Study of Combustion Characteristics of Cables inside a Common Duct by Cone Calorimeter Test

Abstract

The spacial characteristics of an underground common duct often lead to disasters resulting in great damage to life and property. In the case of a cable fire, additional damages such as failure of power and fire prevention equipment occur. Accordingly, to derive the risk factors of an underground common duct cable fire, a cone calorimeter test was performed in this study. The fire simulation factor was obtained by measuring temperature changes with time, while the heat release rate (which depends on the cable type) was determined by a combustion test of the subject. The test and measurements were conducted mainly for incombustible and general power and communication cables used in a common duct. According to the test, for a general power cable, the ignition time was measured to be 26 s with a maximum heat release rate of 187 kW/m<sup>2</sup> for 190 s. For a flame resisting power cable, the ignition time was measured to be 20 s with a maximum heat release rate of 179 kW/m<sup>2</sup> for 40 s. For a general communication cable, the ignition time was measured to be 20 s with a maximum heat release rate of 179 kW/m<sup>2</sup> for 40 s. For a flame resisting power cable, the ignition time was measured to be 40 s with a maximum heat release rate of 154 kW/m<sup>2</sup> for 100 s. The test results will be used as fire simulation factors in response to a fire originating from an underground common duct.