GLASS FUSED-TO-STEEL

COATINGS FOR BOLTED

TANKS
A Simplified Guide to ISO
28765:2016 Vitreous and
Porcelain Enamel Quality and
Service Requirements
Source Document - ISO 28765 - Second Edition 2016-01-15 - International Standard - Vitreous and
porcelain enamels - Design of bolted steel tanks for the storage or treatment of water or municipal or
industrial effluents and sludges

Release 1.0 - 5 August 2020

By James Mansour with Thomas Renich

United Industries Group, Inc. - 11 Rancho Circle, Lake Forest, CA 92630 USA

Telephone +1-949-759-3200 - Email info@unitedind.com - www.unitedind.com

© 2020 United Industries Group, Inc. All rights reserved.

United Industries Group, Inc. 11 Rancho Circle, Lake Forest, CA 92630 USA
Phone +1-949-759-3200 www.unitedind.com Email info@unitedind.com

Trademarks
Everstore® is a registered trademark of United Industries Group, Inc.
gf2s™ is a trademark of JATO Services LLC.
All other trademarks are the property of their respective owners.

Disclaimer
The information provided in this document is provided "as is" without warranty of any kind. United Industries
Group, Inc. and the authors disclaim all warranties, either express or implied, including the warranties of
merchantability and fitness for a particular purpose. In no event shall United Industries Group, Inc., or the
authors, be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of
business profits or special damages, even if United Industries Group, Inc., the authors, or its suppliers have
been advised of the possibility of such damages.

Document Lifetime
United Industries Group, Inc. and the authors may occasionally update online documentation between
releases of the related information. Consequently, if this document was not downloaded recently, it may not
contain the most up-to-date information. Please refer to www.unitedind.com for the most current
information.

Further information
For documentation, release notes, software updates, or for information about United Industries Group, Inc.
products, commercial and technical support, licensing and service, please go to the company website
at http://www.unitedind.com or email info@unitedind.com.

Your comments
Your suggestions will help us continue to improve the accuracy, organization, and overall quality of the user
publications. Please send your opinion of this document to info@unitedind.com and reference “ISO 28765
Glass Quality White Paper”

About the authors

James Mansour is the founder and President of United Industries Group, Inc. Mr. Mansour has over fifty
years’ experience in the design, supply, and installation of cylindrical above ground bolted steel storage tanks.
Thomas Renich is the owner of JATO Services LLC, a private consulting and services business focused on
international marketing. Mr. Renich has more than forty-five years’ experience in concrete and steel tank
construction with an emphasis on international marketing, operations, and project management.

Contents
I Executive Summary 4

II Introduction 4

III The Challenge of ISO 28765 Quality Requirements 4

IV The Four ISO 28765 Quality Classifications 4

V Quality Requirements of the Four ISO Quality Classifications 5

VI A Comparison of ISO 28765 Quality Requirements to AWWA D103 and EEA 7

VII United Industries Group Everstore® Glass Coatings 11

VIII Summary 11

Release History & References 12

I. Executive Summary
The ISO 28765 Standard offers a detailed guide to glass fused-to-steel (gf2s™) bolted tank quality
requirements for glass coatings. The tables provided in the ISO Standard Section 10 (Tables 2 and 3)
provide specific information regarding quality testing and the glass quality requirements for a variety of
applications. These tables, while comprehensive, become somewhat cumbersome when trying to
communicate, compare and/or specify the quality offerings of various bolted steel tank suppliers. In
reviewing and studying the Standard we found the information can be simplified into a format more
practical to both users and producers by providing a class name for the glass properties required for each
tank application. This paper explains our methodology and provides tables to guide the industry in
selecting and specifying glass fused-to-steel coatings. A further outcome is the resulting classification of
our own Everstore® glass fused-to-steel bolted tank offerings into the quality classes indicated by our study.

II. Introduction
The ISO Standard for glass fused-to-steel bolted tanks (ISO 28765 - Second Edition 2016-01-15 -
International Standard - Vitreous and porcelain enamels - Design of bolted steel tanks for the storage or
treatment of water or municipal or industrial effluents and sludges) was originally published in 2008. At the
time of its initial publication, it was the only standard issued specifically to accommodate the inherent
advantages of gf2s bolted steel tanks. The Standard addresses thoroughly the areas of applicable tank
design loads, tank design elements and processes, and vitreous enamel coatings. The purpose of this article
is to review the vitreous-enamel coatings information found in Section 10, specifically Tables 2 and 3, of the
Standard.

III. The Challenge of the ISO 28765 Quality Requirements

Tables 2 and 3 of the ISO 28765 Standard provide a thorough, well-structured guide for the quality of glass
coating as it relates to a number of common bolted steel tank applications. In these tables the specific
quality requirements for the various gf2s tank applications are defined. The tables are structured such that
one first selects the tank application and then follows the table information to note the specific
performance tests and requirements. We find this approach to be effective for the purpose of the
Standard, but somewhat cumbersome when trying to apply the Standard to writing design specifications.
Further, the structure of the Standard’s tables makes it difficult to determine whether or not a
manufacturer offers glass quality levels meeting the range of applications.

IV. The Four (4) ISO 28765 Quality Classifications

Regarding the ISO 28765 Section 10 applications, our goal was to develop a way to view the information
presented that would be straightforward for tank users, specifiers, and buyers. With the Standard, it is
difficult for suppliers to communicate to buyers what they are offering within their range of gf2s products
and likewise, it is difficult for buyers/specifiers/users to understand what gf2s quality levels various
suppliers are offering. In reviewing the ISO Standard, we found there are actually only four (4) different

sets of requirements. Stated another way, the sixteen (16) listed tank applications can be grouped into four
categories, and within each of these categories the quality guidelines are the same for all the applications.
Hence, we have reorganized the information into a format that lists the requirements for each application
grouping. For ease of use, we have arbitrarily labeled the application groupings as Class AA, Class A, Class
B, and Class C with Class AA representing the highest quality glass, and Class A, B and C groupings offering
progressively lower quality requirements. Table 1 shows these four application groupings.

Table 1 - Glass quality and application groupings - ISO 28765

Glass Quality
Tank Applications
Requirements
Class AA • Thermophilic/ pasteurization digester – roof and rings exposed to gaseous zone
• Industrial effluent process/ treatment
• Biogas digester for agricultural waste - roof and rings exposed to gaseous zone
• Thermophilic/ pasteurization digester - cylinders
Class A • Municipal mesophilic digester - roof and rings exposed to gaseous zone
• Liquid Leachate
• Municipal sludge treatment - roof and rings exposed to gaseous zone
• Borehole/brackish/seawater
• Municipal mesophilic digester - cylinders
• Municipal sludge treatment - cylinders
• Municipal sludge/sludge cake storage
Class B • Filter tanks
• Storm/firewater
• Potable water (DWI listed Reg 31)
• Potable water (ANSI/NSF 61 listed)
Class C • Biogas digester for agricultural waste - cylinders

Utilizing this “Class AA/A/B/C” approach, it becomes readily apparent which gf2s quality level is being
specified or offered.

V. Quality Requirements of the Four ISO Quality Classifications

Each application group has a comprehensive regimen of quality control tests including chemical resistance,
abrasion resistance, hardness, adhesion, thermal shock, thickness, discontinuities and so forth. Table 2
shows the ISO 28765 requirements for each coating “class” along with the notes from the Standard relevant
to the testing requirements.

Table 2 - Application Grouping Quality Requirements

Minimum
Property and Test or
Inspection Class AA Class A Class B Class C
Inspection Method
Frequency
Resistance to chemical
Monthly or
corrosion by citric acid at room
1 with each Class AA Class AA Class A+ Class A
temperature; ISO 28706-
batch
1:2008 Clause 9
Resistance to chemical
Monthly or
corrosion by sulphuric acid at
2 with each Class AA Class A+ Test not required Test not required
room temperature; ISO 28706-
batch
1:2008 Clause 10

Table 2 - Application Grouping Quality Requirements

Minimum
Property and Test or
Inspection Class AA Class A Class B Class C
Inspection Method
Frequency
Resistance to chemical
corrosion by hydrochloric acid Monthly or
3 at room temperature; ISO with each Class AA Class A+ Test not required Test not required
28706-1:2008 Clause 11 (10% batch
solution for 15 minutes)
Resistance to chemical Max mass loss after Max mass loss after Max mass loss after Max mass loss after
4 corrosion by boiling citric acid; Annually 2.5 hours 2.5 hours 2.5 hours 2.5 hours
ISO 28706-2:2008 Clause 10 0.75 gm/m2 1.5 gm/m2 3.0 gm/m2 5.0 gm/m2
Resistance to chemical
corrosion by boiling Max mass loss after Max mass loss after
5 hydrochloric acid – Vapour Annually 7 days 7 days Test not required Test not required
phase; ISO 28706-2:2008 7.0 gm/m2 8.0 gm/m2
Clause 12
Resistance to chemical
corrosion by boiling distilled or
Max mass loss after Max mass loss after Max mass loss after Max mass loss after
6a demineralized water; ISO Annually
48 hours 2.5 gm/m2 48 hours 2.5 gm/m2 48 hours 5.0 gm/m2 48 hours 5.0 gm/m2
28706-2:2008 Clause 13 -
Liquid phase
Resistance to chemical
corrosion by boiling distilled or
Max mass loss after Max mass loss after
6b demineralized water; ISO Annually Test not required Test not required
48 hours 5.0 gm/m2 48 hours 7.5 gm/m2
28706-2:2008 Clause 13 -
Vapour phase
Resistance to chemical
Max mass loss after Max mass loss after
corrosion by standard
7 Annually 24 hours 24 hours Test not required Test not required
detergent solutions; ISO
2.5 gm/m2 5.0 gm/m2
28706-3:2008 Clause 9
Resistance to chemical
Max mass loss after Max mass loss after Max mass loss after Max mass loss after
corrosion by hot sodium
8 Annually 24 hours 24 hours 24 hours 24 hours
hydroxide; ISO 28706-4:2008
6.0 gm/m2 6.0 gm/m2 7.0 gm/m2 7.0 gm/m2
Clause 9
Resistance to thermal shock; No damage at 350 No damage at 350
9 Annually Test not required Test not required
ISO 28763:2008, Annex A degrees C degrees C
Resistance to impact: Pistol
Monthly or
test; ISO 4532 – Max damage <
10 with each 40 N force 40 N force 20 N force 20 N force
2 mm in diameter after 24
batch
hours
Determination of the
Max mass loss 45 Max mass loss 45
11 resistance to abrasion; ISO Annually Test not required Test not required
gm/m2 gm/m2
6370-2
Monthly or
Scratch hardness of surface
12 with each Mohs 5 Mohs 5 Mohs 5 Mohs 5
according to Mohs; EN 15771
batch
Monthly or
Adherence level; EN
13 with each Class 2 Class 2 Class 2 Class 2
10209:2013 Annex C
batch
Determined in
Enamel Thickness - Inside accordance
14 300µm - 500µm 260µm - 460µm 200µm - 400µm 160µm - 360µm
Surface; ISO 2178 with ISO
2859-1:1999
Determined in
Enamel Thickness - Outside accordance
15 160µm - 500µm 160µm - 500µm 160µm - 500µm 160µm - 500µm
Surface; ISO 2178 with ISO
2859-1:1999
ISO 8289:2000
ISO 2746:2015 ISO 2746:2015 ISO 2746:2015
Defects – Inside Surface – No Method A - 9v
16 Every panel Test A Test A Test A
discontinuities (Low voltage wet
Test voltage 1500v Test voltage 1100v Test voltage 700v
sponge test)

Table 2 - Application Grouping Quality Requirements

Minimum
Property and Test or
Inspection Class AA Class A Class B Class C
Inspection Method
Frequency
Defects – Outside Surface,
Visual inspection Visual inspection Visual inspection Visual inspection
17a maximum visible defect size 1 Every panel
(see Note 2) (see Note 2) (see Note 2) (see Note 2)
mm
Defects – Outside Surface,
Visual inspection Visual inspection Visual inspection Visual inspection
17b maximum 3 visible defects per Every panel
(see Note 2) (see Note 2) (see Note 2) (see Note 2)
m2 total panel area
Inspection using a Inspection using a Inspection using a Inspection using a
Color – Outside Surface; Determined in
color comparator color comparator color comparator color comparator
Color and color tolerances accordance
18 approved prior to approved prior to approved prior to approved prior to
shall be agreed between with ISO
production by the production by the production by the production by the
interested parties 2859-1:1999
vitreous enameller vitreous enameller vitreous enameller vitreous enameller
Notes:
1. Consult with supplier for suitability for specific applications. All applications subject to concentration and temperature considerations of
the stored liquid.
2. It is permissible, when agreed between the contracting parties, to rectify defects with a material approved by the vitreous enameller for
the purpose, applied according to the rectification material manufacturer’s instructions.

We want to reinforce that the overall quality designations we have used in the above chart (Class AA, Class
A, Class B, and Class C) use arbitrary nomenclature and are not related to any of the noted tests or testing
protocols. They are used simply to provide a Best - Better - Good - Fair relative position comparison.
Accordingly, please note the first three tests (items 1, 2 and 3 noted in the chart - resistance to citric acid,
sulphuric acid and hydrochloric acid at room temperature) performed in accordance with the ISO 28706-
1:2008 Standard, use a similar relative nomenclature. The ISO 28706 Standard uses a progressive decision
process to classify the test results, briefly as follows:

• Visual Inspection
o Pass - Class AA Type of Examination Class
o Fail - Do Rubbing Test (dry) Visual examination - passed AA
§ Pass - Class A+ Rubbing test (dry) - passed A+
§ Fail - Do Rubbing Test (moist) Rubbing test (moist) - passed A
• Pass - Class A Rubbing test (moist) - failed Unclassified
• Fail - Unclassified

Each test is less stringent than the one before, and therefore Class AA is the most resistant to the tested
chemical attack, Class A+ is less resistant, Class A is even less resistant, with the Unclassified Class being the
least resistant.

VI. A Comparison of ISO 28765 Quality Requirements to AWWA

D103 and EEA (European Enameling Authority)
It is worth noting that ISO 28765 is certainly the most specific and stringent published standard relative to
glass quality. When compared to other standards such as ANSI/AWWA D103-19 (American Water Works
Association - Factory-Coated Bolted Carbon Steel Tanks for Water Storage) and Quality Requirements -
European Enamel Authority e.V. - 4th Edition, the ISO Standard provides greater detail and attention to
currently available testing and measuring technology. For example, in AWWA D103 Standard Section 12.4 -
Glass Coatings, the only quality points mentioned are: a) that the coating thickness shall be between 150
µm and 480 µm, and b) that the interior surface be holiday tested (with no statement as to whether or not

any holidays are allowed). Further, the indicated holiday testing protocol is stated to be a low voltage wet
sponge test that has long been shown to be inferior to the high voltage methods specified in the ISO
standard.

Curiously, as the following chart displays, the AWWA D103 Standard as it relates to gf2s coatings is
essentially unchanged since the Standard’s introduction in 1980, and the changes that were made were
either for simple clarification or, with the exception of the 2009 change stipulating the interior coating wet
sponge test, resulted in the Standard becoming less stringent rather than more so.

gf2s Coating
AWWA D103-1980 AWWA D103-1989 AWWA D103-1997 AWWA D103-2009 AWWA D103-2019
Feature
7 - 11 mils 6 - 19 mils
Interior Thickness Same as 1980 Same as 1997 Same as 1997
(178 - 280 µm) (150 - 483 µm)
7 - 11 mils 6 - 19 mils
Exterior Thickness Same as 1980 Same as 1997 Same as 1997
(178 - 280 µm) (150 - 483 µm)
Changed to
include inspection
Visible defects - if on both interior
Changed to apply
severe conditions and exterior
the wet-pad test
Inspection encountered a Same as 1980 surfaces, and the Same as 2009
on interior
wet-pad test inclusion of a
surfaces only
should be used holiday detection
test on interior
coating only
Wet pad Wet pad Wet sponge test
Holiday Test Same as 1997 Same as 1997
resistance test resistance test maximum 67.5 v

Referencing back to the AWWA D103 standard for water storage, we observe that the AWWA quality
standard for the gf2s coating compares to ISO 28765 quality standards in the two following ways:

1. The AWWA coating thickness range corresponds to the ISO exterior requirement, and AWWA
allows much thinner interior coatings than ISO 28765 Classes AA, A and B. In other words, the
AWWA standard corresponds to the lowest quality class of ISO 28765.

2. The AWWA holiday test compares only to the ISO Class C requirement - the lowest level and the
level ISO reserves for agricultural waste slurry where the material stored effectively seals off any
gf2s defects.

In comparing ISO 28765 to the quality requirements of the European Enamel Authority (EEA), we also find
the ISO 28765 requirements to be more stringent. EEA Section 7.20 addresses industrial tanks, Section 7.24
addresses silos for animal feed, and Section 7.25 addresses silos (tanks) for dung storage applications.
Similar to ISO 28765, the EEA lists various tests for some of the same categories, but the EEA quality
requirements overall are less demanding than ISO 28765. A summarization of the EEA quality requirements
is shown in the following table:

A Comparison of European Enamel Authority (EEA) Quality Requirements to ISO 28765

EEA # Test Description EEA 7.20 EEA 7.24 EEA 7.25 ISO 28765 Comparison to EEA 7.20
Industrial Tanks Animal Feed Dung Tanks
Silos
3.5 Visual Assessment Internal 0 defects Same as 7.20 Same as 7.20 Visual assessment only used on external
External max 5 surface, on every panel, with maximum 3
defects/m2 defects per m2 and maximum size 1 mm
3.9.3 Hardness Mohs = or > 5 Same as 7.20 Same as 7.20 EEA and ISO use the same hardness criteria
4.3 Thickness enamel 180 - 500 µm Same as 7.20 Same as 7.20 Exterior thickness range is the same;
coating Interior minimum thickness varies with
application. Class C minimum is 160 µm, all
others thicker
4.4 Cold citric acid Min. Class A Same as 7.20 Same as 7.20 Comparable to ISO Class C. ISO Class AA, A
and B are more stringent.
4.4 Cold sulphuric acid Min. Class A --- --- EEA 7.20 probably comparable to ISO Class
B and C. ISO Classes AA and A are more
stringent
4.4 Cold hydrochloric Min. Class A --- --- EEA 7.20 probably comparable to ISO Class
acid B and C. ISO Classes AA and A are more
stringent
4.5 Boiling citric acid - 5 g/m2 7 g/m2 Same as 7.24 ISO Class C comparable to EEA 7.20. All
weight loss in 2.5 other ISO classes more stringent
hours
4.6 Boiling water - 10 g/m2 vapour phase Internal 7 g/m2 Same as 7.24 EEA 7.20 comparable to ISO Classes B and
weight loss in 48 5 g/m2 liquid phase liquid phase C. ISO Classes AA and A are more stringent
hours
4.7 Detergent solutions Weight loss 5 g/m2 in 24 --- --- EEA 7.20 comparable to ISO Class A
hours
4.8 Release of toxic --- Conform to --- ---
elements national laws
4.9 Impact resistance Max cracking at 20 N no Same as 7.20 Same as 7.20 EEA comparable to ISO Classes B and C. ISO
damage > 2 mm dia. Classes AA and A are more stringent
after 24 hours
4.10 Adherence Minimum 2 - “Good” Same as 7.20 Same as 7.20 EEA and ISO are the same
4.12 Porosity Internal 0 defects --- --- All ISO classes are internal 0 defects, and
ISO includes high voltage testing protocols
4.13 Defects --- Inner max 5 Same as 7.24 All ISO classes are 0 defects on interior
defects per m2 surfaces
and no defects >
1 mm diameter -
repairs allowed
4.25 Sodium hydroxide Max 8 g/m2 per 24 Same as 7.20 Same as 7.20 ISO classes AA and A allow 6 g/m2 loss,
80o C hours while classes B and C allow 7 g/m2 loss

Combining the information from the three standards reviewed in this study reveals the significant gap
between the AWWA D103 requirements compared to the ISO and EEA requirements. All four classes of ISO
28765 and all three classes of EEA meet or exceed AWWA requirements, and conversely AWWA D103
requirements to not meet (let alone exceed) any of the classes of the other two standards. Once more,
considering that after structural design the most critical part of the tank is the coating system, it is difficult
to comprehend the lack of quality requirements included in AWWA D103 and we hope that future releases
remedy this shortcoming. The following chart will allow for a simple comparison between the three
standards relative to the gf2s coatings.

Relative Comparison of the Glass Quality Requirements of the Three Standards Reviewed
AWWA D103-19 EEA - 4th Edition ISO 28765:2016
AWWA EEA EEA EEA ISO Class ISO Class ISO Class ISO Class
D103 7.20 7.24 7.25 AA A B C
Does AWWA D103 meet or exceed
--- No No No No No No No
the glass quality requirements of:
Does EEA 7.20 meet or exceed the
Yes --- Yes Yes No No No No
glass quality requirements of:
Does EEA 7.24 meet or exceed the
Yes No --- Yes No No No No
glass quality requirements of:
Does EEA 7.25 meet or exceed the
Yes No No --- No No No No
glass quality requirements of:
Does ISO Class AA meet or exceed
Yes Yes Yes Yes --- Yes Yes Yes
the glass quality requirements of:
Does ISO Class A meet or exceed
Yes Yes Yes Yes No --- Yes Yes
the glass quality requirements of:
Does ISO Class B meet or exceed the
Yes Yes Yes Yes No No --- Yes
glass quality requirements of:
Does ISO Class C meet or exceed the
Yes Probably Yes Yes No No No ---
glass quality requirements of:

Using this chart, buyers and specifiers can better distinguish the glass quality levels being offered. This
information also offers a reliable way to recognize and communicate the specific quality requirements of
the bolted tank project. The buyer/specifier now has a simple and consistent method to request specific
compliance information from vendors, and vendors have a simple and consistent way to provide conformity
information to buyers.

To better define gf2s quality requirements when using AWWA D103, we suggest that specifiers consider
referencing the ISO standard relative to the gf2s coatings. At a minimum a Class B coating should be
considered for AWWA water storage applications, and a Class A coating would certainly offer an enhanced
product for the municipal projects.

10


VII. United Industries Group Glass Coatings

As a result of our review of the ISO 28765 standard, United Industries Group now incorporates a more
detailed reference for our glass fused-to-steel coatings. Consistent with the ISO 28765 class designations
developed above, we now include specific nomenclature for our glass coatings - Everstore® Plus and
Everstore®. This chart shows the correlations for our Everstore® tanks and the identified ISO 28765 quality
classifications.

United Industries Group - Everstore® Tank Glass Fused-to-Steel Bolted Tanks

ISO 28765
UIG Everstore® ISO 28765 Applications
Class Level
AA • Thermophilic/ pasteurization digester – roof and rings exposed to gaseous zone
Everstore® Plus • Industrial effluent process/ treatment
meets or exceeds • Biogas digester for agricultural waste - roof and rings exposed to gaseous zone
the requirements of • Thermophilic/ pasteurization digester - cylinders
ISO Class AA and is A • Municipal mesophilic digester - roof and rings exposed to gaseous zone
used for Class AA • Liquid Leachate
and A applications • Municipal sludge treatment - roof and rings exposed to gaseous zone
• Borehole/brackish/seawater
• Municipal mesophilic digester - cylinders
Everstore® meets or • Municipal sludge treatment - cylinders
exceeds the • Municipal sludge/sludge cake storage
requirements of ISO B • Filter tanks
Class B and is used • Storm/firewater
for Class B and C • Potable water (DWI listed Reg 31)
applications • Potable water (ANSI/NSF 61 listed)
C • Biogas digester for agricultural waste - cylinders

VIII. Summary
The review of the three standards has exposed the differences in the technical approach to glass quality
and the recognition in ISO and EEA of the importance of the coating system in considering the overall
durability and appropriateness for service in the specification of the gf2s storage tank. Consequently, we
feel it is important for buyers and specifiers to solicit specific glass quality information on each tank project.
From the perspective United Industries Group, we feel the most comprehensive standard is ISO 28765,
therefore we are identifying our Everstore® glass coating offerings in accordance with the classes noted
above.

For the convenience of both buyers and sellers, the tables presented in this paper are available for
download at the United Industries Group website (www.unitedind.com).

11


Release History
This document has been revised by:

Version Number Release Date Summary of Changes Author(s)

v1.0 5 August 2020 Original Release Mansour/Renich

Reference Documents
Please see the following documents for more information:

Ref Document or Source Version

ISO 28765 - International Standard - Vitreous and porcelain enamels -
Second Edition 2016-01-15 and First
1 Design of bolted steel tanks for the storage or treatment of water or
Edition 2008
municipal or industrial effluents and sludges
ANSI/AWWA D103 - American National Standard Institute, American
Editions 1980, 1989, 1997, 2009 and
2 Water Works Association Standard - Factory-Coated Bolted Carbon Steel
2019
Tanks for Water Storage
European Enamel Authority e.V. (EEA) - Quality Requirements
• Section 7.20 - Quality Requirements for Porcelain and Vitreous
Enamelled Industrial Tanks
3 • Section 7.24 - Quality Requirements for Porcelain and Vitreous 4th Edition - 2013
Enamelled Silos for Animal Feed
• Section 7.25 - Quality Requirements for Porcelain and Vitreous
Enamelled Dung Silos
DIN 15282 - German Standard - Deutsches Institut fur Nomung - Vitreous
4 and porcelain enamels - Design of bolted steel tanks for the storage or June 2007
treatment of water or municipal or industrial effluents and sludges
ISO 28706 - 1 - Vitreous and porcelain enamels - Determination of
5 resistance to chemical corrosion - Part 1: Determination of resistance to 2008
chemical corrosion by acids at room temperature
ISO 28706 - 2 - Vitreous and porcelain enamels - Determination of
resistance to chemical corrosion - Part 2: Determination of resistance to
6 2008
chemical corrosion by boiling acids, boiling neutral liquids, alkaline liquids
and/or their vapours
ISO 28706 - 3 - Vitreous and porcelain enamels - Determination of
resistance to chemical corrosion - Part 3: Determination of resistance to
7 2008
chemical corrosion by alkaline liquids using a hexagonal vessel or a
tetragonal glass bottle
ISO 28706 - 4 - Vitreous and porcelain enamels - Determination of
8 resistance to chemical corrosion - Part 4: Determination of resistance to 2008
chemical corrosion by alkaline liquids using a cylindrical vessel

12