This specification covers thermal insulating bricks made from fire clay that are used as backup insulation for refractory furnace linings of boiler furnaces. The bricks shall be composed of heat-resistant materials that have been burned or fired to produce the desired density, strength, and structure. Representative bricks shall be tested, and shall conform accordingly to specified values of bulk density, modulus of rupture, and reheat change.

1.1 This specification covers two types of thermal insulating brick for industrial or marine boiler furnaces. Type I is a special, 2500 °F (1371 °C) maximum service temperature, insulating firebrick that is used as backup insulation for refractory furnace linings.2 Type II is a standard insulating brick that, in general, is used where there may be direct contact with combustion gases, such as forge and stress relieving furnaces.3

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 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.