Stainless steel grade selection for coastal and chloride environments
How chloride exposure, temperature and maintenance decide between 304, 316L and duplex grades.
Chlorides are the single most common reason a stainless installation fails early. The grade decision is not about the label on the certificate but about the local chloride concentration, the temperature and how often the surface is cleaned. As a practical rule: indoor, low-chloride, food-contact service is usually fine with 304. Coastal air, de-icing salts, chemical media and continuous service above roughly 60°C in chloride-bearing conditions push you to 316L. Above that, duplex 2205 becomes the cost-effective step when strength or chloride stress corrosion cracking matters. Finish and maintenance matter as much as the grade. A rough, crevice-free surface with regular fresh-water rinsing outlasts a mirror finish that never gets cleaned.