ACCELERATED WEATHERING TEST
AND
RELATION WITH REAL SUNLIGHT
Tessiture Pietro Radici SpA manufactures yarns for artificial grass which are protected, against
weathering deterioration due to the UV light, by adding specific anti-UV molecules into the
yarn.
With the exception of direct exposure, the most reliable way of predicting the behavior of yarn
exposed to sunlight is to submit it to an accelerated, artificial UV exposition with a Xenon-arc
lamp. Such lamp contains a gas (Xenon) which is triggered by an electric arc and emits a
radiation ranging from about 270 nm (Ultraviolet) to the visible and the infrared spectrum.
The radiation is attenuated by a filter which can be chosen in a filter combination provided, in
most cases, by the Xenon Lamp producer.
The graph shown in attachment #1 shows the irradiance of real sunlight and the irradiance of a
Xenon-arc lamp. The irradiance (indicated as I [W/(m2.nm)]) represents the energy (W/m2)
emitted at a specific wavelength (nm).
The Xenon-arc irradiance curve can be set by fixing the specific value of irradiance at a certain
wavelength (usually @ 340 nm) and installing a specific filter.
In attachment #1, the curve was set by fixing the irradiance value at 0.55 W/(m2.nm) @ 340 nm
and using a “daylight filter”.
The energy emitted by the lamps (absorbed by the yarn samples exposed in the equipment) will
depend upon the set irradiance point and upon the number of hours of exposure. Having
established this number, the higher is the set irradiance point, the more accelerated will be the
test.
Different norms regulate weathering tests with Xenon-arc lamps. Tessiture Pietro Radici SpA
has adopted the EN ISO 4892-2:2009 norm. According to this norm, besides setting the
irradiance point and the type of filter, it is necessary to set also the so called Cycle (see Table 3
in the norm).
The parameters which characterize a Cycle are: the Exposure period, the Black-standard
Temperature, the Chamber Temperature and Relative Humidity.
Tessiture Pietro Radici SpA has selected Method A and Cycle n°1.
As far as real sunlight energy is concerned, the quantity of energy irradiated by the sun during a
calendar year is recorded by Meteo Stations. Usually, the yearly quantity of energy is measured
in kLy and it largely depends on the geographical area.
Attachment #2 contains a table showing, for all the main countries, the kLy and the number of
hours of Xenon-arc test (according to conditions described above) equivalent to 1 year of
exposure to real sunlight.
It must be clearly said that the relation between accelerated and real data is limited to irradiated
energy. Under real conditions factors such as pollution, the related humidity and other elements
can heavily modify and accelerate the weathering effects on the yarn.
Conventionally, a yarn sample successfully passes the test if its residual tensile strength, after a
certain number of hours of exposure, exceeds 50% of the initial value, recorded before
exposure.
Tessiture Pietro Radici SpA guarantees the UV stability of its yarn in the general “Terms
and Conditions of Supply” (see clause 9).
Tessiture Pietro Radici SpA issues a Technical Data Sheet For each product, indicating the
hours of Xenon-arc lamp exposure for which the UV stability of the product is guaranteed.
For practical reasons, hours of Xenon-arc exposure reported in the Technical Data Sheet are
converted into an equivalent number of years of exposure to real sunlight, in a certain world
region.
The table shown in attachment # 2 can therefore be used for reference taking into due
consideration the above mentioned limits inherent to the accelerated weathering test and not
exceeding the scope of the warrant.
ATTACHMENT #1
ATTACHMENT #2
Hours of
Xenon-arc
COUNTRY
kLy
Hours of
Xenon-arc
COUNTRY
kLy
One year of
sun light
Hours of
Xenon-arc
COUNTRY
kLy
One year of
sun light
One year of
sun light
Austria
80
900
Haiti
160
1800
Pakistan
180
2100
Afghanistan
180
2100
Hong Kong
140
1600
Panama
40
500
Alaska
70
800
Honduras
140
1600
Paraguay
160
1800
Algeria
160
1800
Hungary
80
900
Peru
140
1600
Angola
120
1400
India
180
2100
Philippines
140
1600
Argentina
160
1800
Indonesia
140
1600
Poland
80
900
Australia
180
2100
Iraq
180
2100
Portugal
40
500
Bahamas
140
1600
Iran
180
2100
Rumania
100
1150
Bahrain
200
2300
Israel
180
2100
Russia (North)
70
800
Belgium
80
900
Italy
120
1400
Russia (South)
140
1600
Burma
120
1400
Jamaica
160
1800
Saudi Arabia
200
2300
Bolivia
140
1600
Japan
100
1150
Senegal
180
2100
Brazil
120
1400
Jordan
180
2100
Singapore
140
1600
Bulgaria
100
1150
Kenya
140
1600
South Africa
160
1800
Canada
100
1150
Kuwait
180
2100
Spain
140
1600
Chad
200
2300
Korea
120
1400
Sudan
220
2500
Chile
140
1600
Lebanon
180
2100
Suriname
120
1400
China
140
1600
Luxembourg
80
900
Sweden
70
800
Columbia
100
1150
Libya
180
2100
Switzerland
80
900
Costa Rica
140
1600
Madagascar
140
1600
Taiwan
140
1600
Cuba
140
1600
Mali
200
2300
Thailand
140
1600
Cyprus
140
1600
Malta
160
1800
Tunisia
160
1800
Denmark
70
800
Malaysia
140
1600
Turkey
140
1600
Egypt
200
2300
Morocco
160
1800
Uruguay
160
1800
Ecuador
120
1400
Mauritania
180
2100
USA
El Salvador
140
1600
Mexico
160
1800
North
100
1150
Ethiopia
140
1600
Mozambique
160
1800
Arizona
180
2100
Finland
70
800
Nepal
160
1800
140
1600
France
120
1400
Netherlands
80
900
Uganda
Florida
140
1600
Germany
80
900
Nicaragua
140
1600
Vietnam
140
1600
Great Britain
70
800
Niger
200
2300
Venezuela
160
1800
Greece
120
1400
Norway
70
800
Zambia
180
2100
Guatemala
140
1600
New Zealand
120
1400
Guyana
120
1400
Oman
160
1800