Introducing fire flow modelling and analysis

Step-by-step Guide

InfoWorks WS Pro is capable of modelling fire flow.

• Integral part of water supply modelling
• Used during preliminary design to ensure adequate flow and pressure
• For firefighting compliance to ensure hydrants can supply enough water and pressure during emergencies.
• Help model calibration, during which fire flows and residual pressures can be simulated and compared with field data.

There are three types of fire flow simulation: Fire Flow Availability, Hydrant Testing, and Forced Fire Flow.

The Fire Flow Availability simulation determines the fire flow availability from:

• required fire flow specifications
• local nodal pressure (calculated as in a normal run)
• assumed hydrant characteristics.

It then checks the ability of each hydrant in turn to meet the defined fire flow requirements. Each hydrant is considered independently, as if no other hydrant in the system is open.

Fire Flow Availability results are calculated using the orifice equation. These results can be used to show the ability of individual hydrants to sustain additional levels of demand for firefighting or other similar purposes.

Note: Fire flow is not applied to the network; therefore, the effect of increased flows on the network is not considered.

Note: You may need to carry out more than one fire flow availability simulation in order to analyze and check that availability reaches the required standard throughout the network.

Fire Flow Availability simulation results include:

• FFA Flow – the maintained fire flow
• FFA Residual Pressure – the residual pressure after the fire flow is considered.

These additional results can be viewed via the Node Results Grid, as well as in individual node graphs and grids.