MIL-STD-810H Low Temperature (Method 502.7) Test Machine

MIL-STD-810H (Method 502.7) Low Temperature

MIL-STD-810G (Method 502.5) Test Machine

The MIL-STD-810H (Method 502.7) Low Temperature Test Machine is designed to evaluate a device’s durability under low temperature conditions (icy, cold environments). These conditions can significantly affect battery performance and the functionality of electronic components.

1. Scope

1.1 Purpose:

This test is used to evaluate the effects of low-temperature conditions on material safety, integrity, and performance. The test is conducted to determine the potential adverse effects of low temperatures during storage, operation, and use.

1.2 Application:

This method is suitable for evaluating materials that may be exposed to low-temperature environments. It is specifically used to determine the ability of military, aerospace, and industrial equipment to perform under cold weather conditions.

1.3 Limitations:

• It is not suitable for simulating high-altitude low-temperature environments (Method 500.6 should be used for this purpose).
• It does not evaluate the combined effects of low temperature and humidity (it can be supplemented with Method 520.5).
• It does not directly cover icing or freeze-thaw cycles (Method 524.1 should be used for this purpose).

2. Test Tailoring Guidance

2.1 Selecting this method

The test should be selected by reviewing requirement documents to determine whether low-temperature exposure is expected in the material’s lifecycle.

2.1.1 Effects of Low-Temperature Environments

• Material hardening and increased brittleness.
• Compression and jamming of parts due to differential contraction of materials with different thermal expansion coefficients.
• Increased viscosity and loss of fluidity in lubricants.
• Changes in electronic components (resistors, capacitors, etc.).
• Performance degradation in transformers and electromechanical components.
• Stiffening of shock-absorbing systems.
• Cracking of explosive materials (e.g., ammonium nitrate-based substances).
• Static fatigue and fractures in optical glass.
• Slippery surfaces and ice formation due to condensation and freezing.

2.1.2 Sequencing with other test methods

This test can provide more comprehensive results when combined with the following methods:

• Method 503.7 (Temperature Shock Test)
• Method 505.7 (Solar Radiation Test)
• Method 520.5 (Low Temperature & Humidity Combination Test)

2.2 Test procedure selection

This method includes three different test procedures:

1. Procedure I – Storage: Evaluates the effects of long-term storage at low temperatures on the material.
2. Procedure II – Operation: Tests the ability of the material to function under low-temperature conditions.
3. Procedure III – Use and Handling: Assesses the ability to assemble, disassemble, and operate equipment in low-temperature conditions.

2.3 Determining test levels and conditions

• Climatic conditions: The actual environmental conditions where the material will be used should be considered.
• Exposure duration: Should be determined based on real-world usage scenarios.
• Material configuration: The actual use of the material during storage and operation should be considered.

3. Information Required

3.1 Pre-test preparations

• Configuration of the material to be tested.
• Temperature measurement points and sensor placements.
• Maximum and minimum temperature limits.

3.2 Data to be collected during the test

• Temperature-time records of the test chamber.
• Temperature-time data of the tested material.
• Mechanical and electrical performance variations.

3.3 Post-test data

• Recorded temperature changes.
• Visual inspection results.
• Functional and performance status of the tested component.

4. Test Process

4.1 Test Facility and Equipment

• A cold chamber or cabinet should be designed to maintain the air temperature around the tested material at the specified level.
• Airflow should be adjusted to match real environmental conditions for the tested material.

4.2 Test Controls

• The rate of temperature change should not exceed 3°C per minute.
• During testing, the temperature should not deviate by more than 2°C.

4.3 Test Interruptions

• Test chamber failure: If test conditions are disrupted, the material should be returned to the last successfully completed temperature level before resuming the test.
• Material failure: If the test item fails, a new sample should be used, and the test should be restarted from the beginning.

4.4 Test Implementation Procedures

• Procedure I – Storage: Evaluates the effects of long-term storage at low temperatures on the material.
• Procedure II – Operation: Tests the material’s ability to function under low-temperature conditions.
• Procedure III – Use and Handling: Assesses the ability of personnel wearing heavy cold-weather gear to operate the equipment.

5. Analysis of Results

Test results are analyzed based on the following:

• Physical damage: Cracking, fractures, deformations.
• Functional degradation: Failures in electrical or mechanical components.
• Chemical effects: Changes in material composition.
• Optical systems: Ice formation or fractures in glass and lenses.

6. References and Related Documents

• MIL-STD-810H
• NATO STANAG 4370, AECTP 230 (Climatic Conditions)
• MIL-HDBK-310 (Global Climatic Data)

Key Features

Application Areas

• Polar and Cold Regions: Devices operating in cold climates.
• Military Equipment: Military vehicles operating in cold weather conditions.

For more information about MIL-STD-810H (Method 502.7) and to place an order, please contact us!