CCRC Evacuation

Problem Statement

Due to non-compliances to the Code of Practice for Fire Precautions in Buildings (2007) for the development, a combination of prescriptive approach and alternative solutions supported by performance-based fire engineering analysis was used. The main non-compliance for the multi-storey development is to Clause 7.6.1 for the engineered smoke control to the large auditorium and atrium spaces.


The stipulations under Clause 7.6.1 are to ensure that in the event of a fire, occupants can escape before temperature and visibility conditions become untenable. In other words, the Evacuation Time or the Required Safe Egress Time (RSET)  must be less than the Available Safe Egress Time (ASET). Awareness of available exits significantly affect RSET values. Most evacuation studies assume that the occupants have knowledge of all available exits. However, this may not be the case in reality.


The RSET predicted in the Fire Engineering Report (FER) assumes an Awareness Factor (AF) of 1 for all exits (i.e. all occupants are fully aware of all exits). To add conservativeness, the Peer Review Study conducted by C2D assumes varying AF (from 0 to 1). The AF of a remote exit is set at a lower value while that of an obvious exit is set close to 1.  The RSET predicted by the Evacuation Modelling is then compared against the ASET derived from the CFD Fire Modelling. The Fire Life Safety of the development is acceptable only if the RSET < ASET.


Varying AF increases the  RSET for the Atrium by 30%. This indicates that the awareness of exit points significantly affect efficient egress of the atrium occupants. On the other hand, the RSET for the auditorium does not change significantly (-1%). For both the Fire Engineering and Peer Review Study, the predicted RSETs are less than the predicted ASETs