Riser / Stack

To Above: These Risers extend upward from a given Floor to Supply or Exhaust Fluid or Air to levels above.

• From the perspective of the current Floor, a "to above" Riser moves flow to the higher levels.

To Below: These Risers extend downward from a given Floor to Supply or Exhaust Fluid or Air to levels below.

• From the perspective of the current Floor, a "to below" Riser moves flow through the floor to the levels below.

Peak Flow Rate Calculation Method: This Setting specifies the calculation Standard or Method used to derive the Peak Flow Rate. 

• This Setting is defined in Methods.

• Diversification adjusts flow requirements to reflect realistic peak demand rather than the maximum possible flow for every Fixture. For example, in a residential system, not all Fixtures will be used simultaneously; diversification accounts for this by applying a Factor that reduces total calculated demand.

Loading/Fixture Units of Fixtures and Nodes: Each connected Fixture or Node has an assigned Loading or Fixture Unit value, representing its contribution to peak flow based on expected usage.

• This Unit is assigned to each Fixture or Node in the Design phase.

• Higher loading units increase the peak Flow Rate, as these units are summed across all connected Fixtures to determine total demand.

Continuous Flow Fixtures/Nodes: Fixtures or Nodes that operate with a Continuous Flow (such as certain medical equipment) that bypass diversification. Instead, their flow rates are added directly to the Peak Flow Rate Calculation, representing a constant demand that does not vary.

• Identified as Continuous Flow within Node or Fixture Properties.

• Continuous Flow Fixtures add directly to the Peak Flow Rate without diversification, ensuring that the calculation fully accounts for constant demands.

Spare Capacity: An optional Setting that adds a percentage increase to the Peak Flow Rate for future demand or unexpected increases. Adding Spare Capacity ensures the system can handle higher-than-anticipated flows without the risk of undersizing.

• Configurable in System Settings as a percentage added to the final peak flow rate.

• Spare capacity increases the Peak Flow Rate by a specified percentage, providing a buffer for demand fluctuations or future system expansions.

[Optional] Vent Air Changes Rate Standard: This Setting specifies the Calculation Standard or Method used to derive the Peak Flow Rate. 

• This setting is defined in Methods.

• Each Room typically has a different minimum Ventilation flow rate requirement.

Diffuser/Grille Flow Rate: This defines the Flow Rate assigned to each specific Diffuser/Grille.

Spare Capacity: An optional Setting that adds a percentage increase to the Peak Flow Rate for future demand or unexpected increases. Adding Spare Capacity ensures the system can handle higher-than-anticipated flows without the risk of undersizing.

• Configurable in System Settings as a percentage added to the final Peak Flow Rate.

• Spare capacity increases the Peak Flow Rate by a specified percentage, providing a buffer for demand fluctuations or future system expansions.

Flow Rate: The Pipe Diameter is sized based on the calculated flow requirements.

Maximum Velocity and/or Pressure Drop Limits: The maximum allowable Velocity and/or Pressure Drop along the pipes in the system will not be exceeded based on the calculated Flow Rate.

• Set in the Methods and the Systems.

Enabled Pipe Sizes: System Settings control which sizes are available, restricting or enabling diameters based on project requirements.

• Confirm that the appropriate pipe sizes are enabled/available in System Settings.

Overridden: The Pipe Diameter or the pipes Maximum Velocity/Pressure Drop setting can be Overridden in it’s Properties.

• If any segment of Pipe looks high, it is likely due to this.

Flow Rate:

• The Duct size is determined based on the calculated airflow requirements.

Maximum Velocity and/or Pressure Drop Limits:

• The maximum allowable Velocity and/or Pressure Drop along the ducts in the system will not be exceeded based on the calculated Flow Rate.

• These settings are configured in the Methods and Systems tabs.

Overrides:

• Duct size or maximum Velocity/Pressure Drop settings can be Overridden in the Properties tab.

• If a Duct size looks unusual, it may be due to an Override in its settings.

Assigned Loading/Fixture Units:

• Each Fixture or Node is assigned a Fixture Unit value based on the selected Peak Flow Rate Calculation Method, based on its expected water demand.

• Fixtures with higher Loading Units contribute more significantly to the system's total demand.

Diversification Factors

• Diversification converts the sum of Loading/Fixture Units to reflect realistic peak usage.

• In systems like residential water supply, not all Fixtures operate simultaneously. Diversification applies a factor to reduce total demand and prevent oversizing.

  1. As the total Loading/Fixture Units increase, the Peak Flow Rate grows, but the rate of increase diminishes due to the decreasing likelihood of all Fixtures operating at once.