ASTM D8211-21

Standard Test Method for Hot Surface Ignition Temperature of Gases on Flat Surface

SIGNIFICANCE AND USE
5.1 The autoignition temperature (AIT) of a gas mixture is the minimum temperature at which a gas mixture spontaneously ignites without an external ignition source. AIT is typically determined at atmospheric pressure, using small test vessels open to the atmosphere where gas is quickly injected into the test vessel and heated for a pre-determined time observing ignition or non-ignition (Test Method E659). AIT is often not directly applicable to real world conditions. Therefore, there is need for a test that determines if a gas or liquefied gas ignites or does not ignite when released onto a hot surface in a more unconstrained environment.
SCOPE
1.1 This test method covers a means for the discrimination between gases, which will ignite or not ignite when impinged on a hot surface when that surface is heated to 800 °C (1472 °F) or greater for a period of 2 min in a non-confined environment.  
1.2 This test method may be applied to any non-pyrophoric substance that is a gas or liquefied gas, particularly GHS category 1B gases, at ambient temperature and pressure.  
1.3 This test method should be used subject to the limitations that no single fire hazard property such as flash point, auto-ignition temperature (AIT), or the performance under the conditions of the present method shall be used to describe or appraise the fire hazard or fire risk of a material, product, assembly, or system under actual fire conditions. Fire hazard properties measured under controlled laboratory conditions may nevertheless be employed to describe properly the response of materials, products, assemblies, or systems under said controlled conditions. Properties measured under controlled laboratory conditions may be used as elements of hazard or risk assessment only when such assessments takes into account all of the factors that are pertinent to the evolution of the fire hazard of a given situation.  
1.4 This standard is used to provide a quantitative measure of a gas’s or liquefied gas’s realistic surface ignition temperature in a non-quiescent environment.  
1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.6 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. For specific hazard statements, see Section 9.  
1.7 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-Apr-2021
• ICS: 13.220.40 - Ignitability and burning behaviour of materials and products
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.L0.07 - Engineering Sciences of High Performance Fluids and Solids (Formally D02.1100)

Relations

• Refers: ASTM D4175-23a - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 15-Dec-2023
• Refers: ASTM D4175-23e1 - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Jul-2023
• Refers: ASTM E659-14 - Standard Test Method for Autoignition Temperature of Liquid Chemicals
• Effective Date: 01-Feb-2014
• Refers: ASTM E659-13 - Standard Test Method for Autoignition Temperature of Liquid Chemicals
• Effective Date: 15-Oct-2013
• Refers: ASTM E659-78(2000) - Standard Test Method for Autoignition Temperature of Liquid Chemicals
• Effective Date: 01-Jan-2000
• Refers: ASTM E659-78(1994)e1 - Standard Test Method for Autoignition Temperature of Liquid Chemicals
• Effective Date: 01-Jan-2000

Overview

ASTM D8211-21: Standard Test Method for Hot Surface Ignition Temperature of Gases on Flat Surface establishes a laboratory procedure to determine the hot surface ignition temperature (HSIT) for gases and liquefied gases. This test method is essential for evaluating whether substances ignite when exposed to a hot, flat surface in an unconfined environment, simulating more realistic conditions than traditional autoignition temperature (AIT) tests. The standard supports fire safety risk assessments in industries handling flammable gases by providing quantitative information on the realistic ignition potential of gases and liquefied gases, especially under conditions similar to accidental releases or equipment failures.

Key Topics

• Hot Surface Ignition Temperature (HSIT): The lowest temperature at which a gas or liquefied gas will ignite in air when impinged on a hot surface, without external ignition sources.
• Unconfined Test Environment: Unlike traditional methods that confine test substances, ASTM D8211-21 assesses ignition on a heated surface in a non-quiescent, unconfined environment, reflecting real-world situations.
• Test Apparatus and Procedure:
  • Use of a heated planchet (stainless steel disc) at 800°C or higher.
  • Controlled release of the test substance onto the hot surface under ambient pressure and temperature.
  • Observation for ignition within 2 minutes post-release, using a camera for accurate monitoring.
• Applicability:
  • Suitable for any non-pyrophoric gas or liquefied gas, particularly those classified as GHS category 1B gases.
• Risk Assessment Considerations:
  • HSIT measured under laboratory conditions must be considered as one element of a comprehensive fire hazard or fire risk assessment.
  • Fire hazard properties should not be used in isolation to appraise risk under actual conditions.

Applications

ASTM D8211-21 is widely used in sectors where the management and handling of flammable or potentially explosive gases are critical. Its main practical applications include:

• Safety Engineering:
  • Identification and evaluation of hot surface ignition hazards in chemical plants, refineries, laboratories, and manufacturing environments.
  • Assessment of equipment or process design to minimize the risk of fire due to accidental hot surface contact.
• Regulatory Compliance:
  • Assists organizations in meeting safety regulations and standards for storing and using flammable gases.
• Material and Substance Screening:
  • Used to classify gases or liquefied gases based on their surface ignition risk before large-scale handling, storage, or transport.
• Incident Investigation:
  • Offers a standardized approach to understanding ignition sources in fire or explosion investigations involving gases.

Related Standards

For comprehensive hazard and risk evaluation, ASTM D8211-21 should be considered alongside the following relevant standards:

• ASTM E659: Standard Test Method for Autoignition Temperature of Chemicals. Often used as a reference for traditional AIT determination.
• ASTM D4175: Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants. Provides definitions for terms relevant to fire safety and flammability testing.
• GHS Category 1B Classification: Refers to the Globally Harmonized System for classifying flammable gases based on ignition properties.

By adhering to ASTM D8211-21, organizations can enhance their fire safety protocols, ensure compliance with industry regulations, and support safety-by-design initiatives in the handling of potentially hazardous gases.

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: D8211 − 21
Standard Test Method for
Hot Surface Ignition Temperature of Gases on Flat Surface
This standard is issued under the fixed designation D8211; 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* 1.7 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This test method covers a means for the discrimination
ization established in the Decision on Principles for the
between gases, which will ignite or not ignite when impinged
Development of International Standards, Guides and Recom-
on a hot surface when that surface is heated to 800 °C
mendations issued by the World Trade Organization Technical
(1472 °F) or greater for a period of 2 min in a non-confined
Barriers to Trade (TBT) Committee.
environment.
1.2 This test method may be applied to any non-pyrophoric 2. Referenced Documents
substance that is a gas or liquefied gas, particularly GHS
2.1 ASTM Standards:
category 1B gases, at ambient temperature and pressure.
D4175 Terminology Relating to Petroleum Products, Liquid
1.3 This test method should be used subject to the limita-
Fuels, and Lubricants
tions that no single fire hazard property such as flash point, E659 Test Method for Autoignition Temperature of Chemi-
auto-ignition temperature (AIT), or the performance under the
cals
conditions of the present method shall be used to describe or
3. Terminology
appraise the fire hazard or fire risk of a material, product,
assembly, or system under actual fire conditions. Fire hazard
3.1 Definitions:
properties measured under controlled laboratory conditions
3.1.1 For definitions of terms used in this method, refer to
may nevertheless be employed to describe properly the re-
Terminology D4175.
sponse of materials, products, assemblies, or systems under
3.2 Definitions of Terms Specific to This Standard:
said controlled conditions. Properties measured under con-
3.2.1 auto ignition temperature (AIT), n—the lowest tem-
trolled laboratory conditions may be used as elements of
perature at which a substance spontaneously ignites in normal
hazard or risk assessment only when such assessments takes
atmosphere without an external source of ignition.
into account all of the factors that are pertinent to the evolution
3.2.2 camera, n—capableofrecordingatleast30framesper
of the fire hazard of a given situation.
second.
1.4 This standard is used to provide a quantitative measure
3.2.3 chimney, n—a quartz cylinder tube with the following
of a gas’s or liquefied gas’s realistic surface ignition tempera-
dimensions: length: 229 mm 6 10 mm (9.02 in. 6 0.39 in.);
ture in a non-quiescent environment.
inner dimension: 70 mm 6 5 mm (2.76 in. 6 0.2 in.).
1.5 The values stated in SI units are to be regarded as
3.2.4 environmental chamber, n—a chamber capable of
standard. The values given in parentheses after SI units are
providing a draft-free environment during testing and able to
provided for information only and are not considered standard.
provide ventilation after testing is completed; the chamber
needs to be able to completely remove the test substance and
1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the any potential substance decomposition products after testing
has completed.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
3.2.5 gap height, n—the height of the chimney above the
mine the applicability of regulatory limitations prior to use.
insulation and planchet shall be 4 mm.
For specific hazard statements, see Section 9.
3.2.6 heating element, n—a unit that is capable of heating a
surface in contact with the planchet up to temperatures of at
least 800 °C (1472 °F) up to 1000 °C (1832 °F).
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.L0.07 on Engineering Sciences of High Performance Fluids and
Solids (Formally D02.1100). For referenced ASTM standards, visit the ASTM website, www.astm.org, or
CurrenteditionapprovedMay1,2021.PublishedJuly2021.Originallyapproved contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
in 2018. Last previous edition approved in 2018 as D8211 – 18. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
D8211-21. 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
D8211 − 21
3.2.7 hotsurfaceignitiontemperature(HSIT),n—thelowest ing the test equipment should be quiescent with the exception
temperature at which a substance ignites in normal atmosphere of the convection effect from the planchet.
when impinged upon a heated surface.
4.2 Ignitions are observed during the initial surface im-
3.2.8 ignition, n—for the purposes of this test method,
pingement of the substance and during the 2 min following
ignition shall be defined as any visible flame on or directly
release of the substance in the event any ignition occurs post
above the planchet, including the length of the chimney,
impingement.
generated either initially or up to 2 min after the substance is
5. Significance and Use
impinged on the planchet.
5.1 The autoignition temperature (AIT) of a gas mixture is
3.2.8.1 Discussion—If no flames are visible within the
the minimum temperature at which a gas mixture spontane-
2 min span, the test shall be deemed to have no ignition at the
ously ignites without an external ignition source. AIT is
temperature tested. Any visible flame outside of the testing
typically determined at atmospheric pressure, using small test
chimney shall not be deemed an ignition but shall require a
vessels open to the atmosphere where gas is quickly injected
retest at the same conditions until a definitive ignition/non-
into the test vessel and heated for a pre-determined time
ignition is determined.
observing ignition or non-ignition (Test Method E659). AIT is
3.2.9 insulation, n—ceramic non-RCF insulation board with
3 3
often not directly applicable to real world conditions.
a minimum density of 0.3665 g⁄cm (0.01324 lb⁄in. ).
Therefore, there is need for a test that determines if a gas or
3.2.9.1 Discussion—Insulation board shall have a minimum
liquefiedgasignitesordoesnotignitewhenreleasedontoahot
thickness of 8 mm 6 0.5 mm (0.315 in. 6 0.02 in.) with a hole
surface in a more unconstrained environment.
cut out in the center to allow room for the planchet. The
planchet should fit tight within the opening, but should also fit 6. Interferences
suchthatallportionsofthebottomoftheplanchetevenlymake
6.1 Air Velocity—External air movement in the vicinity of
contact with the heating element.
the planchet can skew the results.
3.2.10 lower flammability limit (LFL), n—the minimum
6.2 Planchet Fouling—The planchet can be fouled such that
concentration in air of a substance that is capable of propagat-
there are highs and lows on the surface from repeated refrig-
ing a flame through a homogenous mixture of the substance
erant releases which can create localized hot spots on the
and air under specified test conditions.
surface, which can skew the results. If the operator feels
3.2.11 planchet, n—a flat 316 stainless steel tapered disc
excessive fouling may be affecting test results, the planchet
having a top section diameter of: 50.8 mm 6 1.0 mm (2 in. 6
may be cleaned by running 60 to 100 grit sandpaper, or another
0.039 in.) and a height of 8.0 mm 6 0.5 mm (0.315 in. 6
fine coarse media, over the surface of the planchet until all
0.02 in.).
fouling is removed.
3.2.11.1 Discussion—The bottom section has a diameter of:
7. Apparatus
63.5 mm 6 1.0 mm (2.5 in. 6 0.039 in.), with a height of
4.7 mm 6 0.5 mm (0.19 in. 6 0.02 in.).
7.1 A diagram of the test apparatus is shown in Fig. 1.
3.2.12 scale, n—method of weighing amount of substance
7.2 Testing is to be performed in a standard laboratory fume
that is released onto the hot surface.
hood or environmental chamber that has ventilation capability.
3.2.13 spray nozzle, n—a 0.3175 cm (0.125 in.) stainless
Since testing is performed without ventilation, the chamber
steel cylindrical tubing with an opening at the release end.
needs to be able to deactivate ventilation during testing.
7.3 The heated surface providing temperature to the
3.2.13.1 Discussion—The tip of the spray nozzle shall have
planchet is generically described in this standard to allow the
a 45° angle. The tubing shall be 152 mm 6 5 mm (5.98 in. 6
researcher flexibility in design options. The heated surface
0.2 in.) in length. T
...

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: D8211 − 18 D8211 − 21
Standard Test Method for
Hot Surface Ignition Temperature of Gases on Flat Surface
This standard is issued under the fixed designation D8211; 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 Scope*
1.1 This test method covers a means for the discrimination between gases, which will ignite or not ignite when impinged on a hot
surface when that surface is heated to 800 °C 6 5 °C (1472 °F)(1472 °F) or greater for a period of 2 min in a non-confined
environment.
1.2 This test method may be applied to any non-pyrophoric substance that is a gas or liquefied gas gas, particularly GHS category
1B gases, at ambient temperature and pressure.
1.3 This test method should be used subject to the limitations that no single fire hazard property such as flash point, auto-ignition
temperature (AIT), or the performance under the conditions of the present method shall be used to describe or appraise the fire
hazard or fire risk of a material, product, assembly, or system under actual fire conditions. Fire hazard properties measured under
controlled laboratory conditions may nevertheless be employed to describe properly the response of materials, products,
assemblies, or systems under said controlled conditions. Properties measured under controlled laboratory conditions may be used
as elements of hazard or risk assessment only when such assessments takes into account all of the factors that are pertinent to the
evolution of the fire hazard of a given situation.
1.4 This standard is used to provide a quantitative measure of a gas’s or liquefied gas’s realistic surface ignition temperature in
a non-quiescent environment.
1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for
information only and are not considered standard.
1.6 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. For specific hazard statements, see Section 9.
1.7 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:
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.L0.07 on Engineering Sciences of High Performance Fluids and Solids (Formally D02.1100).
Current edition approved July 1, 2018May 1, 2021. Published August 2018July 2021. Originally approved in 2018. Last previous edition approved in 2018 as D8211 – 18.
DOI: 10.1520/D8211-18.10.1520/D8211-21.
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.
*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
D8211 − 21
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
E659 Test Method for Autoignition Temperature of Chemicals
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this method, refer to Terminology D4175.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 auto ignition temperature (AIT), n—the lowest temperature at which a substance spontaneously ignites in normal atmosphere
without an external source of ignition.
3.2.2 camera, n—capable of recording at least 30 frames per second.
3.2.3 chimney, n—a quartz cylinder tube with the following dimensions: length: 229 mm 6 10 mm (9.02 in. 6 0.39 in.); inner
dimension: 70 mm 6 5 mm (2.76 in. 6 0.2 in.).
3.2.4 environmental chamber, n—a chamber capable of providing a draft-free environment during testing and able to provide
ventilation after testing is completed; the chamber needs to be able to completely remove the test substance and any potential
substance decomposition products after testing has completed.
3.2.5 gap height, n—the height of the chimney above the insulation and planchet shall be 4 mm.
3.2.6 heating element, n—a unit that is capable of heating a surface in contact with the planchet up to temperatures of at least
800 °C 6 5 °C (1472 °F).(1472 °F) up to 1000 °C (1832 °F).
3.2.7 hot surface ignition temperature (HSIT), n—the lowest temperature at which a substance ignites in normal atmosphere when
impinged upon a heated surface.
3.2.8 ignition, n—for the purposes of this test method, ignition shall be defined as any visible flame on or directly above the
planchet, including the length of the chimney, generated either initially or up to 2 min after the substance is impinged on the
planchet.
3.2.8.1 Discussion—
If no flames are visible within the 2 min span, the test shall be deemed to have no ignition at the temperature tested. Any visible
flame outside of the testing chimney shall not be deemed an ignition but shall require a retest at the same conditions until a
definitive ignition/non-ignition is determined.
3 3
3.2.9 insulation, n—ceramic non-RCF insulation board with a minimum density of 0.3665 g ⁄cm (0.01324 lb ⁄in. ).
3.2.9.1 Discussion—
Insulation board shall have a minimum thickness of 8 mm 6 0.5 mm (0.315 in. 6 0.02 in.) with a hole cut out in the center to allow
room for the planchet. The planchet should fit tight within the opening, but should also fit such that all portions of the bottom of
the planchet evenly make contact with the heating element.
3.2.10 lower flammability limit (LFL), n—the minimum concentration in air of a substance that is capable of propagating a flame
through a homogenous mixture of the substance and air under specified test conditions.
3.2.11 planchet, n—a flat 316 stainless steel tapered disc having a top section diameter of: 50.8 mm 6 1.0 mm (2 in. 6 0.039 in.)
and a height of 8.0 mm 6 0.5 mm (0.315 in. 6 0.02 in.).
3.2.11.1 Discussion—
The bottom section has a diameter of: 63.5 mm 6 1.0 mm (2.5 in. 6 0.039 in.), with a height of 4.7 mm 6 0.5 mm (0.19 in. 6
0.02 in.).
3.2.12 scale, n—method of weighing amount of substance that is released onto the hot surface.
3.2.13 spray nozzle, n—a 0.3175 cm (0.125 in.) stainless steel cylindrical tubing with an opening at the release end.
D8211 − 21
3.2.13.1 Discussion—
The tip of the spray nozzle shall have a 45° angle. The tubing shall be 152 mm 6 5 mm (5.98 in. 6 0.2 in.) in length. The outside
diameter of the tubing shall be 3.2 mm 6 0.2 mm (0.125 in. 6 0.007 in.) with in inside diameter of 1.6 mm 6 0.1 mm (0.06 in.
6 0.003 in.).
3.2.14 substance, n—any gas or liquefied gas at ambient pressure and temperature being tested in this standard.
3.2.15 thermocouple, n—two K type thermocouples are connected to the hot plate to record the surface temperature.
3.2.16 upper flammability limit (UFL), n—the maximum concentration in air of a substance that is capable of propagating a flame
through a homogenous mixture of the substance and air under specified test conditions.
4. Summary of Test Method
4.1 With no external ventilation or fan operating, 5 g of the substance is released from the spray nozzle onto a planchet heated
to 800 °C 6 5 °C. The environmental chamber containing the test equipment should be quiescent with the exception of the
convection effect from the planchet.
4.2 Ignitions are observed during the initial surface impingement of the substance and during the 2 min following release of the
substance in the event any ignition occurs post impingement.
5. Significance and Use
5.1 The autoignition temperature (AIT) of a gas mixture is the minimum temperature at which a gas mixture spontaneously ignites
without an external ignition source. AIT is typically determined at atmospheric pressure, using small test vessels open to the
atmosphere where gas is quickly injected into the test vessel and heated for a pre-determined time observing ignition or
non-ignition (Test Method E659). AIT is often not directly applicable to real world conditions. Therefore, there is need for a test
that determines if a gas or liquefied gas ignites or does not ignite when released onto a hot surface in a more unconstrained
environment.
6. Interferences
6.1 Air Velocity—External air movement in the vicinity of the planchet can skew the results.
6.2 Planchet Fouling—The planchet can be fouled such that there are highs and lows on the surface from repeated refri
...