Corrosion Resistant AHU for Coastal Area

Corrosion Resistant AHU for Coastal Area (Salt Air / Seaside / Marine Climate)

Core Coastal Challenges

High salt spray, humidity, chloride ion, sea breeze corrosion, rust on metal parts, coil fin oxidation, fan motor damage, short service life.

1. Full Material Anti-Corrosion Upgrade (Most Critical)

Casing & Frame

External panel: 304 / 316L stainless steel

Alternative: Aluzinc / Galvanized steel with 50–80μm polyester anti-corrosion coating

Internal frame & bracket: hot-dip galvanized + epoxy paint or full stainless steel

Double skin PU insulated panel, airtight structure, prevent salt air ingress

Cooling / Heating Coil

Tube: Seamless copper tube with tin plating / cupronickel tube

Fin: Epoxy coated aluminum fin / hydrophilic anti-salt coating fin

Whole coil pass salt spray test

Optional: Stainless steel tube coil for heavy coastal corrosive zone

Drain Pan & Internal Parts

Drain pan: 304 stainless steel (no galvanized sheet)

All screws, bolts, fasteners: 304/316 stainless steel

Internal air duct, support, baffle: galvanized + epoxy coating

2. Fan & Motor Anti-Corrosion Design

Fan impeller: glass fiber / aluminum alloy anti-rust treated / 304 stainless steel

Motor: IP55 / IP65 protection

Insulation class F/H, fully sealed winding, anti-salt fog insulation resin

Motor surface epoxy anti-corrosion painting

Direct drive EC fan (reduce belt parts which easy to rust)

3. Filtration & Air Intake Protection

Fresh air louver: 304 stainless steel with bird/insect net

Pre-filter first stage: metal washable anti-salt mesh filter

G4 + F8 multi-stage filtration, reduce salt dust entering unit

Avoid sea breeze direct blowing into AHU air intake

4. Surface Coating & Treatment Process

All carbon steel parts: pickling → phosphating → primer → epoxy intermediate paint → topcoat

Salt spray resistant coating, pass 500–1000 hours salt spray test

No exposed raw metal inside the unit

5. Structural & Design Optimization

Fully enclosed cabinet, minimize air leakage

Sloped drain pan, no water stagnation (stagnant water accelerate salt corrosion)

Isolation mount & flexible duct connector with anti-rust bracket

Control box: sealed type, anti-moisture & salt fog, internal dehumidification optional

6. Suitable Application Scenarios

Seaside hotel, coastal hospital, marine terminal, offshore factory, island project, coastal commercial building.

Quick Selection Standard

Full 304/316 stainless steel casing & drain pan

Epoxy coated fin / cupronickel coil

IP55 sealed anti-corrosion motor

Stainless steel louver and all fasteners

Salt spray certified coating system