This part of EN 1366 specifies a test method for determining the fire resistance of smoke extraction ducts that are used for single compartment applications only. In such applications, the smoke extraction system is only intended to function up to flashover (typically 600 °C). This method of test is only suitable for ducts constructed from non-combustible materials (euro class A1 and A2-s1, d0). It is applicable only to four sided and circular ducts. One-, two- and three-sided ducts are not covered. This standard is applicable only for the standard sizes or smaller as described. This test method of part 9 is applicable only to smoke extraction ducts that do not pass into other fire compartments. For smoke extraction ducts that pass into other compartments, the method of test described in EN 1366-8 is used. The smoke extraction duct is part of the smoke extraction system which also includes smoke control dampers and smoke extract fans.