Page 75 - QRedition5.0 062021

Quality Requirements Edition 5.0 European Enamel Association

7.20.3 Quality requirements

Test method Requirement Remarks Frequency
3.5 visual assessment internal 0 defects in production 100 %
2
external max. 5 defects/m (*)
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 year
4.3 thickness enamel coating 0.34 ± 0.16 mm S4 AQL 2.5

4.4 cold citric acid min. class A EN ISO 28706-1 in production 1 x per month

cold sulphuric acid min. class A in production 1 x per month
cold hydrochloric acid min. class A solution 10 % in production 1 x per month
test duration 15 minutes
2
4.5 boiling citric acid weight loss: max. 5 g/ m per 2.5 hours on test sheets conform to EN ISO 28764, when taking into production a sig.diff.

test duration 2,5 hours, EN ISO 28706-2 enamel recipe, but at least 1 x a year
2
4.6 boiling water weight loss: max. 10 g/m per 48 hrs. vapour phase on test sheets conform to EN ISO 28764, when taking into production a sig.diff.

weight loss: max. 5 g/m per 48 hrs. liquid phase test duration 48 hours, EN ISO 28706-2 enamel recipe, but at least 1 x a year
2
2
4.7 detergent solutions weight loss: max. 5 g/m per 24 hours EN ISO 28706-3 when taking into production a sig.diff.

enamel recipe, but at least 1 x a year
4.9 impact resistance max cracking: at 20 N no damage > 2 mm ø ISO 4532 when taking into production a sig.diff.
after 24 hours enamel recipe, but at least 1 x a year
4.10 adherence min. 2 on test sheets conform to EN ISO 28764 in production 1 x a month
or 4.39 min. ”good” on test sheets conform to EN ISO 28764 in production 1 x a month
4.12 porosity internal 0 defects EN 14430 in production 100 %
2
4.25 sodium hydroxide 80° C max. 8 g/m per 24 hours test duration 24 hours when taking into production a sig.diff.

EN ISO 28706-4 enamel recipe, but at least 1 x a year
4.28 steel quality double-sided enamel grade steel quality
or suitable construction steel for applied processing

(*) Defects at the outside: 5 defects of max. 1 mm diameter (on a test surface of 1 m );
2
Max. 5 defects are allowed to be repaired, for example by means of a sealing kit.

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