Fireflow

From the Run Manager Dialog Box, use the Fireflow Tab to conduct FireFlow Modeling Analysis. The Fireflow modeling process is a batch analysis of either all nodes with a fireflow demand assigned or all nodes within a domain with a fireflow demand assigned. The basic fire-flow analysis is a two-step process and it will automatically assign the fire-flow demand to each junction and solve for the residual pressure. Then it will set the residual pressure to the specified value and solve for the resulting flow. You can then determine the available pressure at the desired fireflow demand and the available flow at the minimum residual pressure.

InfoWater Pro provides comprehensive fireflow modeling capabilities. Fire demand requirements can be specified based on the various types of building structure (e.g., single-family residential, multi-family residential, commercial, industrial, etc.) or other fire demand characteristic.

Based on the fireflows specified, InfoWater Pro will calculate the maximum flow available at the hydrant while maintaining the user-specified residual pressure and, optionally, a maximum velocity constraint can also be applied. Click here to learn more about fireflow demands and how to model a fireflow simulation.

Run Fireflow on Domain Only

If checked, fire-flow analysis will be performed on domain only.

Edit Fireflow Nodes

Opens the Group Edit function. See Group Editing-Fire-Flow.

Edit FireFlow Table

Opens DB Editor -- Fire Flow Demand Table. 

Residual Pressure

The minimum residual pressure, usually 20 psi, targeted at each hydrant (junction node) in the modeled fireflow set. InfoWater Pro will calculate the maximum flow available at the hydrant while maintaining the user-specified residual pressure.

Select Time

The hydraulic time period at which fireflows will be calculated. A hydraulic simulation will be performed for all timesteps up to and including the specified time period where fireflow simulation will be performed. Click Select Time  to launch the Select Time dialog box as shown below:

Left click on the Status bar and move the bar to specify the Fireflow time step. Click OK to save and exit. Click Cancel to cancel and exit from the Select Time dialog box.

Duration

If this option is selected it allows you to extend the fireflow run over an extended time period from the defined fireflow instant. The duration entry in minutes is enabled only if the duration option is selected and the value entered is greater than zero. The module maintains the fireflow at the junction for the entire fire-flow duration. During this extended time period, the program will search for critical junction with the lowest pressure and the critical pipe with the highest velocity from the currently defined searching range. A separate report type “Fireflow Extended Time” will then be available from the Output Report Manager. The report highlights the critical conditions for this extended time run period.

Max. Velocity Constraint

The maximum velocity constraint targeted at the assigned pipes (Connecting Pipes or Domain Pipes). InfoWater Pro will calculate the maximum flow available at the hydrant while maintaining the user-specified residual pressure and satisfying the maximum velocity constraint.

Pipe Search Range

Used to specify which pipes will be selected for the maximum velocity constraint during the fireflow simulation. Choose either Connecting Pipes or Domain Pipes.

Design Fireflow

Minimum Pressure

When checked, InfoWater Pro determines the design flow (or the maximum flow available) from each junction node being simulated such that pressure within the Critical Node Searching Range does not drop below the minimum design pressure specified.

% of Max Static Pressure

When checked, InfoWater Pro determines the design flow (or the maximum flow available) from each junction node being simulated such that pressure within the Critical Node Searching Range does not drop below the percent of the maximum static pressure specified.  

Accuracy

This is the convergence criterion used to signal that a solution has been found to the nonlinear fireflow equations. Trials end when the sum of all flow changes divided by the sum of all link flows is less than this number.

Suggested value is 0.001.

Selection Nodes

This allows you to choose a selection set from the drop-down list.

Maximum Iteration

Maximum number of trials used to solve the nonlinear fireflow equations. Suggested value is 40.

Critical Node Searching Range

Used to specify which nodes will be evaluated for minimum pressures during the fireflow simulation. Choose one option from the following: Fire Nodes, Entire Network, Selection Nodes, and Domain Nodes.

The domain option will be available only when a domain has already been created.

Enable Accelerated Solver

When this is on, InfoWater Pro will use a new solver that can achieve convergence in fewer iterations and also reach better accuracy, especially when used with max velocity threshold. This feature is optional for now in order to maintain access to the previous solver and consistency in results.

Asset Impact Reporting

Pressure Threshold – This pressure is used to count warnings for each junction whenever the pressure falls below the threshold during the selected fireflow condition.

Velocity Threshold – This velocity is used to count warnings for each pipe whenever the velocity exceeds the threshold during the selected fireflow condition.

Include cases with inadequate Design Flow – Check this option to include hydrant cases where the design fireflow value fell below the required fireflow.

Fireflow Condition – This option selects the type of fireflow used at each hydrant to report for all junctions and pipes.

Run Mode

Used to control how the run is managed. Select from the following options from the drop-down menu:

Notes:

Topics in this section
Parent topic: Running a Model