MIL-STD-1622B(SH)
5.8 System blowdown.
5.8.1 Applicability. The system blowdown is applicable to systems meeting the following conditions:
(a)New systems comprised of sections cleaned as specified herein prior to installation.
(b)Only particulate removal, such as desiccant, is required. Flux or hydrocarbon removal is not required.
(c)It is authorized by local engineering.
(d)For diver's air systems, NAVSEA approval is required.
5.8.2 System preparation. The following items shall be accomplished to prepare a system for blowdown:
(a)Valves, valve internals, pressure regulators, filter elements, or other mechanically jointed components that will interfere with the blowdown should be removed and flush plugs, spools, jumpers, and blanks shall be installed which can withstand the anticipated blowdown pressure. Where jumpers are used, their inside diameter should not be less than the piping they are bypassing.
(b)Remove items which could be damaged.
(c)Ensure that any electrically operated components such as
compressors, dehydrators, and solenoid valves are secured and
safety tagged.
5.8.3 Leak-check. All piping within the blowdown boundary shall be tightness tested at all mechanical joints with air or nitrogen to, at a minimum, the anticipated blowdown pressure.
5.8.4 Blowdown. The blowdown shall be accomplished as follows: (a)Blowdown each outlet with air or nitrogen at the maximum system
flow rate not to exceed normal system operating pressure for not
less than 30 seconds. The maximum flow rate shall be determined
by measurement or calculation.
(b)Open and inspect selected valves or other components that bound
individually cleaned sections or areas of suspected contamination.
Verify surface cleanliness as specified in 5.14.1.1. If
particulate contamination is evident, repeat 5.8.4(a) or clean the
system as specified in 5.9.
5.9 Hot or cold water flush.
5.9.1 Applicability. A hot or cold water flush is applicable to systems meeting the following conditions:
(a)The system is contaminated with particulate or sea water. (b)Removal of organic contamination is not required.
(c)The flush is authorized by local engineering.
5.9.2 System preparation. The system shall be prepared as specified in
5.6.3.1 and 5.6.3.2. Components removed shall be visually inspected as
specified in 5.14.1.1. Components contaminated with particulate or sea water
shall be cleaned using one of the following methods.
(a)Rinse with grade C water for general applications or grade B water for critical applications until samples of the rinse water effluent meet the requirements of 5.9.5, or
(b)Locally clean as specified in 5.13.4, or
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