ISO/TS 21488:2020

Plastics - Test method for exposing polyolefins outdoors combining natural weathering and artificial irradiation

This document specifies methods for exposing specimen to alternating outdoor weathering supported with artificial radiation. This method utilizes, as much as possible, the natural outdoor exposure which are then assisted by the artificial radiation during night time and in cloudy conditions. This document is applicable to polyolefin materials as well as to products and portions of products. The artificial and natural outdoor exposures and their practices applicable to this document are described in ISO 4892-1, ISO 4892-3 and ISO 877-1, ISO 877-2 and ISO 877-3, respectively.

Plastiques — Procédé d'exposition de polyoléfines en plein air combinant une irradiation naturelle et artificielle

General Information

• Status: Published
• Publication Date: 06-Jul-2020
• ICS: 83.080.01 - Plastics in general
• Technical Committee: ISO/TC 61/SC 6 - Ageing, chemical and environmental resistance
• Drafting Committee: ISO/TC 61/SC 6/WG 2 - Exposure to light
• Current Stage: 9093 - International Standard confirmed
• Start Date: 28-Sep-2023
• Completion Date: 13-Dec-2025

Overview

ISO/TS 21488:2020 - Plastics: Test method for exposing polyolefins outdoors combining natural weathering and artificial irradiation specifies a hybrid outdoor exposure method that combines natural solar weathering (daytime) with controlled artificial irradiation (night or cloudy conditions). The technique preserves the realism of outdoor exposures while accelerating degradation by adding laboratory radiation when sunlight is absent. It is intended for polyolefin materials and products (or product portions) to evaluate changes in visual, optical, mechanical and other properties caused by outdoor service.

Key topics and technical requirements

• Principle: Continuous, cyclical exposure where specimens receive natural outdoor solar radiation during daytime and controlled artificial irradiation (e.g., UVA-340 fluorescent or metal halide sources) during night or low-sun conditions to provide accelerated, realistic weathering.
• Scope and applicability: Specifically for polyolefins; suitable for specimens taken from materials, parts, or full products.
• Apparatus & instrumentation:
  • Test chamber or movable box enabling alternating exposure to sun and artificial sources.
  • Artificial radiation sources compatible with ISO 4892‑3 (UVA‑340) and IEC 60068‑2‑5 (metal halide).
  • Radiometer for measuring radiant exposure, black‑standard / black‑panel thermometer (BPT/WPT), specimen holders and mounting fixtures.
• Test conditions: Control and record radiation, relative humidity, and temperatures (black‑panel, white‑panel, specimen and air temperatures). Time settings for sunrise/sunset and cloudy conditions determine automated day/night switching.
• Procedure: Specimen conditioning, mounting, cyclic exposure (natural then artificial), radiant exposure measurement and scheduled property assessments. Results are reported per the standard’s test‑report requirements.
• Annexes: Informative examples for sites and apparatus design (e.g., a Seosan example and apparatus sketches).

Practical applications and users

• Who uses it: Materials scientists, polymer formulators, test laboratories, product designers, quality control teams, and standards & compliance professionals working with polyethylene, polypropylene and other polyolefins.
• Why use it:
  • Estimate outdoor lifetime and performance under realistic environmental cycles.
  • Accelerate weathering evaluation in regions with frequent cloud cover or low direct solar irradiance.
  • Combine benefits of natural weathering (authentic exposure) with lab irradiation (shorter test time, controlled dose).
• Typical use cases: Outdoor component validation, formulation comparison, qualification testing for outdoor-grade polyolefin products (pipes, geomembranes, packaging components, outdoor fixtures).

Related standards

• ISO 4892‑1, ISO 4892‑3 (laboratory light exposure)
• ISO 877‑1, ISO 877‑2, ISO 877‑3 (natural and concentrated solar exposure)
• IEC 60068‑2‑5 (simulated solar radiation)
• ISO 9370 (radiant exposure measurement)

Keywords: ISO/TS 21488:2020, polyolefins, outdoor weathering, artificial irradiation, accelerated weathering, UVA‑340, metal halide, radiant exposure, black‑panel temperature.

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 21488
First edition
2020-07
Plastics — Test method for exposing
polyolefins outdoors combining
natural weathering and artificial
irradiation
Plastiques — Procédé d'exposition de polyolefines en plein air
combinant une irradiation naturelle et artificielle
Reference number
©
ISO 2020
© ISO 2020
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ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
5.1 General . 2
5.2 Test chamber . 3
5.3 Artificial radiation source . 3
5.3.1 General. 3
5.3.2 Metal halide lamp . 3
5.3.3 Fluorescent UVA-340 lamp . 3
5.4 Radiometer . 3
5.5 Black-standard/black-panel thermometer . 3
5.6 Specimen holder . 3
5.7 Apparatus to assess changes in properties . 4
6 Test specimens. 4
7 Test conditions . 4
7.1 Radiation . 4
7.2 Relative humidity of air inside the chamber . 4
7.3 Temperature . 4
7.3.1 Black-standard and black-panel temperature (BPT) . . 4
7.3.2 White-standard and white-panel temperature (WPT) . 4
7.3.3 Specimen temperature . 4
7.3.4 Air temperature (AT) . 4
7.4 Time setting of sunrise and sunset . 4
7.5 Exposure conditions . 5
8 Procedure. 5
8.1 General . 5
8.2 Conditioning . 6
8.3 Mounting of test specimen . 6
8.4 Exposure . 6
8.5 Radiant exposure measurement . 6
9 Test report . 6
Annex A (informative) Outdoor weathering supported with artificial radiation at Seosan .8
Annex B (informative) Apparatus for outdoor weathering supported with artificial radiation .13
Bibliography .17
Foreword
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different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
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on the ISO list of patent declarations received (see www .iso .org/ patents).
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iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 6, Ageing,
chemical and environmental resistance.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

Introduction
The performance of polyolefin plastics and products exposed outdoors is reduced by various
environmental factors such as UV radiation, heat, humidity, acid rain, etc. Therefore, the estimation of
the lifetime is an important consideration in designing against performance degradation of materials
and products for the outdoor use. Although the outdoor exposure test method provides degradation
caused by the actual environmental factors, it carries a disadvantage of requiring a prolonged testing
period. Outdoor weathering supported with artificial radiation are also available. In all cases, these
methods are often not effective in regions with a low amount of direct radiation. In response to the
questionnaire conducted, over 150 experts by an expert committee on weathering, the majority of
respondents agreed on the need of a method for outdoor weathering supported with artificial radiation
that would be appropriate for the regional climate, especially for the cloudy regions. That is, a document
to be developed which comprise the advantage of outdoor exposure that would generate actual
environmental exposure and the advantage of shortening the exposure time by utilizing the artificial
irradiation. This test method is developed to provide outdoor weathering supported with artificial
irradiation by continuously and sequentially exposing specimens to natural weathering during daytime
and artificial radiation at night time.
The International Organization for Standardization (ISO) draws attention to the fact that it is claimed
that compliance with this document may involve the use of patents concerning apparatus described in
Annex B.
ISO takes no position concerning the evidence, validity and scope of this patent right.
The holder of this patent right has ensured ISO that he/she is willing to negotiate licences under
reasonable and non-discriminatory terms and conditions with applicants throughout the world. In
this respect, the statement of the holder of this patent right is registered with ISO. Information may be
obtained from the patent database available at www .iso .org/ patents.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights other than those in the patent database. ISO shall not be held responsible for identifying
any or all such patent rights.
TECHNICAL SPECIFICATION ISO/TS 21488:2020(E)
Plastics — Test method for exposing polyolefins outdoors
combining natural weathering and artificial irradiation
1 Scope
This document specifies methods for exposing specimen to alternating outdoor weathering supported
with artificial radiation. This method utilizes, as much as possible, the natural outdoor exposure which
are then assisted by the artificial radiation during night time and in cloudy conditions.
This document is applicable to polyolefin materials as well as to products and portions of products.
The artificial and natural outdoor exposures and their practices applicable to this document are
described in ISO 4892-1, ISO 4892-3 and ISO 877-1, ISO 877-2 and ISO 877-3, respectively.
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.
ISO 877-1, Plastics — Methods of exposure to solar radiation — Part 1: General guidance
ISO 877-2:2009, Plastics — Methods of exposure to solar radiation — Part 2: Direct weathering and
exposure behind window glass
ISO 877-3, Plastics — Methods of exposure to solar radiation — Part 3: Intensified weathering using
concentrated solar radiation
ISO 4582, Plastics — Determination of changes in colour and variations in properties after exposure to
glass-filtered solar radiation, natural weathering or laboratory radiation sources
ISO 4892-1, Plastics — Methods of exposure to laboratory light sources — Part 1: General guidance
ISO 4892-3, Plastics — Methods of exposure to laboratory light sources — Part 3: Fluorescent UV lamps
ISO 9370, Plastics — Instrumental determination of radiant exposure in weathering tests — General
guidance and basic test method
IEC 60068-2-5, Environmental testing — Part2-5: Tests — Test S: Simulated solar radiation at ground level
and guidance for solar radiation testing and weathering
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 877-3 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
outdoor weathering supported with artificial radiation
continuous exposure to natural and artificial weathering sequence in outdoors that provides
accelerated weathering
Note 1 to entry: In general, exposure sequence of natural outdoor weathering during the daytime and artificial
irradiation at night time (or cloudy day) is used.
4 Principle
The basic principle of this method is to combine both, the natural weathering (to solar radiation) and
the laboratory weathering/irradiation, as described in ISO 877-1, ISO 877-2, ISO 4892-1, and ISO 4892-3,
respectively, in continuous cycles of exposures all outdoors. Specimens prepared from the material or
taken from parts of the products or full product are exposed to natural weathering (to solar radiation)
[see Figure 1 a)] and then continue to subject the specimens to artificial radiation source with other
factors controlled during the night time [see Figure 1 b)]. A similar combination would also apply when
cloudy condition prevents direct solar radiation exposure. After the prescribed exposure combination
in time intervals, the specimens are removed from the exposure and tested for changes in visual,
optical, mechanical and/or other properties of interest. The exposure stage may be given as interval
of time, or may be expressed in terms of a given total solar or solar ultraviolet radiant exposure,
separately for natural and for artificial exposure whichever is found to be more appropriate for that
particular property of interest. In general terms, the sun tracking may be used and an automated device
for changing from daylight exposure to artificial exposure is recommended.
NOTE According to the World Meteorological Organization, cloudy conditions mean at least 50 % of the sky
will be covered by clouds — there will be more clouds t
...