A guide to Temperature and Humidity test types in temperature test chambers

Temperature and humidity environmental testing is a critical component of product reliability verification, particularly essential for evaluating the performance of electronic products, automotive electronics, and communication equipment under extreme conditions.

What is the temperature and humidity test chamber knowledge,What types of temperature and humidity test chambers are there, and what kinds of temperature and humidity tests do they cover? TEMAK is a one-stop solution provider for reliability testing. Our temperature and humidity test chambers cover a temperature range of -70°C to +150°C and relative humidity from 10% to 98% RH.

TEMAK supports full customization with a maximum temperature change rate of 30°C/min. These chambers enable environmental adaptation, screening, and life testing, including high/low-temperature storage/operation, temperature-humidity cycling, temperature-humidity alternation, component aging, and thermal shock testing.Environmental test chamber vs field test，Environmental test chambers can more efficiently expose risks.

Common standards for temperature and humidity testing include:

IEC 60068, GB/T 2423: The most widely applied environmental testing standards, specifying key equipment parameters, test conditions, and severity levels.

ISO 16750-4: Commonly used standard for European vehicles, increasingly referenced in national and corporate standards.

SAE J1211, SAE J1455: Environmental testing standards for automotive electrical components established by the Society of Automotive Engineers.

High-Temperature Test: IEC 60068-2-2

Low-Temperature Test: IEC 60068-2-1

Temperature Cycling Test: IEC 60068-2-14

Thermal Shock Test: IEC 60068-2-14, EIA-364, IPC-TM650

Humidity and Heat Test: IEC 60068-2-30

When conducting various temperature and humidity tests, the temperature and humidity test chamber must comply with all applicable test standards.

Effects of High Temperature on Products  

As temperature rises, molecular motion within materials accelerates. Increased kinetic energy causes expansion, phase transitions, and alterations in physicochemical properties, leading to:  

a) Thermal degradation of insulating materials — thermal aging (increased thermal conductivity);  

b) Deformation, jamming, or bursting (structural damage) — Expansion or dimensional increase of gaseous, liquid, or solid objects at high temperatures;  

c) Changes in electrical properties, poor electrical contact, dielectric breakdown — Increased resistivity and conductivity, surface oxidation at high temperatures, accelerated interdiffusion between materials;  

d) Degradation (wear) or loss (structural damage) of lubricating properties — Chemical reactions causing lubricant degradation, viscosity decreasing with rising temperature;

e) Phase transitions — softening, melting, evaporation, or sublimation of substances at high temperatures;

f) At elevated temperatures, solids lose magnetism upon reaching the Curie point, objects lose polarity in strong electric fields, and superconductivity emerges when the critical temperature is attained;

g) Fading, pyrolysis, or cracking of organic materials;

h) High pressure builds within sealed casings (e.g., shells, bombs) due to thermal expansion of contents;

I) Synthetic materials degrade and release gases at elevated temperatures, compromising vacuum integrity.  

In the Application of Environmental Stress Screening Chamber, it is mentioned that to accelerate the exposure of weaknesses prior to mass production, many products undergo thermal stress screening tests.

Effects of Low Temperatures on Products  

Contrary to high temperatures, as temperatures decrease, the molecular motion of materials slows down, leading to contraction, reduced flowability, and even solidification and hardening. Metallic materials may exhibit “cold brittleness,” while liquid substances undergo ‘condensation’ or “solidification.” External performance characteristics include:  

a) Reduced or lost lubricating properties — increased lubricant viscosity or even “solidification”;

b) Reduced impact resistance and diminished toughness — “cold brittleness” or “embrittlement”;

c) Structural stresses from “shrinkage differential” causing structural damage or ‘seizing’ — object “cold contraction”;

d) Alteration of electronic component properties (e.g., resistance, capacitance);

e) Deterioration of electrical and mechanical characteristics due to water condensation and freezing;

f) Reduced combustion efficiency;

g) Performance changes in transformers and electromechanical components;

h) Increased damper stiffness and altered impact strength;

i) Static fatigue in constrained optical devices. 

The Impact of Temperature Shock on Products

What for thermal shock test chamber? When the ambient temperature undergoes sudden and significant changes, any product composed of multiple components, parts, materials, and structures will exhibit differences in heat capacity among its parts. Consequently, their abilities to absorb, conduct, and dissipate heat also vary. This results in substantial differences in how individual components respond to external temperature fluctuations, as well as variations within the same component. This creates substantial temperature gradients between them, generating significant internal thermal stresses due to thermal expansion and contraction. Consequently, this leads to:

a) Structural components deformed or fractured; bonded parts delaminated;

b) Moving parts jammed or clearance increased; fasteners loosened;

c) Cracks in seals causing leakage or vacuum loss;

d) Cracked welds or detached weld points;

e) Poor contact in relays, potentiometers, buttons, etc.;

f) Accelerated aging of electronic components leading to degraded performance;

g) Cracked surface coatings or failure of insulation material protection.

Thermal shock test chambers are categorized into two-box and three-box configurations, differing in chamber structure and test conditions.The application of two-box thermal shock test chamber in reliability and Application of three-box thermal shock test chamber are also different.

Temperature and humidity test chambers evaluate product performance not only by assessing the impact of temperature variations but also by examining the effects of humidity.

Humidity influences both the external physical characteristics and chemical properties of products. Humidity and temperature are always present as mutually coupled environmental factors. The combined action of heat and humidity can cause:

a) Accelerates oxidation and electrolytic corrosion on metal surfaces;

b) Accelerates electrochemical reactions in organic surface coatings, compromising their protective function;

c) Material expansion due to adsorption, leading to structural damage;

d) Deterioration of electrical insulation properties caused by physical phenomena such as moisture absorption and adsorption;

e) Electrical short circuits, degraded thermal transfer characteristics, and impaired imaging and transmission quality of optical components due to condensation and free water vapor.