MIL-DTL-15606J

Abstract

This specification covers refractory brick and burner tile and lining for Naval boiler furnaces.<b><u>Intended Use:</u></b> Refractory bricks and burner tile covered by this specification are intended for use in industrial and naval main propulsion boilers. Brickwork in naval main propulsion boilers is subjected to rapid change in temperature during frequent light-off and securing cycles that will cause thermal spalling. The purpose of the refractory bricks and burner tile is to provide structural stability and protection of back-up insulation from maximum temperatures, flame erosion, slag attack, and rapid temperature changes. Grade A firebrick is more heat resistant than Grade B. However, Grade A will not be superior to Grade B in all applications. Factors adversely affecting Grade A are slightly greater thermal expansion and thermal conductivity, and less spall resistance. The major advantage of Grade B is that under slag attack a gradual wearing away results, as opposed to significant sudden losses of up to &#189; inch that can occur using Grade A or AA brick. The use of distillate fuels has eliminated this advantage of Grade B. Grade AA is intended as an upgrade for Grade A when high furnace temperatures require better refractory (heat resistant) properties than Grade A. NAVSEA approved refractory arrangement drawings should be used to determine firebrick grades for various boiler locations.<br>