Page 81 - 20250602 EEA QM Edition 6.0

Quality Requirements Edition 6.0 European Enamel Association

7.21.3 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: 300 ± 100µm

except for cylinders in biogas digester for agricultural waste:
Inside surface: 260 ± 100µm
4.4 cold citric acid class A+, except for cylinders in biogas digester for agricultural EN ISO 28706-1/9 in production 1 x per month
waste: class A min.
2
4.5 boiling citric acid weight loss: max. 3,0 g/m after 2.5 hours EN ISO 28706-2/11 when taking into production a sig.diff.
on test sheets conform to EN ISO 28764 enamel recipe, but at least 1 x a year
except for cylinders in biogas digester for agricultural waste:
max. 5,0 g/m²
4.6 boiling water liquid phase max. weight loss: 5,0 g/m after 48 hrs. EN ISO 28706-2/14 when taking into production a sig.diff.
2
on test sheets conform to EN ISO 28764 enamel recipe, but at least 1 x a year
no requirement for vapour phase
4.9 impact resistance at 20 N no damage > 2 mm ø after 24 hours EN ISO 4532 in production 1 x a month
4.10 adherence min. class 2 EN 10209 Annex C, on test sheets in production 1 x a month
conform to EN ISO 28764

or 4.39 for thickness >3mm min. “good” EEA Specification 8.6.3, on test sheets in production 1 x a month
conform to EN ISO 28764
4.12 porosity for inside surface only: discontinuity free EN ISO 2746 Test A in production 100 % (every panel)
With test voltage 700V

4.13 defects detection except for cylinders in biogas digester for agricultural waste: EN ISO 8289-1 Method A Frequency determined with
no defect detected using EN ISO 8289-1 method A EN ISO 2859-1
4.25 sodium hydroxide 80° C max. weight loss of 7 g/m after 24 hours EN ISO 28706-4/9 when taking into production a sig.diff.
2
enamel recipe, but at least 1 x a year
4.28 steel quality conforming EN 10111, EN 10025-1, EN 10149–1 and ASTM A quality to be agreed between the determination during design
1011 and others (including grades DD 11, S235, S420, S460, enameller and the steel manufacturer
S500, S550 and S700), with appropriate pre-treatments

(*) 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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