. The coal-burning boiler manufactured by this company is designed and manufactured according to the Iranian national standard ISIRI 4231 and the international standard BS 2790. . The steels used in pressure parts are 17MN4 (DIN 17155) or A516-G70 (ASTM). . All used tubes are ST35.8 (DIN 17175) or A 106-GB (ASTM). . All welding lines under pressure according to national and international standards are subjected to non-destructive testing by the representatives of the standards department, which include: radiography RT, ultrasonic UT, penetrative materials MT and finally hydrostatic testing with a pressure of 1.5 times the design pressure.