Testing that Reaches the World

MIL-STD-810G Method 524 Freeze/Thaw Testing is a testing method that evaluates the ability of equipment that is exposed to variable environmental conditions and its ability to withstand repeated cycles of freezing and thawing. This testing is especially relevant for systems or components that may be exposed to environmental conditions where freezing and thawing occur, such as in cold climates or during transportation through areas with varying temperatures.

Test procedures for Method 524 typically involves subjecting the equipment to controlled temperature cycles that simulate freezing and thawing conditions in accordance with specific test parameters, including the temperature ranges, cycling rates, and durations.  The test engineering team at Clark Testing will help select the appropriate test parameters and ranges based on the equipment's intended use and the expected freeze/thaw conditions.

After the test cycles are completed we will inspect the equipment for any functionality degradation, mechanical integrity, performance variations, or any other relevant factors. The equipment is assessed based on its ability to withstand the specified freeze/thaw conditions without exceeding the acceptable limits. Our team will assess the effects of moisture changes between liquid and solid, in or on material, as the equipment is exposed to ambient temperature cycles through the freeze point along with the effects of moisture induced by transfer from a cold-to-warm or warm-to-cold environment.

When assessing the functional use and operating environment of the equipment the Clark engineer will develop a test plan for the freeze/thaw test using one of three suitable procedures.

The three MIL-STD-810G Method 524 procedures typically used are:

Procedure I: Daytime Cycling Effects - To simulate the effects of daytime cycling on material exposed to temperatures varying slightly above and below the freeze point that is typical of daytime warming and freezing at night when deposits of ice or condensation, or high relative humidity exist. For Procedure I to be effective, frost must form on the test item surfaces during the temperature increase through the freeze point, and then melt just prior to re-freezing.

Procedure II: Fogging - For material transported directly from a cold to a warm environment such as from an unheated aircraft, missile, or rocket, to a warm ground area, or from a cold environment to a warm enclosure, and resulting in free water or fogging.

Procedure III: Rapid Temperature Change - For material that is to be moved from a warm environment to a cold environment (freeze) and then back to the warm environment, inducing condensation (free water).

Determine Test Levels and Conditions

The engineering team at Clark Testing can develop a qualified test plan for MIL-STD-810G Method 524 Freeze/Thaw testing.  We will help determine the test levels and conditions applying specific parameters such as temperature, moisture level/form, test item configuration (operational or storage), and the number of freeze/thaw cycles.

Test item configuration

For the test configuration, we will assess the conditions or environment in which the equipment may be placed during its life cycle. For example, we typically consider some of the following configurations listed below:

1. In a shipping/storage container or transit case.
2. Protected or not protected.
3. In its operational configuration.
4. Modified with kits for special applications.

Temperature range

Clark’s test plan will indicate the appropriate temperatures within the storage or operational range of the test item. Normally, the temperature cycle ranges between + 5°C and -l0°C (41°F and 14°F) for daytime cycling effects, and -l0°C (14°F) to standard ambient based on requirements to achieve the desired effects.

Moisture

In some cases, the Clark test procedure will use water to create moisture and apply the moisture as water vapor or as free water (spray).

Number of cycles

The number of cycles or changes from one thermal-moisture condition to another and back to the original condition is specified in the test plan.  Typically, the test plan or test procedure will recommend holding the test item at each condition for a minimum of one hour following test item temperature stabilization.

Unless otherwise justified by the material's life cycle profile, apply the following minimum number of cycles:

1. Daytime cycling effects; apply twenty freeze-thaw cycles.
2. Cold-to-warm transfer for free water or fogging; apply three cycles.
3. Warm-cold-warm for freezing and melting and/or rapid temperature change; apply three cycles.

The test engineering team at Clark Testing can help ensure that your equipment will operate, function, and maintain its integrity after withstanding rapid freeze/thaw conditions during its operation or transportation.  Call 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 524.