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Quality Requirements Edition 6.0 European Enamel Association

7.20.3 Quality requirements

Test method Requirement Remarks Frequency
3.5 visual assessment Inside surface: discontinuity free (see 4.12) in production 100 %
Outside surface: max. 3 defects/m with a max. defect size of
2
1mm in diameter (*)
3.9.3 hardness hardness Mohs ≥ 5 on test sheets when taking into production a sig.diff.
enamel recipe, but at least 1 x a month
4.3 thickness enamel coating Outside surface: 330 ± 170µm In accordance with EN ISO 2859-1
Inside surface: 360 ± 100µm
except for roofs of thermophilic/pasteurisation digesters, industrial
tanks with aeration processes and aggressive chemical industrial
effluent / high temperature applications:
Inside surface: 400 ± 100µm
4.4 cold citric acid class AA EN ISO 28706-1/9 in production 1 x per month
cold sulphuric acid class A+ min., except for roofs of thermophilic/pasteurisation EN ISO 28706-1/10 in production 1 x per month
digesters, industrial tanks with aeration processes and aggressive
chemical industrial effluent / high temperature applications: class
AA required
cold hydrochloric acid class A min., except for roofs of thermophilic/pasteurisation EN ISO 28706-1/11 10% solution 15min. in production 1 x per month
digesters, industrial tanks with aeration processes and aggressive
chemical industrial effluent / high temperature applications: class
AA required
4.5 boiling citric acid weight loss: max. 1,5 g/m after 2.5 hours EN ISO 28706-2/11 when taking into production a sig.diff.
2
except for roofs of thermophilic/pasteurisation digesters and on test sheets conform to EN ISO 28764 enamel recipe, but at least 1 x a year
industrial tanks with aeration processes: max. 0,75 g/m²
except for aggressive chemical industrial effluent / high
temperature applications: max. 0,5 g/m²
4.6 boiling water liquid phase max. weight loss: 2,5 g/m after 48 hrs. except for EN ISO 28706-2/14 when taking into production a sig.diff.
2
aggressive chemical industrial effluent / high temperature on test sheets conform to EN ISO 28764 enamel recipe, but at least 1 x a year
applications: max. 1,0 g/m²
2
vapour phase max. weight loss: 7,5 g/m after 48 hrs.
except for roofs of thermophilic/pasteurisation digesters and
industrial tanks with aeration processes: max. 5,0 g/m²
except for aggressive chemical industrial effluent / high
temperature applications: max. 2,5 g/m²
(*) When agreed between parties, it is permissible to rectify defects on outside surfaces using an approved material and process, at the condition rectified defects have a
design life similar to that of the original coating.

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