Forced & Induced Draft Fans — Asbestos Exposure Crosswalk
What This Equipment Is
A typical large boiler runs on a balanced-draft combustion-air system:
- Forced-draft (FD) fans push combustion air through the air heater and into the boiler windbox
- Induced-draft (ID) fans pull flue gas through the precipitator / bag house and discharge it up the stack
- Primary-air (PA) fans supply pulverizer air on coal-fired units
- Gas-recirculation fans route a portion of the flue gas back to the furnace for temperature control
These are large centrifugal machines — diameters of 8 to 20+ feet, megawatt-class drive motors. The ID-fan housing runs at flue-gas temperature; both fans require insulated casings, gasketed inlet and outlet flanges, fabric expansion joints to absorb thermal movement, and shaft packing where the rotor passes through the casing.
Asbestos Products Historically Used Around Combustion-Air Fans
| Product Category | Where on the Fan | Notes |
|---|---|---|
| Casing insulation | Fan housing exterior | Block insulation, removable jackets |
| Pipe / duct covering | Inlet and outlet ductwork | Block insulation, magnesia, calcium silicate |
| Fabric expansion joints | Inlet, outlet, and recirc connections | Asbestos cloth — see Expansion Joints |
| Shaft packing | Stuffing boxes where rotor passes casing wall | Braided asbestos rope packing |
| Gaskets | Inlet, outlet, and casing-split flanges | Asbestos sheet gasket material |
| Insulating cement | Joints and irregular surfaces | Mixed dry, hand-applied |
Why Combustion-Air Fan Work Was a High-Exposure Activity
Combustion-air fans require periodic rotor replacement (erosion / fouling), bearing rebuilds, and expansion-joint replacements. ID-fan expansion joints in particular fail repeatedly under sustained thermal cycling and corrosive flue-gas service. Each replacement involves removing legacy fabric, cleaning flange faces (gasket scraping), and installing new components. Casing-insulation strip and re-install during major outages exposed the same crews to legacy fiber alongside fresh insulation work.
Manufacturers Named in Litigation Involving These Products
- Buffalo Forge — fan OEM named in installation/maintenance claims
- American Standard / Aerovent — fan OEM
- Howden — fan OEM
- Westinghouse Electric — fan OEM (some product lines)
- Johns-Manville — block insulation, duct covering
- Owens-Corning / Fibreboard — block insulation
- Garlock Sealing Technologies — fabric expansion joints, gaskets
- A.W. Chesterton — packing
Documented Product References
Images sourced from publicly available product-identification reference materials. Inclusion does not constitute a finding of liability against any company.
Trust Funds That May Apply
- Manville Personal Injury Settlement Trust
- Owens-Corning / Fibreboard Asbestos PI Trust
- Garlock Sealing Technologies LLC Asbestos PI Trust
Trades Most Exposed at Fan Work
Insulators (Heat & Frost), boilermakers, millwrights and rotating-equipment mechanics, pipefitters, iron workers and welders on ductwork modifications, refractory masons in adjacent breeching work.
Jobsites in the Network
- Every Missouri power plant in the network
- See companion pages: Boilers, Breechings, Expansion Joints, Precipitators
Compiled from publicly filed asbestos litigation, EPA / state-DNR records, and industry-publication histories. Product and company references reflect what has been alleged or documented in publicly filed litigation. This page does not constitute a finding of liability against any company. Not legal advice; consult a licensed attorney about your specific situation.