SIST EN ISO 877:2000
(Main)Plastics - Methods of exposure to direct weathering, to weathering using glass-filtered daylight, and to intensified weathering by daylight using Fresnel mirrors (ISO 877:1994)
Plastics - Methods of exposure to direct weathering, to weathering using glass-filtered daylight, and to intensified weathering by daylight using Fresnel mirrors (ISO 877:1994)
Cancels and replaces the first edition (1976). Specifies methods of exposing plastics to solar radiation, either by direct exposure to natural weathering (Method A), to indirect solar radiation by modification of its spectral distribution with glass to simulate ageing of plastics behind building or automotive window glass (Method B), or to solar radiation intensified by the use of Fresnel mirrors to achieve acceleration of the weathering processes (Method C). Specifies the general requirements for the apparatus and operating procedures for using the test methods described and methods for determining radiation dosage. Applicable to plastics materials of all kinds and to products and portions of products.
Kunststoffe - Verfahren zur natürlichen Bewitterung, zur Bestrahlung hinter Fensterglas und zur beschleunigten Bewitterung durch Sonnenstrahlung mit Hilfe von Fresnelspiegeln (ISO 877:1994)
Diese Internationale Norm gibt Verfahren zur Beanspruchung von Kunstoffen mit Globalstrahlung an, entweder durch direkte natürliche Bewitterung (Verfahren A), durch indirekte, in ihrer Spektralverteilung veränderte Globalstrahlung zur Simulation der Alterung von Kunststoffen hinter Fenster- oder Autoscheiben (Verfahren B) oder durch Sonnenstrahlung, die zur Beschleunigung der Bewitterungsvorgänge mit Hilfe des Fresnelspiegeln verstärkt wurde (Verfahren C). Zweck ist es, die erzeugten Änderungen nach bestimmten Stufen solcher Beanspruchungen festzustellen.
Plastiques - Méthodes d'exposition directe aux intempéries, ou d'exposition indirecte sous verre, et a la lumiere du jour intensifiée par des miroirs de Fresnel (ISO 877:1994)
La présente Norme internationale prescrit des méthodes d'exposition des plastiques au rayonnement solaire en procédant à une exposition directe aux intempéries naturelles (méthode A), au rayonnement solaire indirect en modifiant sa répartition spectrale avec du verre pour simuler le vieillissement des plastiques derrière du verre à vitrage automobile ou du verre employé dans le bâtiment (méthode B), ou au rayonnement solaire intensifié par des miroirs de Fresnel afin d'obtenir une accélération des processus de vieillissement (méthode C). L'objectif consiste à évaluer les changements induits par de telles expositions à des niveaux prescrits. La présente Norme internationale prescrit les exigences générales pour l'appareillage et les modes opératoires pour l'utilisation des méthodes d'essais décrites. Bien qu'elle ne traite pas des méthodes d'exposition directe utilisant des configurations d'essai prescrivant l'emploi de boîtes noires, il convient de prêter attention à cette méthode d'essai d'exposition des matériaux dans des conditions simulant leur température lors de leur utilisation finale. 1258 Les méthodes B et C ne comprennent pas les effets des influences climatiques telles que le vent et la pluie, bien que l'appareillage de la méthode C utilisé pour intensifier soit doté de dispositifs fournissant de l'humidité par vaporisation d'eau. En comparant les résultats d'exposition obtenus en utilisant la méthode C avec ceux obtenus en utilisant les méthodes A et B, il convient de tenir compte des différences de températures d'éprouvette, de niveaux d'exposition au rayonnement ultraviolet et de dépôts d'humidité. En outre, lorsqu'on compare les expositions selon la méthode C avec celles selon la méthode B, il y a lieu que les verres ou autres matériaux transparents utilisés comme filtres soient identiques. Il est recommandé que les résultats d'exposition à comparer soient obtenus pour des niveaux d'exposition au rayonnement ultraviolet proches l'un de
Polimerni materiali - Metode izpostave neposrednim vremenskim vplivom, vremenskim vplivom z dnevno svetlobo, filtrirano skozi steklo, in pospešenim vremenskim vplivom, ojačenim z zrcali po Fresnelu (ISO 877:1994)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 877:2000
01-maj-2000
3ROLPHUQLPDWHULDOL0HWRGHL]SRVWDYHQHSRVUHGQLPYUHPHQVNLPYSOLYRP
YUHPHQVNLPYSOLYRP]GQHYQRVYHWORERILOWULUDQRVNR]LVWHNORLQSRVSHãHQLP
YUHPHQVNLPYSOLYRPRMDþHQLP]]UFDOLSR)UHVQHOX ,62
Plastics - Methods of exposure to direct weathering, to weathering using glass-filtered
daylight, and to intensified weathering by daylight using Fresnel mirrors (ISO 877:1994)
Kunststoffe - Verfahren zur natürlichen Bewitterung, zur Bestrahlung hinter Fensterglas
und zur beschleunigten Bewitterung durch Sonnenstrahlung mit Hilfe von
Fresnelspiegeln (ISO 877:1994)
Plastiques - Méthodes d'exposition directe aux intempéries, ou d'exposition indirecte
sous verre, et a la lumiere du jour intensifiée par des miroirs de Fresnel (ISO 877:1994)
Ta slovenski standard je istoveten z: EN ISO 877:1996
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
SIST EN ISO 877:2000 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 877:2000
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SIST EN ISO 877:2000
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SIST EN ISO 877:2000
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SIST EN ISO 877:2000
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SIST EN ISO 877:2000
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SIST EN ISO 877:2000
INTERNATIONAL
ISO
STANDARD 877
Second edition
1994-08-15
Plastics - Methods of exposure to direct
weathering, to weathering using
glass-filtered daylight, and to intensified
weathering by daylight using Fresnel
mirrors
Plas tiques - Mbhodes d ’exposition directe aux intemperies, ou
d ’exposition indirecte sous verre, et 8 Ia lumikre du jour in tensifibe par des
miroirs de Fresnel
Reference number
ISO 877:1994(E)
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SIST EN ISO 877:2000
ISO 877:1994(E)
Contents
Page
1
1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
2 Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Definitions .,.,. 2
4 Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
5 Apparatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
8
6 Test specimen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . .~. 9
7 Test conditions
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8 Exposure stages
12
9 Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
..,.,................................................,.,.,... 13
10 Expression of results
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
11 Test report
Annexes
A Use of dyed blue wo01 references to measure light dosage 16
B Classification of climates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Bibliography pertaining to Method C (accelerated weathering using
C
Fresnel mirrors) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
0 ISO 1994
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronie or mechanical, including photocopying and
microfilm, without Permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-l 211 Geneve 20 l Switzerland
Printed in Switzerland
ii
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SIST EN ISO 877:2000
0 ISO
ISO 877:1994(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide
federation of national Standards bodies (ISO member bodies). The work
of preparing International Standards is normally carried out through ISO
technical committees. Esch member body interested in a subject for
which a technical committee has been established has the right to be
represented on that committee. International organizations, governmental
and non-governmental, in liaison with ISO, also take part in the work. ISO
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard ISO 877 was prepared by Technical Committee
ISO/TC 61, Plastics, Subcommittee SC 6, Ageing, chemica/ and environ-
mental resis tance.
This second edition cancels and replaces the first edition (ISO 877:1976),
which has been technically revised.
Annex A forms an integral part of this International Standard. Annexes B
and C are for information only.
. . .
Ill
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SIST EN ISO 877:2000
ISO 877:1994(E) 0 ISO
Introduction
Outdoor-exposure tests of the type specified in this International Standard
are needed to evaluate the Performance of plastics when exposed to
daylight. The results of such tests should be regarded only as an indication
of the effect of exposure to direct weathering (Method A), or to indirect
weathering using glass-filtered daylight (Method B) or to intensified day-
light (Method C) by the methods described. Results obtained after ex-
posure for a given time may not be comparable to those obtained after
other exposures of equal time using the Same method. When identical
materials are exposed at different times for extended periods of several
years, they generally show comparable behaviour after equal-exposure in-
tervals. However, even in long-term tests, the results may be affected by
the season in which the tests are started. This is particularly true when
exposure tests are performed in accordance with Method C, using the
Fresnel-reflecting concentrators described in this International Standard.
Fresnel-reflecting concentrators of the type described in Method C, which
employ solar radiation as the Source of ultraviolet light, are utilized to pro-
vide accelerated outdoor-exposure testing of many plastics materials.
However, some plastics materials, especially those that may tend to be
comparatively moisture-sensitive, may not exhibit losses in certain
properties at the same rate as in outdoor, natura1 exposures.
The results of short-term outdoor-exposure tests tan give an indication of
the relative outdoor Performance, but should not be used to predict the
absolute long-term Performance of a material. Even results of tests carried
out for longer than 24 months tan show an effect of the season in which
the exposure was started. Comparisons of non-full-year exposure will ex-
hibit seasonal effects.
A System of classifying and characterizing climates in different Parts of the
world is given in annex B.
lt is noted that the test method Chosen is usually designed to expose the
material to the most severe conditions associated with any particular cli-
mate. lt should, therefore, be borne in mind that the severity of exposure
in actual use is, in most cases, likely to be less than that specified in this
International Standard, and allowance should be made accordingly when
interpreting the results. For example, vertical exposure at 90” from the
horizontal is considerably less severe in its effects on plastics than near-
horizontal exposure, particularly in tropical regions, where the sun is most
powerful at high zenith angles.
Polar-facing surfaces are much less likely to be degraded than equator-
facing surfaces because they are less exposed to solar radiation. However,
the fact that they may remain wet for longer periods may be of signifi-
cance for materials affected by moisture.
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SIST EN ISO 877:2000
INTERNATIONAL STANDARD 0 ISO ISO 877:1994(E)
Methods of exposure to direct weathering,
Plastics -
to weathering using glass-filtered daylight, and to
intensified weathering by daylight using Fresnel
mirrors
Method C exposures to Method B exposures, the
1 Scope
glass or other transparent materials used as filters
should be identical. Exposure results being compared
This International Standard specifies methods of ex-
should be for ultraviolet radiant exposure levels that
posing plastics to solar radiation, either by direct ex-
agree closely with each other.
posure to natura1 weathering (Method A), to indirect
solar radiation by modification of its spectral distribu-
This International Standard also specifies methods for
tion with glass to simulate ageing of plastics behind
determining radiation dosage. The methods are appli-
building or automotive window glass (Method B), or
cable to plastics materials of all kinds and to products
to solar radiation intensified by the use of Fresnel
and portions of products.
mirrors to achieve acceleration of the weathering
processes (Method C). The purpose is to assess
NOTE 1 For the determination of changes in properties
changes produced after specified stages of such ex-
after exposure, see ISO 4582.
posures.
This International Standard specifies the general re-
quirements for the apparatus and operating pro- 2 Normative references
cedures for using the test methods described.
Although this International Standard does not include The following Standards contain provisions which,
through reference in this text, constitute provisions
direct weathering using black-box test fixtures, atten-
of this International Standard. At the time of publica-
tion is drawn to this method of exposure testing of
tion, the editions indicated were valid. All Standards
materials under conditions simulating their end-use
are subject to revision, and Parties to agreements
temperatures?
based on this International Standard are encouraged
Methods B and C exclude the effects of weathering
to investigate the possibility of applying the most re-
influences such as wind and rain, although the
cent editions of the Standards indicated below.
Method C apparatus used to produce intensified solar
Members of IEC and ISO maintain registers of cur-
radiation is equipped to provide moisture in the form
rently valid International Standards.
of water Spray.
ISO 105-AOl :-*), Textiles - Tests for colour fastness
When comparing the results of exposure using
- Part AO?: General principles of testing.
Method C with results using Methods A and B, dif-
ferences in specimen temperatures, ultraviolet radiant ISO 105-AO29 993, Textiles - Tests for colour fast-
ness -
exposure levels and moisture deposition should be Part AO2 Grey scale for assessing Change in
taken into account. Additionally, when comparing colour.
1) ASTM G 7-89, Standard practice for atmospheric environmental exposure testing of nonmetallic materials and ASTM
D 4141-82 (reapproved 1987), Standard practice for conducting accelerated outdoof exposure tests of coatings.
2) To be published. (Revision of ISO 105-AO1:1989)
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SIST EN ISO 877:2000
ISO 877:1994(E) 0 ISO
ISO 105-BOI :1989, Textiles - Tests for colour fast- 3.4 natura1 weathering: Long-term exposure of
ness - Part BOI: Colour fastness to light: Daylight. materials to the elements, usually conducted on
fixed-angle or seasonally adjusted racks (see ASTM
ISO 291: 1977, Plastics - Standard atmospheres for
G 7-89 ”).
conditioning and tes ting.
These exposures are used to assess the effects of
environmental factors on various functional and
ISO 293: 1986, Plastics - Compression moulding test
decorative Parameters of interest.
specimens of thermoplastic ma terials.
ISO 294: 1975, Plastics - Injection moulding test 3.5 pyrheliometer: Radiometer used to measure
specimens of thermoplastic ma terials. the direct (beam) solar irradiance incident on a surface
normal to the sun ’s rays.
ISO 2557-1: 1989, Plastics - Amorphous thermoplas-
tics - Preparation of test specimens with a specified 3.6 pyranometer: Radiometer used to measure the
maximum reversion - Part 1: Bars. total solar radiant energy incident upon a surface per
unit time per unit area.
ISO 2818:1994, Plastics - Prepara tion 0 f test speci-
The energy measured includes direct and diffuse
mens by machining.
radiant energy as weil as radiant energy reflected
ISO 3167:1993, Plastics - Multipurpose test speci- from the background.
mens.
4 Principle
- Determination of changes
i SO 4582: 1980, Plas tics
in colour and variations in properties after exposure to
Spetimens or, if required, sheets or other shapes
daylight under glass, natura/ weathering or artificial
.
from which specimens tan be tut, are exposed to di-
Irgh t .
rect natura1 daylight, or to window glass-filtered day-
light, or to intensified sunlight using a Fresnel-mirror
ISO 4892:1981, Plastics - Methods of exposure to
concentrator, as specified. After the prescribed ex-
laboratory light sources.
posure interval, the specimen(s) are removed from
exposure and tested for changes in Optical, mech-
WMO, Guide to meteorological instruments and
anical or other properties of interest. The exposure
methods of Observation, WM0 No. 8, Fifth Edition,
Stage may be a given interval of time, or may be ex-
World Meteorological Organization, Geneva, 1983.
pressed in terms of a given total solar or solar-
ultraviolet-radiation dosage. The latter is preferred
whenever the main objective of the exposure is to
3 Definitions
determine resistance to light ageing, since it mini-
mizes the effect of variations in the quality and inten-
For the purposes o f this International Standard, the
sity of solar radiation with climate, location and time.
wing definitions
follo
aPPlY.
Methods of assessing the radiation dosage may
3.1 direct (beam) solar radiation: Solar flux, com-
comprise one or more of the following:
ing from a small solid angle centred on the sun ’s disc,
incident on a surface perpendicular to the axis of that
- instrumental means of measuring irradiance, and
solid angle.
means for integration to give the light dosage over
a period of time;
Convention dictates that the plane angle of direct
radiation is about 6 ”.
- evaluation of physical Standards which Change in
colour or in other weil-defined properties upon ex-
3.2 direct weathering; direct exposure: By con-
posure to light, the degree of Change indicating the
radiation,
vention, weathering (or exposure) due to
light dosage.
incident on a surface, which is unmodified by either
transmission through transparent materia s or re-
Unless otherwise specified, test pieces for the deter-
flection by mirrors.
mination of Change in colour and Change in mech-
anical properties are exposed in an unstrained state.
33 . Fresnel-reflector System: Flat mirrors arranged
in an array such that they reflect onto a target having Climatic conditions and variations thereof during the
an illuminated area which simulates the shape and test are monitored and reported with other conditions
of exposure.
size of the flat mirror.
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SIST EN ISO 877:2000
0 ISO ISO 877:1994(E)
5.2 Fixture for exposure testing using
5 Apparatus
Method A
The design of the rack shall be suited to the types of
pieces being tested, but for many purposes a flat
5.1 General requirements
frame mounted on a support is suitable. This frame
shall consist of rails of approved timber or other ap-
Exposure equipment consisting essentially of an ap-
proved materials to which the test specimens them-
propriate test rack shall be used. The rack, holders
selves, or suitable specimen holders, may be secured.
and other fixtures shall be made from inert materials
The test fixture may be adjustable with respect to
that will not affect the test results. Noncorrosive alu-
both solar altitude (i.e. tilt) and azimuth.
minium alloy, stainless steel or ceramics have been
found suitable. Certain timbers that have been suit-
ably impregnated with preservatives such as copper-
chromium-arsenic mixtures or that have been shown
not to interact with exposure tests may be used.
Materials having thermal properties which differ from
5.3 Fixture for exposure testing using
these materials may give different results. Copper or
Method B
zinc or their alloys, iron or steels other than stainless
steels, galvanized or plated metals or timbers other
The test fixture consists of either a test rack, or
than those above should not be used in the vicinity
open-bottomed box, with a framed lid of appropriate
of the test specimens.
window, Windscreen or automotive side-window
When installed, the racks employed in test methods glass. The enclosure shall be equipped with a rack
A and B shall be capable of providing the desired an- that is positioned in a plane parallel to that of the glass
gle of inclination (see 7.1), and shall be such that no cover, on which specimens may be mounted directly
Portion of the test pieces shall be closer than 0,5 m or in suitable holders. The test fixture may be adjust-
to the ground or to any other obstruction. Spetimens
able with respect to both solar altitude (i.e. tilt) and
may be mounted directly on the rack, or in suitable
azimuth. A schematic of an acceptable under-glass
holders which are then affixed to the rack. Mounting
exposure case is shown in figure 1.
fixtures shall be secure, but should apply as little
stress as possible to the specimens, and should per-
Sufficient space between the lid and the rack is
mit shrinkage, expansion or warping to occur without necessary to ensure adequate Ventilation; a minimum
constraint, so far as possible. of 75 mm has been found suitable. To minimize
shadows, the usable-exposure area under the glass
If backing is necessary to support the test pieces or
shall be limited to the area of the glass cover with di-
to simulate special end-use conditions, such backing
mensions reduced by the distance from the cover to
shall be of inert material. Spetimens that require
the specimens.
support to prevent sagging of the test piece, but do
not require backing to elevate the temperature, or re-
The glass used for the lid shall be flat, uniformly
quire no “solid” backing, should be supported with
transparent and without defects. For exposure testing
fine-Strand wire netting, or slit-expanded aluminium
under building-window glass, Single-strength glass of
or stainless steel backing.
2 mm to 3 mm thickness having a transmittance of
approximately 90 % at wavelengths in the visible
NOTE 2 For tests on finished products, it is rec-
range of the spectrum from 370 nm and 830 nm and
ommended that, wherever possible, the fixtures should
a transmittance of less than 1 % at wavelengths of
closely simulate those used in practice.
300 nm to 310 nm and shorter, is recommended. To
maintain these characteristics, it is usually necessary
lt is essential that the condition of the apparatus used
to replace the glass at intervals of not more than two
in the two indirect-exposure methods (Methods B and
years.
C) be monitored to ensure that spectrum-modifying
changes do not occur on ageing. For this reason the
Other types of glass or glazing materials may be used
spectral transmittance of the glass for Method B test,
as agreed upon by the interested Parties.
and the specular spectral reflectance of the mirror
System for Method C tests, must be periodically
NOTE 3 Exposure under glass may give rise to different
measured. Alternatively, the glass or the mirrors
results compared to exposure to the open atmosphere be-
should be periodically replaced in their respective ap- Cause of a differente in spectral distribution and a differente
between under-glass and open-air temperature.
paratus.
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SIST EN ISO 877:2000
0 ISO
ISO 877:1994(E)
The test machine ’s effective target area is slightly less
5.4 Apparatus for exposure testing using
than the dimensions of the mirrors used, and is typi-
Method C
cally 130 mm x 1 400 mm. The mirrors shall pos-
sess a high specular spectral reflectance in the
The test fixture is a Fresnel-reflecting concentrator
device comprising 10 flat mirrors that focus direct ultraviolet and visible wavelength regions from
solar radiation onto an air-cooled Sample area. The 295 nm to 700 nm. The mirrors shall be adjusted such
mirrors shall be arranged to simulate tangents to a that the nonuniformity of intensified solar radiation in
parabolic trough such that they reflect sunlight uni- the target plane is less than 5 %. The mirrors em-
formly onto the specimens mounted in the target ployed on Fresnel-reflector test machines shall be flat
and shall have a specular spectral reflectance of
area. An essentially complete description of the ap-
65 % or greater at 310 nm wavelength.3)
paratus is given in documentation cited in annex C.
A schematic of the device is shown in figure2.
The apparatus shall be provided with a mounting area
The test machines are usually deployed with their
for affixing a removable Optical-mirror Sample having
axes oriented in a north-South direction such that the
a minimum area of 25 mm*. The essential require-
mirror System faces the equator. The opposite polar-
ment is that the Optical-mirror specimen be manufac-
facing end is altitude-adjustable to account for
tured from the same batch and lot as the mirror
seasonal variations in solar altitude at zenith.
stock-material used to irradiate the target Sample
area. The Optical-mirror Sample is mounted simul-
The plane of the mirror System shall be maintained
taneously with the mirrors used to irradiate the sam-
at a near-normal orientation to the beam component
ple area, and its specular spectral reflectance shall be
of solar radiation by a sun-tracking mechanism. The
periodically measured.
consists of two
tracking mechanism usually
photoreceptor cells that are installed on top of the
NOTE 4 The degree of weathering acceleration provided
wind tunnel such that they face the sun. A “T”
by the apparatus is greatest when operated in dry, desert
shadow maker is mounted above the cells so that
or high altitude climates.
one-half of each cell is equally illuminated when the
machine is in focus. As one cell receives more solar
Water sprayed on the specimen shall be free of silica
radiation than the other, the balance is disturbed and
(less than 0,Ol mg/litre) and contain less than
a Signal is furnished through a null-operated d.c.
20 mg/litre total solids. Distillation or demineralization
amplifier to a reversible motor which then adjusts the
of the water may be required. All material which
machine to maintain focus.
Comes into contact with specimen Spray water shall
be of a nature that will not contaminate the water.4)
An alternative approach is to use a computer-
controlled tracking System that adjusts the azimuth
The test machines shall be equipped with a mech-
and altitude with respect to the sun throughout the
anism for delivery of water Spray to the samples dur-
year. Alternatively, a clock drive that maintains the
ing irradiation. Use of specific Spray cycles relates to
device ’s azimuthal Position with respect to the sun
the end-use application of the plastics material.
may also be used.
3) This tan be measured using ASTM E 903-82 (1988). Test method for solar absorptance, reflectance, and transmittance of
materials using integrakg spheres, or an equivalent method.
4) A Hach Model SI-7 low-range silica test kit may be used. This information is given for the convenience o-f usess of this
nfji-9@&
Eqjb&nt I-)lf4@JV1,c9 f-qEy be tisecl
International Standard and does no% constitute an er:dorsenxr:2 b ‘; BSC cf ?he o:odi:ict
i
if they c=an be shown ts lead ts the sa-m results
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SIST EN ISO 877:2000
ISO 877:1994(E)
Dimensions in miliimetres
Fran ie leaving a free area of
865 x 560
holes
N
S
E
(Northern hemisphere)
- Typical exposure case for weathering of plastics using glass-filtered daylight
Figure 1
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SIST EN ISO 877:2000
ISO 877:1994(E)
J M
A Air Plenum I Gear box, azimuth drive
B Air blower J
Air flow switch
C Rotor assembly K
Water Spray nozzle
D Turntable assembly L
Clutch disc, elev drive
E A-frame assembly M Solar cells/shadow hat
F Mirror N Sample protection door
G Gear box, elev drive 0 Door release mechanism
H Control box P Air deflector
a) Schematic of machine
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SIST EN ISO 877:2000
ISO 877:1994(E)
Sun
Air Plenum (end view)
-7
Target board
Test specimen
Centre of gravity SkY
-\ radia tion
and rotation
Mirror bed
b) Schematic of Optical System
Figure 2 - Fresnel reflecting concentrator accelerated weathering machine
5.5.1.2 Pyrheliometers
5.5 Apparatus for measurement of climatic
factors
Pyrheliometers shall meet or exceed the require-
ments for a first class instrument as defined by the
World Meteorological Organization (WMO). In addi-
5.5.1 Apparatus for measurement of solar
tion, pyrheliometers shall be calibrated at least annu-
radiation
ally, and their calibration factors shall likewise be
traceable to the world radiometric reference (WRR).
5.5.1 .l Pyranometers
5.5.1.3 Total ultraviolet radiometers (TUVRs)
Pyranometers shall meet or exceed the requirements
for a second class instrument as defined by the World
When used to define exposure stages, TUVRs shall
Meteorological Organization (WMO). In addition,
have a bandpass that maximizes the acceptance of
pyranometers shall be calibrated at least annually, and
radiation in the 300 nm and 400 nm wavelength re-
their calibration factor shall be traceable to the world
gion, and they shall be cosine-corrected to include ul-
radiometric reference (WRR) (see the WM0 Guide, traviolet sky radiation. Commercially available TUVRs
chapter 9). require semi-annual calibration Checks if they are de-
7
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SIST EN ISO 877:2000
0 ISO
ISO 877:1994(E)
ployed between 40” north and 40” South latitudes by the User. For preparation of test specimens, use
(annual calibrations are satisfactory if deployed out- ISO 293, ISO 294, ISO 2557-1 and ISO 3167, as ap-
side this band). propriate.
If the material to be tested is in the form of an
5.5.1.4 Narrow-band ultraviolet radiometers
extrusion, moulding, sheet, etc., test specimens may
(NBUVRs)
be prepared from the materials either before or after
exposure, depending on the specific requirements of
When used to define exposure stages, NBUVRs shall
the tests and the nature of the material. For example,
be cosine-corrected if used in conjunction with either
materials which embrittle markedly on weathering
natura1 fixed angles or glass-filtered exposures; they
shall be exposed in the form in which they are to be
shall possess an acceptance angle that exceeds the
tested, since subsequent machining is difficult; on the
mirror system ’s effective field-of-view if used in con-
other hand, materials such as laminates, which may
junction with intensified solar-radiation exposure test-
delaminate at the edges, should be exposed in sheet
ing using a Fresnel-reflecting concentrator. In either
form and the specimens should be tut after exposure.
case, they shall be calibrated at least every six
months, or more often if required to ensure stability
NOTE 6 For the preparation of test specimens by ma-
of their instrument constants.
chining, see ISO 2818.
5.5.2 Dyed blue wool references
When the behaviour of a specific type of article is to
be established, the article itself should be exposed
When used to define exposure Stages, blue wool ref-
wherever possible. Such articles or portions large
erences shall be used in conformance with
enough for test purposes shall be exposed as they
ISO 105BOI (see annex A).
are. In cases where pieces of material are exposed
and test specimens tut from them afterwards, the
5.5.3 Other climate-measuring instruments
exposed weathered surface shall not be removed.
Instrumentation required for the measurement of air
Test specimens tut from exposed sheet shall be
temperature, Sample temperature, relative humidity,
taken from sheet at least 20 mm from the edge, and
rainfall, wet time and sunshine hours shall be appro-
from fixtures holding the material, or from supports
priate to the exposure method used, and sh
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