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Debugging Method of Oxygen Index tester
2019/03/15
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Methods are provided for testing materials that are structurally self-supporting in the form of vertical bars or sheet up to 10.5 mm thick. These methods are suitable for solid, laminated, or cellular materials characterized by an apparent density greater than 15 kg/m3. The methods may also be applicable to some cellular materials having an apparent density of less than 15 kg/m3 . A method is provided for testing flexible sheet or film material while supported vertically.
1. Inspect the contents of the current test folder to verify that the following information is provided:
Test request
Signed test plan
Test data sheets
Sample preparation sheet
Test material’s MSDS or the Exclusion Statement for the material/component being tested
Pre-test photographs (See section 4.2.)
Oxygen Index Pre-Test Checklist (Figure 7-1).
WARNING: Read the test material’s MSDS to verify familiarity with all safety precautions associated with the material. Verify that the test engineer is aware of all highly hazardous, reactive, or toxic components of the test material. The test engineer shall direct the test operator in proper safety procedures concerning these test materials.
2. Turn on warning lights to indicate that hazardous testing is in progress. This places the test area in a limited-access condition.
3. Don safety glasses.
4. Allow 1 hour for the oxygen cell to warm up and stabilize before calibrating and testing. If the unit is used without performing this warmup, the % Oxygen reading may drift and exhibit instability.
5. Turn on the extraction system. Set the nitrogen and oxygen gas regulators to 2.0 bar (29 psig) if the instrument has a standard flowmeter (1-12 l/min air) or 2.75 bar (39.9 psig) if a 2-25 l/min air flowmeter is fitted. Do NOT allow the line pressure to exceed 3 bar (43.5 psig), as damage to the oxygen analyzer may result.
6. Verify that the Flow Control needle valve located on the rear of the apparatus is fully open (fully counterclockwise), that the nitrogen and oxygen needle valves located on the front of the apparatus are approximately half open, and that the nitrogen and oxygen ON/OFF valves on the front of the control unit are in the OFF position. (Refer to illustrations in section 9.)
7. Check all internal connections for leaks, and seal, if necessary.
8. Place the lower debris screen (the smaller of the screens) over the test sample holder support, and allow it to fall into position. Place the upper debris screen over the test sample holder support so that it rests on the chimney support. Place the cover plate over the chimney support, with the magnetic strips toward the top cover of the unit. Position a chimney in place.
9. Slowly turn the nitrogen ON/OFF ball valve to the ON position, so that only nitrogen is flowing through the system. Turn the nitrogen needle valve so it is fully open; do not backseat the valve. Turn the Flostat needle valve on the back of the instrument (labeled Flow Control) clockwise to close it until the flowmeter indicates a flow rate equivalent to 40 (+2) mm/sec through the chimney.
For a glass chimney of internal diameter 75 mm, 40 mm/sec linear flow is indicated by 10.6 l/min; for an internal diameter of 100 mm, this linear flow is indicated by 18.8 l/min.
Note: Take the flowmeter reading at the top of the float.
10. For a glass chimney internal diameter other than 75 mm or 100 mm, calculate the specified flow rate using equation (1):
V=1.5xl0-5 ? π ? ? ? D2
where:
V = the specified volume flow rate (l/min)
? = the equivalent linear flow rate [40 (±10) mrn/sec]
D = the internal diameter of the glass chimney (mm)
Note: This procedure verifies that the Flostat is not in saturation.
11. Allow the oxygen analyzer to stabilize at or near zero (about 1 minute). While observing the % Oxygen meter, use a flat blade screwdriver to adjust the Zero adjust on the oxygen analyzer until a reading of 0.0% is achieved.
12. Turn the nitrogen valve to the OFF position, and slowly turn the oxygen valve to the ON position. Turn the oxygen needle valve so that it is fully open.
13. Assuming the same line pressure for nitrogen and oxygen, the flow rate indicated shall be the same as that indicated in step 4.4.6 or step 4.4.7. If it is not,readjust the oxygen pressure regulator until the required flow rate is obtained. This verifies that the two gases are at the same pressure.
14. Using the Span adjust on the front panel, match the % Oxygen display reading with the supplied oxygen cocentration. If using an oxygen supply bottle, the reading shall match one of the following purity grades: 99.5% for commercial grade or 99.9(5)% for high purity oxygen. If using the Building 4623 facility oxygen supply, set the % Oxygen display to read 99.9(5)%.
15. Turn the oxygen valve to the OFF position. Turn the nitrogen valve slowly to the ON position, and then turn the oxygen valve slowly to the ON position.
Turn the oxygen needle valve clockwise to close it until a desired oxygen concentration at the flow rate used in steps 4.4.6 and 4.4.7 is displayed.
Note: The Flostat is designed to maintain a constant flow rate through the flowmeter, regardless of the oxygen and nitrogen needle valve positions, providing that at least one of the needle valves remains fully open.
16. Verify that the neck valve on the igniter (located immediately downstream of the igniter handle) is closed. Turn on the propane bottle, set the regulator to 1.0 psig, open the neck valve only a crack, and ignite the gas at the end of the tube. Place the tube vertically in the chimney, and adjust the neck valve to obtain a flame that projects 16 (±4) mm (0.63 in.) vertically downward.
17. Remove the igniter from the chimney, shut off the propane supply from the bottle, and allow the gas in the line to flare off before closing the neck valve on the igniter.
18. Turn on video equipment (monitor, VCR, camera, etc.).
19. Ensure that the field of view of the camera includes the test specimen and the control panel temperature and oxygen concentration readouts. The camera’s focus shall be on the temperature and oxygen concentration readouts.
20. Obtain the latest available video cassette numerically identified by the year, e.g., 06-, 07-, followed by the tape number, e.g., -01, -04. If the time remaining on the cassette is less than 25 minutes, start a new tape, and identify the tape with the next available tape number in the video tape log book in the video file cabinet. The video tape in use is left in the recorder.
21. Record the video cassette number and the test start counter/frame number on the test data sheet.
22. Prepare a test information sign for the video tape using the character generator. The sign shall contain the following information:
Request number
Sample set number (if applicable)
Test type (Oxygen Index or Elevated Temperature Oxygen Index)
Sample number
Test atmosphere
Material designation
Date
Test Conductor initials.
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