GB/T 2423.65-2024Environmental testing - Part 2: Test methods - Combined salt mist, temperature, humidity and solar radiation test (English PDF)

1 Scope

China's national combined environmental test applying salt mist, temperature, humidity and solar radiation together. It is part of the GB/T 2423 series and specifies the apparatus, the severities, the procedure and the evaluation for a test in which these four stresses are applied in combination rather than in sequence. The GB/T 2423 series is largely a catalogue of single-stress tests - a salt mist test, a damp heat test, a solar radiation test, each applied alone - and the reason for a combined test is that the real environment does not work that way and the damage it causes is not the sum of the parts. A coastal environment applies salt, heat, humidity and sunlight simultaneously and cyclically, and the interactions are what destroy equipment. Ultraviolet radiation degrades a polymer and opens the surface, which lets moisture and chloride reach the substrate that the intact coating would have protected. Solar heating drives a diurnal cycle that pumps moist salt air in and out of an enclosure through its breathing, depositing salt inside where no external salt spray would reach. The heat accelerates the corrosion the salt starts, and the wet-dry cycling concentrates the electrolyte far beyond what a continuous salt spray produces - which is why a continuous salt spray test is known to correlate poorly with real coastal service. So the standard specifies a cycle rather than a condition: the sequence and duration of the salt application, the temperature and humidity phases and the irradiation, the severities available, the chamber and its instrumentation, and the evaluation of the specimen. It is aimed at equipment that lives outdoors near the sea. Issued on 23 August 2024 and in force since 1 March 2025.

This document describes a comprehensive testing method for electrical and electronic equipment, components, and materials under the effects of salt spray, temperature, humidity, and solar radiation, including information on testing equipment, conditions, and methods. This document is applicable to evaluate the environmental adaptability of electrical and electronic equipment, components, and materials used in humid and hot marine atmospheric environments under the combined effects of salt spray, temperature, humidity, and solar radiation.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 2423.17, Environmental testing - Part

3 Terms and definitions

There are no terms or definitions that need to be defined in this document.

4 General description of tests

4.1 Overview This test is a comprehensive test that includes salt spray, dry heat, humid heat, and solar radiation. Each test cycle of the comprehensive test consists of three stages. The test phase Z1 is composed of humid heat (high temperature, high humidity), salt spray, and solar radiation. The test phase Z2 is composed of dry heat (high temperature, low humidity) and solar radiation. The test phase Z3 consists of humid heat (high temperature, high humidity) and salt spray. Carry out Z1, Z2, and Z3 in sequence to form the basic cycle of the comprehensive test.

5 Test equipment

5.1 General requirements for test equipment The materials used for devices directly exposed to salt spray inside the equipment shall not affect the corrosion effect of salt spray. They shall have good sealing performance and corrosion resistance. The materials used for devices directly exposed to solar radiation inside the equipment shall not affect the photothermal aging effect of solar radiation. They shall have good anti-aging performance. Annex B provides examples of test equipment.

7 Specimens

The type, quantity, shape, and size of the specimen shall be selected according to the relevant specifications of the tested material or product. If there is no standard, for material specimens, it is advisable to expose at least 3 parallel specimens of each type for statistical evaluation of the results. For equipment and component specimens, both parties can negotiate and determine.

8 Initial testing

Visual, dimensional, and functional inspections shall be conducted on the specimens. If necessary, electrical and mechanical performance testing shall be conducted in accordance with the requirements of relevant specifications.

9 Pretreatment

The specimen shall be pretreated according to relevant specifications and regulations. The relevant specifications shall specify the cleaning procedure to be used on the specimen before the test. They shall also specify whether the protective coating needs to be removed. The cleaning method used shall not affect the corrosion effect of salt spray on the specimen, and shall not introduce any secondary corrosion. Avoid touching the surface of the specimen with hands before the test.

10 Specimen installation

In the workspace, the arrangement of the specimens shall ensure that they do not come into contact with the test chamber. At the same time, maintain sufficient spacing between the specimens and expose them to freely flowing salt spray. If it is necessary to monitor the surface temperature of the specimen, a temperature sensor can be attached to the specimen according to relevant specifications. The angle at which the specimen surface is exposed in the test chamber is very important. If there are no relevant regulations, the angle shall be jointly agreed upon by the relevant parties. The specific requirements are as follows: - For equipment and component specimens, unless otherwise specified, they shall be installed at the same angle as when in terminal use to simulate the final usage conditions of the tested specimen. At the same time, the specimen can be in an unpackaged, non-powered, powered on, or powered on state. Whether the specimen is in a powered working state during the testing process shall be jointly Before the trial run begins, use a calibrated backup humidity sensor to test the humidity sensor inside the box. When the relative humidity deviation exceeds 2%, the sensor needs to be calibrated. It is advisable to continuously monitor the specified temperature and relative humidity throughout the entire Test period. Before the test begins, a no-load test run of at least 8 h shall be conducted to confirm the test conditions. During the trial operation, the salt spray concentration is measured in the workspace after the temperature and relative humidity reach the set test conditions in stages Z1 and Z

3.Take the average of 3 measurements as the salt spray concentration value for this stage. If the relevant parties recognize each other, trial operation is not necessary when the time interval between tests is 5 d or less. In each Test stage, the time required from the start of the test to reach the specified salt spray concentration, temperature, and relative humidity shall not exceed the values listed below. - Z1 stage. 30 min; - Z2 stage. 30 min; - Z3 stage. 60 min. The above time shall be included in the total time of each stage.

11.3 Test duration The duration of the test shall be jointly agreed upon by relevant parties. The cyclic test cycle shall be repeated within the duration of the test. The number of cycles determines the severity of the test. The recommended duration of the test (number of cycles) is 120 h (15 times) 240 h (30 times) 360 h (45 times), 480 h (60 times), 720 h (90 times), and 960 h (120 times).

12 Intermediate testing

The relevant specifications may propose conducting electrical and/or other performance tests on equipment and component specimens during the testing period. Otherwise, the interruption of the test shall be reduced. The total unboxing time per day shall not exceed 1 h. During this period, the specimen surface shall not be touched or any changes made to the test surface. NOTE. If considering the consistency issue of irradiance or salt spray deposition in the exposed area of the test specimen, regularly changing the position of the specimen can reduce the uncertainty caused by irradiation and salt spray exposure. The relevant parties agree on the procedure and schedule for specimen repositioning. WARNING -- There is a possibility of safety issues such as leakage during or after the test of the energized sample. Specimen testing shall be conducted by professionals or under their guidance.

13 Recovery

The relevant specifications shall specify whether the specimen shall be cleaned. If cleaning is required, follow GB/T 2423.17.

14 Final testing

Visual, dimensional, and functional inspections shall be conducted on the specimens. If necessary, electrical and mechanical performance testing shall be conducted in accordance with the requirements of relevant specifications.

15 Information to be provided regarding the specifications

When the relevant specifications include this comprehensive environmental test, the following detailed information shall be provided.

a) Initial testing.

b) Preprocessing.

c) Installation or support details of the specimen.

d) The status and precautions of the specimen (powered on, powered off, packaged, unpackaged, etc.).

e) Test conditions and tolerances. 1) Salt spray concentration; 2) Solar radiation; 3) Temperature; 4) Relative humidity; 5) Duration.