Environmental test chamber simulation test vs. field test: how to choose?

01 Overview of environmental testing

Any product must be formally introduced to the market before the corresponding environmental test chamber adaptability verification, the simpler is based on the transportation and consumer operating conditions to test, so as to avoid problems in the process of product introduction to the market and lead to losses. Serious or even may require compensation or even stop the production and sale of products.

Among them, the environmental test is based on the product transportation and use of the process may occur in the harsh environment to simulate the test, as far as possible in the product development stage through the environmental test chamber to find all the problems. In this way, there will be no major problems after the product is introduced to the market, and all guidelines are based on the actual product user profiles.

Reliability testing is similar to environmental testing, but there are differences. While environmental tests generally consider possible harsh environments, reliability tests are based on typical use conditions that would otherwise lead to over-designed products, which in turn would result in increased costs through environmental test chambers, or even the inability to produce products with the required level of reliability.

This requires us to investigate and summarize the use conditions of typical customers, that is, the specific use conditions in the definition of reliability, otherwise the test can not begin. Environmental test chambers are also mainly used for the verification of product design objectives, mainly the working environment capabilities.

However, it should be noted that the verification of the product through the environmental test chamber can only indicate whether it can operate normally in a particular environment, and can not indicate its ability to continue to work under the conditions, so it can not directly reflect the level of product reliability.

02 Introduction to Environmental Testing

According to literatures. The British R Mallet carried out tests on metal hangings in estuaries, which were the earliest tests in natural environments. With technological advances, these tests were gradually transformed into artificial simulation tests.

After World War I, due to the failure of a large number of weapons on the battlefield or after storage, the militaries of various countries attach importance to environmental testing, the United States in the post-war period, in particular, to promote the development of environmental test chambers related to testing.

The IEC (International Electrotechnical Commission) TC75 Committee on Classification of Environmental Conditions issued the “Classification of Environmental Parameters” in 1981, as follows:

• Climatic environment: temperature, humidity, pressure, solar radiation, dust, snow, etc.

• Biological and chemical: salt spray, mold, sulfur dioxide, hydrogen sulfide and so on.

• Mechanical environment: vibration (including sinusoidal, random), collision, drop, swing, impact, etc.

• Comprehensive environment: temperature and humidity, temperature and pressure and other combined environmental parameters can be realized through the environmental test chamber.

03 Classification of environmental tests

There are three main types of environmental tests: natural environment exposure tests, simulated environment tests and field tests.

a. Natural Environment Exposure Test 

Natural Environment Exposure Test refers to the long-term exposure of a product to real natural conditions, usually for more than two years. Mostly used for mechanical structure, materials, plating or coating environmental adaptability research. This type of test is real, but the cycle time is long and uncontrollable, so in recent years it is mostly replaced by environmental test chamber simulation.

Representative facilities include:

Weathering station in Ustero (Fischland)

Qingdao Atmospheric Corrosion Test Plant

b. Simulated environmental tests

Due to the short life cycle of consumer electronics products, environmental test chambers are increasingly being used. Instead of relying on natural environmental exposure tests, companies are using environmental test chambers to artificially simulate various environmental conditions in the laboratory. This approach breaks through the climatic limitations and greatly improves test efficiency.

With the progress of the test equipment, the laboratory can basically simulate most of the natural environment through the environmental test chamber. But to simulate all the actual conditions there are still technical bottlenecks. Therefore, at present, the simulation test is the main test, supplemented by other tests, to maximize the coverage of product testing.

Typical simulation examples include:

Mars Simulated Environment Test

A350 XWB MSN2 COLD WEATHER TRIAL AT McKINLEY

c. Field tests

For some large products, especially mobile and large complete sets of equipment (some equipment does not produce any prototypes for testing, but is directly assembled into a system at the customer's site), it is often impossible to use an environmental test chamber for complete simulation.For example, testing the environmental adaptability of cars at high speeds can only be done outdoors, as it is impossible to build a sufficiently large, environmentally controlled enclosed environment for conducting vehicle driving tests.

In addition, for those who need to collect actual data on site, field tests must also be conducted in actual environments. For example, the actual vibrations generated during the operation of high-speed trains must be analyzed by collecting the corresponding vibration data on board the train while it is in motion.

d. Environmental testing—automotive industry

The automotive industry widely adopts the ISO 16750 series of standards. The standards detail mechanical, climatic, and chemical environmental profiles applicable to testing in multiple areas such as engine compartments, dashboards, and radiators.

Most automotive companies use these standards as the basis for environmental testing chambers, while some companies make customized adjustments. The following is a summary of test parameters for some typical areas:

Automotive Area Definition