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MIL STD 810 G – Test Method 502.5 – Low Temperature
SCOPE
Purpose
Use low temperature tests to obtain data to help evaluate effects of low temperature conditions on materiel safety, integrity, and performance during storage, operation, and manipulation.
Application
Use this method to evaluate materiel likely to be deployed in a low temperature environment during its life cycle and the effects of low temperature have not been assessed during other tests (e.g., a temperature-altitude test).
Limitations
This method is not intended for testing materiel to be installed in and operated in unpressurized aircraft, since such materiel would usually be tested according to Method 520.3.
Although low temperature testing may be considered for safety or hazard assessment of munitions, accomplish such testing in accordance with MIL-STD-2105C (reference 6.1d).
TEST PROCESS
Procedure I – Storage
Step 1. Place the test item in its storage configuration and install it in the test chamber.
Step 2. Adjust the chamber air temperature to that specified in the test plan for storage at a rate not to exceed 3°C/min (5°F/min).
Step 3. Following temperature stabilization of the test item (Part One, paragraph 5.4), maintain the storage temperature for a period as specified in the test plan. If not possible to instrument internal components, base any additional soak time on thermal analysis to ensure temperature stabilization throughout the test item.
Step 4. Conduct a visual examination of the test item and compare the results with the pretest data. Record any pertinent physical changes or the fact that there were no obvious changes.
Step 5. Adjust the chamber air temperature to standard ambient conditions (at a rate not to exceed 3°C/min (5°F/min)), and maintain it until the test item has achieved temperature stabilization.
Step 6. Conduct a complete visual examination of the test item and document the results.
Step 7. If appropriate, conduct an operational checkout of the test item and document the results. See paragraph 5 for analysis of results.
Step 8. Compare these data with the pretest data.
Procedure II – Operation
Step 1. With the test item in its operational configuration and installed in the test chamber, adjust the chamber air temperature to the low operating temperature of the test item as specified in the test plan at a rate not to exceed 3°C/min (5°F/min). Maintain this for at least two hours following temperature stabilization of the test item. If not possible to instrument internal components, base any additional soak time on thermal analysis to ensure temperature stabilization throughout the test item.
Step 2. Conduct as complete a visual examination of the test item as chamber access limitations will allow, and document the results.
Step 3. Conduct an operational checkout of the test item as in paragraph 4.5.1.2, Step 6, and document the results. If the test item fails to operate as intended, see paragraph 5 for analysis of results, and follow the guidance in paragraph 4.3.2 for test item failure.
Step 4. If manipulation of the test item is required at low temperature, proceed to Step 4 of paragraph 4.5.4. If not, proceed to Step 7 of this procedure.
Step 5. Adjust the chamber air temperature to standard ambient conditions at a rate not to exceed 3°C/min (5°F/min), and maintain it until temperature stabilization of the test item has been achieved.
Step 6. Conduct a complete visual examination of the test item, and document the results.
Step 7. If appropriate, conduct an operational checkout and record results for comparison with data obtained in paragraph 4.5.1.2, Step 6. If the test item fails to operate as intended, see paragraph 5 for analysis of results.
Procedure III – Manipulation
Step 1. With the test item in the test chamber and in its storage configuration, adjust the chamber air temperature to the low operating temperature of the test item as determined from the test plan at a rate not to exceed 3°C/min (5°F/min). Maintain it for two hours following temperature stabilization of the test item.
Step 2. While maintaining the low operating temperature, place the test item in its normal operating configuration by using the options of Step 3.
Step 3. Based on the type of test chamber available, select one of the two following options: Option 1 – To be used when a “walk-in” type chamber is available: With personnel clothed and equipped as they would be in a low temperature tactical situation, disassemble the test item as would be done in the field, and repack it in its normal shipping/storage container(s), transit case, or other mode and configuration. Option 2 – To be used when small chambers (non-walk-in) are used: Perform the option 1 procedure, except the disassembly and packing will be performed by personnel reaching through chamber access holes or the open door while they are wearing heavy gloves such as would be required in the natural environment.
Step 4. Reestablish the temperature to that used in Step 1, above and maintain it for two hours following temperature stabilization of the test item
Step 5. If operation of the test item is required at low temperatures, proceed to Step 1 of paragraph 4.5.3. If not, proceed to Step 6 of this procedure.
Step 6. Conduct a complete visual examination of the test item, and document the results for comparison with the pretest data.
Step 7. Adjust the chamber air temperature to standard ambient conditions (at a rate not to exceed 3°C/min (5°F/min)), and maintain it until the test item has reached temperature stabilization.
Step 8. Conduct a complete visual examination of the test item, and document the results.
Step 9. If appropriate, conduct an operational checkout of the test item and record results for comparison with data obtained in paragraph 4.5.1.2, Step 6. If the test item fails to operate as intended, see paragraph 5 for analysis of results.
NOTE: Tailoring is essential. Please, ask to your confidence laboratory for further details about tailoring of test methods.