MIL-STD 810 Freeze / Thaw Testing
The purpose of this Method is to determine the ability of material to withstand:
- The effects of moisture phase changes between liquid and solid, in or on material, as it cycles through the freeze point.
- The effects of moisture induced by transfer from a cold-to-warm or warm-to-cold environment.
This water enclosure test is best for material that will go through the freeze point while wet or near moisture. It is not intended to evaluate the effects of low temperature, thermal shock, rain, or icing.
Keystone Compliance is a liquid ingress protection lab with significant understanding of MIL-810 Freeze / Thaw testing. Our test engineers have an in-depth knowledge of the requirements of ingress protection testing. They are familiar with the requirement of testing presented in both MIL-810H Freeze / Thaw section and MIL-810G Freeze / Thaw section.
The following information is extremely technical in nature. Below is a summary of Method 512.7, as derived from the MIL-STD-810 freeze / thaw section. It includes information from the MIL-STD 810G freeze / thaw and MIL-STD 810H freeze / thaw.
What are the Possible Effects of the Environment During Enclosure Testing?
All testing should occur in an enclosure testing lab, because this method induces physical changes in or on non-stationary material. This could lead to the distortion or binding of moving parts. It may also cause boning materials or seals to fail. Materials may fail as a result of the freezing or refreezing of water ingress.
Changes in characteristics of electrical components may also be noted. There may be electrical flashover/reduced insulation resistance. Optical systems may fog during freeze-thaw transitions. Material may also be unable to function correctly due to ice adhesion and interference or blockage of moving parts.
What are the Different Procedures for Ingress Protection Testing?
Procedure I – Diurnal Cycling Effects:
This procedure simulates diurnal cycling on material exposed to temperatures that vary slightly above and below the freeze point. This may result from daytime warming and nighttime freezing, when deposits of ice, condensation, or high relative humidity exist. For Procedure I to be effective, frost must form on the test item, and melt just prior to re-freezing.
Procedure II – Fogging:
This procedure is best for material transported directly from a cold to a warm environment. For example material may be transferred from an unheated aircraft, missile or rocket, to a warm ground area. Or from a cold environment to a warm enclosure ingress, which results in free water or fogging.
Procedure III – Rapid Temperature Change
The procedure is best material that will be moved from a warm environment to a cold environment and back.
What are Appropriate Temperature Ranges for the Best Freeze / Thaw Testing?
Use temperatures within the storage or operational range of the test item. Normally, the temperature cycle ranges between +5 °C and -10 °C for diurnal cycling effects. And from -10 °C to standard ambient, but these vary as required to achieve the desired effects.
How Many Cycles Should Occur for Proper IP Code Certification?
A cycle is a change from one thermal-moisture condition to another and back to the original condition. Unless otherwise specified, hold the test item at each condition for a minimum of one hour after temperature stabilization.
For diurnal cycling effects (daily freeze-thaw) a minimum of twenty cycles should occur. For cold-to-warm transfer (for free water or possible fogging) three cycles should occur. For warm-cold-warm (for freezing and melting, rapid temperature change) three cycles should occur.
What Other Information is Necessary for Freeze / Thaw Compliance Testing?
In addition to the information derived from Part One, apply a brief scenario of service conditions to explain the intended simulation. For effective testing information on the type of moisture required (vapor or spray) should be provided. Specifications about the initial test conditions, temperatures, and number of cycles are necessary. Testing may vary based on if the test is a demonstration of survival or of functional performance.
Pretest Information:
- Low temperature extreme and time at that temperature.
- Rate of temperature rise.
- Means of introducing moisture using water vapor.
- Number of cycles.
During Test Information:
For test validation purposes, record deviations from planned procedures or parameter levels, include any procedural anomalies that may occur. Include:
- The transfer times between chambers (door open to door close).
- Conditions at which frost forms.
Post-Test Information:
- Length of time for visual examination and performance checks.
- Results of visual and operational checks (during and after testing).
- Location of any free water on or in the test item.
How Ought the Results of the Test Be Analyzed?
Apply any data that demonstrates the failure of a test item to meet the requirements of the material specifications. Consider related information such as:
- Results of nondestructive examinations of material following the freeze-thaw test, that may be conducted at extreme temperatures.
- Degradation or changes in operating characteristics allowed at the temperature extremes.
- Evidence of improper lubrication and assurance that the lubricants specified for the environmental condition were used.
What Freeze / Thaw Testing Lab Should You Trust?
Keystone Compliance has been recognized as one of the best freeze / thaw labs in the country. We employ experienced test engineers who understand the requirements of MIL-810 testing standards. Our freeze / thaw laboratory is fully equipped with the appropriate devices.
Are you looking for a freeze / thaw certification for your product? Keystone Compliance is equipped to provide 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.
There have been several versions of freeze-thaw testing procedures in MIL-STD-810 freeze-thaw testing. Below is a list of each version and the appropriate method number: