UFC 3-240-13FN
25 May 2005
Table 5-1. Makeup Water Requirements for Closed Systems
System Type
Requirement
High-temperature hot water
Softened and deaerated
Medium-temperature hot water
Softened and deaerated
Less than 100 ppm total hardness as
Low-temperature hot water
CaCO3
Less than 250 ppm total hardness as
Chilled, brine, glycol
CaCO3
1. Less than 50 ppm hardness as CaCO3
Diesel engine jacket
2. Demineralization when brackish water is
used
5-2.2
Corrosion Control Programs. Five basic water treatment programs are
used in closed systems:
Sulfite-caustic soda.
Nitrite-azole.
Molybdate-azole.
Nitrite-molybdate-azole blend.
Polysilicate-azole.
The choice of which chemical treatment system to use should be based
primarily on the water temperature and the metals in the system as well as the relative
cost of the treatment program at the specific installation. The various water treatment
programs are listed in Table 5-2 for each type of closed water system. Table 5-3
provides microbiological control monitoring guidelines for closed water systems.
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