3.1 This classification establishes an orderly grouping of insulating firebrick to provide group identifications for use by those producing or purchasing these materials. The group identification number is not meant to specifically designate the maximum service temperature, although the number times 100 does approximate the temperature (in degrees Fahrenheit) to be used to check the reheat change and can be used as a guide for relative temperature stability. The bulk density limits the weight per unit volume for any group as sold, but is not meant to be used for detailed engineering calculations.

1.1 This classification covers heat-insulating material known as insulating firebrick. This material is suitable for lining certain kinds of industrial furnaces.

Note 1: Insulating materials for use below 1000 °F (538 °C) are covered2 by ASTM Committee C16 on Thermal Insulation.

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 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.