ASTM D2472-15(2023)

Standard Specification for Sulfur Hexafluoride

ABSTRACT
This specification covers the requirements for sulfur hexafluoride intended for use as an electrical insulating gas. However, this specification applies only to gas as purchased. Tests for water content, acidity (hydrolyzable fluorides), noncondensable gas and carbon tetrafluoride content, and assay shall be performed and shall conform to the requirements specified.
SCOPE
1.1 This specification applies to sulfur hexafluoride for use as an electrical insulating gas.  
Note 1: This specification is intended to apply only to gas as purchased. However, the test methods referred to in this standard may be useful in the evaluation of in-service or used gas. Test Method D2284 may be particularly helpful since many sulfur hexafluoride decomposition products are acidic. Test Method D2284 should not be used to evaluate the total amount of sulfur hexafluoride decomposition nor to identify contaminant species. This can only be done by gas chromatography and similar instrumental techniques.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 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: 30-Nov-2023
• ICS: 71.060.50 - Salts
• Technical Committee: D27 - Electrical Insulating Liquids and Gases
• Drafting Committee: D27.02 - Gases and Non-Mineral Oil Liquids

Relations

• Replaces: ASTM D2472-15 - Standard Specification for Sulfur Hexafluoride
• Effective Date: 01-Dec-2023
• Referred By: ASTM D2685-11(2019) - Standard Test Method for Air and Carbon Tetrafluoride in Sulfur Hexafluoride by Gas Chromatography
• Effective Date: 01-Dec-2023
• Referred By: ASTM D2029-97(2017) - Standard Test Methods for Water Vapor Content of Electrical Insulating Gases by Measurement of Dew Point
• Effective Date: 01-Dec-2023

Overview

ASTM D2472-15(2023) – Standard Specification for Sulfur Hexafluoride establishes the requirements for sulfur hexafluoride (SF₆) intended for use as an electrical insulating gas. Developed by ASTM International, this standard is essential for ensuring the purity and quality of SF₆ as purchased for applications in the electrical industry. The standard specifies testing methods for critical properties such as water content, acidity (hydrolyzable fluorides), noncondensable gas (air), carbon tetrafluoride concentration, and overall assay, aligning with international best practices for electrical insulating gases.

Key Topics

• Scope of Application: The standard applies specifically to the SF₆ gas as it is purchased, focusing on new gas supplied to users.

• Testing Requirements: It details required tests for:

  • Water Content – Measured by dew point to prevent electrical breakdown.
  • Acidity (Hydrolyzable Fluorides) – Ensuring chemical stability and preventing corrosive conditions.
  • Noncondensable Gas (Air/Nitrogen) Content – Limiting inert components for optimal dielectric properties.
  • Carbon Tetrafluoride Content – Control of this by-product to maintain gas purity.
  • Assay – Minimum SF₆ purity specified by difference after impurities are accounted for.

• Sampling Procedures: The standard provides guidance for sampling from both the vapor and liquid phases to obtain representative analytical results.

• Referenced Test Methods:

  • ASTM D2029 for water vapor content,
  • ASTM D2284 for acidity,
  • ASTM D2685 for air and carbon tetrafluoride content.

• Safety and Compliance: Users are reminded to establish appropriate safety and environmental practices and to adhere to relevant regulatory requirements.

Applications

Sulfur hexafluoride (SF₆) is a key electrical insulating gas used extensively in high-voltage circuit breakers, gas-insulated switchgear (GIS), transformers, and other critical components in power transmission and distribution networks. The high dielectric strength and arc-quenching properties of SF₆ make it essential for electrical insulation and fault interruption in substations and industrial power systems.

Complying with ASTM D2472-15(2023):

• Manufacturers ensure delivered SF₆ meets stringent purity requirements.
• Utilities and end users rely on the standard for initial gas acceptance testing and, as recommended, may use referenced test methods for evaluating in-service or recovered gas.
• Testing laboratories use specified methods for routine quality control and compliance documentation.
• Procurement teams reference this standard in contracts and specifications to ensure reliable equipment performance and regulatory compliance.

Related Standards

For those working with SF₆ and electrical insulating gases, the following ASTM standards and international documents are relevant:

• ASTM D2029: Test Methods for Water Vapor Content of Electrical Insulating Gases by Measurement of Dew Point
• ASTM D2284: Test Method for Acidity of Sulfur Hexafluoride
• ASTM D2685: Test Method for Air and Carbon Tetrafluoride in Sulfur Hexafluoride by Gas Chromatography

Additionally, this specification aligns with globally recognized standardization principles established by the World Trade Organization Technical Barriers to Trade (TBT) Committee, supporting international trade and regulatory compliance.

Keywords: sulfur hexafluoride, SF₆, electrical insulating gas, ASTM D2472, gas quality, purity standards, high-voltage insulation, power transmission, gas chromatography, dew point measurement, noncondensable gases, international standards.

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: D2472 − 15 (Reapproved 2023)
Standard Specification for
Sulfur Hexafluoride
This standard is issued under the fixed designation D2472; 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 3. Detail Requirements
1.1 This specification applies to sulfur hexafluoride for use 3.1 Sulfur hexafluoride for use as an electrical insulation
as an electrical insulating gas. material shall conform to the requirements prescribed in Table
1.
NOTE 1—This specification is intended to apply only to gas as
purchased. However, the test methods referred to in this standard may be
4. Sampling
useful in the evaluation of in-service or used gas. Test Method D2284 may
be particularly helpful since many sulfur hexafluoride decomposition
4.1 Withdraw a sample of sulfur hexafluoride from either
products are acidic. Test Method D2284 should not be used to evaluate the
the vapor space or liquid phase of the container.
total amount of sulfur hexafluoride decomposition nor to identify con-
taminant species. This can only be done by gas chromatography and
4.2 For samples collected from the liquid phase the user
similar instrumental techniques.
must ascertain whether or not the cylinder valve is attached to
1.2 The values stated in SI units are to be regarded as
a dip tube. Sample cylinders equipped with a dip tube in an
standard. No other units of measurement are included in this upright position. Invert cylinders not equipped with a dip tube
standard.
for sampling to ensure that the sample is obtained from the
liquid phase of the cylinder.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4.3 Analyses may be performed on vapor space samples for
responsibility of the user of this standard to establish appro-
routine or preliminary testing. If the vapor phase analysis
priate safety, health, and environmental practices and deter-
indicates that impurities are not within specification, a liquid
mine the applicability of regulatory limitations prior to use.
phase sample should be obtained and analysed. The liquid
1.4 This international standard was developed in accor-
phase comprises most of the material in the container and is
dance with internationally recognized principles on standard-
more representative of the overall composition of the SF in the
ization established in the Decision on Principles for the
container. When a discrepancy exists between vapor and liquid
Development of International Standards, Guides and Recom-
phase analyses, the liquid phase analysis shall govern, unless
mendations issued by the World Trade Organization Technical
otherwise agreed to by purchaser-seller agreement.
Barriers to Trade (TBT) Committee.
5. Precautions
2. Referenced Documents
5.1 Refer to the section titled Interferences in Test Method
2.1 ASTM Standards:
D2029.
D2029 Test Methods for Water Vapor Content of Electrical
Insulating Gases by Measurement of Dew Point 6. Test Methods
D2284 Test Method for Acidit
...