ASTM D5421-23

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: D5421 − 15 D5421 − 23
Standard Specification for
Contact Molded “Fiberglass” (Glass-Fiber-Reinforced
Thermosetting Resin) Flanges
This standard is issued under the fixed designation D5421; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This specification covers circular contact-molded fiberglass reinforced-thermosetting-resin flanges for use in pipe systems and
tank nozzles. Included are requirements for materials, workmanship, performance, and dimensions.
1.2 Flanges (see Fig. 1) may be produced as integral flanges, Type A, or flange-on-pipe, Type B.
1.3 This specification is based on flange performance and does not cover design.
1.4 These flanges are designed for use with pipe and tanks that are manufactured to Specifications D2996, D2997, D3262, D3299,
D3517, D3754, and D4097.
1.5 Selection of gaskets is not covered in this specification, refer to the manufacturer’s recommendation.
1.6 The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are for information
only.
1.7 The following precautionary caveat pertains only to the test methods portion, Section 9, of this specification: 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.
NOTE 1—There is no known ISO equivalent to this standard.
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:
C582 Specification for Contact-Molded Reinforced Thermosetting Plastic (RTP) Laminates for Corrosion-Resistant Equipment
This specification is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.23 on Reinforced Plastic
Thermosetting Resin Piping Systems and Chemical Equipment.
Current edition approved May 1, 2015May 1, 2023. Published June 2015May 2023. Originally approved in 1993. Last previous edition approve in 20102015 as
D5421 – 05D5421 – 15.(2010). DOI: 10.1520/D5421-15.10.1520/D5421-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5421 − 23
FIG. 1 Flange Types
D883 Terminology Relating to Plastics
D1599 Test Method for Resistance to Short-Time Hydraulic Pressure of Plastic Pipe, Tubing, and Fittings
D1600 Terminology for Abbreviated Terms Relating to Plastics
D2996 Specification for Filament-Wound “Fiberglass” (Glass-Fiber-Reinforced Thermosetting-Resin) Pipe
D2997 Specification for Centrifugally Cast “Fiberglass” (Glass-Fiber-Reinforced Thermosetting-Resin) Pipe
D3262 Specification for “Fiberglass” (Glass-Fiber-Reinforced Thermosetting-Resin) Sewer Pipe
D3299 Specification for Filament-Wound Glass-Fiber-Reinforced Thermoset Resin Corrosion-Resistant Tanks
D3517 Specification for “Fiberglass” (Glass-Fiber-Reinforced Thermosetting-Resin) Pressure Pipe
D3754 Specification for “Fiberglass” (Glass-Fiber-Reinforced Thermosetting-Resin) Sewer and Industrial Pressure Pipe
D4097 Specification for Contact-Molded Glass-Fiber-Reinforced Thermoset Resin Corrosion-Resistant Tanks
2.2 ASME Standards:
B 16.1 Cast Iron Pipe Flanges and Flanged Fittings
B 16.5 Pipe Flanges and Flanged Fittings
B 18.21.1 Type “A” Narrow Washers
3. Terminology
3.1 Definitions:
3.1.1 Definitions are in accordance with Terminology D883. Abbreviations are in accordance with Terminology D1600, unless
otherwise indicated. The abbreviation for reinforced-thermosetting-resin pipe is RTRP.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 contact molding (CM)—a method of fabrication wherein the glass fiber reinforcement is applied to the mold in the form of
all chopped-strand mat, or chopped-strand mat and woven roving, in alternate plies by hand with the resin matrix applied by brush
or roller and the laminate consolidated by a roller.
3.2.2 fiberglass pipe—a tubular product containing glass-fiber reinforcements embedded in or surrounded by cured thermosetting
resin; the composite structure may contain aggregate, granular or platelet fillers, thixotropic agents, pigments or dyes;
thermoplastic or thermosetting liners or coatings may be included.
4. Classification
4.1 General—This specification covers reinforced-thermosetting-resin flanges defined by type (method of manufacture), grade
(generic type of resin), class (pressure end thrust capability), and pressure rating. Flanges complying with this specification are also
given numerical classifications relating to rupture pressure and sealing test pressure.
4.1.1 Types:
4.1.1.1 Type A—Integral flange, contact molded with the stub integral with the flange.
4.1.1.2 Type B—Flange on pipe, contact molded onto an existing pipe or fitting.
Available from American Society of Mechanical Engineers (ASME), ASME International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
www.asme.org.
D5421 − 23
4.1.2 Grades:
4.1.2.1 Grade 1—Epoxy resin.
4.1.2.2 Grade 2—Polyester resin.
4.1.2.3 Grade 3—Phenolic resin.
4.1.2.4 Grade 4—Vinylester resin.
4.1.2.5 Grade 5—Furan resin.
4.1.3 Classes:
4.1.3.1 Class I—Hoop and axial-pressure.
4.1.3.2 Class II—Hoop pressure only.
NOTE 2—All combinations of type, liner, grade, and class may not be commercially available. Additional type, liner, grade, and class may be added as
they become commercially available. The purchaser should solely determine or consult with the manufacturer for the proper class, type, liner, and grade
to be used under the installation and operating conditions that will exist for the project in which the flange is to be used.
4.1.4 Pressure Rating—Pressure rating shall be categorized by single-letter designation. Pressure designations are shown in Table
1.
4.1.5 Short-term rupture pressure and sealing-test pressure limits shall be categorized by single arabicArabic number designations
as indicated by the cell classification system of Table 2.
4.2 Designation Code—The flange-designation code shall consist of the abbreviation for contact molded (CM) followed by the
type as a capital letter, grade as an Arabic numeral, class as a Roman numeral, and the pressure-rating category as a capital letter
and two Arabic numbers identifying the cell-classification designations of the short-term rupture pressure and sealing-test pressure,
respectively. Thus, a complete flange-designation code shall consist of three letters, one Arabic numeral, one Roman numeral, one
letter and two numerals.
4.2.1 Example—Contact molded fiberglass is CM-AlID-46. This designation described a stub flange, made using glass-fiber-
reinforced epoxy resin for full-axial pressure thrust. The flange has a 100-psi (0.69-MPa) pressure rating, a short-term rupture
pressure of 400-psi (2.76-MPa), and a sealing-test pressure of 225-psi (1. 55-MPa).
4.3 Attachment of Flanges to Pipe, Pipe Fittings, or Tanks:
4.3.1 Type “A” flanges are to be butt and strap welded to pipe described in Specifications D2996, D2997, D3262, D3517, and
D3754, or using overlay joint into a tank as described in Specifications D3299 and D4097.
4.3.2 Type “B” flanges are built onto elbows, reducers, or other parts where the use of an integral flange (Type “A”) is not practical
or required.
TABLE 1 Pressure Categories
A
Pressure Rating
Designation
psi MPa
A 25 0.173
B 50 0.345
C 75 0.517
D 100 0.690
E 125 0.862
F 150 1.034
A
Flanges with higher pressure ratings are available by agreement between the
purchaser and the manufacturer.
D5421 − 23
TABLE 2 Short-Term Rupture Pressure and Sealing-Test
A
Pressure
Property/Cell Classification 1 2 3 4 5 6
Short-Term Rupture 100 200 300 400 500 600
Pressure, psi (MPa) (0.69) (1.38) (2.07) (2.76) (3.45) (4.14)
Sealing-test pressure, psi 37.5 75 112.5 150 187.5 225
(MPa) (0.26) (0.52) (0.78) (1.03) (1.29) (1.55)
A
Refer to Test Method D1599 for explanation of failure.
5. Materials and Manufacture
5.1 Flanges manufactured in accordance with this specification shall be composed of reinforcement embedded in or surrounded
by cured thermosetting resin.
5.2 The resins, reinforcements, and other materials, when combined into composite structure, shall produce a flange that will meet
the performance requirements of this specification.
NOTE 3—The term “other materials” does not include recycled or reprocessed thermosetting plastics which might otherwise be added as fillers.
5.3 Flanges manufactured in accordance with this specification shall have an inner corrosion barrier fabricated with the same resin,
reinforcement, ply sequence, and nominal glass/resin ratio as required in the applicable ASTM standard for the tank or pipe on
which the flange will be used.
6. Performance Requirements
6.1 The following performance requirements are intended to provide classification and performance criteria for the purpose of
qualification testing and rating of prototype constructions and periodic reevaluation of the manufacturer’s stated ratings. They are
not intended as routine quality assurance requirements for production runs of rated flanges:
6.1.1 Sealing—Flanges shall withstand a pressure of at least 1.5 times the pressure rating without leakage when tested in
accordance with 9.4.
6.1.2 Short-Term Rupture Strength—Flanges shall withstand a hydrostatic load of at least four times their pressure rating when
tested in accordance with 9.5 using flat-faced steel closure and using the gasket or “O” ring designated by the flange manufacturer.
6.1.3 Bolt Torque—Flanges shall withstand, without visible sign of damage, a bolt torque of two at least 1.5 times that
recommended by the manufacturer. manufacturer for sealing of the flange at its rated pressure when tested in accordance with 9.6.
The use of a non-fluid thread lubricant is recommended on all bolts.
7. Dimensions and Tolerances
7.1 Flange and Bolt Dimensions—Flanges of 24 in. (610 mm) or smaller diameter shall conform to the values for bolt circle and
number and size of bolt holes, for Class-150 cast iron flanges in ASME B 16.5. Flanges larger than 24 in. (610 mm) in diameter
shall conform to the values for bolt circle, nu
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