MIL-STD-1330D(SH) APPENDIX B
w/ Change 1
ANALYSIS OF NON-VOLATILE RESIDUE IN NAVY OXYGEN CLEANER BY GRAVIMETRIC B.1 SCOPE
B.1.1 Scope. This appendix is a mandatory part of the standard. The information contained herein is intended for compliance. This appendix provides a procedure for determination of non-volatile residue (NVR) in the Navy oxygen cleaner (NOC) by gravimetric analysis. The residue could consist of any insoluble low vapor pressure material in the NOC including particulate, gels, and inorganic as well as organic residues which are retained by a Teflon membrane filter of pore diameter 0.45 micrometer.
B.2 APPLICABLE DOCUMENTS
This section is not applicable to this appendix. B.3 PROCEDURE
B.3.1 Summary of test method. The NVR in NOC is determined by passing a given quantity of NOC through a
0.45-micrometer Teflon filter and measuring the increase in the weight of the filter. The NOC sample is either pushed through the filter by pressurizing a filtration reservoir containing the NOC sample with oil-free nitrogen, or the NOC sample is drawn through the filter by a vacuum. The filter collects the NVR residue contained in the NOC.
The filter is subsequently washed with demineralized water, dried, and weighed. The increase in the weight of the
filter is a measure of the NVR in the NOC. This is performed for new, before-use NOC to establish a baseline NVR, and is then compared to a post clean NOC sample to determine a final net after cleaning NVR.
B.4 Significance and use.
B.4.1 NOC is an aqueous inorganic alkaline solution that is filtered to 0.1 micrometers during manufacture resulting in a material specification of 1.0 mg/L for insoluble matter. NOC removes oil and grease by displacement with the resultant removed contaminants existing in NOC as a filterable suspension. This test method measures the amount of NVR contained in NOC. The test is used to verify the cleanliness of oxygen systems and components which have been cleaned by NOC.
B.4.2 This method will determine the amount of all types of NVR washed out of a system or component by NOC including organic material, particulate, and gels. The filtrate is dried at a temperature less than or equal to the NOC application temperature. Therefore, this procedure is not expected to result in any appreciable loss of semi- volatile contaminants.
B.4.3 This analysis is susceptible to interference from demineralized water contaminated with insoluble material, from a filtration column contaminated with dried NOC residue or ambient dust, and to homogenizer wear that could contaminate the NOC sample with particulate.
B.4.4 The quantitative cleanliness standard for systems cleaned as specified in this standard generally applies to organic (hydrocarbon) residues. However, this gravimetric method does not differentiate between organic and inorganic residue. Therefore, when reporting contamination based solely on the results of this analysis, a higher
than actual value may be reported resulting in a built-in safety factor.
B.5 Apparatus.
a. A balance accurate to 0.1 mg with a zero drift less than 0.1 mg. A balance with an accuracy of 0.05 mg with a zero drift less than 0.05 mg is suggested. The balance shall be calibrated in accordance with the Navy Metrology and Calibration Program, or equivalent. Between calibrations, the accuracy of the balance should be verified using certified balance weights. Suitable balances, such as A&D Model ER-182A or OHAUS Model AP250D, are available through laboratory supply houses such as Thomas Scientific.
b. Balance weights of 1.0, 2.0, 5.0, and 10.0 mg, accurate to 0.02 mg (NIST Class S or ASTM Class 2) and made from non-magnetic material.
c. Disposable Teflon membrane filters of 0.45 or 0.50 micrometer pore size and 47 millimeter diameter supplied by Savillex Corp., 6133 Baker Rd, Minnetonka, MN 55345, (612) 935-4100, part number 1121; Millipore Corp., 80 Ashby Rd, Bedford, MA 01730, (617)275-9200, part number FHUP04700, or equal.
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