This standard specifies the general principles for the classification of environmental conditions for the application of electrical and electronic products, provides background information for the selection of environmental parameters and severity levels, and requirements for the selection of use conditions and the duration and frequency of occurrence of environmental parameters. This standard is applicable to provide guidance for the application of various environmental conditions in GB 4798.

National Standard of the People's Republic of China
Environmental conditions existing in theapplication of electric and electronic products
Environmental conditions existing in theapplication of electric and electronic productsIntroduction
GB/T 4798.10—91
Replaces GB4798.10—84
This standard refers to and adopts the international standard IEC721-3-0 (1984) "Classification and grading of environmental parameters and their severity groups" and its first supplement.
This standard is the first part of GB4798.
1 Subject content and scope of application
This standard specifies the general principles for the classification of environmental conditions for the application of electric and electronic products, provides background materials for the selection of environmental parameters and severity levels, and the requirements for the selection of use conditions and the duration and frequency of occurrence of environmental parameters. This standard is applicable to provide guidance for the application of various environmental conditions in GB4798. 2 Reference standards
General rules for basic environmental testing procedures for electric and electronic products
Basic environmental testing procedures for electric and electronic products GB2423
Classification of environmental parameters for electric and electronic products and classification of their severity GB4796
Application environmental conditions for electric and electronic products
GB4798
General description
Environmental conditions are divided into the following categories according to the use of the product: a.
Storage;
Transportation;
Fixed use in places with weather protection:
Fixed use in places without weather protection,
Use on ground vehicles;
For use on ships;
Portable and non-fixed use. www.bzxz.net
3.2 The environmental condition classification mark is stipulated as follows: a.
The first number indicates the application category: 1
Storage; 2-
Transport; 3-
-Fixed use in weather-protected places; 4-Fixed use in weather-unprotected places; 5-Use in ground vehicles; 6-For ship use; 7-Portable and non-fixed use. b.
A letter is used in the middle to indicate the condition category: K-Mechanically active substances; M--
Mechanical conditions.
Climatic conditions; B--
Biological conditions; C
c. The last number indicates the severity level. Generally, the larger the number, the more severe the conditions. Approved by the State Administration of Technical Supervision on December 14, 1991 Chemically active substances; S+
Implementation on October 1, 1992
GB/T 4798.10-91
For example: In the 2K3 level code: 2-transportation; K-climatic conditions, 3-
-severity level.
3.3 The classification table of environmental parameters and their severity levels is listed in the corresponding standards of application environmental conditions. Each standard provides a detailed appendix for the conditions that the product may encounter to guide the selection of environmental condition levels for specific products. 4 Explanation on the selection of environmental parameters and severity levels 4.1 The environmental parameters listed in the classification of each application condition standard refer to those parameters that the product will encounter under the corresponding environmental conditions. These parameters are selected from GB4796.
4.2 The severity level of each environmental parameter listed in the application condition standard only exceeds the value for a very short and negligible time. 4.3 The various application environmental condition standards can be used to determine the maximum short-term environmental stress of the product, but do not give the total (long-term) environmental stress, which is illustrated in the following figure.
P(X>X.)
The probability of exceeding the severity level X. for a time or number of times
P(X>X,) is very small
The probability of exceeding a certain environmental severity level for a time or number of times
In the figure; X. —severity level;
X —severity level given in the classification;
X——severity level occurring at a certain place and time. Severity level
a, X, value represents the severity level given in the classification, while the total amount of environmental stress during the product life cycle is determined by the entire curve of P(X>X,) for all X. values. Although the existing data cannot give an exact value for the probability of classification, P(X>X,) is usually much less than 0.01.
b. The product is exposed to many environmental parameters at the same time, some of which are related, such as low air speed and low temperature, solar radiation and high temperature. But other parameters are usually unrelated, such as vibration and temperature. C. The probability of a product being exposed to extremely severe levels of independent environmental parameters X and Y at the same time is equal to the product of the probabilities of being exposed to each parameter, that is:
P(X,Y>XY)P(X>X)·P(Y>Y)
For example: The probability of exceeding each parameter
P(X ≥ X) = P(Y ≥Y) 0. 01
5 Guidelines for the use of standards for applied environmental conditions
5.1 Overview
P(X,Y>X ,Y)=0. 000 1
GB/T 4798.10-91
5.1.1 The environment basically affects the product in the following two ways: a. A. The product cannot work properly or is damaged due to short-term extreme environmental conditions; b.
A product cannot work properly or is damaged due to long-term non-extreme stress. When the product is new, it may withstand the influence of certain extreme environmental conditions, but when the product is subjected to the same conditions after a long period of use, it will be damaged due to aging.
5.1.2 Situations where extreme environmental conditions affect the product: a. Only when the product is not working (such as during storage and transportation); b. Only when the product is working.
Or both. When a certain level in the GB4798 standard is involved in the product technical conditions, it must be clarified: when the product encounters the conditions of this level, is the product required to be able to work, or is it only required to be free of permanent damage? 5.1.3 The level of environmental parameters can be used as the basis for selecting the design and test levels, but these classification limits should not be used as the design and test levels, nor should the product failure within the classification limit be required to be zero. The magnitude of the design and test must be selected according to the specific circumstances of the allowable failure rate, that is, the higher or lower severity level is selected, depending on the probability of failure allowed by the product. 5.2 Application of GB4798 series standards in product design, selection of environmental condition levels and protective measures 5.2.1 GB4798 series standards are the basis of environmental conditions for product design. Designers must understand that the physical impact of some environmental conditions (such as the maximum temperature around the product) can be caused by several environmental parameters (surrounding air temperature, solar radiation, heat radiation from adjacent heating elements and furnaces, etc.).
5.2.2 The manufacturer or user can take appropriate measures for the product (put it in a box during transportation and storage or put it on an object that is anti-vibration and anti-impact) to reduce the severity of the environmental conditions. Therefore, the severity of these environmental parameters should be applicable to the product together with the protective measures, not directly to the product itself. 5.2.3 The manufacturer or user can use the appendix in the GB4798 series standards to determine the limit values ​​of the product in transportation, storage or use conditions so that the product can be adapted to use within these limits. Usually the best solution can be found from the following three measures: no protective measures for the product;
b. Protective measures for the product;
Control (improve) the transportation, storage and use conditions of the product. 5.2.4 When designing a product, the environmental stress to which the product is subjected should be reasonably considered. In order to withstand more extreme environmental conditions than the actual requirements, the product should not be designed to be too safe or unnecessary protective devices should not be installed. This will make the product too complicated and have more faulty components. Or it is inappropriate to make excessive requirements to improve local environmental conditions. 5.3 Principles for determining test levels
5.3.1 The classification of the GB4798 series of standards can be used as the basis for design, protection and control of the environment. To show the ability of the product to withstand environmental conditions, the basic materials of the product should be selected, including material testing, surface treatment, etc., until the whole machine sample test under simulated environmental conditions. These tests include: a.
Environmental parameters;
b, test procedures;
Test severity level;
d. Product assessment indicators.
5.3.2 The environmental test procedures shall comply with the relevant provisions of GB2421 and GB2423. 5.3.3 The severity of the test should be combined with the test procedure, and the test procedure should simulate the influence of the actual environment as much as possible. For example, the high temperature test of heat dissipation products should be designed to simulate the effects of high temperature conditions, solar radiation and other possible heat sources in use.
For example, according to GB2423.5, the product should be subjected to the impact of a simple pulse waveform (i.e., a half-sine wave). Although the actual conditions cannot be expressed by such a simple pulse, they can be converted by comparing the impact spectrum of the actual conditions with the impact spectrum of the test pulse. 5.3.4 The environmental condition values ​​listed in GB4798 do not include safety margins. When considering the selection of test specifications, in addition to converting the environmental conditions into test conditions, the safety margins of the following items should also be considered. a.
Tolerances of test equipment and control devices;
Differences between the samples used for the test and the same batch or different batches of products b.
c. Others.
5.3.5 The levels in GB4798 determine the actual extreme environmental conditions. These conditions are not used directly as test conditions, but can be used together with the conversion method of actual conditions into test conditions, safety margins, etc. to determine the test levels of these tests. Duration and frequency of occurrence
6.1 Overview
6.1.1 The probability that the environment encountered by the product during transportation, storage and use exceeds the severe level specified in GB4798 is quite small. 6.1.2 When designing the product and providing protective measures (building structure, etc.), in order to make it safe and reliable, the effective level of the environmental parameters that affect the product should be considered; the time of occurrence or how long it occurs, and the environmental parameter conditions in the area where the product is expected to be used (during storage, transportation or use).
Note: The term "effective" in this standard applies to the following conditions: a. a. The state described by the parameter has been reached, such as condensation, icing, etc.; b. The parameter value exceeds the corresponding lower severity level, such as low air pressure, high temperature, low relative humidity, high relative turbidity, etc.; c. The parameter value exceeds a specified critical value with a selected duration or frequency. 6.1.3 The local location or use conditions of the product can affect the duration or frequency of occurrence of a single environmental parameter. Table 1, Table 2 and the examples presented are only applicable to simple cases or when there is not much data on duration. 6.2 Duration and frequency
6.2.1 Table 1 lists the standard values ​​of various durations related to each application. 6.2.2 Table 2 lists the standard values ​​of the longest duration of a single environmental parameter. Table 3 lists the standard values ​​of the duration of occurrence per unit time or the number of effective phenomena per unit time, which are related to the level of each environmental parameter.
Total duration of each type of application
Note: 1) Special purposes may require only a shorter duration, such as meteorological sounding instrument
Table 2 Maximum duration of a single parameter 1s
Duration of occurrence per unit time 1)
30 min
GB/T 4798.10—91
Table 3 Frequency of occurrence
Note: 1) The unit time is selected from the following: seconds, minutes, hours, 24h, weeks, months, years. 6.2.3 Appendix A gives examples of the application of standard values ​​for duration and frequency of occurrence. Number of effective phenomena per unit time 1>
GB/T 4798.10-91
Appendix A
Application examples
(reference)
The standard application of the duration and frequency values ​​of occurrence is illustrated as follows: A1 First example
The product is transported long distances (from the manufacturer to the user) by normal means of transportation without special vehicles or protective equipment. Environmental classification 2K4/2B2/2C3/2S2/2M3
Transport duration 30d
Duration of effective vibration 7d per month
Number of effective collisions 1 time per hour
Number of effective free falls 10 times per month
A2 Second example
The product is on a fixed device without weather protection Environmental classification 3K3/3Z1/3B1/3C2/3M2
Duration of use 10 a
Duration of effective vibration 7d per year
Maximum duration of effective vibration 8h
Number of effective collisions/24h
A3 Example 3
Product used for carrying and non-fixed use
Environmental classification 7K4/7Z2/7Z6/7Z10/7B2/7C3/7M3 Duration of use 5a
Duration of humidity (condensation, precipitation, water spray) 60d per year
Duration of effective influence of chemical active substances 0.5h per 24h
Duration of ice and frost 30d per year 2 times per year
Number of effective free falls
Additional instructions:
This standard is proposed and managed by the National Technical Committee for Standardization of Environmental Conditions and Environmental Tests for Electrical and Electronic Products. This standard is drafted by the Guangzhou Electric Science Research Institute of the Ministry of Machinery and Electronics and the Standard Metrology Institute of the Ministry of Transport. The main drafters of this standard are Yang Lingmin and Shuai Shuncai.10-91
Appendix A
Application examples
(reference)
The standard application of duration and frequency values ​​is illustrated as follows:A1 First example
The product is transported long distances (from the manufacturer to the user) by normal means of transportation without special vehicles or protective equipment. Environmental classification 2K4/2B2/2C3/2S2/2M3
Transport duration 30d
Duration of effective vibration 7d per month
Effective collision number 1 per hour
Effective free fall number 10 per month
A2 Second example
The product is on a fixed device without weather protection Environmental classification 3K3/3Z1/3B1/3C2/3M2
Duration of use 10 a
Duration of effective vibration 7d per year
Maximum duration of effective vibration 8h
Number of effective collisions/24h
A3 Example 3
Product used for carrying and non-fixed use
Environmental classification 7K4/7Z2/7Z6/7Z10/7B2/7C3/7M3 Duration of use 5a
Duration of humidity (condensation, precipitation, water spray) 60d per year
Duration of effective influence of chemical active substances 0.5h per 24h
Duration of ice and frost 30d per year 2 times per year
Number of effective free falls
Additional instructions:
This standard is proposed and managed by the National Technical Committee for Standardization of Environmental Conditions and Environmental Tests for Electrical and Electronic Products. This standard is drafted by the Guangzhou Electric Science Research Institute of the Ministry of Machinery and Electronics and the Standard Metrology Institute of the Ministry of Transport. The main drafters of this standard are Yang Lingmin and Shuai Shuncai.10-91
Appendix A
Application examples
(reference)
The standard application of duration and frequency values ​​is illustrated as follows:A1 First example
The product is transported long distances (from the manufacturer to the user) by normal means of transportation without special vehicles or protective equipment. Environmental classification 2K4/2B2/2C3/2S2/2M3
Transport duration 30d
Duration of effective vibration 7d per month
Effective collision number 1 per hour
Effective free fall number 10 per month
A2 Second example
The product is on a fixed device without weather protection Environmental classification 3K3/3Z1/3B1/3C2/3M2
Duration of use 10 a
Duration of effective vibration 7d per year
Maximum duration of effective vibration 8h
Number of effective collisions/24h
A3 Example 3
Product used for carrying and non-fixed use
Environmental classification 7K4/7Z2/7Z6/7Z10/7B2/7C3/7M3 Duration of use 5a
Duration of humidity (condensation, precipitation, water spray) 60d per year
Duration of effective influence of chemical active substances 0.5h per 24h
Duration of ice and frost 30d per year 2 times per year
Number of effective free falls
Additional instructions:
This standard is proposed and managed by the National Technical Committee for Standardization of Environmental Conditions and Environmental Tests for Electrical and Electronic Products. This standard is drafted by the Guangzhou Electric Science Research Institute of the Ministry of Machinery and Electronics and the Standard Metrology Institute of the Ministry of Transport. The main drafters of this standard are Yang Lingmin and Shuai Shuncai.
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