UFC 3-240-13FN
25 May 2005
= ([125 123]/125) x 100 = 1.6% after 4 months
b) The monthly loss based on the 4-month result is calculated:
EQUATION
1.6% over 4 months = 0.4% per month
(37)
This loss is less than 1% per month and not excessive.
c) If the concentration had dropped to 123 ppm after 1 month, the loss would
be:
EQUATION
Loss = ([125 123]/125) x 100
(38)
= 1.6% after 1 month
d) The monthly loss is calculated:
EQUATION
1.6% over 1 month = 1.6% per month
(39)
This loss is greater than 1% per month, and the system should be inspected
for leaks.
5-2.5
Procedures for Layup of Hot and Chilled Water Systems. Follow the
procedure for wet layup of operational boilers described in paragraph 3-5.4. Note these
additional recommendations:
For hot water systems, completely fill the hot water generator and
expansion tank. Where nitrogen pressurization is used for the system, the
expansion tank should not be filled.
For all steel systems using the sulfite-caustic soda program, increase the
pH to 11.7 with sodium hydroxide (caustic soda). Add sodium sulfite to a
level of 100 ppm (as SO3).
Treat chilled water systems using the nitrite-borax or molybdate-caustic
soda treatments with appropriate chemicals to maintain levels required for
normal operation.
Test monthly for treatment chemicals and check water levels.
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