How to Specify FRP Ducting for Semiconductor Fabs and High-Tech Manufacturing

Semiconductor fabs face a critical challenge: aggressive chemical process exhausts that destroy standard ductwork, threaten million-dollar equipment, and risk regulatory violations.

Corrosive gases from etching, photolithography, and CVD processes—hydrofluoric, sulfuric, and hydrochloric acids, plus solvents and caustics—can lead to catastrophic failures when the correct material is not utilized. As a result, end users experience production shutdowns, cleanroom contamination, equipment damage, and EPA penalties.

Fortunately, fiberglass reinforced plastic ductwork solves this problem, but only when specified correctly. 

Many facility managers approach FRP ducting as a component purchase, then discover system failures because scrubbers, fans, and ductwork weren't engineered together. This is why it’s generally recommended to order complete industrial air cleaning systems rather than purchase them piecemeal or to work with a manufacturer who understands your entire system. 

What Is FRP Ducting and Why Does It Work for Corrosive Environments?

Fiberglass reinforced plastic ductwork combines glass fiber reinforcement with corrosion-resistant vinyl ester resins.

The laminate construction features for severe corrosion resistance:

• Resin-rich inner surface (90% resin, 10% glass)
• Multiple glass fiber layers for structural integrity
• Protective gel coat for environmental resistance

Unlike galvanized duct, which corrodes from the inside out when exposed to harsh chemicals, properly fabricated FRP ducting continuously resists acids, alkalies, and solvents. Manufacturing quality determines whether your system lasts five years or twenty-five.

Selecting the Right Resin System for Chemical Compatibility

Vinyl ester resins offer incredibly broad chemical resistance and are a leading choice for many semiconductor applications. They handle mixed acid streams, caustics, and solvents typical in fab exhaust systems.

The resin must be evaluated for your specific chemical environment.

Temperature ratings matter equally. Vinyl ester FRP offers higher temperature capability than lower‑grade thermoplastics like standard PVC and many polyolefins, but it does not universally exceed all thermoplastic alternatives, especially engineered systems like CPVC or PVDF duct.

Key Resin Selection Criteria

• Chemical exposure type and concentration levels
• Continuous operating temperature requirements
• Class I flame spread ratings for cleanroom installations
• Chemical resistance documentation for your specific application

The Proper Laminate Construction Ensures Long-Term Performance

Specify minimum wall thicknesses based on duct diameter, vacuum ratings, and pressure requirements.

Required Laminate Layers

• Inner surface veil: Resin-rich barrier preventing fiber exposure (90% resin, 10% glass)
• Multiple reinforcement layers: 2/3 resin to 1/3 glass fiber ratio
• Quality fabrication: Computer-controlled processes that maintain exact specifications

Specifications that reference PS 15‑69, SMACNA Thermoset FRP Duct Construction Manual, and an FRP material/resin selection guide (for chemistry and temperature) are recommended, since they tie laminate construction to chemical, thermal, and mechanical demands.

Flame Ratings Impact Installation Requirements

Installations require Class I flame ratings. Codes commonly define Class I/Class A as having a flame spread of ≤25 and a smoke development index of ≤50, as per ASTM E84; however, you should verify specific flame and smoke limits with your authority having jurisdiction and the applicable standard before placing an order.

Confirm the complete system, not just the duct material, meets fire codes:

• Flame spread index: 0-25
• Smoke developed index: 0-50
• Vinyl ester formulations with fire-retardant additives

Request certification documentation before specifying any FRP ducting for class 1 duct applications.

Equipment Protection Strategies That Prevent Million-Dollar Losses

Chemical fumes from improperly sealed ductwork attack semiconductor process tools worth millions. Technical reports on hazardous process exhausts note that corrosive gases leaking from non‑enclosed or compromised exhaust pipes pose risks not only to personnel but also severe damage to fab equipment.

Corrosion specialists in semiconductor environments also describe how acid vapors and corrosive gases can increase electrical resistance, degrade connectors, and damage control electronics in process tools, directly impacting uptime and yield.

So, your FRP air duct specification must address:

1. Flange Design and Gasketing

• Flange thickness adequate for bolt loading
• FRP often comes with a raw end and is bonded in the field, which requires a trained installer
• Metal washers under all nuts and bolt heads

2. Proper Hanger Spacing

• Band-type hangers contacting 180° of duct surface
• Spacing per manufacturer specifications
• Support preventing deflection under system weight

3. Expansion Provisions

FRP ducting expands and contracts with temperature, which means systems without movement accommodation often fail at joints.

This problem becomes more pronounced when ductwork comes from multiple manufacturers because an industrial air cleaning system made of parts from different makers is less likely to integrate as seamlessly as those entirely from a single source. 

Regulatory Compliance Requirements for FRP Systems

EPA and air quality regulations ultimately determine the consequences when your exhaust systems fail inspections. 

To avoid that, specify adequate wall thickness to prevent collapse under scrubber vacuum conditions; if a duct collapses, it shuts your entire system down. 

Degrading ductwork, similarly, develops leaks that release untreated emissions. You should test materials at operating temperatures for your chemicals and retain documentation for expected service life data. 

Lastly, one point about installation: FRP ducting requires specific procedures for cutting, flanging, and joining. So, contractors unfamiliar with fiberglass reinforced plastic can also create leak points that cause compliance failures.

FRP Ducting Specifications for Semiconductor Fabs: The Complete Guide

Material Selection Matters Vinyl ester resin systems handle hydrofluoric, sulfuric, and hydrochloric acids from etching and CVD processes. Specify resin-rich inner surfaces: 90% resin, 10% glass for maximum corrosion resistance.

The Cause of Most FRP Ductwork Specifications Fails

Most specifications treat ductwork as standalone components rather than integrated systems. This leads to three common failure points for ducting used in semiconductor fabs and high-tech manufacturing. 

• Multiple Vendor Coordination - Buying scrubbers, fans, and ductwork separately means no one owns system performance, resulting in incompatible flanges with transitions that leak.
• Poor System Engineering - Inadequate fan performance from incorrect pressure drop calculations, scrubber inefficiency from turbulent flow, and stress concentrations at transitions also cause cracks.
• Fragmented Responsibility During Failures - Component incompatibility leads to a lot of finger-pointing. And when nobody accepts responsibility, root-cause resolution and corrective actions can get delayed.

When specifying FRP ducting, some facilities make a critical error by optimizing component cost without considering installation complexity and long-term maintenance. Don’t overlook installation. 

Viron’s Complete Custom System Solution for FRP Ducting for Fabs and High–Tech Manufacturing

It’s simple: Systems fail when components aren't designed together, while a complete system approach—one manufacturer engineering scrubber, fan, and FRP ducting together—eliminates your coordination failures.

For 50+ years, Viron has specialized in complete industrial air cleaning systems, building our reputation on solving challenging corrosive air applications. It’s easier for you when we’re responsible for the entire system.

Our engineers design for your specific chemical environment and test our integrated scrubbers, fans, and FRP air duct systems before installation, to get your facility up and running as quickly as possible. 

Don't risk million-dollar equipment failures and regulatory violations with piecemeal ductwork solutions. Viron's complete air cleaning systems remove the vendor coordination headaches and component incompatibility that cause most FRP system failures. Request a quote today for a custom-engineered system built to protect your facility for decades.

Frequently Asked Questions About FRP Ducting for Semiconductor Fabs