What salt-spray test durations mean
Salt-spray testing supports corrosion-resistance assessment or comparison under specified conditions. Test hours cannot be converted directly into years of service or days of exposure in a natural environment.
Results depend on the material, surface treatment, test conditions and assessment criteria. ASTM B117 does not provide a universal conversion; any correlation with service exposure requires corroborating long-term atmospheric exposure data for the relevant material system and conditions.
Source and applicability pending verification. This table reproduces the original reference material; its underlying source, assumptions and applicable conditions have not been confirmed. It is not a universal conversion formula provided by ASTM B117 and must not be used directly to predict a product’s service life in a natural environment.
On a narrow screen, swipe horizontally to read all four columns.
| Test | Duration | Coastal exposure equivalent | Natural exposure equivalent |
|---|---|---|---|
| NSS | 1 hour | Approx. 5 days | Approx. 15 days |
| NSS | 24 hours | Approx. 120 days | Approx. 1 year |
| ASS | 1 hour | Approx. 15 days | Approx. 45 days |
| ASS | 24 hours | Approx. 1 year | Approx. 3 years |
| CASS | 1 hour | Approx. 40 days | Approx. 120 days |
| CASS | 24 hours | Approx. 960 days | Approx. 8 years |
Align conditions before comparing results
Before comparing results, confirm the material, surface treatment, test method, exposure duration and acceptance criteria. Identical durations under different conditions do not establish equivalent corrosion resistance.
NSS, ASS and CASS
Neutral salt spray, acetic acid salt spray and copper-accelerated acetic acid salt spray use different test environments. Select the conditions and evaluation method against the customer’s specified standard and revision.
Read results with their test conditions
Retain component identification, preparation, test conditions, observation intervals and photographs to connect the results with the component requirements.