MIL-STD-1330 Precision Cleaning And Testing Of Shipboard Oxygen, Helium, Helium-Oxygen, Nitrogen, And Hydrogen SystemsThis standard provides the requirements for precision cleaning and testing of oxygen or oxygen-enriched systems and components; oxygen generating plants including nitrogen, hydrogen, and demineralized water support systems and components; and helium, helium-oxygen, and hydrogen life support systems and components. Each activity will implement the applicable requirements of this document through a locally prepared and approved procedure. Activities subject to additional quality assurance requirements such as NAVSEA SS800-AG-MAN-010/P-9290 or NAVSEA SS521-AA-MAN-010 will obtain procedure approval from the applicable certifying activity.

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MIL-STD-1330D(SH)

w/ Change 1

5.8.2.3 Cleaning method. The cleaning method consists basically of dividing the plant's producer, storage, and pump-vaporizer process piping into a number of separate piping circuits by using the equipment's isolation valves and temporary jumper hoses and pipe closures. Each piping circuit is leak-checked prior to filling with solvent. Solvent is then circulated through each piping circuit to be cleaned. A fill-and-soak method may be used for large vessels such as distillation columns and storage tanks. Consult NAVSEA, the vendor, or the ship's planning yard if necessary to identify previously used cleaning procedures or to develop a specific procedure for the make and model of the oxygen-nitrogen plant to be cleaned.

5.8.2.4 Sample and removal of cleaning solvent from system. The oxygen-nitrogen plant shall be certified oxygen clean and free of cleaning solvent as specified in 5.8.3.4(b) and 5.8.3.4 (c). The gas cross connect piping shall be sampled for cleaning solvent content as specified in 5.8.3.4 (c).

5.8.3 Oxygen-nitrogen plant piping.

5.8.3.1 Material and equipment. The following material and equipment are required:

a. A supply of cleaning solvent as specified in 4.4. b. A supply of nitrogen.

c. A vacuum pump pulling not less than 25 inches mercury (Hg) vacuum for removing the cleaning solvent. The pump design shall preclude pump lubricant from being drawn into the system being cleaned in the event of a pump failure or stoppage. The pump shall be compatible with the cleaning solvent.

d. Gauges, flowmeters, and thermometers as required which are compatible with the cleaning solvent. e. Equipment to perform the applicable analyses as specified in 5.13.

5.8.3.2 Preliminary joint tightness test. A preliminary joint tightness test shall be performed on the system before introducing the cleaning solvent into the system piping. The preliminary joint tightness test shall be performed with nitrogen to a minimum of 75 lb/in2 or the maximum system operating pressure if lower. Accessible mechanical joints, seal welds, and disturbed welded joints shall be tightness tested using the test duration and acceptance criteria as specified in 5.9 and Table VI.

5.8.3.3 Hydrostatic test. Hydrostatic testing as specified in 5.9 and Table V should normally be accomplished before the final flush.

5.8.3.4 Flush. Flushing shall be accomplished as follows:

a. The system piping shall be flushed at not less than 3 ft/sec with cleaning solvent for not less than 30 minutes. If the flushing circuit is through parallel paths, if necessary, the flow paths shall be isolated to ensure that each path is flushed with full flow for not less than 5 minutes followed by a 30-minute flush of the entire system without full flow required in each leg.

b. Obtain a sample of the cleaning solvent from all sampling locations and verify organic cleanliness as specified in 5.13.2 and verify particulate cleanliness as specified in 5.13.3. If any of the analyses fail, replace or reclaim the solvent and repeat the flush.

c. After acceptable samples are obtained, the cleaning solvent shall be removed by draining and then purging with low pressure nitrogen. A vacuum pump may be used in the final stages of solvent removal. Heat (200 °F maximum) may be applied to the external surfaces of the piping to facilitate removal of the cleaning solvent. The nitrogen exhaust shall be checked for traces of the cleaning solvent with a halide leak detector or equal. Evacuating and purging shall continue until no trace of the solvent is detectable.

d. The system shall be pressurized with nitrogen to a minimum of 75 lb/in2 or the maximum system operating pressure if lower. Samples of nitrogen under pressure shall be taken after a period of not less than 1 hour and analyzed for solvent content. Samples shall be analyzed by gas chromatography or equivalent methods. The solvent content shall not exceed 10 ppm. If this limit is exceeded, the system shall be purged with nitrogen until acceptable samples are obtained.