IEC 60068-2-78: Guide to the 85/85 Steady-State Damp Heat Test

IEC 60068-2-78 , known as the CAB (Damp Heat, Steady State) Test , is commonly known as the 85/85 Test : the sample is held at 85°C and 85% relative humidity for hundreds or thousands of hours. This test is one of the most requested in the semiconductor, automotive, and photovoltaic industries to verify long-term resistance to electrochemical corrosion and humidity-induced degradation.

What is the 85/85 test and why is it so important?

Prolonged exposure to high temperatures and humidity activates degradation mechanisms that don't manifest under normal operating conditions but, over time, can cause failure in the field. The 85/85 test is designed to accelerate these processes and verify that the component has a sufficient service life.

Failure mechanisms that the 85/85 test highlights:

• Electrochemical migration: metal ions (silver, copper, tin) migrate between conductive tracks under the influence of the electric field and humidity, creating dendrites that cause short circuits
• Corrosion of bonding pads and wires: Moisture combined with residual process contaminants attacks the connections
• Insulation degradation: Moisture absorption reduces the insulation resistance between PCB traces and layers.
• Delamination of encapsulants: The interface between mold compound and lead frame degrades, allowing further moisture ingress

Standard test conditions

Note on THB (Temperature-Humidity-Bias): When the sample is subjected to a voltage during the 85/85 test, the test becomes a THB test. The applied voltage accelerates ion migration and electrochemical corrosion, making it significantly more severe. THB is required by JEDEC JESD22-A101 and AEC-Q100/Q200.

Who requests the 85/85 test

• JEDEC (semiconductors): The JESD22-A101 (THB) test is one of the cornerstones of component qualification. It is required for all integrated circuits and passive components.
• AEC-Q100/Q200 (automotive): Automotive qualification requires 85/85 bias testing for 1000 hours at all operating temperatures
• IEC 61215 (photovoltaic): Solar modules must survive 1000 hours at 85°C/85% RH for certification
• IPC (PCBs and Assemblies): The IPC-TM-650 standard includes the 85/85 test for surface insulation resistance (SIR) evaluation.
• Lithium-ion batteries: IEC 62660-2 requires a damp heat test to verify the integrity of the cells

FDM cameras for the 85/85 test

The 85/85 test requires a climate chamber with exceptional long-term temperature and humidity stability. Even minimal variations during the 1,000-hour test can invalidate the results.

• C-PRO: range -25°C / +70°C, humidity 10-98% RH. Temperature stability ±0.5°C and humidity ±2% RH. Ideal for standard 85/85 tests.
• Environmental Chambers: Extended range -70°C to +180°C with optional humidity. For laboratories that also require thermal cycling and extreme temperature testing.

FDM chambers are designed for continuous 24/7 operation with an automatic water supply system, essential for 1,000+ hour tests. The controller records temperature and humidity at regular intervals, generating a comprehensive test report.

Learn more: Discover our hot and humid (85/85) battery test chamber, designed and manufactured by FDM Environment Makers.

Frequently Asked Questions about the 85/85 test

What is the difference between 85/85, THB and HAST?

The 85/85 test (IEC 60068-2-78) is the basic version: 85°C, 85% RH, without bias. The THB (JEDEC JESD22-A101) adds applied voltage. TheHAST (Highly Accelerated Stress Test) uses even higher temperatures and humidity (110-130°C, 85% RH) under pressure, reducing the duration to 96-264 hours. The HAST requires a special pressure chamber, not a standard climate chamber.

1000 hours of continuous testing: can the camera hold up?

FDM chambers are designed for continuous operation. The humidification system has an automatic water supply, the compressor is sized for a 100% duty cycle, and the controller constantly monitors parameters with alarms in the event of deviations.

Can I use the same chamber for the 85/85 test and for thermal cycling?

Yes. The C-PRO and C-BCXPRO series FDM climatic chambers cover both the 85/85 steady-state test and the IEC 60068-2-30 damp-heat cycles, allowing both tests to be performed with a single chamber.

Reference Standards

• IEC 60068-2-78 — Environmental testing – Part 2-78: Tests – Test Cab: Damp heat, steady state. European reference standard for steady-state damp heat testing, typically 40°C / 93% RH for 4, 10, 21, or 56 days.
• IEC 60068-2-30 — Test Db: Damp heat, cyclic (12 h + 12 h cycle). Cyclic variant used in addition to Test 2-78 to simulate daily humidity excursions.
• IEC 60068-2-66 — Test Cx: Damp heat, steady state (HAST). Accelerated version at 110-130°C and 2 bar pressure to reduce test times.
• JEDEC JESD22-A101D — Steady State Temperature-Humidity Bias Life Test (85 C / 85% RH). JEDEC standard for the classic 85/85 profile with semiconductor bias.
• JEDEC JESD22-A110E — Highly Accelerated Temperature and Humidity Stress Test (HAST). Accelerated profile at 130 C / 85% RH / 96 h with bias.
• IPC J-STD-020E — Moisture/Reflow Sensitivity Classification for Nonhermetic Surface Mount Devices. Defines MSL levels 1-6 based on soak 85 C / 85% RH.
• ISO 16750-4 — Road vehicles – Climatic loads. Recalls the hot-humidity profiles for automotive component qualification (classes H1.1, H2.1).

Authoritative Sources

• IEC – International Electrotechnical Commission. Publishes the IEC 60068 series and maintains updates to Method 2-78 on steady-state damp heat.
• JEDEC Solid State Technology Association. Issues the JESD22 standards for 85/85 and HAST reliability testing of semiconductors.
• ACCREDIA. Accredits laboratories to perform climatic tests with chamber mapping according to IEC 60068-3-5 (uncertainty
• ILAC. Ensures the international mutual recognition of test reports issued by ISO/IEC 17025-accredited laboratories.