Page 110 - 20250602 EEA QM Edition 6.0

Quality Requirements Edition 6.0 European Enamel Association

8.5.2 Requirements set on water to be used in the enamelling shop Units of water hardness of different countries and their conversion factors
(mval/kg = 28 mg CaO or 50 mg CaCO3 per 1000 ml water):
Generally
Germany:
In general water is not considered to be an enamel raw material, although it is used
with about 30% in the enamel slip. The other consumer of water in the enamelling 1 GH = German degree of hardness = 10 mg CaO per 100 ml water
0
0
0
shop is the pre-treatment line. Requirements upon the quality of water as requested 1 GH = 1.78 FH = 1.25 BH = 17.8 ppm = 0.357 mval/kg
0
by these two users are quite different.
France:
Water for the pre-treatment
0
1 FH = French degree of hardness = 10 mg CaCO3 per 1000 ml water
0
0
The particular pre-treatment steps are finishing with a rinse. Task of the rinse is to 1 FH = 0.56 GH = 0.7 BH = 10 ppm = 0.2 mval/kg
0
wash-off emulsified and saponified greases, oils and salts. No chemical reaction
must take place between the products arising from the various working processes Great Britain:
and the rinsing water. Water to be used must be extensively free of alkaline earths. 0
The percentage of alkaline earths in the water is expressed in degree of water 1 BH = British degree of hardness = 1 grain CaCO3 per gallon = 14.3 mg
hardness which can be inquired from the water supplier. In order to achieve the CaCO3 per 1000 ml water
highest possible production assurance, the use of at least cation-desalinated water 1 BH = 0.8 GH = 1.43 FH = 14.3 ppm = 0.286 mval/kg
0
0
0
is recommended.
USA:
Water for the preparation of the enamel slip
ppm = 1 part per million = 1 mg CaCO3 per 1000 ml water
On earth, water is the most widespread solvent. The purer a water, the more eager 1 ppm = 0.056 GH = 0.1 FH = 0.07 BH = 0.02 mval/kg
0
0
0
it is to assimilate ions. With the preparation of enamel slips this dissolving behaviour
is undesired because it is looked upon equivalent to the leaching process of enamels. Regulations for the analysis of water
A too high alkali content in the water of the slip normally influences the setting
Determination of the pH-value
characteristics of the clay in a negative way. The properties of the slip become
uncontrollable because of the longer lasting dissolving process. The use of harder The pH-value indicates the acidic or alkaline character of the water. It is measured on
waters for milling is proven. Thereby, additions of clay and setting agents can be an electrometric basis with potentiometers. For the calibration of the testing
reduced. In order to have always the same level of calcium in the milling water, one instruments, test solutions are available.
adjusts by adding calcium silicate hydrate to about 350 GH, which is the degree of
saturation. Determination of the conductivity
The conductivity is measured on an electrometric basis with potentiometers.

© EEA2025 page 110