GB/T 2424.14-1995 Environmental testing for electric and electronic products Part 2: Test methods - Guidelines for solar radiation testing
Some standard content:
GB/T 2424.14—1995
This standard is equivalent to the 1975 edition of the International Electrotechnical Commission standard IEC68-2-9 "Basic Environmental Test Procedures Part 2: Test Methods Solar Radiation Test Guidelines". bZxz.net
By making our standards equivalent to international standards, we can adapt to the development of international trade and the needs of economic and technical exchanges as soon as possible. This standard replaces GB2424.14—81 "Basic Environmental Test Procedures for Electrical and Electronic Products Solar Radiation Test Guidelines". This standard was first issued in 1981 and revised for the first time in August 1995. From the date of implementation of this standard, the original national standard of the People's Republic of China GB2424.14-81 "Basic Environmental Test Procedures for Electrical and Electronic Products Solar Radiation Test Guidelines" will be abolished at the same time. Appendix A and Appendix B of this standard are both appendices of the standard. This standard was proposed by the Ministry of Electronics Industry of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Environmental Conditions and Environmental Testing for Electrical and Electronic Products. The main drafting unit of this standard: the Fifth Research Institute of the Ministry of Electronics Industry. The main drafters of this standard: Fu Wenru, Huang Wenzhong, Zhou Xincai, Xie Jianhua, Zhang Jingen GB/T2424.14--1995
IEC Foreword
1. The formal resolutions or agreements on technical issues formulated by the technical committees of the International Electrotechnical Commission with the participation of all national committees that are particularly concerned about the issue, which reflect and express the international consensus on the issue as much as possible. 2. These resolutions or agreements are used internationally in the form of recommended standards and are accepted by the national committees in this sense. 3. In order to promote international unification, the International Electrotechnical Commission hopes that all member countries will adopt the contents of the International Electrotechnical Commission recommended standards as their national standards when formulating national standards, as long as the specific conditions of the country permit. Any differences between the International Electrotechnical Commission's recommended standards and national standards should be clearly pointed out in the national standards as much as possible. This standard was formulated by the International Electrotechnical Commission Technical Committee 50 (Environmental Testing). The first draft was discussed at the Leningrad Conference in 1971. As a result of the meeting, a new draft was formed. Document No. 50 (Central Office) 171 was sent to the National Committees in July 1973 and voted according to the "six-month method". The following National Committees voted explicitly in favor of this standard: Australia
Belgium
Canada
Czechoslovakia
Federal Republic of Germany
Hungary
Israel
Italy
Portugal
Romania
Historical Overview of "Solar Radiation Test Guide": First Edition (1975)
Spain
Turkey
JFEC Standard No. 68 did not have "Solar Radiation Test Guide" in the past. Related specifications:
IEC 68-1: General principles and guidelines
IEC68-2-5: Test Sa: Simulated solar radiation warning on the ground
National Standard of the People's Republic of China
Environmental testing for electric and electronic products
Part 2: Test methods
Guidelines for solar radiation testing
GB/T2424.141995
idt IEC 68-2-9 : 1975
Generation GB2424.14--1
Envlronmental testing for electric and electronic products Part 2. Test methads
Guldance for solar radiation Solar radiation testing is a direct hazard to the health of test personnel, so the contents of Chapter 9 of this standard must be carefully read before the test. "Introduction
This standard introduces the simulation method of the impact of ground solar radiation on equipment and components. The main characteristics of the simulated environment are the solar harmonic energy distribution observed on the ground and the intensity of the energy absorbed in combination with the controlled temperature conditions. However, it is necessary to consider the comprehensive effects of solar radiation (including sky radiation and other environments, such as temperature, humidity and air flow velocity). 2 Radiant intensity and spectral distribution of the test source
The impact of radiation on the test sample depends mainly on the radiant intensity and spectral distribution of the light source. 2.1 Radiant intensity
Outside the earth's atmosphere at the average distance of the earth and the sun, the vertical incident radiation The solar radiation intensity on the plane is called the solar constant E.
The solar radiation intensity on the earth's surface is affected by the solar constant and the scattering and attenuation of the radiation in the atmosphere. According to the radiation cumulative intensity and spectral distribution recommended by the International Commission on Illumination (C.1.E) Publication No. 20 for the test simulation of solar radiation, the radiation intensity is 1.12kW/m2, which is based on the solar constant E, -1.35kW/m\, that is, the global (total) radiation radiated from the sun and the sky to the surface when the sun is overhead.
2.2 Spectral distribution
According to the recommendation of CIE, the standard spectral distribution specified for global radiation in this test is listed in Table 1 of GB/T2423.24-1995 Test Sa. When the test only examines the thermal effect of solar radiation, it is allowed to use pigeon silk lamps as the light source, but because the spectral distribution is significantly different from the standard natural light (see Figure 2), the radiation intensity should be modified according to the provisions of 2.3 of this standard. 2.3 Radiant intensity to be used when using other spectral distributions When the spectral distribution of the light source does not meet the standards listed in Table 1 of Test Sa, its radiant intensity should be corrected according to Appendix A. This forces the sample to absorb the same amount of radiation as when using the standard light source. For example, a tungsten lamp that is only approved for thermal effects: after the radiant intensity correction, the thermal effect of the sample should be consistent with that of the standard light source. Therefore, the radiation absorbed from the test light source should be the same as the total radiation from the sun and the sky, that is:
Er - 1.120 (kW/m*)
Approved by the State Administration of Radio Frequency and Electronics Technology on August 29, 1995, implemented on August 1, 1996
GB/T 2424.14 1995
Where; E——radiant intensity of the test light source, kW/m; α.---absorption coefficient of the test sample for the radiation from the test source; αs---absorption coefficient of the test sample for the global radiation from the sun and the sky (see Appendix A). 3 Test procedure and test duration
3.1 The duration of exposure and whether it is continuous or intermittent must be considered. Three possible methods are specified: Test procedure A
24 h as a cycle, 8 h exposure, 16 h off. The test is repeated as many times as required (this procedure gives a total radiation of 8.96 kWh/m per day and night, close to the most severe natural conditions. This procedure is mainly used to assess the thermal effects of solar radiation). Test procedure B
24 h as a cycle, 20 h exposure, 4 h off, the test is repeated as many times as required (this procedure gives a total radiation of 22.4 kWh/m per night. This procedure is mainly used to assess the deterioration effects of solar radiation). Test procedure C
Continuous exposure as required (this procedure is a simplified test that can be used in situations where periodic thermal stress is not important but for assessing photochemical effects. It can also be used to assess the thermal effects of low heat capacity test samples). 3.2 This test method does not recommend other accelerated tests with radiation intensity exceeding the specified value of 1.12kW/m ± 10%. As mentioned above, based on the standard sunshine hours of 8 hours per day, the total daily radiation of test procedure A is close to the most severe natural conditions. It can be seen that when the sunshine hours exceed 8 hours, the accelerated test will be more severe and worse than the natural conditions. Based on the assumed maximum sunshine hours of 24 hours, test procedure C can mask the degradation effect caused by periodic thermal stress. Therefore, procedure ℃ is generally not used to evaluate the thermal effect of radiation. 3.3 The test duration is determined by the purpose of the test. If only the thermal effect is considered (except for larger equipment that requires a longer test time to reach the maximum internal temperature), three test cycles are usually sufficient, but when evaluating the degradation effect, the required test time will increase significantly.
4 Other environmental factors to be considered
4.1 Temperature inside the box
During the irradiation phase or the stop phase, the leakage inside the box should be controlled according to the specified test procedure (A, B or C). The relevant specifications should stipulate that the temperature to be reached during the irradiation phase is +40℃ or +55℃ according to the intended use of the equipment or components. 4.2 Humidity
Under different humidity conditions, the photochemical degradation effects of various materials, coatings, plastics and other substances vary greatly, and their requirements for humidity conditions are different. Therefore, the specific humidity conditions are clearly specified by the relevant specifications. For example, it is stipulated that the first 4h of each cycle of test procedure B shall be carried out under damp heat conditions (temperature 40℃±2℃, relative humidity 93%±3%). 4.3 Surface contamination
Dust and other surface contaminants will seriously change the absorption characteristics of the surface of the irradiated object. Unless otherwise specified, the sample should be kept clean during the test. However, when evaluating the effect of surface contaminants, the relevant specifications should specify necessary contents such as sample surface treatment. 4.4 Ozone and other pollutant gases
The ozone generated by the short-wave ultraviolet radiation of the light source can usually be discharged from the test chamber through the radiation filter that corrects the spectral energy distribution. Therefore, ozone and other pollutant gases will affect the degradation process of certain materials. Unless otherwise specified in the relevant specifications, these harmful gases must be discharged from the chamber (see 9.3).
4.5 Air flow speed
The air flow speed close to the sample surface is too low. In addition to affecting the temperature rise of the sample, it can even cause significant errors in the open-type thermocouple stack that monitors the radiation intensity. Generally, a speed of 1 rn/s causes the temperature rise of the thermocouple stack to decrease by more than 20%. F. It can be seen that while effectively controlling the temperature (or humidity) conditions in the chamber, the air flow speed should be monitored and the lowest speed should be used as much as possible. In addition, when adjusting the temperature in the box, high-speed airflow can be avoided by heating or cooling the box. GB/T 2424: 141995
In the natural environment, the probability of the occurrence of special conditions of strong solar radiation and zero wind speed is extremely small. Therefore, when it is necessary to evaluate the effect of different wind speeds on samples such as equipment or components, the relevant specifications should specify specific requirements. 4.6 Brackets and their installation
The thermal characteristics of various brackets and their installation methods will have a serious impact on the temperature rise of the test samples. This should be fully considered so that their heat transfer characteristics can represent typical actual use conditions. During the test, most samples are installed on various elevated brackets or supports with specified thermal characteristics, such as cement boards of certain thickness and size or sand beds with certain thermal conductivity. Detailed requirements for supports, their installation methods and sample placement should be specified by the relevant specifications (see Appendix B). 5 Radiation source
5.1 Overview
A light source that meets the requirements for spectral distribution and radiation intensity can be composed of one or more lamps and various additional optical components such as reflectors and filters.
High-pressure xenon arc lamps are best matched to simulate solar radiation when equipped with appropriate filters. Mercury vapor lamps and mercury xenon lamps both have the obvious disadvantage of inaccurate simulation. Although carbon arc lamps with special doped electrodes have been widely used, they lack practicality due to their poor stability and difficult maintenance. Tungsten filament lamps are only suitable for evaluating thermal effects, not photochemical effects, due to their insufficient ultraviolet components. The characteristics of the light source, the performance of the filter and the composition of the optical components are introduced in the following clauses. 5.2 Chlorine arc lamps
The size and structure of xenon arc lamps depend on the requirements of the test. The spectral distribution of a typical xenon arc lamp is shown in Figure 1. Since the electrode radiates more infrared rays than the xenon body, the effect varies in proportion to the length of the electrode. The shorter the electrode, the stronger the radiation of the electrode, which eventually seriously affects the matching of the spectral distribution. Therefore, the direct radiation emitted by the electrode due to heating should be taken seriously. The relative spectral distribution of the xenon arc body has almost nothing to do with the power of the xenon lamp. The absolute radiation spectral distribution of the electrode varies with the temperature state of the electrode under different powers. For the long arc xenon lamp, the electrode radiation can be easily filtered out. Due to the characteristics of the structural shape, the manufacturing tolerance of the short arc xenon lamp is much larger than that of the long arc xenon lamp. Special attention should be paid to this when replacing the lamp. Whether it is a long arc xenon lamp or a short arc xenon lamp, due to the life characteristics of the lamp and the continuous decline in radiation efficiency, it needs to be replaced after the expiration of use. However, since styrene is a pure elemental gas, the relative spectral distribution of the xenon arc body should remain unchanged. 5.3 Tungsten filament lamp
Since tungsten filament lamps are mainly infrared radiation, their ultraviolet radiation is insufficient, and tungsten filament lamps are not suitable for evaluating various degradation effects. Unless the spectral distribution of tungsten lamps is adjusted to the natural spectrum (see 2.3), the test consistency in assessing thermal effects is also poor. The comparison of the radiation spectrum distribution of a typical tungsten filament lamp with a filament temperature of 2600K and the natural spectrum is shown in Figure 2. As can be seen from the figure, the radiation energy of tungsten filament lamps is mainly concentrated in the infrared region, and the wavelength corresponding to the maximum radiation intensity is 1.0um. In contrast, nearly half of the energy of sunlight falls in the visible light region and ultraviolet light region with a wavelength less than 0.7μm. Quartz halogen tungsten filament lamps can improve the performance consistency during their life.
5.4 Carbon arc lamps
In some cases, after the ultraviolet radiation is corrected by filters, the spectral distribution of carbon arc lamps can be close to the natural spectrum of the earth's surface, but carbon arc lamps have poor positioning accuracy and short life, and there is a defect that the carbon arc body is easily burned. Even with the advanced carbon double body moving mechanism, the continuous burning time is still less than 5.
5.5 Mercury vapor lamp
Mercury vapor lamps do not emit enough infrared and near-infrared radiation, and their radiation spectrum contains high-energy spectral lines. They have been used in solariums in combination with tungsten filament lamps. Although mercury-xenon combination arc lamps can be used for environmental testing, mercury lamps are not suitable as a light source for simulating solar radiation due to the presence of high-energy spectral lines.
GB/T 2424.14—1995
Silver frequency lamp continuous light path
is long.tm-
\M-air quality is the highest
M=1(when the sun is overhead)
Figure 1 Comparison of typical high-pressure arc lamp radiation and solar radiation 2.1)
5.6 Filter
GB/T 2424. 14
Tungsten filament lamp 260K
is long, μm
-M=air quality
Appendix 1] When the sun is overhead
Figure 2 Comparison of tungsten filament lamp radiation and solar radiation
Filters with liquid as the medium have the disadvantages of easy boiling, spectral transmission temperature coefficient and long-term spectral characteristic drift, so glass light leakers are currently more commonly used. Since the current glass manufacturing process cannot guarantee the uniformity of glass filtering parameters, it is necessary to repeatedly try out various thicknesses of corrugated glass filters to obtain good compensation for the radiation intensity of various light waves. Since filters are proprietary products, you should consult the relevant manufacturers when selecting and determine it according to the type of light source and its purpose. For example, the best compensation effect can be obtained by matching xenon lamps with absorption-type near-infrared and far-ultraviolet filter components.
If some infrared filters are excessively exposed to far-ultraviolet radiation, their filtering characteristics will change dramatically. At this time, if the ultraviolet filter is sandwiched between the light source and the infrared filter, its influence can be basically eliminated. Various reflective filters, because they reflect useless radiation instead of absorbing it, thus greatly reducing the heating condition of the corrugated glass filter, so this type of filter is usually more stable than the absorption filter.
5. Uniformity of radiation intensity
Since the sun is far away from the earth, the sunlight reaching the ground is basically parallel beams, and the light source is relatively close to the illuminated surface in the box, so a light guide and focusing device should be used to provide uniform radiation intensity on the irradiated measurement plane. When using a parabolic reflector, the short arc xenon lamp has the problem of shadows from the electrodes and brackets, and the passband is difficult to achieve the above accuracy. At the same time, if only the xenon arc body is located at the focus of the reflector, the hot anode will produce a large amount of radiation slightly deviating from the direction of the main beam at extremely low color temperatures. The long arc xenon lamp only needs to be installed in the parabolic "trough" reflector to obtain radiation uniformity more easily. However, if sophisticated installation technology and the use of several short arc xenon lamps are used, a certain degree of radiation uniformity can also be achieved on a wider illuminated area. Under high humidity conditions or when pollutants on the surface of the test sample are affected by the emission of ozone and other gases by light, the optical components of the light source will gradually deteriorate. GB/T 2424. 14—1995
, so it is best to install the test light source on the outside of the box, but at this time the harmonic transmission coefficient of the transmission window material should be determined. Unless it is a test device such as a solar cell or a sun tracker, the radiation must be accurately aimed. However, some simulation techniques designed for space research can be applied to the study of solar radiation on the earth's surface. 6 Measurement table
6.1 Measurement of radiation intensity
It is believed that the most suitable instrument for monitoring radiation intensity is a solar radiation intensity meter used to measure the radiation contained in the sun and sky on the horizontal plane. There are two types of instruments suitable for measuring the radiation of simulated solar sources. Instruments, each of which works by thermocouples. a) Moll-Gorczinski solar radiation intensity meter The Moll-Gorczinski solar radiation intensity meter is composed of 14 constantan-manganese copper strips (10mmX1mm×0.005mm), with the hot ends located on a plane and a black body with low heat conductivity forming a horizontal plane. The "cold" end is bent down to have a good thermal connection with a copper sheet with large heat capacity, and the light-sensitive area is covered by two concentric glass hemispheres. b) Eppley solar radiation intensity meter The Eppley solar radiation intensity meter consists of two 0.The instrument consists of concentric rings of 25mm foil, the inner ring painted black (to absorb almost all radiation) and the outer ring painted white (to reflect visible light and infrared light), the "hot" and "cold" ends are thermally connected to the rings, and the rings are enclosed in a 76mm diameter glass bulb filled with dry air. The above two instruments are not easily affected by infrared radiation emitted by the sample and the box. One instrument, called Kpip, is a modification of the Moore-Kauchinsky solar radiation intensity meter and is now widely used in meteorological departments around the world. The Aperle solar radiation intensity meter is one of the most widely used instruments in the United States. The glass cover used by the above two instruments can filter out radiation longer than 3μm, but radiation in this wavelength range is usually only slightly noticeable when the tungsten filament lamp is filtered, and a correction factor is required at this time. 6.2 Measurement of spectral distribution
Accurate measurement of spectral distribution is much more difficult than measurement of total radiation intensity, but a low-cost routine check of changes in spectral distribution can be made using a total radiation intensity meter with various selective filters. Accurate measurement of spectral distribution should be made using a precision spectroradiometer, which can be conveniently commissioned to the relevant equipment manufacturer or national calibration center. Regular comparisons are required to achieve consistency between filter/solar radiation intensity meters and spectroradiometric measurements. After a certain period of use, the spectral characteristics of optical devices such as light sources, reflectors and filters will change, resulting in serious spectral distribution deviations. In addition, the tolerance of the light source will mean that the radiation intensity and spectral distribution will exceed the original specified range after the light source is replaced. It can be seen that although the spectral distribution of radiation cannot be monitored during the test, it is possible to monitor the total radiation regularly: 6.3 Temperature measurement
Due to the high radiation values, it is important to properly screen the temperature sensor to prevent radiant heating effects. This is not only applicable to the measurement of air temperature in the test chamber, but also to the temperature monitoring of the test sample/equipment. For air temperature measurement, it is obviously impractical to use the standard louvered box for measuring "shade temperature" in meteorology, because it is too troublesome. Another suitable method is to install the thermocouple freely in the radiation shield, which consists of a straight steel-nickel tube (about 415mm×70mm) covered with a metal shield with a gap, the inner surface is polished and the outer surface is painted white. When monitoring the temperature of the equipment sample, the temperature sensor, such as the thermocouple, should be installed on the inner surface of the outer box instead of connecting it to the outer surface. Since the absorption characteristics of temperature-indicating paint and wax are different from those of the test sample, it is not suitable for monitoring the temperature of the irradiated surface of the test sample. 7 Preparation of test equipment and test samples
7.1 Test equipment
It must be ensured that the optical parts, lamps, reflectors and filters of the test equipment are clean. The radiation value should be measured on the specified radiation measurement surface for each test. During the entire test period, auxiliary environmental conditions such as ambient temperature, humidity and air flow velocity (if specified) shall be continuously monitored: 7.2 Test samples
GB/T2424.14.1995
The placement of the sample and the direction of exposure will seriously affect its thermal effect. During the test, the sample is mostly placed on various elevated supports or bases with specified thermal characteristics, such as cement boards of certain thickness and size or horizontal sand beds with certain thermal conductivity. All of these and the state of the test sample should be specified in the relevant specifications. The surface of the test sample should be kept clean or in accordance with the provisions of the relevant specifications. The surface state of the sample will also seriously affect its thermal effect. When managing the sample, special care should be taken to avoid oil film contamination, ensure that the surface coating and primer layer of the sample can fully represent the product standard, and place the temperature sensor on the inner surface of the sample as required (see 6.3). 8 Interpretation of test results
8.1 Conformity with specifications
The relevant specifications should clearly specify the changes in appearance and performance that are permitted to occur in the test specimens after the specified test time under the specified radiation intensity. In addition, the following aspects should be considered 8.2 Comparison with field experience
The deterioration effects of natural light exposure on materials and equipment are well documented, see 8.5 and 8.6. Any significant difference between these effects and the performance under simulated conditions should be investigated and the cause determined, i.e., whether it is caused by the test equipment or test method, or by some characteristic of the test specimen.
8.3 Short-term effects
Mainly heating effects. In essence, short-term effects are mostly caused by local overheating. 8.4 Long-term effects
The purpose of long-term testing is to determine the mode of degradation, two of which are to see if there is an initial rapid change and to assess the effective life of the test piece.
8.5 Thermal Effects
The maximum surface and internal temperatures reached by the test specimen or equipment will depend on: a) the temperature of the ambient air:
b) the intensity of the radiation:
c) the velocity of the airflow:
d) the exposure time:
e) the thermal properties of the object itself, such as surface reflectivity, size and shape, thermal conductivity and specific heat constant. When the ambient air temperature is below 35℃~40℃, the temperature of the equipment fully exposed to the sun can reach more than 60℃. The reflectivity of the sample surface will seriously affect the temperature rise caused by solar heating. For example, changing the surface color coating to a bright white coating can reduce the temperature rise. Conversely, if the surface paint layer originally used to reduce the radiant temperature rise fades over time, the additional temperature rise will increase. Most materials have selective reflectivity, that is, the spectral reflectivity varies with wavelength. For example, although paints can highly reflect visible light, they usually have low reflectivity for infrared light. Since the spectral reflectance of many materials varies sensitively in the visible (which produces colour perception to the human eye) and near-infrared, it is important that the spectral energy distribution of the radiation source used in any simulation test should closely replicate natural solar radiation, or that the radiation intensity be appropriately adjusted to achieve the same heating effect (see 2.3 and Annex A). 8.6 Degradation of Materials
The combined effects of solar radiation, atmospheric gases, temperature and humidity changes, etc., are generally referred to as "atmospheric corrosion", which causes most organic materials (such as plastics, rubber, paints and wood, etc.) to age and eventually fail. Many organic materials work well in temperate regions, but they are completely unsuitable for use in the harsher tropical conditions. Examples include rapid deterioration and decomposition of paints, cracking and disintegration of cable sheaths, and fading of pigments. The deterioration of various materials under atmospheric corrosion is generally not caused by a single factor, but by the combined interaction of several different types of characteristic factors. Although solar radiation, mainly ultraviolet radiation (which produces photodegradation), is often the main factor, in practice it is difficult to separate its effects from those of climatic corrosion. For example, although the effect of ultraviolet radiation alone on polyvinyl chloride is not obvious, the main effect of oxygen significantly enhances the thermal damage effect. GB/T 2424-14—1995
Artificial tests occasionally show abnormal damage that is inconsistent with natural atmospheric erosion. This can be attributed to one or more of the following reasons:
a) The ultraviolet light source used in many laboratories is very different from the natural spectrum; b) In accelerated tests, when the ultraviolet radiation intensity and temperature and humidity factors are strengthened, the various reaction rates that occur under normal exposure conditions may not increase to the same extent; c) The artificial test band does not simulate all natural climate erosion factors. 9 Hazards and personal safety
9.1 General instructions
To ensure that the specified test operations can be performed correctly and for human health and safety issues, the operation and maintenance of solar radiation test equipment should be carried out by skilled test personnel. 9.2 Ultraviolet light
The most obvious hazard that must be protected is the harmful effects of high-intensity radiation near the ultraviolet light zone. There are two ways to protect the eyes from natural sunlight. One is that the sun is so bright that the eyes can hardly look directly at it. The other is that the atmosphere has a considerable attenuation of ultraviolet radiation. However, this is not suitable for artificial test light sources. Therefore, during the test, especially when installing the test equipment, you should wear filter goggles or use an observation window. If you accidentally expose yourself to an unfiltered arc lamp for a short time, it can cause serious eye injuries, and the exposed skin will also develop severe erythema (sunburn). Koller pointed out that the sun's ultraviolet radiation is the main cause of skin cancer in white Americans. Therefore, even when working indoors with a light source with a filter, you should wear special protective clothing, protective masks and gloves. 9.3 Ozone and harmful gases
During the test, the use of arc lamps such as fluorine arc lamps will cause poisoning accidents due to the local increase in ozone concentration, but usually the highest concentration of ozone occurs in the early stage of the light source being powered on. As the lamp shell and its periphery are continuously heated, ozone can gradually be reduced to oxygen, causing its concentration to decrease. If forced air cooling is used, the cooled air should be exhausted outside the test room and not blown into the lampshade, which can basically eliminate the harm of ozone. When the volume concentration of ozone reaches 1.0ppm~10ppm (×10°5V/V) can cause symptoms such as dizziness, tearing eyes and nasal and throat inflammation. Therefore, the toxic concentration of ozone must be less than 0.1ppm, which is lower than the concentration value of 0.5ppm~1.0ppm that is easy to cause membrane reaction. There are currently commercially available monitoring instruments for monitoring the relevant concentrations. The combined effects of heat and ultraviolet light on certain plastics (such as melamine laminated plastics) can also produce toxic gases. Therefore, special care should be taken when selecting materials for test equipment construction. 9.4 Danger of lamp explosion
Using high-pressure gas discharge lamps as the main radiation source, serious accidents may also occur if proper implementation details for operating these arcing lamps are not formulated and strictly followed. Due to the huge pressure (2 to 3 atmospheres when cold, up to 20 atmospheres when hot), these lamps (whether hot or cold, used or new) are prone to violent explosions. In addition, the surface of the lamp housing should be kept clean and free of oil spots and dust. For this reason, the lamp housing should be cleaned regularly with detergent and alcohol. Cotton gloves and protective masks should be worn when cleaning. When storing cold light sources, using two layers of plastic plates with a thickness of 0.25 mm can limit the damage caused by accidental explosion of the light source. When using multi-lamp light source test equipment, protective measures should also be set to prevent chain burning of light sources. If armored glass plates are used, they can play a dual protective role: preventing lamp explosion and being used as calibration filters. Records of each lamp should be kept as a daily routine to monitor abnormal voltages. 9.5 Electric shock
Conventional anti-electric shock measures must be sound, especially in the case of high-voltage ignition systems used in conjunction with arc lamps. For some xenon lamps, the pulse voltage when the arc is lit will exceed 60kV. At this time, a hip interlock safety protection system should be set. GB/T 2424.14-1995
Appendix A
(Appendix to the standard)
Radiation intensity adjustment calculation
For radiation sources whose spectral distribution does not conform to the provisions of Table 1 of GB/T2423.24-1995 Test Sa (available when conducting tests to assess thermal effects).
A1 In order to obtain an equivalent heating effect, the radiation intensity of the test source E. should be adjusted so that Ex = 1.120 (kW/m)
Where: α—absorption coefficient of the test sample for the radiation of the light source: ae—absorption coefficient of the test sample for the global radiation of the sun and the sky. A2 Absorption coefficients α and α can be calculated using the following formula: Su ·a(a)·da
Where: α(A)——spectral absorption coefficient of the test sample Su—spectral distribution of the test light source;
Su·da
Sa·a(a)·da
Si,——spectral distribution of global radiation from the sun and sky, Note: For calculation, please use the more detailed information in Table A1, A3 For test samples that do not emit radiation
α(A) = 1- 0()
Where: (λ)——spectral reflectance coefficient of the test sample, Note: The spectral absorption coefficient of the surface should generally be determined based on spectral reflectance data. There are several spectral reflectance measuring instruments on the market that use the monochromator/integrator (UIbricht) sphere method.
Spectral region
Ultraviolet B'
Ultraviolet A
Visible light
Infrared
GB/T 2424.14—1995
Table A1 shows the detailed spectral distribution band of global radiation used in the calculation
0. 28 ~0. 32
0. 32 ~ 0. 36
0. 36~0. 40
0.40~0. 44
0. 44-~0. 4B
0, 48~~0, 52
0. 52~0. 56
0.56~~0. 51
0.64~-0.68
0. 68 ~ 0. 72
0. 72~0. 78
0. 78~1. 0
1, 2 ~1. 4
1. 4~1. 6
1.6-~1. 8
2. 0~-2. 5
2. 5~ 3. 0
*Radiation shorter than 0.3 μm reaching the Earth's surface is of no importance. Appendix B
(Standard Appendix)
Heat transfer through substrate
Radiation intensity
Total 1120
B1 In order to specify suitable substrate materials, it is necessary to estimate the possible heat transfer through the substrate. Radiation intensity percentage
B2 If the substrate thermal conductivity k, thickness L, surface area A, and upper and lower surface temperature difference △T (C) are known, the heat flow rate through the substrate can be calculated using the following formula,
The above formula does not include convection and radiation effects, which are usually (but not necessarily) secondary. B3The thermal conductivity of common materials is shown in Table B1. The data in the table are taken from ADI "Wrmeatla1956, Fa4" and other materials, and multiplied by 1.163 to convert to the International (SI) system of units.4B
0, 48~~0, 52
0. 52~0. 56
0.56~~0. 51
0.64~-0.68
0. 68 ~ 0. 72
0. 72~0. 78
0. 78~1. 0
1, 2 ~1. 4
1. 4~1. 6
1.6-~1. 8
2. 0~-2. 5
2. 5~ 3. 0
*Radiations shorter than 0. 3 μm reaching the Earth's surface are unimportant. Appendix B
(Standard Appendix)
Heat transfer through substrate
Radiant intensity
Total 1120
B1 In order to specify the applicable substrate material, it is necessary to estimate the possible heat transfer through the substrate. Radiant intensity percentage
B2 If the substrate thermal conductivity k, thickness L, surface area A, and upper and lower surface temperature difference △T (C) are known, the heat flow rate through the substrate can be calculated using the following formula.
The above formula does not take into account convection and radiation effects, which are usually (but not necessarily) secondary. B3 The thermal conductivity of common materials is shown in Table B1. The data in the table are taken from ADI "Wrmeatla 1956, Fa4" and other materials, and multiplied by 1.163 to convert to the International (SI) system of units.4B
0, 48~~0, 52
0. 52~0. 56
0.56~~0. 51
0.64~-0.68
0. 68 ~ 0. 72
0. 72~0. 78
0. 78~1. 0
1, 2 ~1. 4
1. 4~1. 6
1.6-~1. 8
2. 0~-2. 5
2. 5~ 3. 0
*Radiations shorter than 0. 3 μm reaching the Earth's surface are unimportant. Appendix B
(Standard Appendix)
Heat transfer through substrate
Radiant intensity
Total 1120
B1 In order to specify the applicable substrate material, it is necessary to estimate the possible heat transfer through the substrate. Radiant intensity percentage
B2 If the substrate thermal conductivity k, thickness L, surface area A, and upper and lower surface temperature difference △T (C) are known, the heat flow rate through the substrate can be calculated using the following formula.
The above formula does not take into account convection and radiation effects, which are usually (but not necessarily) secondary. B3 The thermal conductivity of common materials is shown in Table B1. The data in the table are taken from ADI "Wrmeatla 1956, Fa4" and other materials, and multiplied by 1.163 to convert to the International (SI) system of units.
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