ASTM C425-22

Standard Specification for Compression Joints for Vitrified Clay Pipe and Fittings

ABSTRACT
This specification covers vitrified clay pipe and fitting materials and pipe joint assemblies test requirements for compression joints. Sealing elements shall be compressed and bounded between bearing surfaces to assure watertight integrity. Materials and manufacture, such as rubber ring-sealing elements, plastic components, and metallic components, shall conform to the chemical resistance, tensile strength, hardness, compression set, water absorption, ozone resistance, and accelerated oven aging requirements of the specification. Minimum of two assembled joints shall be tested for each diameter of pipe furnished. Joints shall be subjected to water pressure testing and shall not leak even when deflected, displaced or subjected to shear under the limits indicated in the specification.
SCOPE
1.1 This specification covers materials and test requirements for compression joints for vitrified clay pipe and fittings. See Specification C700 for pipe specifications. The test requirements are applicable to pipe joint assemblies prior to field installation of pipe.
Note 1: Install pipe in accordance with Practice C12.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 The following precautionary caveat pertains only to the Test Requirements portion, Section 7, of this standard. 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.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Mar-2022
• ICS: 23.040.60 - Flanges, couplings and joints
• Technical Committee: C04 - Vitrified Clay Pipe
• Drafting Committee: C04.20 - Methods of Test and Specifications

Relations

• Refers: ASTM C896-24 - Standard Terminology Relating to Clay Products
• Effective Date: 01-Apr-2024
• Refers: ASTM A240/A240M-23a - Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
• Effective Date: 01-Nov-2023
• Refers: ASTM C896-17a - Standard Terminology Relating to Clay Products
• Effective Date: 01-Dec-2017
• Refers: ASTM A240/A240M-17 - Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
• Effective Date: 01-Nov-2017
• Refers: ASTM C896-17 - Standard Terminology Relating to Clay Products
• Effective Date: 01-Jun-2017
• Refers: ASTM A240/A240M-16a - Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
• Effective Date: 01-Dec-2016
• Refers: ASTM C12-16a - Standard Practice for Installing Vitrified Clay Pipe Lines
• Effective Date: 01-Nov-2016
• Refers: ASTM C12-16 - Standard Practice for Installing Vitrified Clay Pipe Lines
• Effective Date: 15-May-2016
• Refers: ASTM A240/A240M-16 - Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
• Effective Date: 01-May-2016
• Refers: ASTM C896-15 - Standard Terminology Relating to Clay Products
• Effective Date: 01-Dec-2015
• Refers: ASTM A240/A240M-15b - Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
• Effective Date: 01-Nov-2015
• Refers: ASTM A240/A240M-15a - Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
• Effective Date: 01-Mar-2015
• Refers: ASTM A240/A240M-15 - Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
• Effective Date: 01-Jan-2015
• Refers: ASTM C896-14 - Standard Terminology Relating to Clay Products
• Effective Date: 01-Sep-2014
• Refers: ASTM C12-14 - Standard Practice for Installing Vitrified Clay Pipe Lines
• Effective Date: 01-Sep-2014

Overview

ASTM C425-22: Standard Specification for Compression Joints for Vitrified Clay Pipe and Fittings provides comprehensive requirements and test methods for compression joints used in vitrified clay pipe systems. This standard ensures that the materials and joint assemblies are capable of maintaining watertight integrity under pressure and various field conditions. Applicable before field installation, ASTM C425-22 is fundamental for quality assurance and reliability in the construction and maintenance of wastewater and sewer systems where vitrified clay pipes are specified.

Key Topics

• Materials Requirements: Covers specifications for sealing elements, including rubber ring seals, plastic components, and metallic fittings. Each material must demonstrate resistance to chemicals, tensile strength, hardness, compression set, water absorption, ozone, and aging.
• Joint Design Principles: Joints must secure sealing elements between bearing surfaces to ensure watertight performance. Seals may be either bonded or independent.
• Testing Procedures:
  • Minimum of two joint assemblies per pipe diameter must undergo testing.
  • Joints are subject to water pressure tests and must not leak when straight, deflected, displaced, or under shear within specified limits.
  • Material-specific tests verify chemical resistance (to sulfuric and hydrochloric acids), mechanical properties, and environmental durability.
• Inspection and Sampling: Assembled joints for testing are selected from supply stocks, with requirements to avoid testing damaged samples.
• Federal and Military Compliance: Contains supplementary requirements for government procurement, packaging, and marking.

Applications

ASTM C425-22 is crucial in the following sectors:

• Municipal Sewer Systems: Ensures leak-free, resilient pipe joints in gravity sewer lines, enhancing system longevity and reducing maintenance risks.
• Commercial and Residential Drainage: Supports watertight vitrified clay piping systems for stormwater and sanitary applications.
• Industrial Facilities: Assists in specifying joints for clay pipes exposed to varied effluent characteristics-chemical resistance is particularly critical here.
• Infrastructure Projects: Compliance with ASTM C425-22 is often required in public works and government-funded projects to meet quality and performance standards.
• Quality Control and Product Certification: Manufacturers and testing labs utilize this standard to validate pipe joint performance before market release or installation.

Related Standards

Several ASTM standards are referenced or closely associated with ASTM C425-22:

• ASTM C700 - Specification for Vitrified Clay Pipe, Extra Strength, Standard Strength, and Perforated
• ASTM C12 - Practice for Installing Vitrified Clay Pipe Lines
• ASTM D395 - Test Methods for Rubber Property - Compression Set
• ASTM D412 - Test Methods for Vulcanized Rubber and Thermoplastic Elastomers-Tension
• ASTM D471/D543/D573/D1149/D2240 - Additional test methods for evaluating rubber and plastic materials under physical and chemical stress

Practical Value

Implementing ASTM C425-22 compliance ensures that vitrified clay pipe systems are durable, reliable, and maintain a watertight seal over their service life. By defining rigorous testing and material standards, the specification reduces the risk of leaks, environmental contamination, and costly repairs. It also helps designers, contractors, and asset managers reliably select products suitable for diverse operational environments, supporting infrastructure resilience and regulatory compliance.

Keywords: compression joints, vitrified clay pipe, sealing elements, watertight, chemical resistance, ASTM C425-22, joint integrity, sewer pipe standards, pipe fittings, leakage testing, quality assurance.

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:C425 −22
Standard Specification for
Compression Joints for Vitrified Clay Pipe and Fittings
This standard is issued under the fixed designation C425; 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 A240/A240M Specification for Chromium and Chromium-
Nickel Stainless Steel Plate, Sheet, and Strip for Pressure
1.1 Thisspecificationcoversmaterialsandtestrequirements
Vessels and for General Applications
for compression joints for vitrified clay pipe and fittings. See
C12 Practice for Installing Vitrified Clay Pipe Lines
Specification C700 for pipe specifications. The test require-
C700 Specification for Vitrified Clay Pipe, Extra Strength,
ments are applicable to pipe joint assemblies prior to field
Standard Strength, and Perforated
installation of pipe.
C896 Terminology Relating to Clay Products
NOTE 1—Install pipe in accordance with Practice C12.
D395 Test Methods for Rubber Property—Compression Set
1.2 The values stated in inch-pound units are to be regarded
D412 Test Methods forVulcanized Rubber andThermoplas-
as standard. The values given in parentheses are mathematical
tic Elastomers—Tension
conversions to SI units that are provided for information only
D471 Test Method for Rubber Property—Effect of Liquids
and are not considered standard.
D518 Test Method for Rubber Deterioration—Surface
1.3 The following precautionary caveat pertains only to the
Cracking (Withdrawn 2007)
Test Requirements portion, Section 7, of this standard. This
D543 Practices for Evaluating the Resistance of Plastics to
standard does not purport to address all of the safety concerns,
Chemical Reagents
if any, associated with its use. It is the responsibility of the user
D573 Test Method for Rubber—Deterioration in an Air
of this standard to establish appropriate safety, health, and
Oven
environmental practices and determine the applicability of
D583 Methods of Test for Water Resistance of Textile
regulatory limitations prior to use.
Fabrics (Withdrawn 1971)
1.4 This international standard was developed in accor-
D1149 Test Methods for Rubber Deterioration—Cracking in
dance with internationally recognized principles on standard-
an Ozone Controlled Environment
ization established in the Decision on Principles for the
D1566 Terminology Relating to Rubber
Development of International Standards, Guides and Recom-
D2240 Test Method for Rubber Property—Durometer Hard-
mendations issued by the World Trade Organization Technical
ness
Barriers to Trade (TBT) Committee.
3. Terminology
2. Referenced Documents
3.1 Definitions—Terms relating to plastics and rubber shall
be as defined in Terminologies D583 and D1566, respectively.
2.1 ASTM Standards:
A167 Specification for Stainless and Heat-Resisting
3.2 Terminology C896 can be used for clarification of
Chromium-Nickel Steel Plate, Sheet, and Strip (With-
terminology in this specification.
drawn 2014)
4. Principles of Joint Design
4.1 Sealing elements shall be compressed between bearing
This specification is under the jurisdiction of ASTM Committee C04 on surfaces to assure watertight integrity as required in Section 7.
Vitrified Clay Pipe and is the direct responsibility of Subcommittee C04.20 on
4.2 Sealing elements shall either be bonded to bearing
Methods of Test and Specifications.
Current edition approved April 1, 2022. Published April 2022. Originally surfaces or be independent elements.
approved in 1958. Last previous edition approved in 2021 as C425 – 21. DOI:
10.1520/C0425-22. 5. Materials and Manufacture
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.1 Rubber ring-sealing elements shall conform to the
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on requirements of Table 1.
the ASTM website.
5.2 Rubber for other than ring-sealing elements shall con-
The last approved version of this historical standard is referenced on
www.astm.org. form to the requirements of Table 2.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C425−22
TABLE 1 Tests for Rubber—Ring-Sealing Elements
NOTE 1—Except for the water absorption test (Test Method D471), the tests shall be run on specimens cut from rubber test slabs representative of the
finished product.
Test Test Requirement ASTM Standard
Chemical resistance: D543 (48 h at 23 ± 2°C)
1N sulfuric acid no weight loss
1N hydrochloric acid no weight loss
Tensile strength 1500 psi (10.4 MPa) min; 500 % min elongation at break D412
Hardness Shore A durometer 35 min to 50 max D2240
Compression set 16 % max of original deflection D395, Method B (22 h at 70 ± 2°C)
Water absorption 5 % max D471—Immerse a 2-in. (51-mm) long section cut
from a rubber-sealing element in distilled water
for 7 days at 70 ± 2°C
Ozone resistance no visible cracking under 2× specimen magnification us- D1149
ing D518, Procedure B, stretched 20 % and exposed
to ozone concentrations of 0.5 ppm for 24 h at 40 ±
1°C
Accelerated oven aging 80 % min of original tensile strength D573 (7 days at 70 ± 2°C)
75 % min of original elongation
TABLE 2 Tests for Rubber—Other than Ring-Sealing Elements
NOTE 1—Except for the water absorption test (Test Method D471), the tests shall be run on specimens cut from rubber test slabs representative of the
finished product.
Test Test Requirements ASTM Standard
Chemical resistance: D543 (48 h at 23 ± 2°C)
1N sulfuric acid no weight loss
1N hydrochloric acid no weight loss
Tensile strength 1000 psi (6.9 MPa) min; 250 % min elongation at break D412
Hardness Shore A durometer 55 min to 70 max D2240
Compression set 20 % max of original deflection D395, Method B (22 h at 70 ± 2°C)
Water absorption 5 % max D471—Immerse a 2-in. (51-mm) long section cut
from a rubber coupling in distilled water for 7
days at 70 ± 2°C
Ozone resistance no visible cracking under 2× specimen magnification, us- D1149
ing D518, Procedure B, stretched 20 % and exposed
to ozone concentrations of 0.5 ppm for 24 h at 40 ±
1°C
Accelerated oven aging 85 % min of original tensile strength D573 (7 days at 70 ± 2°C)
85 % min of original elongation
5.3 Plastic
...

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: C425 − 21 C425 − 22
Standard Specification for
Compression Joints for Vitrified Clay Pipe and Fittings
This standard is issued under the fixed designation C425; 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 materials and test requirements for compression joints for vitrified clay pipe and fittings. See
Specification C700 for pipe specifications. The test requirements are applicable to pipe joint assemblies prior to field installation
of pipe.
NOTE 1—Install pipe in accordance with Practice C12.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.3 The following precautionary caveat pertains only to the Test Requirements portion, Section 7, of this standard. 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.
1.4 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:
A167 Specification for Stainless and Heat-Resisting Chromium-Nickel Steel Plate, Sheet, and Strip (Withdrawn 2014)
A240/A240M Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and
for General Applications
C12 Practice for Installing Vitrified Clay Pipe Lines
C700 Specification for Vitrified Clay Pipe, Extra Strength, Standard Strength, and Perforated
C896 Terminology Relating to Clay Products
D395 Test Methods for Rubber Property—Compression Set
D412 Test Methods for Vulcanized Rubber and Thermoplastic Elastomers—Tension
D471 Test Method for Rubber Property—Effect of Liquids
D518 Test Method for Rubber Deterioration—Surface Cracking (Withdrawn 2007)
This specification is under the jurisdiction of ASTM Committee C04 on Vitrified Clay Pipe and is the direct responsibility of Subcommittee C04.20 on Methods of Test
and Specifications.
Current edition approved April 1, 2021April 1, 2022. Published April 2021April 2022. Originally approved in 1958. Last previous edition approved in 20182021 as
C425 – 04C425 – 21.(2018). DOI: 10.1520/C0425-21.10.1520/C0425-22.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C425 − 22
D543 Practices for Evaluating the Resistance of Plastics to Chemical Reagents
D573 Test Method for Rubber—Deterioration in an Air Oven
D583 Methods of Test for Water Resistance of Textile Fabrics (Withdrawn 1971)
D1149 Test Methods for Rubber Deterioration—Cracking in an Ozone Controlled Environment
D1566 Terminology Relating to Rubber
D2240 Test Method for Rubber Property—Durometer Hardness
3. Terminology
3.1 Definitions—Terms relating to plastics and rubber shall be as defined in Terminologies D583 and D1566, respectively.
3.2 Terminology C896 can be used for clarification of terminology in this specification.
4. Principles of Joint Design
4.1 Sealing elements shall be compressed between bearing surfaces to assure watertight integrity as required in Section 7.
4.2 Sealing elements shall either be bonded to bearing surfaces or be independent elements.
5. Materials and Manufacture
5.1 Rubber ring-sealing elements shall conform to the requirements of Table 1.
5.2 Rubber for other than ring-sealing elements shall conform to the requirements of Table 2.
5.3 Plastic components shall conform to the requirements of Table 3.
5.4 Metallic components shall be of corrosion-resistant metal conforming to Specifications A167 and A240/A240M.
5.5 If any of the test specimens fail to meet the chemical resistance requirements, the manufacturer will be allowed a retest of two
additional specimens, representative of the original material tested, for each one that failed. The jointing material will be acceptable
if all retest specimens meet the test requirements.
5.6 Joints complying with this standard are suitable for most domestic and commercial applications. However, attention is called
to the fact that industrial effluents vary in content, concentration, duration of discharge and temperature; and specific evaluations
of joint performance in such environments are necessary. In those instances, consult the manufacturer.
TABLE 1 Tests for Rubber—Ring-Sealing Elements
NOTE 1—Except for the water absorption test (Test Method D471), the tests shall be run on specimens cut from rubber test slabs representative of the
finished product.
Test Test Requirement ASTM Standard
Chemical resistance: D543 (48 h at 23 ± 2°C)
1N sulfuric acid no weight loss
1N hydrochloric acid no weight loss
Tensile strength 1500 psi (10.4 MPa) min; 500 % min elongation at break D412
Hardness Shore A durometer 35 min to 50 max D2240
Compression set 16 % max of original deflection D395, Method B (22 h at 70 ± 2°C)
Water absorption 5 % max D471—Immerse a 2-in. (51-mm) long section cut
from a rubber-sealing element in distilled water
for 7 days at 70 ± 2°C
Ozone resistance no visible cracking under 2× specimen magnification us- D1149
ing D518, Procedure B, stretched 20 % and exposed
to ozone concentrations of 0.5 ppm for 24 h at 40 ±
1°C
Accelerated oven aging 80 % min of original tensile strength D573 (7 days at 70 ± 2°C)
75 % min of original elongation
C425 − 22
TABLE 2 Tests for Rubber—Other than Ring-Sealing Elemen
...