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HVAC Ductwork Coordination for Architects

Ductwork is usually the biggest thing in the ceiling void, so it tends to drive the coordination around it.

Ductwork is often the largest element in ceiling voids and risers. Its size and routing have a big effect on ceiling heights, structure and floor layouts. Coordinating ductwork early helps avoid the most common MEP clashes.

Why ducts need space

Ducts carry air at relatively low pressures and velocities, so they need large cross sections compared with pipes. Main ducts near plant rooms and risers are typically the largest. Insulation adds further size.

Main routes

Plan main duct routes with the MEP engineer early. Corridors are common routes, but they're also where other services concentrate. Agree zones for main ducts and check them with sections.

Duct shapes

Rectangular ducts can be shallower than round ducts carrying the same air, which can help in tight ceiling voids. Round ducts are efficient and often used where space allows. The engineer chooses based on performance, space and cost.

Crossing beams

Ducts often need to pass below beams, which can drive ceiling heights. Options include:

• Routing ducts between beams
• Openings in beams, coordinated with the structural engineer
• Locating ducts in corridors with lower ceilings

Terminals

Grilles, diffusers and linear slots are visible in finished spaces. Coordinate them with:

• Ceiling grids and layouts
• Lights and sprinklers
• Architectural features

Show them on reflected ceiling plans.

Fire dampers

Ducts passing through fire-rated walls and floors may need fire dampers or fire-rated ductwork, depending on the code and fire strategy. Dampers need access for inspection and testing, so coordinate access panels.

Smoke control

Some buildings have smoke extract or pressurisation systems with dedicated ductwork. These may need fire-rated ductwork and specific routes.

Acoustics

Ducts can transmit noise between spaces and from plant. Attenuators, lined ducts and careful routing help. Acoustic attenuators add length and size.

External louvres

Intake and exhaust louvres affect elevations. Coordinate their size, position and appearance with the facade design. Separation between intakes and exhausts is important.

Maintenance access

Equipment such as fan coil units, dampers and filters need access. Coordinate access panels and clearances.

Exposed ductwork

When ducts are exposed, they become part of the interior design. Agree finishes, alignment and supports.

Standards

Ductwork design and construction follow published standards, such as SMACNA guidance in the US and guidance from bodies such as CIBSE and BESA in the UK. The engineer will specify which apply.

1. 01Why ducts need space
2. 02Main routes
3. 03Duct shapes
4. 04Crossing beams
5. 05Terminals
6. 06Fire dampers

Check plant connections

Connections between plant, risers and main ducts are often congested. Coordinate these areas in detail early.

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