PVC duct pipe and metal duct (galvanized steel, stainless steel, aluminum) are the two dominant material families in industrial ventilation. Each has clear strengths — PVC excels in chemical resistance and cost, metal excels in temperature tolerance and fire safety. Choosing the wrong material can mean premature failure, safety hazards, or unnecessary expense.
This guide compares PVC and metal duct across every factor that matters for industrial applications: temperature, chemicals, fire, cost, static, and code compliance. We also cover when flexible duct alternatives make sense.
Material Comparison Table
| Property | PVC (Schedule 40) | Galvanized Steel | Stainless Steel |
|---|---|---|---|
| Max temperature | 140°F (60°C) | 400°F (204°C) | 1500°F+ (816°C) |
| Chemical resistance | Excellent (acids, bases) | Poor (corrodes) | Good (304), Excellent (316) |
| Fire rating | Combustible, toxic smoke | Non-combustible | Non-combustible |
| Cost per foot (6") | $2-4 | $4-7 | $12-25 |
| Weight (6" per ft) | ~1.5 lb | ~3 lb | ~3.5 lb |
| Static buildup | High (non-conductive) | None (conductive) | None (conductive) |
| Joining method | Solvent cement | Screws + sealant | Welded or clamped |
| Lifespan | 25+ years (indoor) | 15-20 years | 30+ years |
Temperature: The Deciding Factor
Temperature is usually the first filter in the PVC-vs-metal decision. PVC softens at 140°F and deforms under load at 160°F. If your exhaust stream exceeds 120°F sustained (with a safety margin), PVC is not an option — use metal.
Applications that stay well below 120°F include laboratory fume hoods (room temperature exhaust), chemical storage ventilation, swimming pool dehumidification exhaust, wastewater treatment plant ventilation, and general ambient-temperature process exhaust. These are PVC's core territory.
Applications that exceed 140°F include oven/furnace exhaust, welding fume extraction, engine exhaust, laundry dryer exhaust, and any process involving heated air. These require metal duct — galvanized steel for temperatures up to 400°F, or stainless steel for higher temperatures.
Chemical Resistance
PVC's greatest strength is its broad chemical resistance. It withstands most inorganic acids (hydrochloric, sulfuric, phosphoric), bases (sodium hydroxide, potassium hydroxide), salt solutions, and many organic compounds. This makes PVC the default choice for chemical plant ventilation, semiconductor fab exhaust, metal finishing fume extraction, and any application where corrosive fumes would destroy metal duct within months.
Galvanized steel is vulnerable to acid fumes — the zinc coating corrodes first, then the steel underneath fails. In a hydrochloric acid environment, galvanized duct can develop pinholes within 6-12 months. Stainless steel (316 grade) resists many chemicals but costs 3-6x more than PVC.
For corrosive exhaust applications where PVC's temperature limit is not an issue, PVC is typically the best value — it is cheaper than stainless, lighter to install, and lasts longer in corrosive environments than any carbon steel.
PVC for Dust Collection: The Static Debate
Using PVC pipe for woodworking dust collection systems is one of the most debated topics in the woodworking community. The concern: airborne dust particles moving through a non-conductive PVC pipe generate static charge that could theoretically produce a spark and ignite the dust cloud.
The reality is nuanced. Documented cases of PVC dust collection fires from static ignition in small woodshop environments are exceedingly rare. The energy required to ignite a dust cloud (the minimum ignition energy, or MIE) is higher than what typical PVC static generates in a small-diameter, low-velocity system. Large industrial dust collection systems with high airflow volumes and fine explosive dust (such as grain dust or aluminum powder) are a different matter — these should always use grounded metal duct.
If you choose PVC for a shop dust collection system, ground the system by running a bare copper wire along the outside of the pipe, attaching it to each PVC section with a sheet metal screw that penetrates the pipe wall, and connecting the wire to an earth ground. This drains static charge and largely eliminates the ignition risk.
For those who prefer to avoid the debate entirely, our PVC flexible hose with embedded ground wire provides built-in static protection, and PVC steel wire duct offers a flexible alternative with inherent grounding through the wire helix.
Fire and Building Code Considerations
PVC is combustible. When it burns, it releases hydrogen chloride (HCl) gas, which is toxic and corrosive. This is the primary reason building codes restrict PVC duct in occupied and plenum spaces. The International Mechanical Code (IMC) and most local codes prohibit PVC in HVAC supply and return duct systems, in plenum spaces above dropped ceilings, and anywhere within fire-rated assemblies.
PVC duct is permitted in exhaust-only systems (pulling air away from occupied spaces), in industrial applications where chemical resistance is necessary, and in underground or exterior installations. Specific allowances vary by jurisdiction — always verify with your local code official before specifying PVC duct in a commercial or industrial installation.
Metal duct is non-combustible and accepted by all building codes for any ventilation application. If code compliance is uncertain, metal is the safe default.
When Flexible Duct Makes More Sense
Rigid PVC pipe and rigid metal duct both require precise routing, custom fabrication for bends, and significant installation labor. For many industrial applications, flexible duct offers a faster, more adaptable solution:
Nylon fabric duct hose handles temperatures up to 250°F, resists abrasion, and flexes around equipment without custom fittings. Ideal for fume extraction and welding smoke capture. Silicone fabric duct hose extends the temperature range to 500°F+ for oven exhaust and high-heat process ventilation. Polyurethane flexible hose provides excellent abrasion resistance for dust and particle transport. Read our industrial flexible duct guide for a detailed comparison of all materials.
Decision Summary
Choose PVC when the exhaust temperature is below 120°F, chemical resistance is needed, the application is exhaust-only (not supply air), and building code allows it. PVC saves 30-50% over metal and lasts longer in corrosive environments.
Choose galvanized steel when temperature exceeds 140°F, the application involves flammable dust or vapors, building code requires non-combustible duct, or the duct runs through occupied or plenum spaces. Galvanized steel is the universal default that codes accept everywhere.
Choose stainless steel when you need both high temperature tolerance and chemical resistance — such as chemical process exhaust above 200°F. Stainless is the premium option at 3-6x the cost of galvanized.
Choose flexible duct when you need adaptability, quick installation, or connection to movable equipment. Our industrial hose catalog covers materials from PVC to silicone for every temperature and application. Contact us for custom sizing and material recommendations.