## 5 Conclusions  
The literature review suggests that it is necessary to adopt both technical and human organizational errors for realistic risk assessment of building design from a practical viewpoint. Furthermore, during the operational phase of the building, it is not reasonable to assume that the reliability of the fire equipment remains constant and its aging over time will need to be considered to derive more realistic risk assessment values. To address the literature gaps and follow the suggestions made by researchers in their studies, we developed a Technical-Human-Organizational Risk (T-H-O-Risk) methodology in [12]. In this paper, our aim is to employ T-H-O-Risk methodology of [12] to seven buildings in various geographical locations with different climatic conditions to assess and compare HOE risks due to fires in high-rise residential buildings. Particular focus is given to active fire safety systems in high-rise residential buildings by comparing the impact of HOEs on individual and/or combinations of active fire safety systems. This study breaks down the impact of HOEs on sprinklers, building occupant warning systems (BOWS), smoke detectors, and smoke control systems. For each of seven buildings (cases), 16 trial designs are considered. The building risk levels are compared to each other and against the absolute benchmark criteria to determine if they exceed the acceptable risk threshold. It is hypothesized that the ERL for each building design has different human and organizational scenarios based on either no HOEs or with HOEs-where organizational standards such as maintenance, safety culture, and emergency planning are determined to be low and human errors occur routinely. The quantification of difference in ERL for seven buildings for each of 16 trial designs is a novel aspect of this study. The T-H-O-Risk model addresses the methodological gap in quantifying technical, human, and organizational risks and uncertainties in PRAs of high-rise residential buildings. To keep the study focused, we selected buildings in geographical locations with representative non-extreme climatic conditions of temperate, sub-tropical, and tropical zones and while we applied the BCA as the reference code for all seven cases, the T-H-O-Risk methodology can be applied to any other jurisdictions. The methodology incorporates HOEs by utilizing BN, while employing SD modelling to account for risk variations over time. Results are presented using multiple F-N curves encompassing ALARP criteria. Key outcomes are:  
* The influence of HOEs increases with the complexity of the system. The increase in ERL can reach 33% in a design with the full set of safety provisions while the simpler designs with only the sprinkler system have a +20% increase in the ERL. * HOEs have a significant risk impact on active safety systems with combinations of sprinklers. BOWS, smoke detectors, and smoke control systems. HOEs have limited or no impact on passive protection systems. Active systems require regular maintenance which increase the likelihood of human and organizational errors and increase in corresponding risk. * Strong positive correlation exists between the ratio HOE/ERL with the number of active systems. With one active system, the HOE values range from 8-13% and increased to 25-38% when all four active systems are present in the trial design. * For active systems, ERL values obtained from this study matches reasonably well with those obtained from the literature. * For all cases, trial design 1 which consists of all active systems results in the lowest ERL, but this design is also most influenced by HOEs. * Tenability conditions remain infinite for corridors having natural ventilation. * Case #7 has the highest overall risk on account of the sole stairwell and low tenability due to the corridors filling up with smoke rapidly. * The F-N curve with HOE is at a higher level than without HOE case indicating that risks increased with HOEs.