## 4 Conclusions  
This study was conducted as part of a project to develop a program for fire safety managers to establish evacuation plans in the event of a fire outbreak in a building. A program with low computational costs and the ability to integrate fire evacuation simulations in real time was required, prompting the use of CFAST. The objective was to compare the prediction accuracies of FDS and CFAST for the smoke and heat detector activation times, which are crucial factors applied as key parameters for determining the RSET in the fire risk assessment of buildings. The major results of this study are as follows.  
To improve the prediction performance of smoke and heat detectors using CFAST, the results were compared and reviewed with FDS results for the same computational domain. A limitation of CFAST is that in multiple computational domains, the flow velocity is fixed depending on the presence or absence of a fire source in the same space. Therefore, if the area of interest is separated from the fire room, even if the area is very close to the source, the flow rate is fixed at 0.1 m/s. In addition, FDS and CFAST use different methods to predict the temperature and smoke concentrations.  
The smoke concentration required by the smoke detector can be set such that mass moves between each adjacent compartment, provided the computational domain is appropriately partitioned with the fire room, due to CFAST's application of mass and energy conservation. In addition, because the temperature and flow rate are not considered in the smoke concentration calculation, partitioning the calculation area without a fixed flow rate can improve the prediction of the appropriate smoke detector activation time.  
The empirical correlation for predicting the activation times of heat detectors was observed to be significantly influenced by the velocity. Therefore, particular attention should be paid to the partitioning between the fire source and the areas of interest, as a constant velocity is applied according to the presence of a fire within the designated computational region. Additionally, when the fire source is in the same compartment, the velocity is determined using an empirical correlation that considers both the distance from the fire and the height of the calculation region, producing results that are similar to those of FDS.  
Based on these results, it can be suggested that CFAST, requiring significantly lower computational costs than FDS, can estimate the activation times for smoke and heat detectors. In addition, our results expected that the information can be utilized to identify trends in fire engineering technology and fire dynamics in general.  
Conceptualization, C.-H.H.; methodology, H.-Y.J. and C.-H.H.; validation, H.-Y.J. and C.-H.H.; formal analysis, C.-H.H.; investigation, H.-Y.J. and C.-H.H.; resources, C.-H.H.; data curation, H.-Y.J.; writing--original draft preparation, H.-Y.J.; writing--review and editing, C.-H.H.; visualization, H.-Y.J.; supervision, C.-H.H.; project administration, C.-H.H.; funding acquisition, C.-H.H. All authors have read and agreed to the published version of the manuscript.  
This paper was supported by the \"National Fire Agency\" R&D program (20016433).  
Not applicable.  
The data presented in this study are available on request from the corresponding author. The data are not publicly available due to restrictions on privacy.  
The authors declare no conflict of interest.