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Water Quality Standards
and Recommendations
Unfavorably high total ionized solids (TIS) can accelerate the rate of galvanic corrosion. These
contaminants can function as electrolytes which increase the potential for galvanic cell corrosion and
lead to localized corrosion such as pitting. Eventually, the pitting could become so extensive that
leaking will occur between the process water and facility water diminishing the System's heat transfer
capability.
High water hardness (Calcium and Maganese) can also produce scaling. Scaling will inhibit heat transfer
between the process and facility side by building up a deposit layer on metal surfaces. As an example,
raw water in the United States averages 171 ppm (of NaCl). The recommended level for use in a water
system is between 0.5 to 5.0 ppm (of NaCl).
Recommendation: Initially fill the tank with distilled/deionized water. Do not use untreated tap water as
the total ionized solids level may be too high.
The desired level for long time usage is 1 to 3 MOhmcm (compensated to 25°C).
The above recommendations will reduce the electrolytic potential of the water and prevent or reduce the
galvanic corrosion observed.
15.00
10.00
3.00
1.00
0.10
0.05
Microbiologicals
(algae, bacteria, fungi)
Inorganic Chemicals
Calcium
Chloride
Copper
Iron
Lead
Magnesium
Manganese
Nitrates\Nitrites
Potassium
Silicate
Sodium
Sulfate
Hardness
Total Dissolved Solids
Other Parameters
pH
Resistivity
* MOhmcm (Compensated to 25°C)
Not Recommended, Increasingly Corrosive
Operations with Stainless Steel Systems
Operations with
Mixed Metals
Copper/Brass/
Stainless Steel
10
20
30
Water Quality Considerations
- 8 -
Permissible (PPM)
0
<40
250
<1.3
<0.3
<0.015
<12
<0.05
<10 as N
<20
<25
<20
<250
<17
<50
6.5-8.5
0.01*
CONSULT MATERIALS ENGINEER
40
50
60
70
Desirable (PPM)
0
<0.6
<25
<1.0
<0.1
0
<0.1
<0.03
0
<0.3
<1.0
<0.3
<50
<0.05
<10
7-8
0.05-0.1*
80
°C
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