Views: 3 Author: Sanwood Technology Publish Time: 2026-11-05 Origin: Sanwood Technology
85/85 testing exposes a device under test (DUT) to 85°C and 85% relative humidity to evaluate moisture-related reliability. In electronics reliability testing, a temperature and humidity test chamber creates this environment for electronic components, PCB assemblies, connectors and protective materials. Electrical measurements, functional checks and inspection then establish how the specimens respond.
Two tests can use the same 85°C/85% RH settings yet answer different questions. A connector measured while hot and humid may behave differently after cooling and recovery. Likewise, an unpowered assembly and a powered assembly may experience different local moisture conditions because of self-heating.
A useful test plan therefore goes beyond “1000 hours at 85/85.” It identifies the electrical state, measurement stage and acceptance criteria alongside the exposure duration. Whether measurements occur during exposure, after specified recovery, or at both stages is a central decision for interpreting results and selecting the chamber configuration.
The 85/85 designation identifies an environmental condition. The applicable product specification or agreed test method determines how that condition is applied and how the product is evaluated.
Before equipment selection, the test brief should establish:
●Exposure: temperature and humidity limits, stabilization requirements and the reference used to assess them.
●Duration: required hours, the starting rule and treatment of intermediate measurements or interruptions.
●Electrical state: unbiased exposure, specified bias or a defined operating mode.
●Evaluation: baseline measurements, measurement stages, properties to assess and acceptance criteria.
For an equipment enquiry, these requirements belong alongside sample dimensions, quantity and estimated heat dissipation. They give SANWOOD a basis for reviewing the proposed chamber against the actual test, rather than a pair of nominal setpoints.
No. A 1000-hour humidity test is used when required by the adopted specification or test program; the term “85/85” does not prescribe the duration. Different products and investigations can have different exposure periods and readout schedules.
The exposure clock also needs a defined starting point. Reaching the chamber air setpoint does not necessarily mean that the specimens have satisfied the procedure’s stabilization requirement. Preparation, transitions, recovery and final measurements add to the total laboratory schedule.
Intermediate readings can affect that schedule. If a specimen must leave the chamber, its exposure is interrupted and its temperature and moisture state may begin to change. The procedure determines how that interval is treated and how exposure resumes. A planned measurement break and an unexplained interruption should remain distinguishable in the test record.
Unbiased exposure applies no intentional electrical stress bias during conditioning. A voltage used for an insulation-resistance reading is a separate part of the measurement method.
Temperature humidity bias (THB) testing adds specified electrical bias to the temperature and humidity exposure. Voltage, polarity, connection points and the bias schedule become part of the test definition. Moisture and contamination, together with electrical potential, can contribute to corrosion or conductive-path formation under suitable conditions.
Bias, normal operation and functional monitoring are also different activities. Applying voltage to a component does not necessarily reproduce its operating workload. Powering a module does not establish that its outputs are being measured.
Powered specimens introduce another consideration: heat. At the same local water-vapour pressure, a warmer surface experiences a lower relative humidity. The operating state and heat dissipation therefore help explain the specimen’s moisture exposure, as well as the load the chamber must accommodate.
The timing of a measurement determines which condition it describes. For a connector assembly evaluated by insulation resistance, the three arrangements below answer different questions. This is an illustrative planning example, not a reported SANWOOD test result.
Measurement stage | Question the result can answer | Consequence for the test arrangement |
During exposure | Does insulation resistance meet its criterion while the connector is at the specified exposure condition? | The measurement system must obtain a suitable reading while the required environment and electrical state are maintained. |
After specified recovery | Does insulation resistance meet its criterion after the prescribed exposure and recovery sequence? | Transfer, recovery conditions and the measurement window must be controlled as the procedure requires. |
Both stages | How does performance differ between the exposure and recovery stages? | Specimen identities, stage labels and measurement conditions must remain traceable, with results assessed against the relevant criteria. |
An in-exposure reading may reveal reduced insulation resistance that is no longer apparent after recovery. A post-recovery pass cannot establish that the connector maintained acceptable insulation resistance throughout exposure. Conversely, a low in-exposure reading does not automatically establish permanent damage. Temperature, moisture state and the measurement arrangement may all affect the result.
The practical interpretation depends on the pattern:
●A change seen during exposure but absent after recovery may indicate behaviour that depends on the hot, humid condition. It still matters if acceptable performance during exposure is a product requirement.
●A change that remains after recovery warrants comparison with baseline results under the specified measurement conditions. Further analysis may be needed to identify its cause.
●A change associated with the fixture or measurement path may distort the apparent DUT response. The measurement arrangement needs to be suitable for the resistance or leakage levels being assessed.
For recovery-stage readings, a delayed measurement may describe a cooler, drier specimen than intended. Recording exposure end time, recovery conditions and measurement time helps the laboratory identify that difference. For in-exposure readings, matching the DUT timestamp to the environmental history provides the corresponding context.
An 85/85 humidity reliability test can examine several types of change, but the useful checks depend on the product and its requirements.
For a connector, insulation resistance or contact performance may be relevant. For a powered electronic module, the concern may be functional interruptions, leakage or output drift. For a coated assembly, inspection and electrical checks may help assess whether the protective system retains its intended function.
Visible corrosion or discoloration should be related to electrical or functional evidence. Appearance alone may not establish the failure mechanism or whether the product has failed its specified criterion. Suspected internal damage may require additional analysis.
This distinction keeps the report useful: chamber records describe the environmental exposure, DUT measurements establish performance against the criteria, and failure analysis investigates the cause of a change.
For an 85/85 program, the chamber’s role includes maintaining the specified exposure and providing an environmental history that can be reviewed alongside DUT results.
Available SANWOOD temperature and humidity chamber configurations provide fixed-value and programmable operation, running-curve display and test-data export. Fixed-value operation supports a defined hold; programmable operation supports specified sequences within the chamber’s operating capability. Exported environmental records help the laboratory relate exposure conditions to measurement times and investigate interruptions. The applicable functions and recording settings should be agreed for the selected configuration.
These capabilities support the environmental part of the test. Insulation resistance, leakage current and functional performance still require suitable DUT measurements. Environmental data and electrical results become more useful together when their time references and specimen identities are consistent.
SANWOOD , founded in 1995, develops and manufactures environmental and climatic test equipment. Its temperature and humidity test chambers serve applications involving electronic and electrical products, components and materials. For an 85/85 project, the equipment review should connect the required measurement workflow with the chamber’s operating conditions and intended load.
The relevant performance is 85°C and 85% RH together. Separate temperature and humidity range endpoints do not prove suitability at that combined condition.
Sample quantity, spacing, fixtures and heat dissipation influence the loaded arrangement. A powered assembly may need a different performance review from an unpowered specimen of the same size. The proposal should state the loading basis and environmental limits that apply to the intended test.
SANWOOD’s guide to temperature humidity chamber control, operating range and test load explains these equipment principles in more detail.
Long-duration testing requires continuity as well as a suitable operating point. Water supply, routine operating checks, scheduled readings and interruption handling should be compatible with the planned exposure.
Measurements that require door opening or specimen removal deserve particular attention because they can disturb the environment. Where readings must be taken during exposure, the chamber arrangement and external measurement system need to support that workflow. Where readings follow recovery, the transfer and measurement sequence becomes part of the laboratory plan.
Visible water droplets are not a requirement of 85/85 testing. Condensation can form when a surface is colder than the surrounding air’s dew point, including when a cool specimen enters a warm, humid environment.
For a non-condensing procedure, specimen introduction, transitions and interruptions matter as well as the steady hold. Liquid water on a specimen can change the applied stress. A deliberately condensing test therefore needs its own defined method.
A passing result shows that the tested specimens met the specified criteria under the defined exposure and evaluation sequence. It does not provide a universal conversion from test hours to years of service. A service-life estimate needs a suitable acceleration model, supporting data, relevant failure mechanisms and defined use conditions.
A useful 85/85 report makes its scope explicit: exposure duration, electrical state, measurement stage, recovery conditions where applicable, and the criteria used. Those details make the result interpretable and help another laboratory understand the basis of the evaluation.
For a chamber enquiry, send SANWOOD the required exposure and duration, sample dimensions and quantity, electrical operating state, estimated heat dissipation and measurement timing. Include the applicable procedure or a non-confidential summary of the requirements. This gives the equipment discussion a clear starting point before capacity and configuration are selected.
Contact SANWOOD or email info@sanwood.com to discuss your 85/85 temperature and humidity testing requirements.
