SR195 Smoke filling in large spaces using BRANZFIRE (2018)

This study provides guidance to fire engineers, design reviewers and regulators regarding the limitations and appropriateness of using a two-zone fire model to simulate smoke development in large spaces.

Smoke filling of seven enclosures ranging in area from 625–5,000 square metres and height 6–12 m was simulated using the zone model BRANZFIRE and the computational fluid dynamics model FDS and the results were compared. For the cases examined, it was found that the BRANZFIRE zone model provides good agreement with FDS for room areas up to about 1,200 sqm.

Multicell (virtual room) simulations were also investigated using the zone model and were found to provide more realistic representation of the smoke layer position compared to a zone model single room simulation. However, average gas temperatures may be overestimated close to the fire plume and underestimated far from the plume.

It was recommended that, for larger enclosures up to 5,000 sqm, additional simulations and sensitivity analysis should be conducted subdividing the enclosure into virtual rooms as well as a single zone simulation.