HH-I-523C (NOTICE-1), FEDERAL SPECIFICATION: INSULATION BLOCK AND PIPE COVERING THERMAL (CALCIUM SILICATE, FOR TEMPERATURES UP TO 1,2000 DEGREES F.) (10-JUL-1979) [REPLACED BY ASTM C 533]

HH-I-523C (NOTICE-1), FEDERAL SPECIFICATION: INSULATION BLOCK AND PIPE COVERING THERMAL (CALCIUM SILICATE, FOR TEMPERATURES UP TO 1,2000 DEGREES F.) (10-JUL-1979) [REPLACED BY ASTM C 533]., This specification covers calcium silicate block and pipe thermal insulation for use on surfaces with temperatures between 80 and 1700°F (27 to 927°C), unless otherwise agreed upon between the manufacturer and the purchaser.