How Thick Should HVAC Coil Coating Be?
Key facts
| System | Dry film | Typical use |
|---|---|---|
| PG-S1 | 5–15 μm | Coastal and industrial coils, dip before shipment |
| PG-S2 | 5–10 μm | Aluminium radiators, bakeable heat exchangers |
| PG-W | 5–10 g/m² per side | Coil lines, mild coastal and humid sites |
| PG-C | 20–40 μm | Complete units, chemical and wastewater sites |
Thickness follows chemistry
Each coating system is designed for a film range. A sol-gel system at 5–15 μm forms a dense, hard film; a two-component air-dry system needs 20–40 μm to reach its barrier properties. Comparing thicknesses across systems says little on its own.
Coverage beats thickness
A thin film that reaches every collar and joint protects better than a thick film that misses them. Dip application gives full coverage at thin film; spray builds thickness on faces and less inside.
The cost of going thicker
Thick films add thermal resistance, and at high fin density they bridge the gaps between fins. The resulting loss in capacity and airflow lasts for the life of the coil.
What this means for your project
Specify a film range for the chosen system, how it is measured and where. Ask for the batch film thickness record rather than a single nominal value.
