the rovings
to the matrix resins in which they can be used.
D578/D578M − 23
9.3.1 The designation shall follow the form ”[matrix resin] compatible.”
9.3.2 Examples of this designation would be “epoxy compatible” or “polyester compatible.”
9.3.3 The resin compatibility is not part of the three segment description outlined in 9.1.2, but is available upon request from the
manufacturer of the roving.
NOTE 6—Discontinued MIL-R-60346 referred to the resin compatibility by the term “Class 1” for epoxy compatible rovings and “Class 2” for polyester
compatible rovings.
10. Chopped Strand from Continuous Filament Strands
10.1 Descriptions of Chopped Strand from Continuous Filament Strands—The description of chopped strand from continuous
filament strands consists of either two, three, or four segments. For chopped strand used to reinforce thermoplastic and
thermosetting plastic compounds, the description consists of two segments. For dry sized glass chopped strand, the description
consists of three segments. For wet sized glass chopped strand, the description consists of four segments.
10.1.1 Two Segment Description for Chopped Strand Used to Reinforce Thermoplastic and Thermosetting Compounds—The
segments in a description for chopped strand used to reinforce thermoplastic and thermosetting compounds are:
Segment 1 Segment 2
Product type Strand length
10.1.1.1 Segment One—The first segment of the description of chopped strand used to reinforce thermoplastic and thermosetting
compounds represents the manufacturer’s product type. It consists of numbers that are sometimes followed by letter designations,
or both, letter and number designations that reference the manufacturer’s code. The designation for the manufacturer’s code will
directly follow the product type.
10.1.1.2 Segment Two—The second segment of the description of chopped strand used to reinforce thermoplastic and
thermosetting compounds specifies the length of the chopped strand. For chopped strands described in SI units, the nominal
chopped length is specified in millimetres. For chopped strands described in inch-pound units the nominal chopped length is
specified in inches.
10.1.2 Three Segment Description for Dry Sized Chopped Strand—The segments in a description of dry chopped strand are:
Segment 1 Segment 2 Segment 3
Filament diameter Sizing or product type Strand length
10.1.2.1 Segment One—The first segment of the description of dry sized chopped strand represents the nominal filament diameter
range. When using SI units, this segment consists of a number specifying the nominal filament diameter range in micrometers as
directed in Table 1. When using inch pound units, this segment consists of one or two letters as directed in Table 1.
10.1.2.2 Segment Two—The second segment of the description of dry sized chopped strand represents the manufacturer’s sizing
or product type. It consists of numbers that are sometimes followed by letter designations, or both, letter and number designations
that reference the manufacturer’s code. The designation for the manufacturer’s code will directly follow the sizing or product type.
10.1.2.3 Segment Three—The third segment of the description of dry sized chopped strand specifies the length of the chopped
strand. For chopped strands described in SI units, the nominal chopped length is specified in millimetres. For chopped strands
described in inch-pound units the nominal chopped length is specified in inches.
10.1.3 Four Segment Description for Wet Sized Chopped Strand—The segments in a description of wet chopped strand are:
Segment 1 Segment 2 Segment 3 Segment 4
Filament Sizing or Moisture Strand
diameter product type content length
D578/D578M − 23
10.1.3.1 Segment One—The first segment of the description of wet sized chopped strand represents the nominal filament diameter
range. When using SI units, this segment consists of a number specifying the nominal filament diameter range in micrometres as
directed in Table 1. When using inch-pound units, this segment consists of one or two letters as directed in Table 1.
10.1.3.2 Segment Two—The second segment of the description of wet sized chopped strand represents the manufacturer’s sizing
or product type. It consists of numbers that are sometimes followed by letter designations, or both, letter and number designations
that reference the manufacturer’s code. The designation for the manufacturer’s code will directly follow the product type.
10.1.3.3 Segment Three—The third segment of the description of wet sized chopped strand specifies the nominal percent moisture
content. This segment consists of a number representing the percent moisture content in both SI units and inch pound units.
NOTE 7—Some manufacturers omit this segment when describing wet sized chopped strand.
10.1.3.4 Segment Four—The fourth segment of the description of wet sized chopped strand specifies the length of the chopped
strand. For chopped strands described in SI units, the nominal chopped length is specified in millimetres. For chopped strands
described in inch-pound units the nominal chopped length is specified in inches.
10.2 Examples of Descriptions of Chopped Strands:
10.2.1 Example 7a, Chopped Strand Used to Reinforce Thermoplastic and Thermosetting Compounds Using SI Units—The
description of chopped strand used to reinforce thermoplastic and thermosetting compounds using SI units might be:
405AB 13 mm
where:
where:
405AB = manufacturer’s product type and process code, and
13 = length, mm.
10.2.2 Example 7b, Dry Sized Chopped Strand Using SI Units—The description of dry sized chopped strand using SI units might
be:
9 µm 685 13 mm
where:
where:
9 = symbol for filament diameter average range 8.50 to 9.49 μm,
685 = manufacturer’s sizing code or process code, or both, and
13 = length, mm.
10.2.3 Example 7c, Wet Sized Chopped Strand Using SI Units—The description of wet sized chopped strand using SI units might
be:
16 µm 775 14.5 32 mm
where:where:
16 = symbol for filament diameter average range 15.5 to 16.49 μm,
775 = manufacturer’s sizing code or process code, or both,
14.5 = moisture content, % (Note 7), and
14.5 = moisture content, wt % (Note 7), and
32 = length, mm.
10.2.4 Example 7d, Chopped Strand Used to Reinforce Thermoplastic and Thermosetting Compounds Using Inch-Pound
Units—The description of chopped strand used to reinforce thermoplastic and thermosetting compounds using inch-pound units
might be:
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405AB ½ in.
where:
where:
405AB = manufacturer’s product type and process code, and
⁄2 = length, in.
10.2.5 Example 7e, Dry Sized Chopped Strand Using Inch-Pound Units—The description of dry chopped strand using inch-pound
units might be:
G685 ½ in.
where:
where:
G = symbol for filament diameter average range 0.00035 to 0.000399 in.,
685 = manufacturer’s sizing code or process code, or both, and
⁄2 = length, in.
10.2.6 Example 7f, Wet Sized Chopped Strand Using Inch-Pound Units—The description of wet sized chopped strand using
inch-pound units might be:
M 775 14.5 1¼ in.
where:
where:
M = symbol for filament diameter average range 0.00060 to 0.000649 in.
775 = manufacturer’s sizing code or process code, or both,
14.5 = moisture content, %, and
14.5 = moisture content, wt %, and
1 ⁄4 = length, in.
11. Ordering Information
11.1 The purchase order or other agreement shall specify: specification conformance number, title, and year of issue; designation
of strand construction; product quantity; and any special provisions.
REQUIREMENTS
12. Material
12.1 The fibers shall be free of any free alkali metal oxides, such as soda or potash, and from foreign particles, dirt, and other
impurities. The glass classification shall be agreed upon between the purchaser and the supplier in an applicable material
specification or other agreement. The composition of the E-Glass classification of glass fiber shall be within the limits specified
in 4.2.1 or 4.2.2 as agreed upon between the purchaser and supplier.
13. Workmanship
13.1 As agreed upon between the purchaser and the supplier, the defects listed in Table 3 shall be considered cause for rejection
of the package in which they occur. The allowable quality level (AQL) shall be agreed upon between the purchaser and the supplier.
14. Physical Properties
14.1 The nominal and physical properties of glass fiber strands shall conform to the requirements of Tables 1, 2, 4, and 5, as
applicable. The tolerances shall be subject to the tolerances as agreed upon between the purchaser and the supplier. However, the
following maximum tolerances apply:
14.1.1 Yarn Number, Tex [Yards per Pound), Individual Value—Plus or minus 10 % for continuous filament yarns. Plus or minus
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20 % for discontinuous or staple yarns. Plus or minus 15 % for textured yarns. Plus or minus 8.5 % for roving produced by either
conventional or nonconventional roving winding processes, except certain rovings produced by other than conventional winding
processes shall have a 613 % tolerance when agreed upon between the purchaser and the supplier.
NOTE 8—Historically, it has been conventional practice to attenuate glass through bushings having 204 or 408 holes to produce strands containing those
numbers of filaments. Then, rovings were made from those strands having 1, 12, 15, 20, 30, and 60 ends. Although this practice is still used by some
suppliers, others are attenuating fiber glass through bushings consisting of up to several thousand holes to make heavy rovings containing only a single
strand. Since the strands are not twisted, rovings made with the larger single strands are equivalent, for most purposes, to those made with the smaller
conventional made multiple strands. Since many older material specifications specify in accordance with the older multiple strand designation, a
purchasing activity should review and agree upon with the supplier activity, the acceptability of the single strand roving having an equivalent yarn number.
14.1.1.1 The tex [yards per pound] as determined in Section 23 and specified in Tables 2, 4, and 5 are the bare glass nominal. A
commercial yarn normally has a size (binder) treatment which will increase tex [decrease yards per pound] in proportion to the
amount of size.
14.1.2 Breaking Strength—No individual break shall be less than the specified minimum requirement in Tables 2, 4, and 5.
14.2 When required for roving and chopped strand, the nominal and physical properties shall be agreed upon between the
purchaser and the supplier in an applicable material specification or other agreement, subject to the requirements of Table 2 and
14.1.1.
15. Ignition Loss (Organic Content)
15.1 The ignition loss (organic content) shall be within the tolerances as agreed upon between the purchaser and the supplier, or
as specified in an applicable material specification or other agreement.
16. Packaging
16.1 The glass fiber strand shall be put up on packages, and in containers whose dimensions shall be agreed to between the
purchaser and supplier.
16.2 Each package of strand, put up as specified, shall be further packaged to afford adequate protection against physical damage
during shipment from the supply source to the receiving activity. The supplier may use his standard practice when it meets this
requirement.
16.3 For government procurement, the contracting instrument shall specify the put up (see 11.1) and AQL (see 13.1).
17. Marking
17.1 Each package of strand shall be marked to show the construction designation of the glass fiber strand as specified in Sections
5 – 10. Each container of packages shall be marked as agreed upon between the purchaser and supplier.
18. Sampling, Inspection, and Number of Specimens
18.1 Lot Size—A lot shall consist of each shipment, date code, or consignment of a single strand designation. This may constitute
all or part of any one customer order. The lot size is the total number of packages of strand in the incoming shipment date code,
or consignment.
NOTE 9—An adequate specification or other agreement between the purchaser and the supplier requires taking into account the variability between
packages of strand and between test specimens from a package of strand to produce a sampling plan with meaningful producer’s risk, consumer’s risk,
acceptable quality level, and limiting quality level.
18.2 Lot Sample—As a lot sample for acceptance testing, take at random the number of shipping units specified in Practice
D2258/D2258M. Consider shipping cases or other shipping units to be the primary sampling units.
18.3 Laboratory Sample—As a laboratory sample for acceptance testing, take at random from each shipping unit in the lot sample
the number of packages or ends directed in 18.3.1 and 18.3.2. Preferably, the same number of packages should be taken from each
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shipping unit in the lot sample. If differing numbers of packages are to be taken from shipping units in the lot sample, determine
at random which shipping units are to have each number of packages drawn.
18.3.1 Workmanship—Take at random the number of packages or ends of strand as directed in ANSI/ASQC Z1.4. Select an
acceptable quality level (AQL) that is agreeable to both the purchaser and the supplier.
18.3.2 Other Properties—Take at random the number of bobbins or packages of strand specified in Table 6.
18.4 Test Specimens—Proceed as follows:
18.4.1 Workmanship—Use the packages of strand in the laboratory sample as the specimens. Evaluate the results of inspecting the
specimens using ANSI/ASQC Z1.4, normal inspection, and an acceptable quality level agreed upon between the purchaser and the
supplier.
18.4.2 Other Properties—Take the number of specimens per laboratory sampling unit specified in the applicable test method.
TEST METHODS
19. Conditioning
19.1 Condition the laboratory samples without preconditioning for a period of at least 5 hhours in the atmosphere for testing glass
textiles, unless otherwise specified.
20. Material
20.1 Upon prior agreement, accept the supplier’s certification that the material is of the correct family of glass fiber as specified
in Section 4. Verify that the fiber is the specified filament type during testing for strand construction a
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