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MIL STD 810 G – Test Method 510.5 – Sand and Dust
SCOPE
Purpose
Dust (< 150μm) procedure. This test is performed to help evaluate the ability of materiel to resist the effects of dust that may obstruct openings, penetrate into cracks, crevices, bearings, and joints, and to evaluate the effectiveness of filters.
Sand (150 to 850μm particle size) procedure. This test is performed to help evaluate the ability of materiel to be stored and operated in blowing sand conditions without degrading performance, effectiveness, reliability, and maintainability due to abrasion (erosion) or clogging effects of large, sharp-edged particles.
Application
Use this method to evaluate all mechanical, optical, electrical, electronic, electrochemical, and electromechanical devices likely to be exposed to dry blowing sand or blowing dust-laden atmospheres.
Limitations
This method is not suitable for determining erosion of airborne (in flight) materiel because of the particle impact velocities involved, or for determining the effects of a buildup of electrostatic charge. Additionally, because of control problems, this method does not address sand or dust testing out-of-doors.
TEST PROCESS
Test Procedure I – Blowing Dust
Step 1. With the test item in the chamber and stabilized at standard ambient temperature, adjust the air velocity to 8.9 + 1.3 m/s (1750 + 250 ft/min), or as otherwise determined from the test plan.
Step 2. Adjust the dust feed control for a dust concentration of 10.6 ± 7 g/m3 (0.3 + 0.2 g/ft3)
Step 3. Unless otherwise specified, maintain the conditions of Steps 1 and 2 for at least 6 hours. If required, periodically reorient the test item to expose other vulnerable faces to the dust stream. SEE THE ABOVE WARNING NOTE REGARDING HEALTH HAZARDS.
Step 4. Stop the dust feed. (See paragraph 4.1.1.7.) Reduce the test section air velocity to approximately 1.5 +1 m/s (300 + 200 ft/min) and adjust the temperature to the required high operational temperature (see paragraph 4.1.1.1), or as otherwise determined from the test plan.
Step 5. Maintain the Step 4 conditions for a minimum of 1 hour following test item temperature stabilization.
Step 6. Adjust the air velocity to that used in Step 1, and restart the dust feed to maintain the dust concentration as in Step 2.
Step 7. Continue the exposure for at least 6 hours or as otherwise specified. If required, operate the test item in accordance with the test plan. If the test item fails to operate as intended, follow the guidance in paragraph 4.2.3.3.2. Otherwise proceed to Step 8.
Step 8. Stop the dust feed and allow the test item to return to standard ambient conditions at a rate not to exceed 3°C/min (5°F/min). Stop any air flow and allow the dust to settle (possibly up to 12 hours).
Step 9. Remove accumulated dust from the test item by brushing, wiping, or shaking, taking care to avoid introduction of additional dust or disturbing any that may have already entered the test item. Do NOT remove dust by either air blast or vacuum cleaning unless these methods are likely to be used in service.
Step 10. Perform an operational check in accordance with the approved test plan, and document the results for comparison with pretest data. See paragraph 5.1 for analysis of results.
Step 11. Inspect the test item for dust penetration, giving special attention to bearings, grease seals, lubricants, filters, ventilation points, etc. Document the results.
Test Procedure II – Blowing Sand
Step 1. Increase the chamber temperature (at a rate not to exceed 3°C/min (5°F/min)) and stabilize the test item at its high operating temperature.
Step 2. Adjust the air velocity according to test plan (see paragraph 4.2.1.2).
Step 3. Adjust the sand feeder to obtain the sand mass flow rate determined from the pretest calibration.
Step 4. Maintain the conditions of Steps 1 through 3 for the duration specified in the test plan. If required, re-orient the test item at 90-minute intervals to expose all vulnerable faces to blowing sand, and repeat Steps 1-3.
Step 5. If operation of the test item during the test is required, perform an operational test during the last hour of the test, and document the results. If the test item fails to operate as intended, follow the guidance in paragraph 4.2.3.3. Otherwise proceed to Step 6. SEE THE ABOVE WARNING NOTE REGARDING HEALTH HAZARDS.
Step 6. Stop the sand feed. Allow the test item to return to standard ambient conditions at a rate not to exceed 3°C/min (5°F/min). Stop any air flow and allow the sand to settle. Remove accumulated sand from the test item by using the methods anticipated to be used in service such as brushing, wiping, shaking, etc., taking care to avoid introduction of additional sand into the test item.
Step 7. Conduct an operational check of the test item in accordance with the approved test plan, and record results for comparison with pretest data. See paragraph 5.2 for analysis of results.
Step 8. Visually inspect the test item looking for abrasion and clogging effects, and any evidence of sand penetration. Document the results.
NOTE: Tailoring is essential. Please, ask to your confidence laboratory for further details about tailoring of test methods.