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AI drafting for ductwork plans

AI HVAC Ductwork Drafting

Ductwork plans eat drafting hours because every diffuser comes off the reflected ceiling plan, every main has to fit under the steel, and every rated wall needs a damper someone remembers to tag. Nomic drafts the supply and return layout in CAD from your backgrounds and the engineer's sizing criteria, saves the DWG in your standards, and checks it against the IMC and the structure before your engineer reviews it.

Start for freeAll drafting work
Last reviewed: November 2026

You send

  • Architectural backgrounds and the reflected ceiling plan as DWG or PDF
  • Structural framing plans with beam sizes
  • The engineer's duct sizing criteria and equipment schedule
  • The life safety plan showing rated walls, shafts, and smoke barriers
  • Your CAD standards file and past ductwork sheets

Nomic hands back

  • HVAC ductwork plans as DWG files on your layers
  • An air device schedule in Excel and on the sheet
  • Damper and access door tags at rated assemblies
  • Plotted PDFs with every drawn change clouded, plus open questions for the engineer of record
1234567ABCNURSE STATION201EXAM202EXAM203EXAM204EXAM205EXAM206EXAM207EXAM208PATIENT ROOM209PATIENT ROOM210NURSE STATION211PATIENT ROOM212STAIRS224x14AHU-127'-3"27'-0"27'-3"27'-3"27'-0"27'-3"94'-8"1AHVAC PLANSCALE: 1/8" = 1'-0"N1234CONSULTING ENGINEERSREVISIONS1ISSUED FOR REVIEWPROJECTNORTHGATE MEDICALSCALE1/8" = 1'-0"DATE06/06/2026KEY PLANSHEET TITLEHVAC PLANSHEET NUMBERM-101

On the sheet

HVAC Plan, annotated

A mechanical plan with supply and return ductwork, diffusers, and the equipment that serves each zone.

  1. 1Main supply duct, sized width by depth
  2. 2VAV box feeding the zone
  3. 3Supply diffuser at the end of the branch
  4. 4Return grille

The problem

Every RCP revision moves the ductwork

A mechanical plan for one floor of a mid-size office can carry 200 air devices, and each one is tied to a ceiling tile, a light fixture, and a branch duct with a CFM tag. When the architect shifts the lighting grid or drops a soffit, the diffusers move, the branches get rerouted, and the sizes on the tags stop matching the airflow. Drafters spend the week redrawing runouts instead of chasing the conflicts that matter.

The expensive misses show up in the field: a 24x14 main drawn under a W21 beam with 2 inches to spare before insulation, a combination fire/smoke damper left off a shaft wall because the life safety plan changed after the duct was routed, or damper access doors nobody showed. Those are coordination errors, and they come from too little time to check the sheet against the structure, the RCP, and the rated wall layout.

01 / Layout

Supply and return drawn from the ceiling plan

Attach the RCP, the architectural backgrounds, the structural framing plan, and the equipment schedule, then describe the zones. Nomic places diffusers and grilles where the ceiling has room for them, routes mains and branches from the air handler to each device, and sizes every run from the friction rate and velocity limits your engineer sets.

  • Diffusers, return grilles, and linear slots placed on the RCP grid
  • Mains and branches sized from the engineer's equal friction or static regain criteria
  • CFM, neck size, and device tags on every air device
02 / Air devices

An air device schedule that matches the plan

Nomic counts every air device it placed by type and ties the count back to the air device schedule, so the schedule and the plan agree before anyone plots. Devices the ceiling could not fit, or that need a type the schedule does not carry, come back as open items for your engineer.

  • Air device schedule written in Excel and drawn on the sheet
  • Device types matched to the ceiling type, lay-in grid or hard lid
  • Total supply CFM per zone checked against the unit schedule
03 / Check

Checked against the structure and the rated walls

Before the sheet reaches your engineer, Nomic checks it against the IMC edition you name, the structural framing, and the life safety plan. Everything it drew is clouded, and the findings say which conflicts Nomic resolved and which ones need a decision from the engineer of record.

  • Fire and smoke dampers at every duct penetration of a rated shaft or barrier
  • Bottom of duct plus insulation checked against beam depth and ceiling height
  • Flex duct lengths and damper access doors checked against the spec

Checked against

The code and documents behind every sheet

Name the editions the project is designed to and Nomic checks its own drawing against them before handing it back. Your engineer or architect of record makes the final call and stamps the set.

  • International Mechanical Code Chapter 6
  • IBC Section 717 ducts and air transfer openings
  • SMACNA HVAC Duct Construction Standards
  • NFPA 90A
  • ASHRAE 90.1 duct insulation and sealing
  • Project specifications Division 23

How it works

From a sentence to a stamped set

  1. Step 1

    Ask for the drawing

    Say what the sheet needs to show and attach the backgrounds, markups, cutsheets, or photos. A sentence is enough to start.

  2. Step 2

    Nomic drafts it in CAD

    Nomic works in CAD on its own computer, on your layers and blocks, following how your firm drew the same thing before. It saves real DWG files to the project.

  3. Step 3

    Nomic checks its own work

    The drawing is checked against the code editions you name and the source documents. Everything Nomic drew is clouded, and open questions are listed.

  4. Step 4

    Your team reviews and stamps

    Your engineers and architects review the clouded changes, make the final call, and issue the set under their own stamp.

FAQ

Frequently asked questions

Yes. Nomic works in CAD on its own computer and saves DWG files with supply and return ductwork, diffusers, grilles, dampers, and tags. It lays out the system from your RCP and backgrounds, applies your CAD standards, and checks the plan against the IMC and the structure before your engineer reviews it.

Nomic sizes each run from the criteria your engineer sets, such as an equal friction rate of 0.08 inches of water per 100 feet and a velocity cap on branches over quiet rooms. The engineer chooses the method, the airflows, and the equipment, reviews the sizes Nomic drew, and makes the final call.

Nomic reads the rated walls, shafts, and smoke barriers from the life safety plan and tags a fire, smoke, or combination damper with an access door wherever a duct crosses one. Each tag cites the IBC Section 717 or IMC Section 607 requirement, and any penetration where the rating or an exception is unclear goes on the open questions list for your engineer.

Send the new background. Nomic compares it with the version it drew from, moves the air devices and branches the change affects, updates the tags and the schedule, and clouds every edit so your reviewer starts with what moved.

No. Nomic works in CAD on its own computer and saves DWG files to your project, which open in AutoCAD or any DWG editor. If your mechanical design lives in Revit, Nomic hands back DWGs and a change list your modeler links into the model.

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