ASTM B-117 Salt Spray / Salt Fog
ASTM B-117 outlines that procedures to conduct salt spray testing, salt mist testing and salt fog testing. This testing can occur on both material samples and finished products. ASTM B 117 testing provides a controlled corrosive environment to determine the resistance that manufactured products and raw materials have to the high-concentrate salt conditions. Essentially, salt-fog testing is a simulation of ocean conditions.
Why is ASTM-B-117 Salt Fog Testing Important?
Salt-spray tests are important because they provide insight on the corrosive resistance of materials. Working with a salt fog test lab is crucial for any products that will be permanently placed on a ship. It is also important for products that will be placed in service near a body of salt water undergo salt spray tests. A salt spray test lab can assist manufacturers in comparing the performance of multiple finishes and materials.
ASTM B117 salt fog testing can be combined with other standards to provide more detailed information about a product or material. For instance, when ASTM B 117 salt spray tests are combined with ASTM D3359 adhesion tests, manufacturers can measure coating creep and coating adhesion. ASTM B-117 salt mist tests can be combined with ASTM D1654 to determine the corrosive characteristics of a metal or coated surface when it is scratched and exposed to a corrosive environment. ASTM D1654 is the standard test method for the evaluation of painted or coated specimens subjected to corrosive environments.
What Happens to Materials and Products Exposed to Salt Spray Conditions?
There are three primary impacts that salt and corrosive atmospheres can have. The first is corrosion. The corrosion can result from an electrochemical reaction. The corrosion can be accelerated stress corrosion as well. Lastly, the corrosion can be salt ionization in water causing the formation of acidic/alkaline solutions.
The results of salt spray tests can also be electrical. Salt mist conditions can create corrosion that creates conductive coatings. Salt deposits can cause the impairment of electrical material. Corrosion can also impair the performance of insulating metals and materials.
Lastly, the corrosion from salt spray tests can cause physical effects. Salt can bind or clog moving parts of mechanical assemblies and components. The salt corrosion can cause paint blistering from electrolysis.
What is involved in ASTM-B-117 Salt Mist Testing?
A test specimen is placed in a salt fog chamber. These chambers control the temperature, humidity and salt concentration. The salt-fog chamber consists of a salt solution reservoir, one or more atomizing nozzles, a supply of suitably conditioned compressed air specimen, supports, provision for heating the chamber, and necessary means of control.
The ASTM B117 salt fog test standard calls for the temperature to be 35⁰C and relative humidity to be 6.5pH to 7.2pH. The salt atmosphere is to be five parts sodium chloride to 95 parts water. The water is ASTM D1193 Type IV water. Compressed air is used to introduced he salt solution into the chamber. There are tolerances for each of these conditions.
The duration of exposure will vary on the product, it’s category and the manufacturer’s request. Most testing is conducted in 24-hour increments. The most common salt fog test durations are 72 hours, 96 hours, 240 hours and 600 hours.
Keystone Compliance has expertise in completing salt fog testing per ASTM-B-117. With multiple salt fog chambers, including one that has an inside dimension of 8’ x 4’ x 4’. The primary test equipment required for salt-spray testing is a salt fog chamber.
In addition to completing testing within its lab, Keystone Compliance can also conduct on-site testing. Please contact us to discuss you salt spray testing need and learn why Keystone Compliance has been recognized as of the fastest-growing companies in the country.