Salt-Fog, Salt Spray, and Corrosion Testing 

Salt-Fog Testing Overview

Salt-fog testing, also known as salt spray or corrosion testing, determines the corrosion resistance of materials. The testing evaluates the impact of a humid, salty solution on materials and electrical components.

This type of testing is crucial in industries where materials are frequently exposed to corrosive environments, such as coastal areas or industrial settings. Industries that require salt spray testing can range from automotive to consumer, electronics, railway, and the aerospace industry.

Furthermore, the controlled environment of the salt-fog chamber allows for consistent and repeatable testing conditions, which are essential for accurate and reliable results. Ready to get started? Request a quote and receive the peace of mind that all of your testing needs will be met under one roof.

Why is Salt Spray Testing Important?

Salt is one of the most persuasive chemical compounds in the world and is impossible to avoid. The worst salt fog effects occur in coastal regions.

The effects of material to an environment where there is a corrosive atmosphere can be divided into three categories:

Corrosion Effects

• Corrosion due to electrochemical reaction.
• Accelerated stress corrosion.
• Formation of acidic/alkaline solutions following salt ionization in water.

Electrical Effects

• Impairment of electrical material due to salt deposits.
• Production of conductive coatings.
• Corrosion of insulating materials and metals.

Physical Effects

• Clogging or binding of moving parts of mechanical components and assemblies.
• Blistering of paint as a result of electrolysis.

The most common coatings tested are steel, brass and zamak. The salt-fog test essentially tests corrosion resistance through an accelerated process within a salt-fog chamber.

The chamber controls the amount of salt-fog, concentration of salt and pH. Different coatings have different behaviors and require different types of testing with varying durations.

How to Conduct Salt Spray Corrosion Testing

What are Corrosion Testing Requirements?

Salt-fog testing is designed to simulate and accelerate the corrosive effects of a salty, humid environment. The testing is carried out in specialized chambers that can precisely control various parameters to ensure consistent and repeatable results.

Chamber Environment

• • Salt Concentration: Typically a 5% sodium chloride solution, adjustable per test requirements.
  • Fog Amount: Uniformly distributed mist ensures consistent exposure.
  • pH Levels: Maintained between 6.5 and 7.2, mimicking natural seawater.
  • Temperature: Kept at 35°C (95°F) to accelerate corrosion without damaging specimens.

How Long Does Salt Fog Testing Last?

The period of exposure a material or unit is subjected to a salt solution is agreed upon between the manufacturer and the testing laboratory.

Testing can last anywhere from 24 hours to 1,000 hours. However, the most common salt fog tests generally only lasts 48 to 72 hours. Depending on testing needs, the unit can be regularly monitored for corrosion or degradation of material.

Evaluation and Results

After testing, specimens are visually inspected for signs of corrosion, such as rust, pitting, or blistering of coatings.

In addition to visual inspection, an operational function check is conducted. This involves testing the mechanical and electrical functionality of the components to ensure they still operate correctly after exposure to the corrosive environment.

Salt Fog Testing Capabilities at Keystone Compliance

Keystone Compliance has a salt fog chamber that is one of the largest salt fog chambers manufactured. The chamber has internal dimensions of 8’ x 4’ x 4’. The chamber is capable of salt fog testing, salt mist testing, salt spray testing and salt laden testing as described in most popular test specifications.

In addition to a finely calibrated salt fog chamber, Keystone has created custom oversized chambers to accommodate much larger devices including cars, drones, and large pieces of machinery. If you have a large unit that is not suited to traditional chambers, our team of engineers will work with you to find a solution that will get the job done.

Expert Salt Fog Regulatory Compliance Testing

Salt fog testing is just one of the climatic testing services we offer and our lab is fully equipped with the necessary equipment.

Keystone Compliance is a salt-fog test lab with a large chamber and significant experience. Contact us to find out how we can help you meet your salt-fog testing needs. Ready to get started? Request a quote and see why hundreds of manufacturers choose Keystone for their testing needs.

Salt Fog Testing Specifications

• ASTM G85 09 Standard Practice for Modified Salt Spray Testing
• ASTM B117 09 Standard Practice for Operating Salt Spray (Fog) Apparatus
• ASTM D610 Rusting Testing
• ASTM D1654 Rust 
• EN 50155 Section 10.2.10 Salt-Fog Test
• ISO 9227 Corrosion tests in artificial atmospheres — Salt spray test
• ISO 12944-6:1998 Paints and varnishes — Corrosion protection of steel structures by protective paint systems — Part 6: Laboratory performance test methods
• MIL-STD-202 Method 101 Salt-Fog Test
• MIL-STD-810 Method 509 Salt-Fog Testing
• MIL-STD-883 Method 1009 Salt Fog Test
• MIL-STD-1344 Section 1001 Salt Fog Testing
• RTCA/DO 160 Section 14 Salt-Fog Test