Shop-fabricated ductwork
Custom Welded Ductwork
Fully welded G90 galvanized duct and fittings for heavier-gauge HVAC, exhaust, process, and custom equipment connection work.
- Best for custom geometry, heavier gauges, or duct runs where mechanical lock seam construction is not the right fit.
- Round, rectangular, transitions, offsets, field-fit sections, and coordinated connection faces can be fabricated from released dimensions.
- Confirm gauge, G90 coating requirement, liner, connection style, and touch-up expectations before release.
MaterialG90 Galvanized Steel
Gauge range20 ga - 10 ga
Standard connections1/2" flange
Construction Standard
| Application | Custom welded galvanized ductwork and fittings for HVAC, exhaust, process, outdoor equipment connections, and industrial airflow applications. |
| Material | G90 galvanized sheet steel is standard unless another coating requirement is listed on the quote. |
| Gauge range | Welded galvanized duct is available from 20 gauge through 10 gauge, supplied as quoted based on size, pressure, and project requirements. |
| Welding process | Galvanized duct is typically MIG welded; longitudinal seams and fitting seams are shop welded for continuous welded construction. |
| Straight sections | Produced in 5'-0" nominal lengths, less end flange allowance. Shorter sections and coordinated field-fit pieces can be fabricated when required. |
| End preparation | 1/2" flanges are standard. Angle rings, custom flange types, special bolt patterns, collars, and companion flange details can be fabricated as shown or quoted. |
| Liner options | Fiberglass liner, rigid duct board insulation, and Armaflex can be quoted for acoustic or thermal protection when required. |
| Coating note | G90 galvanized steel has a zinc coating for corrosion resistance. Welded areas are cleaned and touch-up painted with rust-proof paint. |
| Quality check | Weld seams receive visual inspection before release. Leak testing, pressure testing, NDT, or certified inspection are by others unless quoted. |
Build Quality
Made to specBuilt from released dimensions, gauges, and connection details.
Built toughHeavier-gauge duct for custom welded galvanized systems.
Quality checkedWeld seams receive visual inspection before release.
Release readyPiece marks and field-fit faces coordinated before fabrication.
Fabrication Capabilities
| Duct sections | Rectangular and round straight duct, field-fit pieces, risers, drops, and custom lengths. |
| Fittings | Rectangular and round elbows, radius bends, offsets, tapers, reducers, transitions, branches, and tees. |
| Connections | 1/2" flanged duct systems are typical for fully welded connections. Equipment transitions, collars, curb adapters, wall/shaft connections, and roof penetration fittings are available. |
| Field-fit work | Short sections, piece-marked runs, and coordinated connection faces. |
| Shop details | Tabs, brackets, companion flanges, angle frames, reinforcement, and special flange details when requested. |
| Release support | Built from released drawings, verified field dimensions, or approved sketches; piece marks and coordinated connection faces can be included when supplied before fabrication. |
Material Notes
G90 coatingG90 galvanized sheet is zinc-coated steel, commonly specified as 0.90 oz/sq ft total coating weight across both sides.
Welded constructionUse this product when the project needs heavier material, continuous welded seams, or custom shapes beyond normal lock seam ductwork.
Liner availableInternal liner or insulation can be included when acoustic, condensation, or thermal protection is part of the released scope.
Welded areasHeat from MIG welding can discolor or burn back galvanizing near seams. Welds are cleaned and touch-up painted with rust-proof paint.
Connection Options
Couplings
Raw endsRaw ends with couplers for screw assembly.
1/2" flange
Field welded1/2" flanges for field welded assembly.
TDC / Ductmate
Bolted sealBolted connections with butyl sealant.
Rings / flanges
Custom patternVanstoned or welded angle rings, frames, and bolt flanges.
Optional Accessories
LinerFiberglass liner, rigid duct board insulation, Armaflex, liner pins, adhesive, and exposed-edge details.
AccessDoors, cleanout openings, inspection panels, and drain fittings.
SealingFire-rated gasket, gasketed access hardware, or seal details where specified.
Custom detailsAngle rings, custom bolt patterns, special hardware, reinforcement, or special coating requirements.
Required for Quote / Release
- Gauge, duct size, quantity, material coating, and required nominal or field-fit lengths.
- Approved drawing, sketch, or verified field dimensions with airflow/orientation noted.
- Flange type, bolt pattern, companion flange needs, and connection face details.
- Liner or insulation type, thickness, exposed edges, access needs, and any acoustic or thermal requirements.
- Piece marks, access openings, reinforcement, pressure class, and any testing requirements.
- Hardware, gasket, sealant, liner, insulation, touch-up paint, or special coating requirements if included.
Not Included Unless Quoted
- Installation, field welding, hoisting, rigging, roofing, or roof penetration work.
- Engineering, permits, inspections, balancing, cleaning, field coating repair, fire wrap, fire-rated enclosure, or listed-system certification.
- Leak testing, pressure testing, gaskets, sealant, hardware, companion flanges, or rework from changed release dimensions unless quoted.
Scope & Responsibility
Code note: Welded galvanized duct systems may be governed by mechanical code, local code, project specifications, pressure class, liner requirements, material/coating requirements, and AHJ requirements. Empire fabricates duct and fittings to released dimensions and quoted scope; final system design, material selection, installation method, field welding, field coating repair, sealant/gasket requirements, clearances, and acceptance remain the responsibility of others unless expressly included.
Ready to Quote?
Let's get your duct package moving.
Send drawings, sketches, photos, or field measurements. Empire is ready to go to work for you.
quotes@empiremetalproducts.com
602-424-9980