Some typical specifications of Indian refractories commonly used in the furnaces and kilns in steel, cement, non-ferrous metals and glass industries are given blow. These are illustrative and do not cover the full range of products and some of the improved items which have been recently developed.

INSULATING BRICKS
CHEMICAL PROPERTIES
Al2O3(%) (Min)	96
SiO 2 (%) (Max)	1.5
Fe 2 O3(%)	0.2
PHYSICAL PROPERTIES
Hot Face Temp. (°C) (Max)	1850
B.D. (gm/cc) (Max)	1.5
C.C.S. (Kg/cm²) (Min)	60
Permanent Linear Change (Max) at 1450°C for 24 hrs.	±0.5
Thermal Conductivity (W/mk)
at Hot Face Temp. 800°C	1.22
at Hot Face Temp. 1000°C	1.33
at Hot Face Temp. 1200°C	1.50

HIGH TEMPERATURE INSULATING BRICKS
CHEMICAL PROPERTIES
Al2O3(%) (Min)	60	70	85	90
Fe 2 O3 (%) (Max)	1.0	0.7	0.7	0.6
PHYSICAL PROPERTIES
Service Temperature (°C)	1550	1650	1750	1800
B.D. (gm/cc) (Max)	1.1	1.2	1.4	1.5
C.C.S. (Kg/cm²)	50	50	50	70
PCE (Orton) (Min)	37	37	38	38
PLC (%)
at 1550°C for 5 hrs.	+0.8/-0.2
at 1600°C for 5 hrs.		+1.0/-0.2
at 1650°C for 5 hrs.			+1.0/-0.2	+0.8/-0.2
Thermal Conductivity (Kcal/M/hr/°C)  (Max) at 800°C HF	0.4	0.42	0.6	0.7