Duct Layout

The Layout pane is where you design the duct distribution system, including routing, sizing, and component selection.

Duct Routing

Creating Duct Runs

Draw duct runs on the floor plan:

1. Select the duct tool
2. Click to place duct segments
3. Connect to terminals and registers
4. Close loops where needed

Duct Types

Select the appropriate duct type:

• Supply duct - From AHU to terminals
• Return duct - From spaces back to AHU
• Exhaust duct - From spaces to exhaust fan
• Outdoor air - From intake to AHU

Routing Considerations

Plan duct routes to:

• Minimize total length
• Avoid obstructions
• Allow for insulation and access
• Fit within available plenum space

Duct Sizing

Sizing Methods

HVAKR supports multiple sizing methods:

Velocity Method

Size ducts for a target velocity:

• Higher velocity = smaller ducts
• Lower velocity = quieter system
• Typical: 1500-2000 FPM main, 800-1200 FPM branch

Equal Friction

Size for constant friction rate:

• Typical: 0.08-0.10 in. wg per 100 ft
• Self-balancing in symmetric layouts
• May result in high velocity in mains

Static Regain

Size to maintain static pressure:

• Pressure regained at branches
• Self-balancing
• More complex calculations

Automatic Sizing

HVAKR automatically sizes ducts:

1. Set the sizing method and parameters
2. Run the sizing calculation
3. Review and adjust as needed

Fittings and Transitions

Fitting Types

Select fittings for duct connections:

• Elbows - 90°, 45°, or radius
• Tees - Branch takeoffs
• Transitions - Size changes
• Offsets - Vertical or horizontal shifts

Fitting Loss Coefficients

Fittings add pressure loss:

• ASHRAE fitting loss coefficients
• Based on fitting geometry
• Included in total pressure calculation

Reducing Losses

Minimize fitting losses:

• Use larger radius elbows
• Avoid abrupt transitions
• Use turning vanes where needed

Pressure Calculations

Pressure Graph

View the pressure profile through the system:

• Static pressure at each point
• Velocity pressure
• Total pressure

Critical Path

Identify the critical path:

• Highest pressure drop path
• Determines fan sizing
• Other paths need balancing

Fan Sizing

The fan must overcome:

• Total duct pressure drop
• Terminal unit pressure drop
• Filter pressure drop
• Coil pressure drop

3D Visualization

View the duct layout in 3D:

• Rotate and zoom the model
• Check for interferences
• Verify routing and sizing

Duct Schedule

Generate a duct schedule report:

• Duct sizes by segment
• Fitting schedule
• Insulation requirements
• Total duct area

Best Practices

1. Route before sizing - Establish routing first
2. Use consistent sizing method - Don’t mix methods
3. Check velocities - Stay within acceptable ranges
4. Verify pressure drop - Within equipment capability
5. Document routing - For construction drawings