4.2 GB/T4797&IEC60721-2 'Natural Environmental Conditions for Electrical and Electronic Products'

GB/T4797 mainly introduces the natural environmental conditions in which electrical and electronic products are located, including 8 parts: temperature and humidity, atmospheric pressure, biology, solar radiation and temperature, precipitation and wind, dust and salt mist, seismic vibration and impact, and fire exposure.

4.2.1 GB/T4797.1 Classification of Environmental Conditions Natural Environmental Conditions Temperature and Humidity

This section of the standard lists outdoor climate types represented by temperature and humidity parameters as background materials for selecting temperature and humidity severity levels during product testing and application.

Except for areas with elevations exceeding 5000m, these climate types include all regions of the country.

This section can also serve as background material when determining the climatic conditions for product application.

This section specifies a series of outdoor climate types based on temperature and humidity parameters, which are often used for the transportation, storage, installation, and use of products.

1. Overview

This standard references data from GB/Z32126, which collects daily temperature and humidity data from 1973 to 1992 worldwide, mainly measured at airports and major cities around the world. The relevant data in China is based on outdoor temperature and humidity data from 1971 to 2000 across the country.

2. General verification procedures

There are three main stages of data processing validation:

——Identify and collect data;

——Compare the analysis data with the current values;

——Update data appropriately.

As a result of data collection and analysis, outdoor climate types worldwide have been simplified, as shown in Table 1:

Table 1 Climate Types

表2给出了世界范围每个气候类型对应的定义。

3. Outdoor climate type

1) Overview

A series of climate types have been proposed for different outdoor temperature and humidity conditions in the world, hereinafter referred to as 'outdoor climate'. To enable a product to be used in a specific geographical area, outdoor temperature and humidity values should be determined from the climate data of the area, and the product should be designed based on these data to ensure normal operation in such climatic environments.

2) Environmental parameters

The outdoor climate in this section is specified by temperature and relative humidity values. The relative humidity at a certain temperature is defined as the ratio between the actual water vapor pressure and the saturated water vapor pressure at the same temperature. The definition of absolute humidity refers to the mass of water vapor per cubic meter of air in the air. Information on relative and absolute humidity can be found in Appendix B.

The annual low temperature extreme usually only appears for about 10 hours, while the annual high temperature extreme usually only appears for about 5 hours.

3) Statistical classification of outdoor climate

The following table provides the climate types defined by outdoor climate statistics (including climate types only applicable to China). Table 3 presents the average annual extreme values of daily average temperature and humidity for various climate types (including climate types only applicable to China), Table 4 presents the average annual extreme values of temperature and humidity for various climate types (including climate types only applicable to China), and Table 5 presents the absolute extreme values of temperature and humidity for various climate types (including climate types only applicable to China).

Table 3: Various Climate Types Classified by Daily Average Extreme Values

Table 4: Various Climate Types Classified by Annual Extreme Values

Table 5: Various Climate Types Classified by Absolute Extreme Values

4) Outdoor Climate Type Map

Outdoor climate statistics for the world region can be found in Appendix A.

Appendix A: (Informative Appendix) Climate Type Map

This appendix provides outdoor climate statistics for the world region, and the map of world climate types is shown in Figure 5 of GB/Z32126.

Appendix B: (Informative Appendix) Climatic Data for Various Sites of Climate Types in China

Tables B.1 to B.7 provide climate data for various locations of climate types in China. The data in the table is based on the China Surface Meteorological Station dataset of the China Climate Data Network from 1971 to 2000. Among them:

——Calculation of absolute humidity: Refer to the Clapeyron Clasius formula and combine it with the saturated water pressure and related parameter table in the appendix of the national standard - Humidity Measurement Method (GB/T11605-2005), and calculate it based on temperature, relative humidity, and atmospheric pressure.

——Calculation of the average annual extreme value of the daily mean of temperature and humidity: List the average temperature and absolute humidity of a certain area every day for a year, select the highest average temperature, lowest average temperature, and highest average absolute humidity for a year, and average the highest, lowest average temperature, and highest absolute humidity for each year from 1970 to 2000, to obtain the high temperature The average annual extreme value of the daily average of low temperature and absolute humidity.

——Calculation of the average annual extreme values of temperature and humidity: List the highest temperature, lowest temperature, and absolute humidity of a certain region in a year, and average the highest temperature, lowest temperature, and highest absolute humidity from 1970 to 2000 each year to obtain the 'average annual extreme values' of high temperature, low temperature, and absolute humidity in a certain region.

——Calculation of absolute extreme values of temperature and humidity: Refers to the highest temperature, lowest temperature, and highest absolute humidity in a certain region during a certain period of time. By comparing the highest temperature, lowest temperature, and highest absolute humidity from 1970 to 2000, the highest temperature, lowest temperature, and highest absolute humidity for each year from 1970 to 2000 are selected to obtain the 'absolute extreme values' of high temperature, low temperature, and absolute humidity in a certain region.

The specific data in Tables B.1 to B.7 can be found in the standard.

4.2.2 GB/T4797.2 Classification of Environmental Conditions Natural Environmental Conditions Atmospheric Pressure

This standard provides the atmospheric pressure values at different altitudes in the natural environment as background materials for selecting appropriate levels of atmospheric pressure during product storage, transportation, and use.

When selecting the severity of air pressure parameters for product applications, the values in this section can be used.

1. The influence of atmospheric pressure

1) Overview

The product air pressure severity should comply with IEC60721-1 Environmental Condition Classification Part 1: Environmental Parameters and Their Classification.

Air pressure usually affects the performance of products in different ways, mainly in two aspects: below standard atmospheric pressure and above standard atmospheric pressure.

2) Below standard atmospheric pressure

Above sea level, low air pressure has the following effects on product performance:

——Gas or liquid may leak from sealed containers;

——Pressure vessel rupture;

——Changes in the physical and chemical properties of low-density materials;

——As the air pressure decreases, the discharge voltage, corona voltage, and breakdown voltage between the electrodes of the product decrease, and the product may fail or malfunction due to arc or corona (Bashen's law states that in a uniform electric field, for a given electrode shape and material, the breakdown voltage of air depends on the product of air pressure and electrode air gap);

——Reduce the efficiency of air convection and conduction heat dissipation;

——Expected acceleration of physical effects, such as volatile plasticizers, lubricant evaporation, etc.

3) Above standard atmospheric pressure

The high pressure that exists in natural basins and mines can generate significant mechanical pressure on sealed containers.

2. Barometric value

Under standard atmospheric conditions, the standard pressure value at sea level is 101.325kPa. According to meteorological conditions, the atmospheric pressure at sea level may fluctuate, and similar situations may occur at altitudes below or above sea level.

In areas above sea level, atmospheric pressure is lower than sea level. In areas below sea level (natural basins and mines), atmospheric pressure is higher than sea level.

The atmospheric pressure values at different altitudes are shown in Table 1.

Table 1 Correspondence between Altitude and Standard Air Pressure

According to ISO2533, the conversion between altitude and atmospheric pressure can be found in formulas (1) and (2)

P=p0 × {[1- (L × h) /T0] g/(R × L) (Altitude below 11000m)......... (1)

P=p1 × E [- g × (h-h1)/(R × T1) (altitude between 11000m~2m)......... (2)

In the equation:

P - Air pressure, in kilopascals (kPa);

P0- Sea level standard pressure, 101.325kPa, in kilopascals (kPa);

P1-11000m standard air pressure, 22.632kPa, in kilopascals (kPa);

H - altitude (less than 2m), in meters (m);

H1- altitude value, 11000m, in meters (m);

L - Temperature decrease rate, 0.0065K/m, in kilometers per meter (K/m);

T0- Sea level standard temperature, 288.15K, unit: K;

T1- Standard temperature at an altitude of 11000 meters, 216.65K, in kilowatt hours (K);

G - acceleration of gravity on the Earth's surface, 9.80665g/m2, in meters per square second (g/m2);

R - General gas constant, 287.053J/(kg ● K), in joules per kilogram.

4.2.3 GB/T4797.3 Classification of Environmental Conditions Natural Environmental Conditions Biological Conditions

This part of the standard specifies the biological environmental conditions that pose a threat to electrical and electronic products under natural environmental conditions, and based on this, regional divisions are made.

This section describes the biological effects that products may be subjected to during storage, transportation, and use.

The purpose of this section is to provide background information for selecting the appropriate severity level for product applications.

When selecting the appropriate severity level for product applications, the classification of GB/T4796 should be considered.

The harmful organisms involved in this section mainly refer to molds, insects, birds, and mice.

1. The main impact of biology on electrical and electronic products

1) Mechanical force damage

1.1) The reasons for product damage under biological physical invasion include:

a) Animal groups, especially rodents and insects, may damage product materials in the following ways:

——Using product materials as food;

——Bite and nibble on product materials;

——Damaged product materials;

——Chewing product materials;

——Punch holes into the product material.

Note: Special attention needs to be paid to termites causing serious damage to product materials in this way.

Wood, paper, leather, fiber, plastic materials (including synthetic rubber), and even certain metals (tin and lead) are all susceptible to invasion.

Another way for product materials to be attacked by various animals is as follows:

——Strike or impact;

——Puncture.

b) The growth of plant communities, especially molds and plant branches, may damage product materials in the following ways:

——Growth transition;

——Puncture;

——Impact.

1.2) The types of product damage caused by biological physical effects include:

——Physical damage to product materials, components, units, and devices;

——Mechanical deformation or compression;

——Mechanical failures, such as running components;

——Surface degradation;

——Electrical failure caused by mechanical damage mentioned above.

2) Deterioration caused by sediment

2.1) The functionality of the product is affected by sediment from animal and plant communities, which affects the product through chemical and mechanical processes.

2.2) The reasons for product damage under the action of sediment include:

a) Sediments caused by animals, especially insects, rodents, birds, etc., may consist of the following components:

——Animals themselves;

——Nest or nest;

——Feeding materials;

——Metabolites, such as excreta and enzymes.

b) The sediment of various plants may consist of the following components:

——The branching parts of plants (leaves, flowers, seeds, fruits, etc.);

——The growth layer of mold or bacteria and their metabolites.

2.3) Under the action of sediment, the types of product damage include:

——Deterioration, corrosion, etc. of materials;

——Mechanical failure of components in operation;

——Electrical faults caused by:

● An increase in the conductivity of insulators;

● Insulation failure;

● An increase in contact resistance.

——Electrolysis and aging caused by moisture or chemical substances;

——Absorption and adsorption of moisture;

——Deterioration of heat dissipation.

Note: The following are two examples of causing these destructive effects:

● Interruption of the circuit;

● Optical surface blurring (including glass).

2. The emergence of fauna and flora

Except in a few cases, animal and plant communities may appear in various places where products are stored, transported, and used.

Fauna may cause damage outdoors and inside buildings, while flora mainly causes damage under outdoor conditions. Mold and bacteria may appear outdoors and inside buildings.

The frequency of the occurrence of animal and plant communities that may cause damage to the product depends on temperature and humidity conditions. In the geographical location of warm and humid climates, animal and plant communities, especially insects and microorganisms such as molds and bacteria, have a good living and growing environment. However, rooms inside buildings that are moist or damp, or generate moisture, are also suitable places for the survival and growth of rodents, insects, and microorganisms.

For example, the growth temperature range of mold is 0 ℃~40 ℃, while for the vast majority of organisms, the optimal growth temperature range is 22 ℃~28 ℃.

If there are organic coatings (such as grease, oil, dust, etc.) or sediment from animals and plants on the surface of the product, these surfaces will be an ideal environment for mold and bacterial growth.

3. Harmful biological species and distribution

1) Mold

1.1) Environmental conditions

Mold can cause harm to electrical and electronic products under environmental conditions with temperatures ranging from 18 ℃ to 37 ℃ and relative humidity exceeding 60%.

1.2) Main harmful strains

The main harmful bacteria include:

——Aspergillus andersonii;

——Aspergillus niger;

——Aspergillus flavus;

——Aspergillus oryzae;

——Aspergillus variegatum;

——Aspergillus saharani;

——Aspergillus niger;

——Aspergillus terrestris;

——Penicillium ochre;

——Penicillium frequently appears;

——Penicillium citri;

——Penicillium chrysogenum;

——Penicillium apicalis;

——Penicillium circulatum;

——Penicillium cordiformis;

——Penicillium brevis;

——Paecilomyces vannamei;

——Sprouting mold;

——Fusarium oxysporum;

——Trichoderma viride;

——Alternaria alternata;

——Fusarium globosum;

——Black root mold.

1.3) Hazardous areas and cities

Regions: Shandong, Jiangsu, Zhejiang, Anhui, Hubei, Sichuan, Yunnan, Guizhou, Hunan, Jiangxi, Guangdong, Hainan, Guangxi, Fujian, Hong Kong, Macau, Taiwan, etc.

Cities: Beijing, Tianjin, Shanghai, Chongqing, Harbin, Changchun, Shenyang, Shijiazhuang, Zhengzhou, Xi'an, Lanzhou, etc.

2) Insects

2.1) Overview

The harmful insects involved in this section can corrode electrical and electronic products during their life activities, leading to product damage.

2.2) Harmful main insects

Termites, ants, cockroaches, wasps, beetles, beetle larvae, beetle larvae, and moths.

2.3) Hazardous areas

Guangdong, Hainan, Guangxi, Fujian, Yunnan, Sichuan, Chongqing, Guizhou, Hunan, Hubei, Zhejiang, Shanghai, Jiangsu, Shandong, Hong Kong, Macau, and Taiwan.

3) Birds

3.1) The harmful birds involved in this section can cause damage to electrical and electronic products during their life activities.

3.2) Harmful main birds

Crows, magpies, sparrows.

3.3) Harmful bird hazard areas

Hunan, Jiangxi, Henan, Heilongjiang, etc.

4) Rodents

4.1) Overview

The harmful rodents involved in this section can cause damage to electrical and electronic products during their life activities.

4.2) Harmful main rodents

The main harmful rodents include:

——Apodemus agrarius;

——Slate toothed mouse;

——Grassland squirrels;

——Black line hamster;

——Long clawed gerbils;

——Brandt's vole;

——Mus musculus;

——Chinese zokor;

——Plateau rabbits;

——Yellow breasted rat;

——Yellow haired mouse;

——Brown house mouse;

——Chinese bamboo rat.

4.3) Harmful rodent hazard areas

Throughout the country.

4. Principles for dividing biological environmental conditions

1) Regional division based on atmospheric temperature and humidity conditions.

2) Regional classification is based on the degree of harm caused by organisms to electrical and electronic products.

3) Regionalize based on ground environmental conditions and the distribution of harmful organisms.

5. Regional division of biological environmental conditions

According to the division principles in the previous chapter, the country is divided into four regions (see Figure 1).

1) B1 Zone

1.1) Scope

Starting from Erguna River in the north, the area to the north of Hailar, Xilinhot, Hohhot, Yulin, Wuzhong, Lanzhou, Xining, Changdu, Linzhi and the Yarlung Zangbo River (see Figure 1).

1.2) Environmental conditions

1.2.1) The climate conditions in this area are complex, although they are in the southern temperate zone, middle temperate zone, or plateau climate zone, most of them are arid areas.

1.2.2) There are only rodent hazards in this area.

2) B2 Zone

2.1) Scope

Starting from Fujin in the east, it is an area west of Harbin, Changchun, Shenyang, Liaoyang, Qinhuangdao, Beijing, Shijiazhuang, Zhengzhou, Xi'an, Baoji, Tianshui, Wudu, Malkang, Kangding, Deqin, and south of B1 district (see Figure 1).

2.2) Environmental conditions

2.2.1) The monthly average relative humidity is greater than or equal to 70% throughout the year, and the monthly average temperature is greater than or equal to 18 ℃ for 1-2 months.

2.2.2) The annual average relative humidity is greater than 60%, and the annual average temperature is about 0-5 ℃.

2.2.3) There are hazards of mold, rodents, and birds in this area.

3) B3 area

3.1) Scope

Starting from Lianyungang in the east, it is an area north of Jingjiang, Nanjing, Lu'an, Wuhan, Yichang, Wanxian, Nanchong, Mianyang, Yachang, Nanchang, Dukou, Tengchong, and south of B2 district (see Figure 1).

3.2) Environmental conditions

3.2.1) Months with an average monthly relative humidity greater than or equal to 70% throughout the year and an average monthly temperature greater than or equal to 18 ℃ can last for 3-4 months.

3.2.2) The annual average relative humidity is greater than 60%, and the annual average temperature is about 10-15 ℃.

3.2.3) Biological activities in this area are relatively frequent, and there are hazards from major organisms such as molds, mice, ants, and birds.

4) B4 Zone

4.1) Scope

The area south of Zone B3 (see Figure 1).

4.2) Environmental conditions

4.2.1) Months with a monthly average relative humidity greater than or equal to 70% and a monthly average temperature greater than or equal to 18 ℃ can last for more than 5 months.

4.2.2) The monthly average relative humidity exceeds 70% for 10 months.

4.2.3) The rainy season lasts for 2-3 months each year.

4.2.4) There are frequent biological activities and various biological hazards in this area.

4.2.4 GB/T4797.4 Classification of Environmental Conditions Natural Environmental Conditions Solar Radiation and Temperature

This standard summarizes and divides solar radiation areas into several types, mainly providing some background materials for selecting appropriate levels of solar radiation severity for product applications.

Except for areas with elevations exceeding 5000m, this section covers various terrains.

When selecting the severity of solar radiation for a product, it is advisable to use the values given in IEC60721-1.

1. Overview

Solar radiation mainly affects electrical products by heating materials and the environment, as well as causing photochemical degradation reactions of materials. The ultraviolet radiation in the solar radiation can cause the photochemical degradation of most polymer materials, affecting the elasticity and plasticity of certain rubber and plastics, and optical glass may become blurry.

Solar radiation can fade paint, textiles, paper, etc., and in some cases, color may be important, such as the color code of components.

Heating the material is the most significant impact of solar radiation exposure. The severity of solar radiation is related to the surface radiation power intensity or radiation intensity, expressed in W/m2.

The temperature reached by an object subjected to solar radiation mainly depends on the surrounding air temperature, solar radiation energy, and the angle of incidence of solar radiation. Other factors, such as wind and the thermal conductivity of the installation components, may also be important. In addition, the absorption coefficient as of the surface to the solar spectrum is also important.

The virtual air temperature ts, which has the same temperature as the surface of the object under steady-state conditions, can be defined by a combination of actual air temperature tu and solar radiation E.

The approximate value can be obtained by the following equation:

Ts=tu+as * E/hy

The coefficient hy is the thermal conductivity coefficient of the surface, expressed in W/(m2 * ℃), which includes the surrounding thermal radiation, as well as heat conduction and convection caused by wind. The absorption coefficient as depends on the surface color, reflectivity, and conductivity.

The values for a clear sky are as follows:

As=0.7; Hy=20 W/(m2 * ℃), E=900 W/m2

The overheating temperature caused by solar radiation is approximately 30 ℃. Therefore, it can be seen that the 10% error in estimating solar radiation intensity will not have an impact on temperature exceeding 5 ℃, so it is not necessary to accurately classify the severity level of solar radiation, and the influence of other small factors is ignored here.

The thermal effect is mainly caused by short-term high-intensity solar radiation, such as solar radiation during cloudy noon. Table 1 provides some numerical values.

In order to determine the low temperature of products exposed to night, it is also necessary to determine the lowest possible value of atmospheric radiation on clear nights.

Figure 1 shows some numerical values.

2. Physical processes of solar radiation

The electromagnetic radiation emitted by the sun to the ground includes a relatively wide spectrum from ultraviolet to near-infrared. Most of the energy reaching the Earth's surface is concentrated at 0.3 μ M~4 μ m. At visible light 0.5 μ There is a maximum value at m, and its typical spectrum is shown in Figure 2

Figure 2 Electromagnetic Spectrum of Radiation from the Sun and Earth's Surface

Explanation:

A - Extraatmospheric solar radiation, represented by a blackbody with a temperature of 6000K (1.60kW/m2);

B - Extraatmospheric solar radiation (1.37 kW/m2);

C - Direct solar radiation perpendicular to the radiation direction on the ground (such as 0.9 kW/m2);

D - solar scattering on the ground (such as 0.1 kW/m2);

E - absorption band of water vapor and carbon dioxide;

F - Oxygen and ozone absorption;

G - radiation from a blackbody at a temperature of 300K (0.47 kW/m2);

H - Earth's thermal radiation (such as 0.07 kW/m2).

The amount of solar radiation received per unit area perpendicular to the solar rays outside the atmosphere at the average distance from the sun to the Earth is called the solar constant, which is approximately 1.37 kW/m2.

Almost 99% of solar radiation energy comes from 4 μ Wavelengths below m. zero point three μ Most of the solar radiation below m is absorbed by the atmosphere and will not reach the ground. During the process of passing through the atmosphere, further absorption and scattering occur due to the presence of particles and gases. The scattering of direct solar radiation in the atmosphere leads to sky scattering, therefore, the energy received at a certain location on Earth is the sum of direct solar radiation and scattering, defined as total radiation. From the perspective of thermal effects, the focus is on this and, therefore, the levels given in this section are related to total radiation.

3. Total radiation level

1) Maximum level

The maximum level of total radiation on a sunny day occurs at noon. The maximum amount of energy received by the surface perpendicular to direct solar radiation during a cloudless noon depends on the content of particles, ozone, and water vapor in the atmosphere. There are significant differences in numerical values among different geographic latitudes and climate types.

On a cloudless noon, the water vapor content is about 1cm, the ozone content is 2mm, and the aerosol β= 0.05, where β It is the Estron turbidity coefficient, and the total energy received by the surface perpendicular to direct solar radiation can reach 1120 W/m2. For flat land far from industrial areas and metropolises, 1120 W/m2 is representative when the solar incidence angle exceeds 60 °.

Note: The water vapor content in the vertical volume of the atmosphere is measured using the corresponding precipitation height cm. Similarly, the ozone content is measured using the corresponding height of ozone at standard temperature and pressure. Scattering and absorption of aerosol particles β The Estrand turbidity coefficient is represented by a wavelength of 1 μ The extinction distance of a single wavelength radiation of m in the atmosphere.

Direct solar radiation decreases as air turbidity increases. In sub humid hot and desert areas, the concentration of particles in the air is relatively high and the turbidity is relatively high. The air turbidity in large cities is also higher, while in mountainous areas it is lower.

Table 1 provides recommended values for the maximum total radiation received on a surface perpendicular to direct solar radiation during a cloudless noon. Within a few hours of noon, this value only changes by a few percent, so it can represent the situation of several hours within a certain period of time.

Table 1 Typical Peaks of Total Radiation

2) Monthly and annual averages of total solar radiation

The thermal effect of solar radiation on the surface usually depends on short-term radiation near noon, but the effect of photochemical reactions is related to the integral of radiation intensity over time, i.e. the amount of radiation. For comparison purposes, the daily total radiation exposure is the most commonly used data.

In December, due to the long duration of sunlight, the monthly average daily total irradiation near the South Pole was 10.8kWh/m2. The area outside Antarctica is approximately 8.4kWh/m2.

The maximum annual average daily total irradiation amount reaches 6.6kWh/m2, mainly occurring in desert areas.

3) Synchronized values of maximum temperature and solar radiation

Air turbidity coefficient β The minimum value of is measured in cold air. Therefore, the values listed in Table 1 will not appear at the highest temperature. It can be assumed that at the highest temperature given in IEC60721-2-1, the total irradiation dose will not exceed 80% of the values given in Table 1.

4) World and China distribution of total daily radiation exposure

Please refer to Appendix A, Appendix NA, and Appendix NB for the distribution of daily total radiation exposure.

4. Minimum value of nighttime atmospheric radiation

On cloudless nights, atmospheric radiation is very low, and the surface temperature of objects exposed at night is lower than the temperature of the surrounding atmosphere.

The theoretical thermodynamic temperature T0 when an object reaches equilibrium with atmospheric radiation is given by Boltzman's law:

T0=(A/ σ) 1/4

In the equation:

σ—— Stefan Boltzman constant, 5.67 * 10-8W/(m2 * K4)

A - Atmospheric radiation, in watts per square meter W/m2 (see Figure 1).

In fact, due to heat conduction, convection, and water vapor condensation, the temperature will be relatively high.

On a clear night, the horizontal surface temperature exposed to ground insulation can reach -14 ℃, while the atmospheric temperature is 0 ℃ and the relative humidity is close to 100%.

Figure 1 shows that the atmospheric radiation of nighttime air is a function of the atmospheric temperature at a height of 2 meters above the ground. On a clear night, the relative humidity is usually very high.

5. Appendix A (informative appendix) World distribution of total daily radiation exposure

Figures A.1, A.2, and A.3 show the isohelial lines (June, December, and annual average values) of relative total radiation exposure, measured by satellites (see Note 1). The definition of relative total radiation is as follows: the ratio of the total radiation measured on the Earth's surface to the total radiation outside the Earth (i.e., the solar radiation in the plane perpendicular to the direction of solar radiation outside the atmosphere).

To obtain the daily average of the total radiation on the Earth's surface, the percentage indicated on the graph is multiplied by the daily average of the total radiation outside the Earth, which is given as a function of geographic latitude, as shown in Table A.1.

Note 1: Reference documents for data sources:

G. Major et al.: A world map of relative total solar radiation.

World Meteorological Organization, Technical Note No. 172 Appendix, WMO-No.5570, Geneva (1987).

Note 2: The daily irradiation value in kWh/m2 is determined by averaging the monthly and annual irradiation values in MJ/m2. For example, dividing the monthly irradiation value by 30 in June, dividing it by 31 in December, and dividing the annual irradiation value by 365.

For example:

Provide an example of how to determine the average daily total solar radiation in June at the southern tip of the California Peninsula.

From the point in Figure A.1 (at approximately 23 ° north latitude) around the 60% isosolar line, the percentage value of this point is estimated to be 62%.

According to Table A.1, the estimated latitude of the list in June at 23 ° is approximately 11.16kWh/m2. Multiply this value by the percentage ratio above.

Therefore, the average daily total solar radiation is approximately 6.9 kWh/m2.

The specific values of the daily average total radiation outside the Earth in Table A.1 are detailed in the standard.

Figure A.1 shows the average relativ

Figure A.2 shows the average relative total radiation exposure in December as shown in the following figure.

Figure A.3 shows the average annual relative total radiation exposure as shown in the following figure.

6. Appendix NA (informative) Monthly and Annual Average Total Radiation Exposure in Major Regions of China

The monthly and annual average total radiation exposure in major regions of the country is shown in Table NA.1, as well as the standards.

7. Appendix NB (informative appendix) Solar radiation intensity in China

Table NB. 1 provides the levels of solar radiation intensity in China.

Table NB. 1 Levels of Solar Radiation Intensity in China

4.2.3 GB/T4797.3 Classification of Environmental Conditions Natural Environmental Conditions Biological Conditions

This part of the standard specifies the biological environmental conditions that pose a threat to electrical and electronic products under natural environmental conditions, and based on this, regional divisions are made.

This section describes the biological effects that products may be subjected to during storage, transportation, and use.

The purpose of this section is to provide background information for selecting the appropriate severity level for product applications.

When selecting the appropriate severity level for product applications, the classification of GB/T4796 should be considered.

The harmful organisms involved in this section mainly refer to molds, insects, birds, and mice.

1. The main impact of biology on electrical and electronic products

1) Mechanical force damage

1.1) The reasons for product damage under biological physical invasion include:

a) Animal groups, especially rodents and insects, may damage product materials in the following ways:

——Using product materials as food;

——Bite and nibble on product materials;

——Damaged product materials;

——Chewing product materials;

——Punch holes into the product material.

Note: Special attention needs to be paid to termites causing serious damage to product materials in this way.

Wood, paper, leather, fiber, plastic materials (including synthetic rubber), and even certain metals (tin and lead) are all susceptible to invasion.

Another way for product materials to be attacked by various animals is as follows:

——Strike or impact;

——Puncture.

b) The growth of plant communities, especially molds and plant branches, may damage product materials in the following ways:

——Growth transition;

——Puncture;

——Impact.

1.2) The types of product damage caused by biological physical effects include:

——Physical damage to product materials, components, units, and devices;

——Mechanical deformation or compression;

——Mechanical failures, such as running components;

——Surface degradation;

——Electrical failure caused by mechanical damage mentioned above.

2) Deterioration caused by sediment

2.1) The functionality of the product is affected by sediment from animal and plant communities, which affects the product through chemical and mechanical processes.

2.2) The reasons for product damage under the action of sediment include:

a) Sediments caused by animals, especially insects, rodents, birds, etc., may consist of the following components:

——Animals themselves;

——Nest or nest;

——Feeding materials;

——Metabolites, such as excreta and enzymes.

b) The sediment of various plants may consist of the following components:

——The branching parts of plants (leaves, flowers, seeds, fruits, etc.);

——The growth layer of mold or bacteria and their metabolites.

2.3) Under the action of sediment, the types of product damage include:

——Deterioration, corrosion, etc. of materials;

——Mechanical failure of components in operation;

——Electrical faults caused by:

● An increase in the conductivity of insulators;

● Insulation failure;

● An increase in contact resistance.

——Electrolysis and aging caused by moisture or chemical substances;

——Absorption and adsorption of moisture;

——Deterioration of heat dissipation.

Note: The following are two examples of causing these destructive effects:

● Interruption of the circuit;

● Optical surface blurring (including glass).

2. The emergence of fauna and flora

Except in a few cases, animal and plant communities may appear in various places where products are stored, transported, and used.

Fauna may cause damage outdoors and inside buildings, while flora mainly causes damage under outdoor conditions. Mold and bacteria may appear outdoors and inside buildings.

The frequency of the occurrence of animal and plant communities that may cause damage to the product depends on temperature and humidity conditions. In the geographical location of warm and humid climates, animal and plant communities, especially insects and microorganisms such as molds and bacteria, have a good living and growing environment. However, rooms inside buildings that are moist or damp, or generate moisture, are also suitable places for the survival and growth of rodents, insects, and microorganisms.

For example, the growth temperature range of mold is 0 ℃~40 ℃, while for the vast majority of organisms, the optimal growth temperature range is 22 ℃~28 ℃.

If there are organic coatings (such as grease, oil, dust, etc.) or sediment from animals and plants on the surface of the product, these surfaces will be an ideal environment for mold and bacterial growth.

3. Harmful biological species and distribution

1) Mold

1.1) Environmental conditions

Mold can cause harm to electrical and electronic products under environmental conditions with temperatures ranging from 18 ℃ to 37 ℃ and relative humidity exceeding 60%.

1.2) Main harmful strains

The main harmful bacteria include:

——Aspergillus andersonii;

——Aspergillus niger;

——Aspergillus flavus;

——Aspergillus oryzae;

——Aspergillus variegatum;

——Aspergillus saharani;

——Aspergillus niger;

——Aspergillus terrestris;

——Penicillium ochre;

——Penicillium frequently appears;

——Penicillium citri;

——Penicillium chrysogenum;

——Penicillium apicalis;

——Penicillium circulatum;

——Penicillium cordiformis;

——Penicillium brevis;

——Paecilomyces vannamei;

——Sprouting mold;

——Fusarium oxysporum;

——Trichoderma viride;

——Alternaria alternata;

——Fusarium globosum;

——Black root mold.

1.3) Hazardous areas and cities

Regions: Shandong, Jiangsu, Zhejiang, Anhui, Hubei, Sichuan, Yunnan, Guizhou, Hunan, Jiangxi, Guangdong, Hainan, Guangxi, Fujian, Hong Kong, Macau, Taiwan, etc.

Cities: Beijing, Tianjin, Shanghai, Chongqing, Harbin, Changchun, Shenyang, Shijiazhuang, Zhengzhou, Xi'an, Lanzhou, etc.

2) Insects

2.1) Overview

The harmful insects involved in this section can corrode electrical and electronic products during their life activities, leading to product damage.

2.2) Harmful main insects

Termites, ants, cockroaches, wasps, beetles, beetle larvae, beetle larvae, and moths.

2.3) Hazardous areas

Guangdong, Hainan, Guangxi, Fujian, Yunnan, Sichuan, Chongqing, Guizhou, Hunan, Hubei, Zhejiang, Shanghai, Jiangsu, Shandong, Hong Kong, Macau, and Taiwan.

3) Birds

3.1) The harmful birds involved in this section can cause damage to electrical and electronic products during their life activities.

3.2) Harmful main birds

Crows, magpies, sparrows.

3.3) Harmful bird hazard areas

Hunan, Jiangxi, Henan, Heilongjiang, etc.

4) Rodents

4.1) Overview

The harmful rodents involved in this section can cause damage to electrical and electronic products during their life activities.

4.2) Harmful main rodents

The main harmful rodents include:

——Apodemus agrarius;

——Slate toothed mouse;

——Grassland squirrels;

——Black line hamster;

——Long clawed gerbils;

——Brandt's vole;

——Mus musculus;

——Chinese zokor;

——Plateau rabbits;

——Yellow breasted rat;

——Yellow haired mouse;

——Brown house mouse;

——Chinese bamboo rat.