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GB/T 16422.3-2022 English PDF (GBT16422.3-2022)

GB/T 16422.3-2022 English PDF (GBT16422.3-2022)

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GB/T 16422.3-2022: Plastics -- Methods of exposure to laboratory light sources -- Part 3: Fluorescent UV lamps

GB/T 16422.3-2022
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 83.080.01
CCS G 31
GB/T 16422.3-2022 / ISO 4892-3:2016
Replacing GB/T 16422.3-2014
Plastics – Methods of Exposure to Laboratory
Light Sources – Part 3: Fluorescent UV Lamps
(ISO 4892-3:2016, IDT)
ISSUED ON: APRIL 15, 2022
IMPLEMENTED ON: NOVEMBER 01, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
Introduction ... 5
1 Scope ... 6
2 Normative References ... 6
3 Terms and Definitions ... 7
4 Principle ... 7
5 Apparatus ... 8
5.1 Laboratory light source ... 8
5.2 Test chamber ... 11
5.3 Radiometer ... 11
5.4 Black-panel/black-standard thermometer ... 11
5.5 Wetting ... 11
5.6 Specimen holders ... 12
5.7 Apparatus to assess changes in properties ... 13
6 Test Specimens ... 13
7 Test Conditions ... 13
7.1 Radiation ... 13
7.2 Temperature ... 13
7.3 Condensation and spray cycles ... 14
7.4 Cycles with dark periods ... 14
7.5 Sets of exposure conditions ... 14
8 Procedure ... 14
8.1 General ... 14
8.2 Mounting the test specimens ... 15
8.3 Exposure ... 15
8.4 Measurement of radiant exposure ... 15
8.5 Determination of changes in properties after exposure ... 16
9 Exposure Report ... 16
Annex A (Informative) Relative Irradiance of Typical Fluorescent UV Lamps ... 17 Bibliography ... 23
Plastics – Methods of Exposure to Laboratory
Light Sources – Part 3: Fluorescent UV Lamps
1 Scope
This Document specifies methods for exposing specimens to fluorescent UV radiation, heat and water in apparatus designed to simulate the weathering effects that occur when materials are exposed in actual end-use environments to global solar radiation, or to solar radiation through window glass.
This Document is applicable to the specimens that are exposed to fluorescent UV lamps under controlled environmental conditions (temperature, humidity and/or water). Different types of fluorescent UV lamp can be used to meet all the requirements for testing different materials. Specimen preparation and evaluation of the results are covered in other Standards for specific materials.
General guidance is given in ISO 4892-1.
NOTE: Fluorescent UV lamp exposures for paints, varnishes and other coatings are described in GB/T 23987-2009.
2 Normative References
The provisions in following documents become the essential provisions of this Document through reference in this Document. For the dated documents, only the versions with the dates indicated are applicable to this Document; for the undated documents, only the latest version (including all the amendments) is applicable to this Document.
ISO 4582 Plastics – Determination of Changes in Color and Variations in Properties after Exposure to Glass-Filtered Solar Radiation, Natural Weathering or Laboratory Radiation Sources
NOTE: GB/T 15596-2021 Plastics – Determination of Changes in Color and Variations in Properties after Exposure to Glass-Filtered Solar Radiation, Natural Weathering or Laboratory Radiation Sources (ISO 4582:2017, IDT)
ISO 4892-1 Plastics – Methods of Exposure to Laboratory Light Sources – Part 1: General Guidance
NOTE: GB/T 16422.1-2019 Plastics – Methods of Exposure to Laboratory Light Sources – Part 1: General Guidance (ISO 4892-1:2016, IDT)
3 Terms and Definitions
For the purposes of this Document, the terms and definitions given in ISO 4892-1 apply. 4 Principle
4.1 Fluorescent UV lamps, when following the manufacturer’s recommendations for lamp maintenance and/or rotation, may be used to simulate the spectral irradiance of global solar radiation in the short wavelength ultraviolet (UV) region of the spectrum. 4.2 Specimens are exposed to various levels of UV radiation, heat and moisture (see 4.4) under controlled environmental conditions.
4.3 The exposure conditions may be varied by selection of the following: a) type of fluorescent UV lamp;
b) irradiance level;
c) temperature during the UV exposure;
d) type of wetting (see 4.4);
e) wetting temperature and cycle;
f) timing of the UV/dark cycle.
4.4 Wetting is usually produced by condensation of water vapor on to the exposed specimen surface or by spraying the test specimens with demineralized/deionized water. 4.5 The procedure(s) may include measurement of the irradiance and the radiant exposure in the plane of the specimen.
4.6 It is recommended that a similar material of known performance (a control) be exposed simultaneously with the test specimens to provide a standard for comparative purposes. 4.7 Intercomparison of results obtained from specimens exposed in different types of apparatus or to different types of lamps should not be made unless an appropriate statistical relationship has been established between the different types of equipment for the material to be tested. 5 Apparatus
5.1 Laboratory light source
5.1.1 Fluorescent UV lamps are fluorescent lamps in which radiant emission in the ultraviolet region of the spectrum, i.e., below 400 nm, makes up at least 80 % of the total light output. There are three types of fluorescent UV lamp used in this Document.
— UVA-340 (type 1A) fluorescent UV lamp: these lamps have a radiant emission below 300 nm of less than 1 % of the total light output, have an emission peak at 343 nm, and are more commonly identified as UVA-340 for simulation of global solar radiation from 300 nm to 340 nm (see Table 1). Figure A.1 is a graph of spectral irradiance from 250 nm to 400 nm of a typical UVA-340 (type 1A) fluorescent lamp compared to global solar radiation. — UVA-351 (type 1B) fluorescent UV lamp: these lamps have a radiant emission below 310 nm of less than 1 % of the total light output, have a peak emission at 353 nm, and are more commonly identified as UVA-351 for simulation of the UV portion of solar radiation behind window glass (see Table 2). Figure A.2 is a graph of spectral irradiance from 250 nm to 400 nm of a typical UVA-351 (type 1B) fluorescent UV lamp compared to global solar radiation filtered by window glass.
— UVB-313 (type 2) fluorescent UV lamp: these lamps are more commonly identified as UVB-313 and have a radiant emission below 300 nm that is more than 10 % of the total output and a peak emission at 313 nm (see Table 3). Figure A.3 is a graph of the spectral irradiance from 250 nm to 400 nm of two typical UVB-313 (type 2) fluorescent lamps and FS40 fluorescent lamps compared to global solar radiation. UVB- 313 (type 2) lamps may be used only by agreement between the parties concerned. Such agreement shall be stated in the test report.
— Four different UV lamps used as one combination: these four different UV lamps are used together as one combination with a suited filter. See Figure A.4.
NOTE 1: UVB-313 (type 2) lamps have a spectral distribution of radiation, which peaks near the 313 nm mercury line and can emit radiation down to λ = 254 nm, which can initiate ageing processes that never occur in end-use environments.
NOTE 2: The solar spectral irradiance for a number of different atmospheric conditions is described in CIE Publication No. 85. The benchmark global solar radiation used in this Document is from CIE Publication No. 85:1989, Table 4.
5.1.2 Unless otherwise specified, UVA-340 (type 1A) fluorescent UV lamps shall be used to simulate the UV part of global solar radiation (see Table 4, method A). Unless otherwise specified, UVA-351 (type 1B) lamps shall be used to simulate the UV part of solar radiation through window glass (see Table 4, method B). The four-lamp UV combination may be used (see A.2.3) and shall be stated in the test report.
Specimens may be exposed to moisture in the form of condensation or water spray. Specific test conditions describing the use of condensation or water spray are described in Table 4. If condensation or water spray is utilized, the specific procedures and exposure conditions used shall be included in the test report.
NOTE: The duration of the condensation or water spray period can have a significant influence on the photodegradation of polymers.
5.5.2 Spray and condensation system
The test chamber shall be equipped with a means of producing intermittent condensation on, or directing intermittent water spray on to the front of the test specimens, under specified conditions. The condensate or spray shall be uniformly distributed over the specimens. The spray system shall be made from corrosion-resistant materials that do not contaminate the water employed.
Check the specimens in the test chamber during the condensation period at least 1 h after the start of the condensation cycle to verify that the condensation is visibly forming on the specimens. Then, perform this visual check at least once per week.
NOTE 1: If condensation is not evident on the specimen, the most likely cause involves the following: a) inadequate room air cooling,
b) laboratory temperature that is too high,
c) condensation temperature that is set too low or set too close to the room temperature, d) thick specimens of insulating material that might be preventing the room air cooling necessary for condensation. For example, a 25 mm specimen can exhibit poor condensation with a condensation set point of 40 °C and a laboratory temperature of 30 °C, or
e) improper mounting that is allowing vapor to escape from the chamber. Water sprayed on specimen surfaces shall have a conductivity below 5 μS/cm, contain less than 1 mg/L of dissolved solids and leave no observable stains or deposits on the specimens. Care shall be taken to keep silica levels below 0.2 mg/L. A combination of deionization and reverse osmosis may be used to produce water of the desired quality.
NOTE 2: The spray water temperature might have a significant effect on the test results. 5.6 Specimen holders
Specimen holders shall be made from inert materials that will not affect the results of the exposure. The behavior of specimens can be affected by the presence of backing and by the backing material used. The use of backing shall therefore be by mutual agreement between the interested parties.
5.7 Apparatus to assess changes in properties
The apparatus required by the International Standards relating to the determination of the properties chosen for monitoring (see ISO 4582) shall be used.
6 Test Specimens
Test specimens are specified in ISO 4892-1.
7 Test Conditions
7.1 Radiation
Unless otherwise specified, control the UV irradiance at the levels indicated in Table 4. Other irradiance levels may be used when agreed upon by all interested parties. The irradiance and wavelength passband in which it was measured shall be included in the test report. 7.2 Temperature
Fluorescent UV lamps emit relatively little visible and infrared radiation compared to solar radiation, xenon-arc sources, and carbon-arc sources. Unlike solar radiation, in fluorescent UV apparatus, heating of the specimen surface is primarily by convection of heated air across the panel. Therefore, the difference between the temperature of a black-panel thermometer, a black- standard thermometer, the specimen surface and the air in the test chamber is typically < 2 °C. Additional measurement of white standard temperature or white-panel temperature as recommended in ISO 4892-1 is not necessary.
For reference purposes, Table 4 specifies black-panel temperatures. Black-standard thermometers may be used in place of black-panel thermometers, when agreed upon by all interested parties.
NOTE: The surface temperature of the specimens is a crucial exposure parameter. Generally, degradation processes run faster with increasing temperature. The specimen temperature permissible for accelerated exposure depends on the material under test and on the ageing criterion under consideration. Other temperatures may be selected when agreed upon by all interested parties but shall be stated in the test report.
If condensation periods are used, the temperature requirements apply to the equilibrium conditions of the condensation period. If water spray periods are used, the temperature requirements apply to the end of the dry period. If the temperature does not attain equilibrium during a short cycle, the specified temperature shall be established without water spray and the maximum temperature attained during the dry cycle shall be reported.
8.2 Mounting the test specimens
Attach the specimens to the specimen holders in the apparatus in such a manner that the specimens are not subjected to any applied stress. Identify each test specimen by suitable indelible marking, avoiding areas to be used for subsequent testing. As a check, a plan of the test specimen positions may be made.
If desired, in the case of specimens used to determine change in color and appearance, a portion of each test specimen may be shielded by an opaque cover throughout the test. This gives an unexposed area adjacent to the exposed area for comparison. This is useful for checking the progress of the exposure, but the data reported shall always be based on a comparison with file specimens stored in the dark.
Fill all spaces in the exposure area in order to ensure uniform exposure conditions. Use blank panels if necessary.
8.3 Exposure
Before placing the specimens in the test chamber, be sure that the apparatus is operating under the desired conditions (see Clause 6). Programme the selected test conditions to operate continuously throughout the entire exposure period selected. The test conditions selected shall be agreed between all parties concerned and within the capabilities of the apparatus used. Maintain these conditions throughout the exposure. Interruptions to service the apparatus and to inspect specimens shall be minimized.
Expose the test specimens and, if required, the irradiance-measuring device for the specified period of exposure. Repositioning of the specimen during exposure is desirable and may be necessary to ensure uniformity of all exposure stresses. Follow the guidance in ISO 4892-1. If it is necessary to remove a test specimen for a periodic inspection, care shall be taken not to handle or disturb the test surface. After inspection, the test specimen shall be returned to its holder or to the test chamber with its test surface in the same orientation as before. 8.4 Measurement of radiant exposure
If used, mount the radiometer so that it indicates the irradiance at the exposed surface of the test specimen.
UV radiometers may be calibrated for either narrow band (e.g., at 340 nm) or broad band (e.g. 290 nm to 400 nm) measurements.
When radiant exposures are used, express the exposure interval in terms of the incident radiant energy per unit area of the exposure plane in joules per square meter (J/m2) in the wavelength band from 290 nm ~ 400 nm or joules per square meter per nanometer [J/(m2·nm)] for the wavelength selected (e.g., 340 nm). Common SI units 1 J = 1Ws.
Annex A
(Informative)
Relative Irradiance of Typical Fluorescent UV Lamps
A.1 General
A variety of fluorescent UV lamps may be used for the purposes of exposure. The lamps described in this Annex are representative of their types (type 1A, 1B or 2); these are commonly available from manufacturers plainly labelled as either UVA-340, UVA-351 or UVB-313. Other lamps may also be used. The particular application determines which lamp should be used. The lamps discussed in this Annex differ in the absolute spectral emission of UV radiation emitted and in their wavelength spectrum. Differences in lamp irradiance values or spectrum might cause significant differences in the results of exposure. Consequently, it is extremely important to report the irradiance value and lamp type in the exposure report. A.2 Relative spectral irradiance data
A.2.1 UVA-340 (type 1A) and UVA-351 (type 1B) lamps
A.2.1.1 Figure A.1 shows the relative spectral irradiance for UVA-340 (type 1A) lamps and Figure A.2 shows the relative spectral irradiance for UVA-351 (type 1B) lamps. For non-irradiance-controlled test apparatus, actual irradiance levels vary depending on the type and/or manufacturer of the lamp used, the age of the lamps, the distance to the lamp array and the air temperature within the exposure chamber. For test apparatus with feedback loop irradiance control, the irradiance can be programmed at various levels within a selected range. A.2.1.2 For most applications, the wavelength spectrum of UVA-340 (type 1A) lamps is recommended. Figure A.1 illustrates the spectral distribution for a UVA-340 (type 1A) lamp compared to CIE No. 85:1989, Table 4, global solar radiation.
A.2.1.3 UVA-351 (type 1B) lamps are mostly used for behind-window-glass simulations. Spectral irradiance for a typical UVA-351 (type 1B) lamp is compared to CIE No. 85:1989, Table 4, solar radiation behind window glass is shown in Figure A.2.
NOTE: UVA-340 (type 1A) and UVA-351 (type 1B) lamps have different spectral irradiance distributions and can produce very different results.

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