Singapore Fire Safety Engineering Guidelines 2015_1.pdf

Slice files iii for slice parameter fse has to

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Slice files (iii) For slice parameter, FSE has to include slices in all three planes (x, y and z-planes). (1) At least 3 slices of X-plane & Y-plane with one cut along the centreline of the fire origin. Include additional slices at critical areas in the model. More slices may be required if a spill plume forms part of the analysis.
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30 (2) At least 2 slices of Z-plane at 1.7m (estimated human height level), and 2.5m above the finished floor level. Include additional slices at critical areas in the model. Where the mesh does not match, FSE shall provide slices at the next higher/available height (i.e. 1.8m and 2.6m). (3) For the X, Y and Z planes, the slice/snapshot shall be taken at : At 8 minutes RSET RSET with safety factor Steady state (If it is earlier than RSET with safety factor) Any other slices that SCDF or the FSE deems fit. (iv) Include the following CFD results in the FER. Heat Release Rate Visibility readings Temperature readings FED (if applicable) Visibility, temperature and FED readings should be taken at the reference height as defined under the tenability acceptance criteria. 3.5 Zone modelling Zone models can be adopted to determine ASET. However, the compartment size limits for the use of zone models shall be according to the maximum reservoir sizes stated in the Fire Code, or the size limits stipulated by the respective software user manual, whichever is lower. In projects where zone models are used to determine ASET, SCDF may still require the FSE to conduct CFD simulation. Zone modelling
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31 3.6 The list of approved zone modelling softwares are : CFAST Branzfire/B-Risk Approved modelling software
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32 CHAPTER 4 4.0 REQUIRED SAFE EGRESS TIME (RSET) Required safe egress time or RSET is the time required for escape. This is the calculated time required for occupants to travel from their location at the time of ignition of fire to a place of safety. The RSET would need to be less than the ASET, with relevant safety factors applied. RSET = (t d + t n + t pre ) + (t trav and/or t flow ) - - - - - - - - - - (4.1) where: t d = detection time from deterministic modelling t n = time from detection to notification of occupants t pre = time from notification until evacuation begins t trav = time spent moving toward a place of safety, and t flow = time spent in congestion controlled by flow characteristics 4.1 Detection time (t d ) Time interval between ignition of a fire and its detection by an automatic or manual system. The detection time shall be based on the activation of the 1 st ring of the detector system. The following methods can be used to estimate the detection time (t d ): Detection time (a) Based on CFD modelling conducted with the detectors/sprinklers above a fire using approved fire models (b) Based on Alpert’s [11] ceiling jet correlation.
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