ISO 9227
Corrosion Tests in Artificial Atmospheres — Salt Spray Tests
Defines neutral, acetic-acid, and copper-accelerated acetic-acid salt-spray test atmospheres for corrosion testing.
What ISO 9227 specifies
ISO 9227 defines three continuous salt-spray environments: NSS neutral salt spray, AASS acetic-acid salt spray, and CASS copper-accelerated acetic-acid salt spray. The document controls solution, pH, cabinet temperature, collection rate, specimen placement, and operating checks. It does not assign a universal test duration or pass criterion to a finish; those come from the coating or product specification. NSS is widely applied to metallic and organic coatings, while AASS and especially CASS are more aggressive acidic tests used for selected decorative coating systems. Results compare process quality under a defined test and should not be converted directly into outdoor service years.
ISO 9227 types and classes
Every designation the document defines, with the thickness it requires and the tests it imposes.
| Designation | Meaning | Requirement / test |
|---|---|---|
NSS | Neutral sodium chloride salt-spray atmosphere | Duration and acceptance supplied by governing specification |
AASS | Acidified sodium chloride salt-spray atmosphere | Duration and acceptance supplied by governing specification |
CASS | Acidified salt spray accelerated with copper salt for selected coating systems | Duration and acceptance supplied by governing specification |
Tests and the drawing call-out
Tests the document imposes
- NSS neutral salt spray
- AASS acetic acid salt spray
- CASS copper-accelerated acetic acid salt spray
- Cabinet corrosivity checks
How to cite it
Drawing call-out
SALT SPRAY TEST PER ISO 9227, <NSS|AASS|CASS>, <HOURS> H; ACCEPTANCE: <CRITERIA>Angle brackets mark the choices the drawing must make; every finish page shows a completed example.
ISO 9227 — frequently asked
What is the difference between ISO 9227 NSS, AASS, and CASS?
NSS is neutral salt spray, AASS is acidified with acetic acid, and CASS adds copper acceleration to the acidic environment.
How many hours does ISO 9227 require?
ISO 9227 defines operation of the exposure but does not set one universal duration. The governing product or coating specification supplies hours and acceptance criteria.
Is ISO 9227 equivalent to outdoor exposure?
No. It is a controlled accelerated comparison and has no universal conversion to outdoor service life.
ISO 9227 is copyrighted by International Organization for Standardization. This page explains the document so a drawing can be read; it does not reproduce the standard. Purchase the current edition from the publisher. Official source ↗