Views: 12 Author: Sanwood Technology Publish Time: 2026-10-20 Origin: Sanwood Technology
A temperature humidity test chamber controls the temperature and relative humidity of the air surrounding a test specimen. Heating, cooling, moisture control and air circulation work together to create that environment. The specimen then responds according to its material, arrangement and operating state.
For a SANWOOD temperature humidity test chamber, three connected questions explain what the equipment does: how it controls the air, which temperature–humidity combinations it supports, and what changes when a specimen occupies the working space.
Heating and cooling adjust the air temperature. Humidification adds water vapour, while dehumidification removes moisture. Sensors feed measurements back to the controller, which adjusts the relevant outputs. Circulating air transfers heat and moisture through the working space and around the specimen.
These functions interact because relative humidity depends on temperature. Relative humidity is the ratio of water-vapour pressure to saturation vapour pressure at the same temperature, expressed as a percentage. At the same water-vapour pressure, increasing the temperature lowers RH.
A temperature change therefore affects the humidity condition even before considering moisture released or absorbed by the load. The humidification method, cooling arrangement and sensor locations depend on the chamber configuration; the functional explanation alone does not identify those details for every SANWOOD model.
A chamber's temperature-only range and its RH range describe different aspects of operation. Combining their endpoints does not establish a valid temperature–humidity test point. The chamber must be able to manage both heat and moisture at the required condition.
Use the temperature–humidity operating diagram or combined-condition specification for the proposed model. Locate each required temperature–RH pair, then read the configuration, loading conditions and notes attached to that information. A point outside the documented region is not established by that document. If a boundary is unclear, ask SANWOOD to confirm the point rather than estimating an exact limit from the drawing.
Dew point describes another part of the relationship: condensation can form on a surface colder than the surrounding air's dew point. Whether condensation is intended or acceptable comes from the test procedure, not simply from the chamber's ability to reach a temperature or RH setting.
A specimen and its fixture add thermal mass, occupy space and can redirect airflow. A powered specimen also adds heat during operation. Materials that release or absorb moisture can change the humidity environment.
The SANWOOD interior illustration accompanying this article shows shelving, openings in the rear panel and a circular opening in the side wall. These visible features help explain why the installed arrangement matters: a specimen can fit inside the cabinet while its fixture or cables still obstruct space around it. The illustration does not establish airflow speed, a measured flow path or a permissible loading limit.
When assessing a temperature humidity test chamber, consider the complete specimen, fixture and cable arrangement. Nominal chamber volume tells you the size of the working space, but not the conditions around an installed load. Required clearances and support limits should come from the documentation for the selected configuration.
A setpoint, a chamber indication and a specimen measurement answer different questions. Keeping them separate makes a test record easier to interpret.
Reference | What it represents | What it does not establish on its own |
Temperature setpoint | The temperature requested by the program. | That the air or specimen has reached it. |
Chamber temperature indication | The value reported by the chamber's configured measurement system. | Conditions at every position or the specimen's temperature. |
Independent air probe near the specimen | Air temperature at that probe location, subject to its installation and response. | Temperature inside the specimen or throughout the working space. |
Sensor attached to a specified specimen location | Temperature at that monitored location, subject to the measurement method. | The temperature of every component in the assembly. |
Interpretation guide only; no model-specific performance values or measured results are represented.
Consider an electronic controller assembly held at a specified temperature and RH while operating under power. Its housing or an internal board may remain warmer than the nearby air because the assembly releases heat. A stable chamber indication does not resolve that difference. An air probe near the assembly and a sensor at the required specimen location provide different evidence; the test procedure determines which measurement governs the exposure.
If the specimen temperature differs from the chamber indication, that observation alone does not prove that the chamber is out of tolerance. Check the measurement locations, operating state and stabilization requirements before interpreting the result. This is an illustrative example, not a SANWOOD test result.
Empty-chamber figures also describe their stated setup. They cannot automatically establish loaded performance. Spatial variation across positions and temporal variation at one position are separate quantities, so comparisons must retain the manufacturer's definitions and measurement conditions. EURAMET Calibration Guide No. 20, Version 5.0 discusses loading effects and differences between air, probes and objects in temperature- or humidity-controlled enclosures.
Use the stabilization and timing rule in the adopted test procedure. Reaching the programmed air setpoint is not a universal signal to begin counting exposure time. Where the procedure requires specimen stabilization, use the specified specimen measurement and acceptance criterion. Record the start condition so the reported duration has a clear basis.
Do not infer this from successful holds at the two endpoints. The full temperature–RH path, change rate and load must be covered by the proposed operating specification. Ask SANWOOD to distinguish humidity control during transitions from humidity control at steady holds when reviewing the required program.
New materials may absorb or release water vapour, while a changed layout can alter air circulation. These effects can change the time needed to reach a stable humidity condition. Compare the material, arrangement and operating state with the previous setup, and retain the same measurement reference when comparing records.
Not automatically. A calibration applies to its documented quantities, positions, conditions and uncertainty. A single-point result does not, by itself, characterize other test points, the full working volume or a different loaded setup. Compare the certificate's scope with the intended program and agree any additional characterization needed.
To discuss a SANWOOD configuration, provide the required temperature–RH pairs and the stages in which they apply, together with a specimen-and-fixture layout and the specimen's powered operating modes. State whether the test requirement refers to chamber air, a specified specimen location, or both. Include available heat-dissipation information and identify estimates as estimates.
For a broader purchasing review, see SANWOOD's environmental test chamber selection guide. For this product family, contact SANWOOD with the profile and load information so the relevant operating range, working-space arrangement and measurement basis can be discussed together.
