🔩 Exposure of paint and varnish coating specimens to filtered xenon-arc radiation under controlled temperature, humidity and wetting, reproducing ageing under daylight (method A, daylight filters) or daylight behind window glass (method B) — spectral distribution in the 290–400 nm bands according to Tables 1 and 2, measurement of irradiance and radiant exposure in the specimen plane, uniformity at least 80 % of the maximum, PN-EN ISO 16474-2

Materials and NDT PN-EN ISO 16474-2

Overview

WHAT THE STANDARD COVERS. We read the text of the standard in two iTeh samples: SIST EN ISO 16474-2:2014 (English text) — title page of EN ISO 16474-2:2013, European foreword, contents, ISO foreword and introduction — and ISO 16474-2:2013 (French version) — from the title page to the beginning of 5.2 (test chamber) on page 5. Outside the samples remain the rest of the test chamber, radiometer (5.3), black-standard/black-panel thermometer (5.4), wetting and humidity-control equipment (5.5), specimen holders (5.6), specimens (6), exposure conditions (7: radiation, temperature, humidity, spray cycle, cycles with dark periods, sets of conditions), procedure (8), test report (9) and Annexes A (spectral power distribution of filtered xenon-arc radiation) and B (additional exposure cycles, normative). We did not read amendment A1 (ISO 16474-2:2013/Amd 1:2022, “Classification of daylight filters”).

ACCORDING TO THE TEXT OF ISO 16474-2:2013 AND THE FOREWORD OF EN ISO 16474-2:2013. The standard was prepared by ISO/TC 35 “Paints and varnishes”, Subcommittee SC 9 “General test methods for paints and varnishes”, in collaboration with CEN/TC 139 “Paints and varnishes” (secretariat DIN); CEN approved EN ISO 16474-2:2013 on 26.10.2013 without modification to ISO; it superseded EN ISO 11341:2004. The first edition of ISO 16474-2 together with ISO 16474-1 replaced ISO 11341:2004 as its technical revision; the ISO 16474 series has parts: 1 — general guidance, 2 — xenon-arc lamps, 3 — fluorescent UV lamps, 4 — open-flame carbon-arc lamps. Introduction: coatings of paints, varnishes and similar materials are exposed to laboratory light sources to reproduce in the laboratory the ageing processes occurring in natural weathering or in exposure tests under glass. Scope (1): methods for exposing specimens to xenon-arc light sources in the presence of moisture to reproduce the weathering effects occurring when materials are exposed in actual end-use environments to daylight or daylight filtered through window glass; specimens are exposed to filtered xenon-arc sources under controlled conditions (temperature, humidity and/or wetting), and various lamp types and filter combinations allow the test requirements of different materials to be met; specimen preparation and evaluation of results are covered by other standards for specific materials, general guidance by ISO 16474-1; according to the note exposure of plastics to xenon-arc lamps is described in ISO 4892-2. References (2): ISO 4618 (paints and varnishes vocabulary), ISO 9370 (instrumental determination of radiant exposure), ISO 16474-1. Terms (3): radiant exposure H — the amount of radiant energy to which a test panel has been exposed, H = ∫E·dt (J/m², irradiance E in W/m², time t in s), and with constant E simply E·t. Principle (4): a xenon arc fitted with suitable, properly maintained filters simulates the spectral power distribution of daylight in the ultraviolet and visible regions; specimens are exposed to various levels of irradiance (radiant exposure), heat, relative humidity and water under controlled environmental conditions; conditions are varied by the choice of filters, irradiance level, temperature during light exposure, relative humidity of the chamber air during light and dark exposures (when humidity control is required), type of wetting, water temperature and wetting cycle, and the length of the light/dark cycle; wetting is usually produced by spraying with demineralized or deionized water, immersion in water or condensation of water vapour on the specimen surfaces; the procedure shall include measurement of irradiance and radiant exposure in the specimen plane; it is recommended to expose a similar material of known performance (a control) together with the specimens as a comparison standard; results from different devices should not be compared unless an appropriate statistical relationship has been established between them for the material tested. Light source (5.1): one or more xenon-arc lamps in a quartz tube emitting from below 270 nm through the visible to the infrared; to simulate daylight, filters removing short-wavelength UV shall be used (method A, Table 1), to simulate daylight through window glass — filters limiting radiation below 310 nm (method B, Table 2); filters removing infrared may also be used to avoid unrealistic heating of specimens and thermal degradation not occurring outdoors; the reference daylight is taken from Table 4 of CIE publication No. 85:1989. Method A (Table 1, share of irradiance 290–400 nm, minimum / CIE 85 / maximum): λ < 290 nm — max. 0,15 %; 290–320 nm — 2,6 / 5,4 / 7,9 %; 320–360 nm — 28,2 / 38,2 / 39,8 %; 360–400 nm — 54,2 / 56,4 / 67,5 %; filter compliance is checked from the 250–400 nm spectrum, usually measured in 2 nm steps; the limits are based on more than 100 measurements of water- and air-cooled lamps and represent at least ±3 sigma; for each lamp with filters the share in each band shall lie within the limits; spectral differences within the tolerances can give different exposure results; for the CIE 85 spectrum the UV share (290–400 nm) is 11 % and the visible share (400–800 nm) 89 %. Method B (Table 2): λ < 300 nm — max. 0,29 %; 300–320 nm — 0,1 / ≤ 1 / 2,8 %; 320–360 nm — 23,8 / 33,1 / 35,5 %; 360–400 nm — 62,4 / 66,0 / 76,2 %; limits from more than 30 measurements; the reference values are CIE 85 multiplied by the transmittance of 3 mm window glass (UV about 9 %, visible 91 % in the 300–800 nm range). Uniformity (5.1.4): irradiance at any position of the exposure area shall be at least 80 % of the maximum, and if not, specimens are repositioned periodically according to ISO 16474-1; for highly reflective materials or those sensitive to radiation and temperature, repositioning is recommended even when the requirement is met. Chamber (5.2): of inert material, with control of irradiance and temperature, and for exposures with humidity control — with equipment according to ISO 16474-1.

STATUS (as of 03.10.2026). The PKN search (term “PN-EN ISO 16474-2”, 03.10.2026) shows PN-EN ISO 16474-2:2014-02 in the Polish and English versions (“Introduces: EN ISO 16474-2:2013 [IDT], ISO 16474-2:2013 [IDT]”) and the amendment PN-EN ISO 16474-2:2014-02/A1:2023-02 in the Polish and English versions (“Introduces: EN ISO 16474-2:2013/A1:2022 [IDT], ISO 16474-2:2013/Amd 1:2022 [IDT]”), all without a withdrawal note. In the iTeh catalogue (read on 03.10.2026) ISO 16474-2:2013 has the status “Published”, stage 90.93 (standard confirmed) since 24.06.2026, amended by ISO 16474-2:2013/Amd 1:2022.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, load up to 17.09.2026, read on 03.10.2026). The number 16474-2 appears in 5 records at 5 laboratories: AB 128, AB 163, AB 369, AB 910, AB 1552. In the current PCA documents (read on 03.10.2026, issues from 17.12.2025 to 01.09.2026) the number appears in 5 items — one at each laboratory (8 text lines, because at AB 163 the item lists the standard, amendment A1:2023-02 and correction Ap2:2016-11, and at AB 1552 the standard and amendment A1:2023-02); in each of the five documents the number of page markers equals the number of PDF pages, without repetitions; a search of all 1291 PCA documents downloaded from BIP on 03.10.2026 found no laboratories outside the database copy (17 laboratories on the list have no link to a scope document on BIP). The form “PN-EN ISO 16474-2:2014-02” (AB 163, AB 1552) and “PN-EN ISO 16474-2” without year (AB 128, AB 369, AB 910); always in one cell with PN-EN ISO 16474-1. None of these items is suspended. The “Laboratories” tab (term “PN-EN ISO 16474-2”) shows all 5 laboratories — checked with a tab query on the production server labcoda.pl on 03.10.2026.

WHAT THE LABORATORIES TEST (items in PCA). Object: metal products, plastics and plastic products, textiles, foams, rubber and rubber products, parts and assemblies of machines and equipment (AB 128; the last group in the flexible scope of accreditation), varnish coatings and plastics (AB 163), paint systems, anticorrosive coatings and linings (AB 369, flexible scope), materials for the production of consumer products, including children’s articles, plastics, textiles, paints, varnishes (AB 910, flexible scope), construction products and materials, building hardware, parts of machines and electrical equipment, including mining (AB 1552). Characteristic: resistance to solar radiation and weather using laboratory light sources — fluorescent UV, xenon-arc and metal-halide lamps (AB 128), resistance to weathering and artificial radiation (AB 163), resistance to a light source (AB 369), resistance to light radiation and weathering, assessment of colour change (AB 910), resistance to daylight under controlled environmental conditions (AB 1552).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. With filters: method A (daylight) and B (behind glass) have different spectra and are not interchangeable (5.1, Tables 1 and 2); filter compliance with the table is checked by measuring the 250–400 nm spectrum. With comparisons: results from different devices are compared only after establishing a statistical relationship for the given material (4.7), and even spectra within tolerance can give different results (Table 1, footnote c). With uniformity: below 80 % of the maximum — repositioning of specimens (5.1.4). With heating: without infrared filters thermal degradation not occurring outdoors is possible (5.1.1). With control: a control material exposed together with the specimens (4.6). With the edition: the PKN catalogue also has amendment A1:2023-02 (classification of daylight filters), cited by AB 163 and AB 1552.

WHAT WE DO NOT GIVE. We did not read the irradiance levels, black-standard thermometer temperatures, humidity, spray cycles and dark periods, sets of exposure conditions, procedure or report (from 5.2, Clauses 6–9, Annexes A and B), nor amendment A1:2022.

Method principle

Coating specimens are exposed in a chamber to the radiation of xenon-arc lamps with filters — daylight (method A) or window glass (method B) — under controlled irradiance, temperature, relative humidity and wetting (spray, immersion or condensation), with measurement of irradiance and radiant exposure in the specimen plane. Property changes after exposure are assessed according to product standards, by comparison with a control material exposed at the same time.

Applications

• Coatings of paints, varnishes and similar materials — simulation of ageing in daylight and behind window glass (introduction, 1)
• Comparison of coating resistance to light and weathering against a control material (4.6)
• Coatings, plastics, metal, rubber, textile and consumer products — items in the accreditation scopes of 5 laboratories in PCA

Key parameters

Standard

Standard number

PN-EN ISO 16474-2:2014-02 (+A1:2023-02)

Title (PL)

Farby i lakiery — Metody ekspozycji na laboratoryjne źródła światła — Część 2: Lampy ksenonowe łukowe

Title (EN)

Paints and varnishes — Methods of exposure to laboratory light sources — Part 2: Xenon-arc lamps

Step-by-step procedure

1. Choice of method

   Method A (daylight) or B (behind window glass); filters complying with Table 1 or 2 (5.1). PN-EN ISO 16474-2:2014-02 and A1:2023-02 without a withdrawal note (03.10.2026).

2. Setting conditions

   Irradiance, temperature, humidity, type of wetting, light/dark cycle (4.3); values according to Clause 7 and Annex B (not read).

3. Exposure

   Specimens with control material; measurement of irradiance and radiant exposure in the specimen plane; repositioning if uniformity < 80 % (4.5, 4.6, 5.1.4).

4. Evaluation

   Property changes according to product standards; procedure and report according to Clauses 8–9 (not read).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• UV radiation of xenon lamps — do not look into the source, device shields
• High supply voltage of the lamps and hot chamber parts

Frequently asked questions