💧 Resistance of coatings to humidity — exposure in a climatic chamber with a heated water reservoir: constant (CH) or alternating (AHT, AT) condensation, 40 °C ± 3 °C, 24 h cycle, PN-EN ISO 6270-2

Automotive PN-EN ISO 6270-2

Overview

WHAT THE STANDARD COVERS. We have the sample extract of ISO 6270-2:2017 (second edition) — from the cover to 8.1 (page 3), and the extract of the draft ISO/FDIS 6270-2 of 2025 — cover, table of contents, foreword and introduction. Scope (clause 1 of the 2017 edition): the general conditions and procedures to be observed when testing coated specimens in constant or alternating condensation-water atmospheres, so that results obtained in different laboratories are reproducible; the shape and preparation of the specimens, the test duration and the assessment of results are not covered. Introduction: the test is intended to show the behaviour of specimens in humid surroundings and to pinpoint defects in the corrosion protection; it does not predict the lifetime of the coating; after conditioning the specimens are assessed according to agreed documents, e.g. parts of ISO 4628, or according to procedures agreed between the parties. Principle (clause 6): the coated specimen is exposed to condensation in a climatic chamber and the effects are assessed by criteria agreed in advance — usually subjective. Limitations (clause 5): temperature and humidity are important parameters; deviations give results that are not comparable, and parameters agreed otherwise must be stated in the report.

ATMOSPHERES AND CHAMBER (clauses 4, 7 and 8.1 of the 2017 edition). Designations of the atmospheres: CH — condensation with constant humidity, AHT — with alternating humidity and air temperature, AT — with alternating air temperature. Water condenses on specimens that are cooler than the saturated air of the chamber (radiation to the walls or cooling of the specimen); the air temperature in the chamber during condensation is 40 °C ± 3 °C. Table 1: CH — from warm-up to the end of exposure 40 °C ± 3 °C and humidity about 100 % with condensation on the specimens; AHT — 24 h cycle: 8 h (including warm-up) at 40 °C ± 3 °C with humidity about 100 % and condensation, then 16 h (including cooling down) with the chamber open or ventilated, at 18–28 °C and humidity approaching ambient; AT — the same 8 h, then 16 h with the chamber closed, at 18–28 °C and humidity about 100 % (approximately saturated). A 24 h cycle is the rule; for AT a shorter one (12 h or 16 h) with correspondingly shortened periods is allowed; other cycles — by agreement. An alternating atmosphere is chosen when changes in temperature and humidity also have an important effect on the specimens; the effect of the water also depends on the amount of condensate, which depends on the temperature of the room housing the chamber. Condensate dripping off the specimens may contain dissolved constituents of the coating; reproducible results are obtained only with a constant procedure and conditions within a test series. Chamber (8.1): vapour-tight, inner walls corrosion-resistant and not affecting the specimens, usually with a floor trough for water; controlled by heating the water in the trough (possibly with additional air heating), and the water temperature should preferably not exceed 60 °C to avoid excessive vapour; a chamber without a trough must ensure adequate condensation on the specimens. The foreword of the 2017 edition lists the changes from 2005: new clauses on principle, terms and limitations, a changed recommendation on distilled or deionised water for the trough, a requirement for condensation on all specimens and a method for determining the comparison quantity of condensation water.

THE 2025 EDITION. Foreword of the draft ISO/FDIS 6270-2 (vote from 31 March to 26 May 2025): the third edition cancels and replaces ISO 6270-2:2017 and ISO 11503:1995 as a technical revision; the intermittent condensation cycle (IC) from ISO 11503 was added, chamber ventilation and specimen loading were clarified, spacing requirements for specimens were turned into recommendations (with their purpose explained), a simplified visual verification of condensation was added, and the previous determination of the comparison quantity of condensate was moved to the normative Annex A; the references were updated. Table of contents: 8.2 — installation of the chamber, 8.3 — device for accommodating the specimens, 9.4 — visual verification of condensation, 9.5.2 — CH atmosphere, 9.5.5 — intermittent condensation (IC). The standard was prepared in collaboration with CEN/TC 139 (Vienna Agreement).

STATUS (state of the cards on 30 September 2026). The card of PN-EN ISO 6270-2:2026-01 (English version) has no "Withdrawn" header — the standard is CURRENT: published 12-01-2026, 24 pages, price group M, Chemistry Sector, KT 175 for Paints and Varnishes, ICS 87.040, "Introduces: EN ISO 6270-2:2025 [IDT], ISO 6270-2:2025 [IDT]", "Replaces: PN-EN ISO 6270-2:2018-02 - English version, PN-EN ISO 6270-2:2018-02 - Polish version". The "Scope" field of the card gives the scope of the 2025 edition in Polish (our translation): "This document specifies the general conditions and procedures used when testing painted test specimens by exposing them to an atmosphere with a constant content of condensation water or an atmosphere with an alternating content of condensation water in a chamber with a heated water reservoir. These conditions and procedures ensure the reproducibility of test results obtained in different laboratories. This document does not deal with the shape and preparation of the test specimens, the test duration or the evaluation of test results." The card of PN-EN ISO 6270-2:2018-02 (Polish version): "Withdrawn and replaced by PN-EN ISO 6270-2:2026-01 - English version", published 20-11-2019, "Withdrawal date: 12-01-2026", 16 pages, it introduced EN ISO 6270-2:2018 and ISO 6270-2:2017 [IDT] and replaced PN-EN ISO 6270-2:2006 (Polish version); its "Scope" field is the scope of the 2017 edition. The PKN search for "PN-EN ISO 6270" (30 September 2026) also shows part 1 — PN-EN ISO 6270-1:2018-02 (condensation with single-sided exposure) in Polish and English versions, without a "Withdrawn" label in the list of results — and withdrawn editions of part 2 from 2005 (English version) and 2006 (Polish version).

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation-scope database, data loaded up to 17 September 2026, read on 30 September 2026). All notations of number 6270-2: 11 entries at 11 laboratories — the same number of occurrences in the current PCA documents. The 2026-01 edition: AB 163, AB 240 and AB 1631 (with "point 9.5.2" — in the 2025 edition this is the CH atmosphere; the laboratory describes it as "resistance to continuous condensation"); the withdrawn 2018-02 edition: AB 089, AB 1424, AB 1644 (atmospheres CH, AHT and AT) and AB 1700; without a year: AB 023, AB 128, AB 369 and AB 904 (flexible scopes). The "Laboratories" tab looks for notations that BEGIN with "PN-EN ISO 6270-2" and will show all 11 laboratories — checked with the tab's query on the production server labcoda.pl on 30 September 2026: 11. Current scopes on the PCA website (read on 30 September 2026, issues from 16.07.2025 to 02.09.2026): all entries are in the issues in force and none is suspended; at AB 1644 the asterisk marks a test on the basis of which the laboratory gives opinions and interpretations. The entries have no numerical ranges.

MATERIALS. Paint and varnish coatings, paint systems and anti-corrosion systems (AB 023, AB 163, AB 240, AB 369, AB 1424, AB 1631), metal products with organic or inorganic coatings (AB 1644), organic and inorganic (metallic, oxide) coatings on ferromagnetic and non-ferromagnetic substrates (AB 1700), and more broadly — metals, plastics, composites, rubber, textiles and foams (AB 089, AB 128) as well as finished products and components (AB 904). Names of the tested property: "resistance to humidity", "resistance to moisture and condensation water", "to an atmosphere saturated with water vapour", "to an atmosphere with condensing moisture", "to continuous condensation" and "corrosion resistance in an atmosphere with condensing moisture in a chamber with a heated water reservoir" (AB 1700).

ALONGSIDE THIS STANDARD. In the same entries: PN-EN ISO 6270-1 (condensation with single-sided exposure) — AB 128, AB 163 and AB 240 (at AB 023 in a separate entry "continuous condensation"), PN-EN 60068-2-78 — AB 128, and at AB 089 company specifications: AA-0213, DBL 7381:2021-01 (annex A, p. A.7, table 9), DBL 7382:2020-12 (annex A, p. A.7, table 6), GS 90011:2023-04 (p. 9.3.2) and MBN 50494-6:2025-09 (p. 6.2). Neighbouring entries of the same laboratories contain tests in a humid atmosphere with sulphur dioxide (PN-EN ISO 22479 or PN-EN ISO 3231 — AB 023, AB 089, AB 128, AB 1424) and salt spray (PN-EN ISO 9227 — among others AB 904, AB 1644, AB 1700; described in the Knowledge Base in a separate entry).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. First — the atmosphere: CH, AHT and AT act on the coating differently, and the standard says to choose an alternating one when changes in temperature and humidity matter; a result "no defects" without the atmosphere, cycle and exposure time stated is not comparable. Second — time and assessment: the standard sets neither the exposure time nor the criteria — they come from the product specification or from an agreement (e.g. the assessment of blisters according to PN-EN ISO 4628), so the report must state them. Third — condensation: the result is meaningful only if water really condenses on all specimens — this depends on the temperature of the room housing the chamber and on the cooling of the specimens; the 2025 edition introduced a visual check of condensation. Fourth — the edition: four laboratories cite the withdrawn 2018-02 edition, and three the 2026-01 edition with the new IC cycle and changed rules for loading the chamber; for comparative results it matters which one.

WHAT WE DO NOT GIVE. The extract of the 2017 edition ends at 8.1, and that of the 2025 edition at the introduction: we do not give the figure of the chamber, the installation of the chamber (8.2), the specimen holder (8.3), the filling of the trough (9.1), the specimens and their arrangement (9.2, 9.3), the method of checking condensation (9.4, Annex A), the course of the cycles (9.5), including intermittent condensation IC, interruptions of the test (9.6), the end of the test (9.7), evaluation (10), precision (11) or the test report (12).

Method principle

Coated specimens are placed in a vapour-tight climatic chamber in which heated water from a trough in the floor saturates the air with vapour; because the specimens are cooler than the air, water condenses on their surface. According to the 2017 edition, the atmosphere is constant (CH — throughout 40 °C ± 3 °C and humidity about 100 %) or alternating with a 24 h cycle (AHT, AT — 8 h of condensation at 40 °C, then 16 h at 18–28 °C with the chamber open or closed); the 2025 edition keeps these three atmospheres and adds intermittent condensation IC. After exposure the coating defects are assessed by criteria agreed in advance.

Applications

• Paints, varnishes and paint systems, including anti-corrosion systems — in the scopes of 11 laboratories
• Metal products with organic and inorganic (metallic, oxide) coatings; finished products and components (AB 904)
• Tests according to company specifications (AB 089: AA-0213, DBL 7381, DBL 7382, GS 90011, MBN 50494-6)

Key parameters

Standard

Standard number

PN-EN ISO 6270-2:2026-01 (wersja angielska; EN ISO 6270-2:2025, ISO 6270-2:2025 IDT)

Title (PL)

Farby i lakiery — Oznaczanie odporności na wilgoć — Część 2: Kondensacja (ekspozycja w komorze z podgrzewanym zbiornikiem wody)

Title (EN)

Paints and varnishes — Determination of resistance to humidity — Part 2: Condensation (in-cabinet exposure with heated water reservoir)

Step-by-step procedure

1. Agreements

   Atmosphere (CH, AHT, AT, in the 2025 edition also IC), exposure time, specimens and assessment criteria — from the product document or agreed between the parties; deviations from the parameters of the standard must be stated in the report.

2. Preparing the chamber

   Filling the trough with water (9.1 — we DO NOT GIVE the details), arranging the specimens so that water condenses on all of them.

3. Exposure

   According to the 2017 edition: CH — continuously 40 °C ± 3 °C and about 100 % humidity; AHT and AT — 24 h cycles (for AT 12 h or 16 h allowed).

4. End of test

   Removal of the specimens; we DO NOT GIVE the procedure for interruptions and the end of the test (9.6, 9.7).

5. Assessment

   According to criteria agreed in advance, e.g. according to the appropriate parts of PN-EN ISO 4628.

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• The chamber works with hot water and saturated vapour — beware of steam burns and a floor made slippery by condensate when opening it
• TECHNICAL NOTE: the standard describes only the conditioning — the exposure time and the assessment criteria must come from the product document or from an agreement

Frequently asked questions