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MIL-STD-810 Method 509 Salt Fog Testing

MIL-STD-810G, Method 509.5, covers salt fog testing to evaluate equipment's resistance and performance when exposed to salt fog or salt spray environments. The test team at Clark Testing conduct salt fog testing to assess the equipment's ability to withstand and operate in corrosive salt-laden environments, such as coastal areas or maritime environments. 

Salt fog testing evaluates the resistance to corrosion and functionality in salt-laden environments of equipment. The tests help identify potential issues related to material degradation, corrosion of metal parts, electrical conductivity, and functional performance when exposed to salt fog. 

Clark’s Dynamic Test Lab applies Method 509 procedures to subject equipment to a controlled environment where a fog of saltwater solution is generated and sprayed onto the equipment's surfaces. The test duration and concentration of the saltwater solution are specified based on the equipment's intended use and the expected environmental conditions. 

Clark’s salt fog test chamber generates the salt fog along with specific environmental conditions, such as temperature and humidity, during the test. These conditions are specified to simulate realistic salt fog environments that the equipment may encounter during its operational life. 

MIL-STD-810, Method 509 standard defines acceptance criteria that include allowable corrosion, material degradation, functionality, and other performance parameters. The equipment is assessed based on its ability to withstand the specified salt fog exposure without sustaining excessive corrosion or exhibiting performance degradation beyond acceptable limits. 

As we prepare for and conduct the salt fog test, the Clark’s team of test engineering & technicians will implement the following processes & procedures to execute the salt fog test: 

  • Collect the technical information concerning the test item in a salt fog environment. 
  • Determine the test procedure, test item configuration, cycles, durations, and parameters for storage/operation. 
  • Prepare the test item for testing and ensure the test item surfaces are free of contamination such as oil, grease, or dirt that could cause a water break.  
  • Configure the test item as specified in the test plan and insert it into the test chamber.  
  • Use sodium chloride containing (on a dry basis) not more than 0.1 percent sodium iodide and not more than 0.5 percent total impurities.  
  • Adjust to and maintain the solution at a specific gravity by using the measured temperature and density of the salt solution.  
  • If necessary, add sodium tetraborate (borax) to the salt solution as a pH stabilization agent in a ratio not to exceed 0.7g sodium tetraborate to 75 liters of salt solution.  
  • Maintain the pH of the salt solution, as collected as fallout in the exposure chamber, between 6.5 and 7.2 with the solution temperature at +35 ±2 °C (95 ±4 °F).  
  • Verification of the chamber must be done unless the chamber has been used within five days.  Verify the nozzle are not clogged, immediately before the test and with the exposure chamber empty, adjust all test parameters to those required for the test.  
  • Maintain conditions for at least one 24-hour period to ensure proper operation and salt fog collection can be verified. To verify the chamber is operating properly, measure the salt fog fallout after 24 hours.  

The salt concentration for the fog generated during testing is specified in the MIL Standard and is typically defined as a percentage of salt content in the water solution used for generating the salt fog. The specific concentration levels are determined based on the equipment's intended use and the anticipated exposure scenarios. 


In addition to corrosion exposure testing, Clark’s salt fog test chamber generates specific environmental conditions, such as temperature and humidity, during the test. 

The test engineering team at Clark Testing can help ensure that equipment will function and maintain its performance while operating in a corrosive environmentCall or email the Clark Dynamics Test Laboratory for assistance in developing a test plan and conducting the appropriate test to validate your equipment in accordance with MIL-STD-810G Method 509.5. 

Test Set Up

In house custom design and fabrication capabilities (machining and welding) to ensure test fixtures accurately simulation environmental conditions.  FEA capabilities to support fixture design along with welding, fabrication & machining services.  Multiple vibration adapter plates and prefabricated test fixtures help to streamline the testing process.

Instrumentation capabilities including accelerometers and strain gages with multi-channel control and data acquisition equipment ensuring accurate test data is being recorded.  All instrumentation and equipment is provided with measurement uncertainty and compliant   with Clark’s ISO 17025-2017 Quality Program.

Lab technicians and engineers record daily test activities to register all activities, events, and responses during the test.  The daily test logs along with test data, pictures and test procedures are included in comprehensive test report that is the industry standard.

 We work closely with you to validate engineering, ensure quality, analyze test spectrums, and execute accurate testing programs for successful qualification and marketing of your product.

We work closely with you to validate engineering, ensure quality, analyze products and qualify equipment while supporting the time constraints and product cycles that are vital to your success.

Paul Heffernan, CEO of Clark Testing