acid exhaust

Acid exhaust is a dedicated ventilation system specifically designed to handle corrosive acidic fumes from semiconductor processes. **Purpose**: Safely capture and remove corrosive acid vapors from wet benches, etch tools, and chemical stations without damaging ductwork. **Corrosive-resistant materials**: PVDF, polypropylene, FRP (fiberglass reinforced plastic), or PFA-lined ductwork. Metal would corrode rapidly. **Sources**: Wet etch baths (HF, HNO3, H2SO4), cleaning chemicals, CVD exhaust with corrosive byproducts. **Separation**: Kept separate from other exhaust systems (solvent, general, heat) to prevent reactions and allow appropriate treatment. **Scrubbing**: Routes to acid scrubber before environmental release. Neutralization with caustic solution. **Velocity**: Maintained at sufficient velocity to prevent condensation and corrosion inside ducts. **Drainage**: Ductwork sloped with drains for condensate collection. **Detection**: Exhaust monitors for abnormal concentrations. **Maintenance**: Regular inspection for corrosion, leaks, build-up. Corrosion-resistant fasteners and seals. **Fire codes**: Specific requirements for acid exhaust systems in building codes and NFPA standards.