Contamination by Fluids | Contaminazione da fluidi

MIL STD 810 G – Test Method 504.1 – Contamination by Fluids

 

SCOPE

 

Purpose
Use contamination by fluids tests to determine if materiel (or material samples) is affected by temporary exposure to contaminating fluids (liquids) such as may be encountered and applied during its life cycle, either occasionally1/, intermittently2/, or over extended periods3/.
Application
Select one of the two procedures described in this method when there is a high probability of fluid contamination during the life cycle of the materiel. Contamination may arise from exposure to fuels, hydraulic fluids, lubricating oils, solvents, and cleaning fluids, de-icing and anti-freeze fluids, runway deicers, insecticides, disinfectants, coolant dielectric fluid, and fire extinguishants.
WARNING: This method requires the use of substances and/or test procedures that may have an environmental impact or be injurious to health, if adequate precautions are not taken. Additional information is provided in annex a. Refer to the supplier’s material safety data sheet (msds) or equivalent for chemical compatibility and health hazard data on the various chemicals used, and coordinate with local environmental authorities. Ensure all post-test materials are disposed of in accordance with local, state and federal regulations.
Limitations
This test is not intended to demonstrate the suitability of materiel to perform during continuous contact with a fluid; e.g., an immersed fuel pump, nor should it be used to demonstrate resistance to electrolytic corrosion.

 

TEST PROCESS

 

Procedure I – Large Items
  • Step 1. With the test item in its required configuration (operational, storage, etc.), install it in the test facility. If appropriate, the configuration may include appropriate electrical or mechanical connections.
  • Step 2. Stabilize the test item at the appropriate temperature for the identified contamination scenario (see paragraph 2.2.5).
  • Step 3. Stabilize the temperature of the specified fluid(s) (see Table 504.1-I) to that determined from paragraph 2.2.5.2. If simultaneous application of more than one fluid is required, apply the fluid with the highest application temperature first, then the next highest, and so on until all required fluids have been applied.
Occasional Contamination
  1. Apply the specified fluid(s) (e.g., immerse, dip, spray, etc.) to the entire surface of the test item that is likely to be exposed.
  2. Allow the test item to drain naturally for 5 to 10 minutes. Shaking or wiping is not permitted but, if representative of service conditions, it may be rotated about any axis to allow for drainage from different positions.
  3. Maintain the test item at the temperature determined in paragraph 2.2.5.1 for eight hours (paragraph 2.2.6). Ramp the chamber to standard ambient temperature (avoiding temperature shock) prior to removal of test item(s).
  4. Visually examine the test item for degradation of materials, protective finishes, and record any physical characteristics for comparison with previous results or if appropriate, conduct an operational check of the test item similar to that in paragraph 4.5.2, step 3, and document the results for comparison with the pretest data.
  5. Clean the test item with a known fluid that will not cause any changes to the test item. If testing sequentially, repeat steps a (1) through (4) for each specified fluid without cleaning between each chemical application.
Intermittent Contamination
  1. Apply the specified fluid(s) (e.g., immerse, dip, spray, etc.) to the entire surface of the test item that is likely to be exposed. Maintain surfaces in a wetted condition for 8 hours followed by a drying period of 16 hours at the temperature specified in paragraph 2.2.5.1. Remove the test item(s) from the chamber and allow it to stabilize at standard ambient temperature.
  2. Visually examine the test item for degradation of materials, protective finishes, and physical changes. Repeat Step 1b until three 24-four hours cycles have been completed. After the last cycle, ramp the chamber to standard ambient temperature (avoiding temperature shock) prior to removal of test item(s).
  3. If appropriate, conduct an operational check of the test item similar to that in paragraph 4.5.2, step 3, and document the results for comparison with the pretest data.
  4. Clean the test item with a known fluid that will not cause any changes to the test item. If testing sequentially, repeat steps b(1) through (4) for each specified fluid.
Extended Contamination
  1. Immerse the test item in the specified fluid and maintain for the period specified in the requirements document. If not specified, use a fluid temperature as given in Table I, and immerse the test item for at least 24 hours.
  2. Remove the test item from the chemical and allow it to drain naturally for 5 to 10 minutes.
  3. Place the test item in a chamber set at the temperature determined in paragraph 2.2.5.1 for eight hours (paragraph 2.2.6). Ramp the chamber to standard ambient temperature (avoiding temperature shock) prior to removal of test item(s). Steps c (1) through (3) can be repeated if long term analysis is needed as per the test plan.
  4. After all cycles have been performed, visually examine the test item for degradation of materials, protective finishes, and physical changes and if appropriate, conduct an operational check of the test item similar to that in paragraph 4.5.2, step 3, and document the results for comparison with the pretest data Record results.
  5. If testing sequentially, repeat steps c (1) through (4) for each specified fluid.
Procedure II – Small Items
  • Step 1. Select the appropriate chemicals/solutions for the test (Table 504.1-II). Include any or all of the chemicals in testing, and possibly add other solutions not on the list (Table 504.1-I) if the environment the test item will see requires it. Prepare the test items. If etching will not affect the test item, number the parts to help with identification. Use all test items and chemicals that are at standard ambient conditions (Part One, paragraph 5.1) during testing. Record the standard ambient conditions.
  • Step 2. Record the item nomenclature, serial or lot numbers, manufacturer, chemicals/solutions, and any other pertinent test data.
  • Step 3. Immerse, spray, splash, or brush each item with a required chemical(s). If immersing the items, let them soak for one hour. If spraying, wiping, or brushing on the chemical, make additional applications to ensure the item is kept wet for one hour. After one hour, stop applying the fluids or remove the test items from the chemicals and visually observe any deterioration including softening, color changes, cracking, or dissolving of the material into the solution. If any hardness or other tests are to be performed, blot the items of any excess chemical and proceed with the testing. When the physical properties or the visual only check has been performed, either place the items back into the solutions or re-apply the solutions, and continue the test for another seven hours (total of eight hours in contact with chemicals). If moderate or greater deterioration is noted on any test item after one hour, discontinue testing in that chemical and record all pertinent data.
  • Step 4. After a total exposure time of eight hours, remove the test item(s) from the solutions or stop applying, blot excess chemicals from the item, and inspect again for any type of chemical reaction resulting from the additional exposure to that particular compound. Record any weight, hardness, or other physical data for each piece where appropriate. Let all items dry for a maximum of 24-hours. After the drying period, record final measurements and weights, if any, and record final visual observations.

 

NOTE: Tailoring is essential. Please, ask to your confidence laboratory for further details about tailoring of test methods.

 

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