Temperature Humidity Test

Environmental Tests

Temperature Humidity Test

The temperature humidity test determines how components, subsystems, and all systems behave at high temperatures as well as in heavy environments with high or fluctuating relative humidity. The tests can be static with constant temperature and humidity, can include both cycles, temperature-humidity bias tests (where moisture is used to induce a malfunction in an electrical appliance) or a combination thereof.

Temperature Humidity Test

Among other things, temperature / humidity tests examine the effects of climate change on electronic components such as parameter changes, mechanical failures (due to rapid water or frost formation), optical failures (fogging), water tightness (package) failures, materials. Temperature / humidity tests are a critical component of a full qualification program. While many electrical components are inexpensive to purchase, they can be expensive to replace. For example, an LCD in an oil search device or marine instrument can cause serious downtime costs in the event of a temperature / humidity related failure. The temperature and humidity combined test extends to complete systems and finished products that go beyond electronic components: copiers, computers, cars, satellites and even parachutes require temperature humidity testing.

In today's engineering and manufacturing world, it is not enough to design, create and distribute products. Manufacturers have the responsibility to ensure that their products will withstand all environmental pressures and stresses that they will experience after being used in the "real world". Two of the biggest environmental factors that determine whether products will stand up are temperature and humidity. Fortunately, today there are advanced forms of temperature and humidity tests that provide optimum product performance for all designers and manufacturers.

Temperature test and humidity test work hand in hand. These two environmental forces are inevitable in the world, except for a vacuum that simulates space conditions. However, in terrestrial environment, every product produced from military ammunition to electronic components will encounter a range of temperature and humidity conditions. Some of these ranges may be excessive.

Environmental changes in environments such as temperature and humidity greatly affect the product performance produced. There may be external conditions in which weather conditions change with fluctuating seasons or with artificial environments where room conditions affect products. Also, adjacent products in surrounded environments also affect the performance of others.

Professional temperature and humidity testing takes into account all these interactions and the testing process is carried out to help improve the long-term durability and service life of the products. The manufacturing industry uses temperature and humidity testing to accurately see how their products will perform in any environment. This process serves to ensure product reliability and compliance with the legislation.

Our laboratory has been performing climate tests for many years and has everything needed for temperature humidity testing. Our test rooms have been collected and kept up to date to meet every conceivable requirement. 

What is Temperature and Humidity Test?

Temperature and humidity test is an umbrella term. It is an engineering and production generalization for environmentally stressful experiments such as high / low temperature test, moisture resistance test or temperature cycle test. Procedures such as temperature humidity deviation test also fall under the umbrella.

Whatever the name of each test type, they all determine how the complete systems, subsystems and individual components of the manufactured products perform or behave in normal and harsh environmental conditions. Often, extreme variations are in temperature and humidity. However, other environmental factors such as sand, dust, corrosion and vibration are also under the performance test umbrella.

The main basis of the temperature and humidity test is to put the products in high environmental stresses and cause malfunction. There is a wide range of forces exerted during temperature and humidity tests, which depend on the specific product and its intended use. Test technicians place subject materials in controlled environmental test rooms, then artificially adjust temperature, humidity and other forces. These high and low parameter shifts can cause products to malfunction, fog or condensation, allow water ingress and degrade structural materials.

Manufacturers see temperature and humidity tests as a high priority in quality control programs for many good reasons. Properly executed environmental testing places products at the outer boundaries of natural or artificial conditions, which they realistically encounter. For example, electronic assemblies and components are the best candidates for temperature and humidity testing. Experienced manufacturers know that parts failure in a test room is much better than an operational application where downtime and repairs can be quite expensive.

There are two basic environmental test forms. Temperature and humidity tests fall into both categories called simulation and stimulation. To address any confusion regarding these similar drilling terms, a brief description of the two most important parts of the temperature and humidity test:

Test simulation: Environmental test chambers artificially simulate or imitate the conditions that products may reasonably encounter in their final operating environment. Normal-use environmental tests are the “pass test” criterion, where regularly expected stresses such as temperature, humidity, abrasives and vibrations are evaluated. If the products meet the routine mark, they are certified and sent to production and distribution.

Test stimulation: This test procedure or method is a step above routine simulation. Environmental stresses are raised to reveal product weaknesses and points of failure. Conversely, the stimulation of excessive stresses such as accelerated temperature and humidity confirms the ability of a product to withstand environmental factors above and beyond what they will see in their services. Test stimulation is also known as accelerated testing.

Temperature is the most common product stress in environmental fluctuations. Temperature changes cause products to expand or contract. The rates vary depending on the type of material tested. Plastics react differently than metals and temperature test parameters are always adjusted to the materials in the test procedure.

Moisture is the second environmental stress factor that affects the products produced. Moisture fluctuations also cause expansion and contraction, but environmental testing technicians are more concerned about how moisture affects internal work in products. It contributes greatly to moisture penetration or leakage, oxidation and corrosion. Moisture resistance is an important performance factor for products that include electrical or computerized mechanisms.

While most product testing procedures focus primarily on temperature and humidity, many test rooms contain additional examinations. The vibration test usually accompanies the basic temperature and humidity test. When expansion, contraction, entry and leakage movements are combined with physical vibrations, they often cause compound problems. When three stresses come together, it causes mechanical strength loss due to cracking, swelling, displacement and deterioration of physical properties. They contribute to product fatigue and early breakdown.

Finally, the umbrella of temperature and humidity may contain additional tests for stress factors caused by altitude or groundwater compression. Corrosion is a constant concern for metal products. It contributes to wear on all types of products, regardless of whether they are made of sand, dust and sand, metal, plastic or any composite material.

Through controlled and deliberate environmental stress factors, product testing is the only way to artificially determine how well a designed or manufactured component or assembly will perform in its intended role. Different stressed products ensure that they work as intended during normal use. The key to accurate product evaluation is how temperature and humidity tests are performed.

How are Temperature and Humidity Tests Done?

Technicians immerse the products in artificial environments and carry out temperature and humidity tests. It includes test rooms where temperature and humidity changes are induced, controlled, monitored and evaluated. Test rooms generally include vibration tables and apparatus that regulate exposure to abrasives such as sand and dust.

The test chamber dimensions vary. Some rooms are small and designed to test miniature components such as circuit boards and controllers. Medium sized containers allow larger objects or a large number of small products to be used for mass testing. Sometimes, very large candidates, such as vehicles and machines, require temperature and humidity testing. Special test rooms are usually created for these applications.

Each room has physical controls specially designed for temperature and humidity testing. The restrictions depend on simulated environmental stress factors that engineers think a product can withstand. One of the most common temperature and humidity test controls includes the 85/85 test.

85/85 Test

The 85/85 test uses a valid temperature and humidity test threshold for the vast majority of environmental assessments. It includes setting the test chamber conditions to an internal temperature of 85 degrees Celsius and a relative humidity index of 85 percent. This warm, humid environment can be kept for up to 1.000 hours, as specified by many engineering assessment specifications.

Also known as a moist heat test, the 85/85 test tries to simulate 20 years of moisture ingress into a particular product. This number is a valuation parameter called a bias application or Temperature-Humidity-Bias (THB) reliability test. Bias refers to the electrical induction of constant voltage to electro-activate the device or test subject. The THB test can be applied especially to objects exposed to abrasive factors.

Seems like a long time to endure 85/85 a thousand hours. However, it is a very real possibility in the operational world where many production products are expected to be realized. To shorten this long test time, temperature and humidity testers use two accelerated processes:

High Accelerated Life Test (HALT): This testing process applies aggressive temperature and humidity changes. High accelerated life testing also uses multi-axis shock vibrations, which, while remaining true to artificially induced real-time stress factors, greatly reduces test time. HALT tests reveal product weaknesses and strengths much faster than passive room tests. This accelerated method detects defects at the design and prototype stage and allows product engineers to react quickly with positive solutions.

Highly Accelerated Stress Screening (HASS): This temperature and humidity test procedure quickly scans faulty products and parts before shipping. Testers use the HASS stress screening process for pre-designed and proven products that need final quality control control before dispensing from the production center. HASS is a similar test with HALT, but less aggressive.

The thermal cycle is another term often associated with testing temperature and humidity. It involves subjecting the test subjects to a controlled cycle for various periods of hot / cold and wet / dry. The length of exposure and environmental excesses depend entirely on the type of product and its intended use.

The most common final temperature and humidity assessment is the thermal shock test. It involves heating or cooling a product to its maximum range and then quickly reversing the temperature. Thermal shock test is an extreme method. It is usually reserved for products used in the military and aerospace industry, where components and assemblies are exposed to severe climatic conditions.

Temperature and Humidity Test Certificates and Specifications

Every professional temperature and humidity test procedure tries to meet and exceed industry standard certificates and specifications. Many government and non-governmental organizations write test thresholds and benchmarks for thousands of commonly produced products. Unique products are also subject to the rules and parameters set by regulatory and consulting agencies.

They are referred to as MIL-SPEC Defense Specification, MIL-STD Defense Standard and MIL-HDBK Defense Handbook. Each standard, specification, and manual element is thoroughly detailed and is often used for civil production test checks.

Other institutions offer guidance and control standards to the temperature and humidity testing profession. The two common authorities are the American Testing and Materials Association (ASTM) and the Automotive Engineers Association (SAE). For most temperature and humidity tests, these are the main standard documents:

  • MIL-STD 883
  • MIL-STD 810
  • MIL-STD 750
  • MIL-STD 202
  • ASTM B117
  • SAE J1455

Weaknesses Caused by Temperature and Humidity Test

Temperature and humidity testing is the leading method of the manufacturing industry to identify and correct weakness in all product forms. The test reveals weaknesses due to high and low temperature, high and low humidity, thermal cycle and thermal shock. These sophisticated tests reveal product sensitivity and predict product survival.

All temperature and humidity tested products have been tested, analyzed and qualified for life. The result is a recognized certificate that protects the consumer and advances the manufacturer as the industry leader. The following are a few weaknesses that are typically identified by temperature and humidity testing:

Epoxy coatings: Many products designed for harsh environments contain epoxy coatings. The temperature and humidity test exposes epoxy coated products to excessive stress, where weakness occurs due to expansion, contraction, moisture ingress, and surface corrosion or wear.

Fogging: Leak-proof units such as windows and windshields are commonly tested. Any product weakness occurs quickly when hot and cold are emphasized on moist and dry cycles. Moisture steaming between layers is a sure sign of product failure.

Waterproof: Products exposed to wet environments are excellent candidates for testing. Water leaks or inlet weaknesses are easily visible after testing. These faults can occur quickly under testing or take a long evaluation period.

Mechanical failures: Changes in the heat and cold cycles can cause trouble in many products, often resulting in minor or catastrophic mechanical failures. The test is pre-insured against products that fail on site and cause damage or injury.

Products and Objects Suitable for Temperature and Humidity Tests

The list of products suitable for temperature and humidity testing is long. It really depends on the intended working environment of the product. The type of test also depends on the industry that applies it. The following are some common industries that regularly test temperature and humidity:

  • Space
  • Automotive
  • Defense
  • Energy
  • Telecommunication

Each industry has its own products, individual characteristics and test parameters. The list is as diverse as industry and intended application. A few products and objects suitable for temperature and humidity testing:

  • Electric parts
  • Engine groups
  • Batteries and solar panels
  • Medical diagnostic products
  • Drug containers
  • Military ammunition and weapons
  • Adhesives and refills
  • Glass products

EUROLAB offers solutions through a reliable network of easily accessible test laboratories that are fully accredited to provide professional testing services. This network includes test laboratories and certification houses. We work as a reliable team and an extension of our customers' engineers and design departments.

As EUROLAB, we perform the necessary checks and maintenance in a wide range of industries. Our engineers and technical experts are proud to be problem solvers. We are ready to produce fast and accurate results in testing temperature, humidity, corrosion and any possible product failure problems.

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