Industry procurement solution · Reviewed 10 August 2026
Metals for HVAC Systems
HVAC metal selection depends on air chemistry, moisture, pressure class, leakage, fire and hygiene requirements, external exposure, insulation and cleaning—not duct gauge alone.
Answer first
There is no single metal specification for an entire project
Divide the project into systems, document each service environment and governing code, then select compatible materials, product standards, fabrication routes, protection systems and inspection plans.
Dry conditioned air, outdoor air, condensate and moisture-laden exhaust
Corrosive fumes, salt, grease, cleaning chemicals or abrasive particulates
Positive or negative pressure, vibration, thermal movement and fire/smoke controls
System map
Material and product selection by project system
| System | Selection drivers and alternatives | Reviewed starting points |
|---|---|---|
| General supply and return ducts |
| Galvanized coilAluminum sheet & plate |
| Moisture-laden and outdoor ducts |
| Galvanized coilStainless sheet |
| Corrosive and process exhaust |
| Stainless sheet316L |
| Equipment casings and accessories |
| Stainless sheetGalvanized coil |
Project control
Standards, certification and documents
- Applicable mechanical, fire, smoke-control and energy codes
- Air-system schedule with pressure class, leakage class, contaminants and temperatures
- Duct construction, coating, joint, support, insulation and cleaning specifications
- Material certificates, coating verification, leakage tests and inspection records
Fabrication and logistics
Package interfaces to control
- Fabrication drawings, welding, heat treatment, coating and repair procedures
- Inspection hold points, testing methods, acceptance criteria and document approval
- Identification through cutting and assembly, preservation, packing and consolidated shipping
- Destination rules, site storage, installation interfaces and delivery sequence
Risk register
Common procurement risks
Selecting duct solely by nominal gauge
Using dry-service galvanized details in wet or corrosive exhaust
Ignoring cut edges, condensate drainage and insulation interfaces
Failing to coordinate metal, sealant, gasket and cleaning chemistry
Comparable offers
Structured RFQ checklist
Project location, service environment, design life and governing codes
System or component, selected material and governing product specification
Dimensions, tolerances, quantity and required delivery sequence
Condition, finish, metallic coating, paint system or corrosion allowance
Fabrication, forming, welding, heat treatment and qualification requirements
Inspection and test plan, acceptance criteria, certificates and hold points
Marking, traceability, packing, preservation and destination
Required delivery date, shipment terms and approved-vendor constraints
Evidence
Sources and review
Project engineering documents and current governing standards supersede this general selection map.
ASHRAE · HVAC Systems and Equipment, Chapter 19
ASTM International · A653/A653M-20 scope; ordered edition controls
worldstainless · Industry technical guide, reviewed July 2026
Project sourcing from China
Build a traceable HVAC systems supply package
Share the design basis, system list, specifications, quantities, inspection plan, destination and delivery schedule.