Maze Fire personnel have extensive experience of the use of both zone and field models for smoke flow within buildings. We utilise a number of in-house and third-party computer programs that assist in both types of analysis.
Zone Models – Zone models are based on experimental data and give simple relationships between the amounts of smoke generated in certain smoke flow scenarios. Within their field of application zone models give very accurate results of smoke flow rates. However, as they are based on experimental data, they can only be used for situations where the layout is similar to that used in the experiments. Nonetheless they may remain suitable for informing the development of more detailed models at an early stage of design.
Field Models – Field models are commonly referred to as computational fluid dynamics (CFD). These models break the space to be analysed into a large number of blocks and uses the fundamental equations of fluid and energy dynamics to model smoke flow within a space. As such they are not limited to any particular physical layout and so are more flexible than zone models. However, they can be computationally intensive. For cases where zone models are inappropriate, Maze Fire Consulting use a CFD program (Fire Dynamics Simulator – FDS) developed by the National Institute of Science and Technology (NIST) in the USA. This is a highly flexible model that can be used.
To enhance development of such models Maze Fire Consulting also use the PyroSim program developed by Thunderhead Engineering. PyroSim allows CAD imports and advanced simulation management in order to automatically generate the text-only FDS input file. It streamlines the model build and can produce detailed 3D model graphics depicting results.