UFC 3-240-13FN
25 May 2005
Table 3-17. NAVSEASYSCOM Shore-To-Ship Steam Purity Requirements
PH
8.09.5
< 25 micromhos/cm
Dissolved silica
< 0.2
< 0.10 ppm
Dissolved oxygen
< 15 ppb
3-3.7
Treatment Guidelines for Low-Pressure Steam. Treatment guidelines
for boilers operating at less than 103 kilopascals (15 pounds per square inch gauge) are
determined by size and type, as described in Table 3-18. Cast iron boilers and boilers
less than 334 watts (10 horsepower) are not treated. Boilers with greater than 95%
condensate return can either be treated the same as a closed hot water boiler (see
Chapter 5), or treated the same as boilers with less than 95% condensate return. The
latter uses external treatment, usually softening, and internal chemical treatment that
includes a scale inhibitor (precipitating type i.e., phosphate) or solubilizing type (i.e.,
phosphonates and polymers) sulfite to control pitting due to oxygen, and a neutralizing
amine to control pH in the condensate system. Sometimes raising pH in the boiler water
requires a supplemental source of alkalinity. Usually this supplemental source is caustic
soda, but it can also be sodium carbonate (soda ash).
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