This specification covers dry air-setting refractory mortar for use in laying and bonding refractory brick in ship boiler furnaces and wet air-setting refractory mortar for use in laying refractory brick in stationary boiler furnaces, bright annealing furnaces, controlled atmosphere furnaces, and furnaces heated by electric elements. The values stated in inch-pound units are to be regarded as standard. The SI units in parentheses are for information purposes only and may be approximate. 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.