EN 4688:2021

SLOVENSKI STANDARD
01-marec-2021
Nadomešča:
SIST EN 4688:2012
Aeronavtika - Barve in laki - Dvokomponentni temeljni premaz, korozijsko
obstojen, kromiran, ki se suši pri sobni temperaturi - Visoka korozijska odpornost,
za vojaško uporabo
Aerospace series - Paints and varnishes - Corrosion resistant chromated two-
components room temperature curing epoxy primer - High corrosion resistance for
military application
Luft- und Raumfahrt - Beschichtungsstoffe - Zweikomponenten-Epoxid-Grundierung,
chromathaltig, korrosionsbeständig, raumtemperaturhärtend - Hohe
Korrosionsbeständigkeit für militärische Anwendung
Série aérospatiale - Peintures et vernis - Peinture primaire époxy anticorrosion
chromatée à deux composants polymérisant à température ambiante - Haute résistance
à la corrosion pour applications militaires
Ta slovenski standard je istoveten z: EN 4688:2021
ICS:
49.040 Prevleke in z njimi povezani Coatings and related
postopki, ki se uporabljajo v processes used in aerospace
letalski in vesoljski industriji industry
87.040 Barve in laki Paints and varnishes
95.020 Vojaštvo na splošno Military in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 4688
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2021
EUROPÄISCHE NORM
ICS 49.040 Supersedes EN 4688:2012
English Version
Aerospace series - Paints and varnishes - Corrosion
resistant chromated two-components room temperature
curing epoxy primer - High corrosion resistance for
military application
Série aérospatiale - Peintures et vernis - Peinture Luft- und Raumfahrt - Beschichtungsstoffe -
primaire époxy anticorrosion chromatée à deux Zweikomponenten Grundierung, chromathaltig,
composants polymérisant à température ambiante - korrosionsschützend, raumtemperaturhärtend - Hoher
Haute résistance à la corrosion pour applications Korrosionsschutz für militärische Anwendung
militaires
This European Standard was approved by CEN on 2 November 2020.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 4688:2021 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 6
4 Surface pretreatments . 6
5 Classification. 6
6 Batch release and qualification testing . 7
6.1 General. 7
6.2 Qualification tests . 7
6.3 Batch acceptance testing . 7
6.4 Purchaser batch release testing . 7
7 Designation . 18

European foreword
This document (EN 4688:2021) has been prepared by the Aerospace and Defence Industries
Association of Europe — Standardization (ASD-STAN).
After enquiries and votes carried out in accordance with the rules of this Association, this
document has received the approval of the National Associations and the Official Services of the
member countries of ASD, prior to its presentation to CEN.
This document shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by July 2021, and conflicting national standards shall be
withdrawn at the latest by July 2021.
Attention is drawn to the possibility that some of the elements of this document may be the subject
of patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 4688:2012.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this document: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
1 Scope
This document defines the requirements for a two-components, high corrosion inhibiting epoxy primer.
The coating applies to suitably prepared metallic substrates, chromic acid anodised, or conversion
coated aluminium alloys and other suitably prepared substrates.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 2101, Aerospace series — Chromic acid anodizing of aluminium and wrought aluminium alloys
EN 2334, Aerospace series — Chromic-sulphuric acid pickle of aluminium and aluminium alloys
EN 2437, Aerospace series — Chromate conversion coatings (yellow) for aluminium and aluminium alloys
EN 3665, Aerospace series — Test methods for paints and varnishes — Filiform corrosion resistance test
on aluminium alloys
EN 3837, Aerospace series — Paints and varnishes — Nature and method for surface preparation of test
pieces in aluminium alloys
EN 3840, Aerospace series — Paints and varnishes — Technical specification
EN 3847, Aerospace series — Paints and varnishes — Determination of sedimentation rating
EN 4160, Aerospace series — Paints and varnishes — Determination of the effect of thermal exposure
EN 4689, Aerospace series — Paints and varnishes — Two-components room temperature curing
polyurethane finish — High flexibility and chemical agent resistance for military application
EN 4704, Aerospace series — Tartaric-Sulphuric-Acid anodizing of aluminium and aluminium wrought
alloys for corrosion protection and paint pre-treatment (TSA)
EN ISO 1513, Paints and varnishes — Examination and preparation of test samples
EN ISO 1518-1, Paints and varnishes — Determination of scratch resistance — Part 1: Constant-loading
method
EN ISO 1519, Paints and varnishes — Bend test (cylindrical mandrel)
EN ISO 1520, Paints and varnishes — Cupping test
EN ISO 1524, Paints, varnishes and printing inks — Determination of fineness of grind
EN ISO 2409, Paints and varnishes — Cross-cut test
EN ISO 2431, Paints and varnishes — Determination of flow time by use of flow cups
EN ISO 2811-1, Paints and varnishes — Determination of density — Part 1: Pycnometer method
EN ISO 2811-2, Paints and varnishes — Determination of density — Part 2: Immersed body (plummet) method
EN ISO 2811-3, Paints and varnishes — Determination of density — Part 3: Oscillation method
EN ISO 2811-4, Paints and varnishes — Determination of density — Part 4: Pressure cup method
EN ISO 2812-1, Paints and varnishes — Determination of resistance to liquids — Part 1: Immersion in
liquids other than water
EN ISO 2812-2, Paints and varnishes — Determination of resistance to liquids — Part 2: Water immersion
method
EN ISO 2813, Paints and varnishes - Determination of gloss value at 20°, 60° and 85°
EN ISO 3251, Paints, varnishes and plastics — Determination of non-volatile-matter content
EN ISO 3675, Crude petroleum and liquid petroleum products — Laboratory determination of density —
Hydrometer method
EN ISO 3679, Determination of flash no-flash and flash point — Rapid equilibrium closed cup method
EN ISO 4628-2, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity
and size of defects, and of intensity of uniform changes in appearance — Part 2: Assessment of degree of
blistering
EN ISO 4628-8, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity
and size of defects, and of intensity of uniform changes in appearance — Part 8: Assessment of degree of
delamination and corrosion around a scribe or other artificial defect
EN ISO 4628-10, Paints and varnishes — Evaluation of degradation of coatings — Designation of quantity
and size of defects, and of intensity of uniform changes in appearance — Part 10: Assessment of degree of
filiform corrosion
EN ISO 6270-1, Paints and varnishes — Determination of resistance to humidity — Part 1: Condensation
(single-sided exposure)
EN ISO 9117-1, Paints and varnishes — Drying tests — Part 1: Determination of through-dry state and
through-dry time
EN ISO 9117-3, Paints and varnishes — Drying tests — Part 3: Surface-drying test using ballotini
EN ISO 9117-6, Paints and varnishes — Drying tests — Part 6: Print-free test
EN ISO 9227, Corrosion tests in artificial atmospheres — Salt spray tests
EN ISO 9514, Paints and varnishes; Determination of the pot life of multicomponent coating systems —
Preparation and conditioning of samples and guidelines for testing
*
EN ISO 11664- , Colorimetry
EN ISO 11890-1, Paints and varnishes — Determination of volatile organic compound (VOC) content —
Part 1: Difference method
ISO 3270, Paints and varnishes and their raw materials — Temperatures and humidities for conditioning
and testing
MIL-PRF-5606H, Performance specification: Hydraulic fluid, petroleum base; aircraft, missile, and
1)
ordnance. (NATO H-515)
1)
MIL-PRF-6081D, Performance specification: Lubricating oil, jet engine. (NATO O-133)

*
And all its parts quoted in this document.
1)
Published by: DoD National (US) MIL. Department of Defense http://www.defenselink.mil/.
MIL-PRF-23699F, Performance specification: Lubricating oil, aircraft turbine engine, synthetic base,
1)
NATO code number O-156
MIL-DTL-83133G, Detail specification: Turbine fuel, aviation, kerosene type, JP-8 (NATO F-34), NATO F-35,
1)
and JP-8+100 (NATO F-37)
2)
AMS 1526B, Cleaner for aircraft exterior surfaces water-miscible, pressure- spraying type
2)
AMS 1527B, Cleaner for aircraft exterior surfaces water-miscible, foam-on, pressure-spraying
2)
AMS 1533A, Cleaner for exterior aircraft surfaces gel-type, solvent-base
ASTM B117, Standard Practice for Operating Salt Spray (Fog) Apparatus
DEF STAN 68-10 Issue 5, Corrosion Preventive, Water Displacing NATO Code: C-634 Joint Service
Designation: PX-24
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 3840 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• ISO Online browsing platform: available at http://www.iso.org/obp
• IEC Electropedia: available at http://www.electropedia.org/
4 Surface pretreatments
In accordance with EN 3837, the surface pretreatments applicable to aluminium alloy test panels are
the following:
EN 3837 — Procedure A: Sulfochromic pickling in accordance with EN 2334
EN 3837 — Procedure B: Chromic acid anodizing in accordance with EN 2101
EN 3837 — Procedure C: Chromate conversion coating in accordance with EN 2437
EN 3837 — Procedure D: Tartaric-Sulphuric-Acid anodizing in accordance with EN 4704
5 Classification
The primer is classified according to the following types:
TYPE I: Standard solvent content (VOC < 680 g/l)
TYPE II: Low volatile organic content (VOC < 350 g/l)
TYPE III: Waterborne (VOC < 250 g/l)

2)
Published by: SAE International (US) Society of Automotive Engineers http://www.sae.org/.
6 Batch release and qualification testing
6.1 General
The general requirements for qualification and batch
...