Austenitic stainless (304/316) under wet insulation risks external chloride stress-corrosion cracking. Specs therefore demand low-leachable-chloride insulation tested to ASTM C795/C871 — standard for quality mineral wools, with expanded perlite and cellular glass as inherently low-chloride options — plus inhibited or barrier systems where wetting is credible. Many CUI-aware sites also prefer inspectable removable covers over critical stainless lines: open, inspect for staining, close.
Compute your own case: free heat-loss calculator · materials library: 12 datasheets · related: What is CUI (corrosion under insulation)? · What is economic thickness of insulation? · R-value vs k-value (λ) — what's the difference? · How hot can an exposed surface be for worker safety?
