ASTM-E681:2004 Edition

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E681-04 Standard Test Method for Concentration Limits of Flammability of Chemicals (Vapors and Gases)

Published By	Publication Date	Number of Pages
ASTM	2004	12

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Description

ASTM E681-04

Historical Standard: Standard Test Method for Concentration Limits of Flammability of Chemicals (Vapors and Gases)

ASTM E681

Scope

1.1 This test method covers the determination of the lower and upper concentration limits of flammability of chemicals having sufficient vapor pressure to form flammable mixtures in air at atmospheric pressure at the test temperature. This test method may be used to determine these limits in the presence of inert dilution gases. No oxidant stronger than air should be used.

Note 1—The lower flammability limit and upper flammability limit are also referred to as the lower explosive limit (LEL) and the upper explosive limit (UEL), respectively.

1.2 This test method is based on electrical ignition and visual observations of flame propagation. Users may experience problems if the flames are difficult to observe (for example, irregular propagation or insufficient luminescence in the visible spectrum), if the test material requires large ignition energy, or if the material has large quenching distances.

1.3 provides a modified test method for materials (such as certain amines, halogenated materials, and the like) with large quenching distances which may be difficult to ignite.

1.4 In other situations where strong ignition sources (such as direct flame ignition) is considered credible, the use of a test method employing higher energy ignition source in a sufficiently large pressure chamber (analogous, for example, to the methods in Test Method E 2079 for measuring limiting oxygen concentration) may be more appropriate. In this case, expert advice may be necessary.

1.5 The flammability limits depend on the test temperature and pressure. This test method is limited to an initial pressure of the local ambient or less, with a practical lower pressure limit of approximately 13 kPa (100 mm Hg). The maximum practical operating temperature of this equipment is approximately 150°C (302°F).

1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information only.

1.7 This test method should be used to measure and describe the properties of materials, products, or assemblies in response to heat and flame under controlled laboratory conditions and should not be used to describe or appraise the fire hazard or fire risk of materials, products, or assemblies under actual fire conditions. However, results of this test method may be used as elements of a fire risk assessment that takes into account all of the factors pertinent to an assessment of the fire hazard of a particular end use.

1.8 This standard may involve hazardous materials, operations, and equipment. 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 and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8.

Keywords

flammability; chemicals; vapors; gases

ICS Code

ICS Number Code 13.300 (Protection against dangerous goods)

DOI: 10.1520/E0681-04

PDF Catalog

PDF Pages	PDF Title
1	Scope Referenced Documents Terminology
2	Summary of Test Method Significance and Use Interferences Apparatus Safety Precautions
3	Calibration Procedure FIG. 1
4	FIG. 2
5	Calculation
6	Report Precision and Bias A1. TEST METHOD FOR MATERIALS WITH LARGE QUENCHING DISTANCES, WHICH MAY BE DIFFICULT TO IGNITE A1.1 Scope A1.2 Terminology
7	A1.3 Precision and Bias FIG. A1.1 FIG. A1.2
8	FIG. A1.3 FIG. A1.4
9	X1. DIMENSIONS AND SPECIFICATIONS OF APPARATUS IN FIG. 1 X1.1 Test Vessel X1.2 Insulated Chamber X1.3 Heater X1.4 Ignition Device X1.5 Stirring Devices X1.6 Test Vessel Cover
10	X2. ESTIMATION OF LOWER FLAMMABLE LIMITS FOR THE PURPOSE OF SELECTING SAMPLE SIZE FOR INITIAL TESTS X2.1 X2.2 X2.3 X2.4 X2.5 X2.6 X2.7
11	X3. ESTIMATION OF UPPER FLAMMABLE LIMITS FOR THE PURPOSE OF SELECTING SAMPLE SIZE FOR INITIAL TESTS X3.1 X3.2 X4. CORRELATION OF KNOWN UPPER AND LOWER FLAMMABLE LIMITS WITH STOICHIOMETRIC COMPOSITION X4.1 X5. CALCULATION OF FLAMMABLE LIMITS FROM TEST DATA X5.1 Basis of X5.2 Sample Calculation

Additional information

Standard Title	E681-04 Standard Test Method for Concentration Limits of Flammability of Chemicals (Vapors and Gases)
Published Code	ASTM
Publication Date	2004
Pages Count	12