Meaning and Purpose
5.1 This test method uses a slow heating rate to provide uniform temperature throughout the specimen. Slow heating rates are required due to low thermal conductivity of certain liquids such as paints, resins, and related products and poor convective heat transfer in products with high viscosity. Since the sample was heated at a reduced rate, a long time interval between each determination was used to re-determine the saturation concentration of steam in the air space above the sample after each flash test.

Note 1: ISO 1523 is used in the United Nations Recommendation on the Transport of Dangerous Goods and similar regulations in the International Civil Aviation Organization (ICAO) rules and the International Maritime Dangerous Goods (IMDG) Rules. Test method D3941 is similar to ISO 1523 for use in United States Department of Transportation (USDOT) regulations. The International Civil Aviation Organization and International Maritime Dangerous Goods Rules are used for the transshipment of hazardous materials to other countries through the United States.

ASTM D3941-2020 “Determination of Flash Point by Balance with Closed Cup Apparatus”

Scope of
1.1 The test method consists of the determination of the flash point of a liquid in which the sample and the air/steam mixture above it are approximately in temperature equilibrium.

1.2 This test method is limited to a temperature range of 0 to 110°C (32 to 230°F).

1.3 Values expressed in SI units shall be regarded as standards. The values given in parentheses are for reference only.

1.4 Warnings – Mercury has been designated by many regulatory agencies as a hazardous substance that may cause serious medical problems. Mercury or its vapors have been shown to be harmful to health and corrosive to materials. Be careful when handling mercury and mercury-containing products. For more information, see the applicable Product Safety Data Sheet (SDS). It is possible for local or national laws to prohibit the sale of mercury or products containing mercury, or both. Users need to determine the legality of sales in their location.

ASTM D3941-2020 “Determination of Flash Point by Balance with Closed Cup Apparatus”

1.5 This standard is used to measure and describe the reaction of materials, products or components to heat and flame under controlled conditions, but does not in itself contain all the factors required for fire hazard or fire risk assessment of materials, products or components under actual fire conditions.

1.6 This standard is not intended to address all safety issues, 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 to determine the applicability of regulatory restrictions prior to use.

1.7 This international Standard has been developed in accordance with the internationally recognized standardization principles established in the Decision on Principles for the Development of International Standards, Guidelines and Recommendations issued by the Committee on Technical Barriers to Trade of the World Trade Organization.