You’ve likely encountered the terms environmental chamber, climatic chamber, and test chamber. But what is the difference between each of these, and which is most appropriate for your testing needs?
In reality, these terms are interchangeable, with no meaningful difference. Although environmental chamber is likely the most common term used, the most important distinction involves identifying which type of environmental testing is best suited for your organization’s needs.
So let’s take a brief look at the three most common types of environmental chambers.
Common Environmental Chambers
Environmental chambers are required to address a wide range of requirements, pushing devices under testing (DUTs) to their physical limits and imitating all real-world conditions they’re likely to encounter.
Temperature, humidity, salt spray, and thermal shock are common environmental test chambers utilized today.
Temperature And Thermal Chambers
Also known as thermal chambers and designed to give engineers precise control necessary for temperature cycling or steady-state testing, temperature chambers are used to test medical devices, pharmaceuticals, electronics, batteries (with adjustable fixtures for different cell types), military and defense, communications, shipping, and more.
Temperature chambers rely on sophisticated heating systems to ensure testing conditions are reliable and in line with industry standards. Performance chambers typically feature a range of -70°C to 180°C (-94°F to 356°F), while those designed for stability testing operate best between -20°C and 94°C (-4°F to 201°F). They come in a range of volumes, from benchtop models less than 1 cubic foot to walk-in chambers.
The chambers’ airflow design enables fast-reacting heaters to retain fierce control of the temperatures within the chamber to achieve a precision of ±0.5°C.
Temperature chambers also feature air-cooling or water-cooling systems.
While air cooling is less expensive, its pull-down rate is typically slower than the water-cooling option. Alternatively, water-cooling setups are more efficient but entail a more complex installation and require a permanent water source. You can further enhance cooling efforts by integrating liquid nitrogen (LN2) or carbon dioxide (CO2) into your system. These facilitate even more rapid pull-down rates.
Regarding safety features, temperature chambers have an adjustable high/low control feature that prevents temperatures from rising above or falling below a certain limit during testing. Additionally, these test chambers benefit from an internal high-temperature safety feature and refrigeration system with an over-pressure safety circuit.
All of these components combine to create an environmental testing system that identifies the durability and safety of leading technologies.
Humidity Chambers
Many standards require humidity components in addition to temperature. Humidity chambers, similar to temperature or thermal chambers, range in size (from benchtop to walk-in models) and performance.
They rely on a vapor generator system to create humidity conditions within a workspace, with exacting control.
These vapor systems consist of a closed stainless steel or copper tube. Another component then heats water that becomes vapor or steam and passes through the tube, combining with conditioned air in a plenum before traveling into the internal workspace.
A standard humidity chamber will accommodate testing conditions between 20% and 95% relative humidity (RH), the amount of humidity achievable at a given temperature. For example, RH at 5 degrees Celsius varies dramatically from RH at 32 degrees Celsius. For those needing more extreme RH levels, up to 98% RH can be achieved using a high humidity sensor, while as low as 5% RH with a desiccant air dryer.
Salt Spray, Salt Fog, or Corrosion Chambers
Many of the same industries that benefit from temperature and humidity testing take advantage of salt spray test chambers (also known as salt fog or corrosion chambers), as well.
Designed to imitate the effects of corrosion, salt spray chambers help engineers establish user expectations for the lifecycle of DUTs, the durability of materials, and reveal potential failure points.
The most advanced salt spray chambers employed today consist of a transparent workspace contained by premium Lucite ® ️plexiglass. This enables engineers to view testing from 360-degree angles, unobstructed.
In the form of a fog or mist, spray mechanisms atomize conditioned water and a salt solution, which is then injected into the workspace, typically at a steady ambient temperature near 35°C (95°F).
Salt spray tests are utilized in testing a variety of elements that DUTs are likely to encounter during their lifetime use, including:
- Organic coatings
- Paint coatings
- Zinc and zinc-alloy plating
- Coatings not applied electrolytically, such as zinc flake coatings
- Phosphated surfaces with subsequent paint, primer, lacquer, or rust preventive
- Electroplated chromium, nickel, copper, and tin
- And more
Thermal Shock Chambers
Thermal shock chambers enable users to conduct thermal shock testing by rapidly moving DUTs between extreme temperatures. They feature at least two zones with a pneumatic basket that transfers the DUT between them. Some thermal shock chambers feature a third, ambient zone to accommodate standards that require DUTs to cool to room temperature.
This list is far from exhaustive. Additional environmental chambers include AGREE chambers (which accommodate vibration tables) and those that add conditions such as sand and wind to the workspace.
So whether you call them environmental chambers, climatic chambers, or test chambers, one thing doesn’t change: accuracy and performance are paramount. An experienced manufacturer will get you the chamber you need and the support and service to keep it running for years to come.
