Total dissolved
solids (mg/l)
A Temperature
(˚C)
B Ca-hardness (ppm
CaCO
3
)
C M-alkalinity (mval/l) D
28 - 31 1.9 44 - 55 1.3 0.90 - 1.10 1.7
32 - 37 1.8 56 - 69 1.4 1.12 - 1.38 1.8
38 - 44 1.7 70 - 87 1.5 1.40 - 1.76 1.9
45 - 50 1.6 88 - 110 1.6 1.78 - 2.20 2.0
51 - 56 1.5 111 - 138 1.7 2.22 - 2.78 2.1
57 - 63 1.4 138 - 174 1.8 2.80 - 3.54 2.2
64 - 71 1.3 175 - 220 1.9 3.54 - 4.40 2.3
72 - 80 1.2 230 - 270 2.0 4.6 - 5.4 2.4
280 - 340 2.1 5.6 - 7.0 2.5
350 - 430 2.2 7.2 - 8.8 2.6
440 - 550 2.3 9.0 - 11.0 2.7
560 - 690 2.4 11.2 - 13.8 2.8
700 - 870 2.5 14.0 - 17.6 2.9
880 - 1000 2.6 17.8 - 20.0 3.0
Interpretation of the value obtained
RSI Water condition Action
RSI<3.9 Very high scale formation Water cannot be used.
4.0<RSI<5.5 High boiler scale formation Regular inspection and descaling operation
necessary.
5.6<RSI<6.2 Slight boiler scale formation Water treatment not necessary.
Occasional inspection recommended.
6.3<RSI<6.8 Neutral water Water treatment not necessary.
Occasional inspection recommended.
6.9<RSI<7.5 Slight corrosion at higher
temperature
Water treatment not necessary.
Occasional inspection recommended.
7.6<RSI<9.0 Strong corrosion Regular inspection necessary, use of corrosion
inhibitor recommended.
9.1<RSI<11 Very strong corrosion Regular inspection necessary, use of corrosion
inhibitor required.
RSI>11 Very strong corrosion in
complete water system
Water should not be used.
The table indicates that distilled or demineralised water should never be used, as their RSI is > 11.
The RSI only indicates the equilibrium of scaling - descaling. A cooling water showing good RSI conditions
can still be unsuitable due to other factors.
From the table above, the RSI index should be between 5.6 and 7.5; otherwise, contact a specialist.
pH
The effect of pH is already calculated in the Ryznar index, but the pH itself has some additional limitations :
6.8 < pH
Instruction book
72 2920 1475 06
To Next Page
Loading...
