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 test has been designed to cover horizontal smoke extraction ducts intended for single compartment applications only. This test method of part 9 is applicable only to smoke extraction ducts that do not pass through into other fire compartments. It represents fire exposure of a developing fire (pre-flashover). For smoke extraction ducts that pass through into other compartments, the method of test described in EN 13668 should be used. The smoke extraction duct is part of the smoke extraction system which also includes smoke control dampers and smoke extract fans. The method described in this test standard is complex and requires sophisticated instrumentation. It is not recommended therefore to try to test multiple assemblies in this test.