MIL-STD-1330D(SH)
20 September 1996
(a) It is authorized by local engineering. (b) All pipe sections have been pre-cleaned.
(c) All valve bodies, filter housings, and other large component housings shall have been cleaned to oxygen cleanliness requirements.
(d) Prior to the flush, all cartridges, filter elements, regulators, and other components shall be removed and flush plugs or bypass lines installed. After the flush, all cavities shall be visually inspected as specified in 5.13.1. Any evidence of contamination shall be removed by either local cleaning with NOC or TSP or additional flushing. The results of the visual inspection shall be recorded.
(e) For oxygen enriched systems only, the system piping and components shall be fabricated from material that will not propagate a flame at maximum operating pressure when determined in accordance
ASTM G 94. For information, brass, bronze, copper, copper-nickel, nickel-aluminum-bronze, and nickel-copper (monel) will not propagate a flame in an oxygen or oxygen enriched atmosphere at pressures up to 7500 lb/in2.
5.5.9 Rinsing and particulate flushing. Rinsing and particulate flushing shall be accomplished as follows:
(a) Remove the majority of NOC with nitrogen and collect for future use, or proceed to 5.5.9(b). When using nitrogen, do not allow NOC to dry before proceeding to 5.5.9(b).
(b) Remove cleaning solution by rinsing the system once-through with grade B water at a velocity of not less than 3 ft/sec. Return filters that were used during the flush step should be removed, replaced, or bypassed prior to rinsing to prevent contamination trapped by the filter from being introduced into the system. The water temperature shall be not less than 110EF for NOC and 160EF for TSP. Systems flushed with large in-line volumes, such as moisture separators, where the flushing velocity is less than 3 ft/sec shall be back flushed with rinse water to ensure all cleaning agent is removed.
(c) Obtain a sample of the rinse effluent and measure the pH as specified in 5.13.4.2. When the effluent pH is not greater than
8.0, outlets shall be opened one at a time to help clean valve bodies and other probable pocketing areas. The rinse water shall then be recirculated until the pH of the effluent at each branch, vent, or drain is not greater than 8.0.
(d) At the completion of rinsing, obtain a sample of the rinse effluent from each branch and verify particulate cleanliness as specified
in 5.13.3. If any of the samples do not pass the required inspection, recirculate grade B water through the system at a velocity of not less than 3 ft/sec for not less than 30 minutes. The water temperature does not need to be elevated. Filters should be installed to trap particulate. Continue flushing until a sample of the effluent from each branch passes the particulate cleanliness as specified in 5.13.3.
(e) Any residual NOC or TSP in the cavities should be removed prior to drying. Remove flush plugs and inspect for residual NOC or TSP. Remove all visible traces of NOC or TSP by wearing cleanroom gloves and wiping each cavity and flush plug with a clean lint- free cloth wetted with grade B water at a temperature of 100 to
120EF. The flush plugs should be reinstalled prior to drying with nitrogen.
5.5.10 Drying and reinstalling components. Drying and reinstallation of components shall be accomplished as follows:
(a) Remove rinse water and dry the system with nitrogen until a minus
40EF dew point is reached. For systems which operate at elevated humidity, such as electrolytic oxygen generator systems, or in the absence of an elevated dryness requirement, a dew point of plus
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