The heat detector is located on the ceiling at a
distance of 1m to the centreline of fire plume, other parameters are shown in Table 1. By varying the ceiling height H from
3m to 4m, the detection time of heat detector are calculated respectively by the proposed model and the existing model without
considering the confined situations. The results are shown in Fig.2(a). It can be seen that the detection time of the proposed model
is more than that of the existing model for anyone of given scenarios. Furthermore, the detection times of these two models
show a good linear relationship with H.