ASTM B117
Standard Practice for Operating Salt Spray (Fog) Apparatus
Defines apparatus and operating conditions for a controlled neutral salt-spray cabinet but does not set coating-specific exposure duration or acceptance limits.
What ASTM B117 specifies
ASTM B117 is the operating practice most often referenced for neutral salt-spray exposure. It controls cabinet construction, specimen positioning, atomized salt solution, temperature, fog collection, pH, and continuity of exposure. It does not prescribe how many hours a coating must survive, what failure looks like, or how laboratory hours convert to outdoor life. Those requirements come from the coating, product, or procurement specification. Reports should distinguish white corrosion products, red rust, blistering, scribe creep, and other failure modes. B117 is principally a comparative quality-control exposure and should not be presented as a universal service-life predictor.
ASTM B117 types and classes
Every designation the document defines, with the thickness it requires and the tests it imposes.
| Designation | Meaning | Requirement / test |
|---|---|---|
Neutral salt spray | Cabinet exposure using a nominal 5% sodium chloride solution under controlled neutral-pH conditions | Exposure duration and acceptance criteria supplied by the governing coating or product specification |
Tests and the drawing call-out
Tests the document imposes
- Cabinet temperature control
- Collected-fog rate
- Solution concentration
- Solution pH
- Specimen exposure and reporting
How to cite it
Drawing call-out
SALT SPRAY TEST PER ASTM B117 FOR <HOURS> H; ACCEPTANCE: <FAILURE CRITERIA>Angle brackets mark the choices the drawing must make; every finish page shows a completed example.
Finishes specified to ASTM B117
Also referenced by: Anodizing Type II, Boric-Sulfuric Acid Anodizing Type IC, Chemical Conversion Coating, Chromic Acid Anodizing Type I, Hard Anodizing Type III, Hard Anodizing Type III With PTFE, Magnesium Chemical Conversion Coating, Zinc-Flake Dip-Spin Coating, Zinc-Nickel Plating.
ASTM B117 — frequently asked
How many hours does ASTM B117 require?
ASTM B117 itself requires no universal duration. The coating or product specification must state exposure hours and acceptance criteria.
Does 1,000 hours ASTM B117 equal a number of outdoor years?
No reliable universal conversion exists. Salt spray is an accelerated comparative test and does not reproduce every outdoor wet-dry, ultraviolet, or pollutant cycle.
What should an ASTM B117 report say?
It should state exposure time, specimen preparation and orientation, interruptions, evaluation method, and the observed failure mode and area.
ASTM B117 is copyrighted by ASTM International. 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 ↗