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MIL-STD 202 Immersion Testing

Water enclosure testing is performed to determine the effectiveness of the seal of component parts. Materials are subject to thermal and mechanical stresses, by being immersed under liquid at widely different temperatures. Defective terminal parts,  partially closed seams, or molded enclosures are usually readily detected by water ingress.  Defects like this can result from faulty construction or mechanical damage like might occur during physical or environmental tests. 

Generally, immersion testing occurs immediately after such tests, and reveals defects in seals, seams, and bushings which might otherwise go unnoticed. This test should be performed in an immersion testing lab. The procedure is intended only as a measurement of the effectiveness of the seal following this test. The test is not intended as a thermal shock or corrosion test, though it may reveal failures in these respects.

The choice of fresh or salt water as a test liquid depends on the nature of the part being tested. For electrical measurements after immersion cycling, salt solution instead of fresh water better reveals leaks in seals. This test provides a simple and ready means of detecting the migration of liquids. Effects can include lowered insulation resistance, corrosion of internal parts, and appearance of salt crystals. 

Keystone Compliance is an immersion ingress protection lab with significant MIL-202 immersion experience. Our test engineers understand the requirements of MIL-STD 202G immersion testing and MIL-STD 202H immersion testing. Below is outlined the requirements of IP code testing. The following is extremely technical as it provides a summary of MIL-202G immersion testing and MIL-202H immersion testing. 

What is the Correct Procedure for Water Ingress Protection Testing? 

This test consists of successive cycles of immersions. Each cycle consists of immersion in a hot bath of fresh water followed by immersion in a cold bath.  The transfer of specimens from one bath to another should happen as rapidly as practicable. After finishing the final cycle, specimens should be washed, and all surfaces in the immersion laboratory wiped or air-blasted clean. 

Test conditions may vary. The number of cycles, duration of immersion, and nature/temperature the liquid for various conditions is indicated in the table below.

Test Condition

Number of Cycles

Duration of Each Immersion (Minutes)

Immersion Bath (Cold)

Temperature of Cold Bath ()

A

2

15

Fresh (tap) water

25 (+10, -5)

B

2

15

Saturated solution of sodium chloride and water

25 (+10, -5)

C

5

60

Saturated solution of sodium chloride and water

0 +3

What Information is Needed for the Best Immersion Testing? 

Generally enclosure testing labs should track some specific information prior to, during, and after testing. Test engineers will need to know water temperature and the temperature above this to which the test item is heated. They must also know how long the item should remain at that temperature, and the appropriate depth/duration of immersion. Tiedown precautions to prevent unrealistic stress should also be noted prior to testing. 

During the test engineers should note the location of any bubbles, as this indicates leaks. Additionally, it is important to note the water temperature 15 minutes following immersion. After completion of the test, data should be gathered, to be included in the test report. 

The amount of any free water found inside the test item and probable point(s) of entry should be reported. The actual covering depth of the water should also be included. Notes should also be made regarding the duration of immersion. Any deviations from the original test plan must be reported, and any appropriate photographs submitted.  

Who Should You Trust for Immersion Certifications for Your Product?

Keystone Compliance has been recognized as one of the best immersion labs in the country. We employ experienced test engineers who understand the requirements of  immersion compliance standards. Our water enclosure ingress lab is fully equipped with the appropriate devices, to provide quality testing. 

Are you looking to get an IP code certification for your product?  Keystone Compliance is equipped to provide immersion compliance testing for commercial, military, and aerospace products. Contact us to learn why so many manufacturers rely on Keystone Compliance to meet their compliance testing needs.