ASTM B 117 Salt Spray (Fog)
The US National Bureau of Standards (now called NIST) began doing neutral salt spray testing almost 100 years ago. ASTM agreed upon a standard set of conditions in the late 1930s and designated the test as B 117. This standard is among the most widely used corrosion prediction tests. Although there is debate about how accurately the test method predicts performance in the field, there is no question that volumes of test data exist that provide a basis of comparison for samples under a tightly controlled set of conditions.
UDRI’s ISO 17025 scope of accreditation is certified by the Laboratory Accreditation Bureau (L-A-B). UDRI has six Q-Fog cabinets in which we perform ASTM B 117 - Standard Practice for Operating Salt Spray (Fog) Apparatus certified tests. We take pride in operating the corrosion cabinets in a uniform manner. Our quality control includes checking and recording the following parameters daily (except for holidays and weekends) during the entire time the test is being conducted:
- If samples are scribed, the scribing is done with an engraving machine which produces precise, uniform cuts.
- Cabinet temperature (35o ±2oC) is checked twice daily, at least seven hours between readings.
- Condensate is collected in each funnel having an 80 cm2 (12.4 in2 ) of horizontal collecting area. Condensate is measured at five locations in each cabinet at a collection rate of 1-2 ml per hour.
- Condensate checked for pH of 6.5 - 7.2.
- Sample racks are rotated weekly.
Test specimen preparation is done in accordance to the test plan (some with an X-scribe and others without). Panels are often rated after each 504 hours of exposure. Because there are a variety of expectations for the test, the rating scale and schedule are chosen before testing begins and are spelled out in the test plan. Before each rating, panels are rinsed with warm tap water and then with deionized water. Although there is no overall procedure for rating according to ASTM B 117, UDRI usually rates the samples using a protocol that evaluates the panels for:
- Corrosion in the scribe
- Undercutting away from the scribe
- Blistering (ASTM D 714)
In addition, samples are photographed if requested.
If you would like a quote on how much it would cost to test your samples, please contact UDRI's Bill Culhane or call 937-255-0955.
Other Corrosion Testing Available:
GM 9540P: Accelerated Corrosion
ASTM G 85-A5: Standard Practice for Modified Salt Spray (Fog) Testing (Prohesion)
NAS 1534: Filiform Corrosion