There are a number of factors that determine the size of the test chamber you need. The first, and arguably most obvious, is the size of the device under testing (DUT)—an overly large or heavy one requires space to accommodate it. Then there’s the characteristics of the material (which absorb heat and moisture differently), live loads (which generate heat, necessitating a larger testing space), and the density of the DUTs.
For the most part, however, most tests require a ratio of at least one-to-three (the volume of the DUTs to the workspace) to allow for adequate airflow.
If you consider all of the above factors, you may find that a benchtop test chamber is the solution for you. In addition to providing flexibility in how you arrange your lab, these models are designed to fit on tables or counters, which leads to maximizing testing space. Especially with rack-and-stack models, you can double your testing with limited floor space.
Here’s what you need to know about benchtops and what to consider before purchasing one.
Benchtop Chamber Capabilities: Temperature and Humidity Testing
The most common uses for benchtop test chambers focus on temperature and humidity testing.
Benchtop Temperature Chambers
From battery testing and temperature cycling to stability and product testing, temperature chambers are expected to reach a wide range of alternating heat levels. While performance levels vary per model, you can expect a temperature range anywhere from -37°C to 180°C (-34.6°F to 356°F).
Benchtops are able to sustain long-term tests at a constant, steady-state temperature and humidity.
To ensure environmental testing remains on schedule, you need to verify your benchtop chamber can achieve the necessary ramp-up and pull-down rates your industry requires. These change rates refer to how quickly your chamber can heat up or cool down.
Benchtop Humidity Chambers
Similarly, humidity testing is vital for determining how DUTs perform in real-world conditions. Benchtop humidity chambers feature vapor generator systems that pump conditioned air into the internal workspace.
Since dew point (the temperature at which wet air condenses when cooling) varies depending on how much water is in the air, chambers rely on relative humidity (RH) for precise testing.
Humidity testing with these chambers has a standard range between 10% RH and 95% RH. High humidity sensors, dry nitrogen purges, dry air purges through desiccant air dryers, and recirculating desiccant air dryers can also be added to extend the humidity range—but at an additional cost.
Components of Benchtop Chambers
Intended to rest on top of desks and tables, benchtop test chambers generally range in size from 1 to 8 cubic feet of internal space—making them ideal for testing smaller components with easy access to the internal workspace.
To accommodate heating tests, these chambers are equipped with open ceramic-core nichrome heaters capable of accurately and reliably controlling temperatures within ±0.5°C.
Furthermore, the cooling system in a benchtop routinely consists of a self-contained, compact, mechanical, single-stage refrigeration system.
While these chambers are designed specifically for use on desks and benches, they can be fitted onto an optional floor stand, should you want to increase mobility or lab testing flexibility. Stacking can also be an effective means of saving valuable lab space, gaining more test workspace, or running independent tests concurrently with relative ease.
Modern models also give you the ability to monitor and operate chambers remotely.
The Super 508 and Battery Testing
If you’re looking for the most powerful benchtop to date, you might consider the Super 508 which combines the benefits of a tabletop with the power of a much larger chamber. Designed by Associated Environmental Systems (AES), the Super 508 boasts a larger-than-usual compressor capable of reaching temperatures between -40°C and 180°C and change rates of 5°C/min.
It packs much more power into a smaller space than a standard temperature and humidity chamber. These high-performance capabilities are what make it a popular chamber for battery testing, with an ATPPRIME model or the addition of an ATPHEAVY battery testing fixture.
Now, it’s helpful to know the features and instrumentation for standard and top-end benchtop test chambers, but what should you ask a manufacturer before purchasing one?
Consider These Factors Before Buying a Benchtop Test Chamber
Given the major investment a purchase like this entails, you probably have many questions for the manufacturer. Here are several things to keep in mind when considering a benchtop test chamber purchase.
Ensure the manufacturer understands your testing requirements. Everything comes down to whether you can confirm your products meet industry standards. If a manufacturer either can’t guarantee that or overlooks important requirements, you’re going to be frustrated (and out a lot of money). Seasoned test chamber experts will try to understand your pain points and offer specific solutions.
For example, they may ask you specifics about your DUTs (size, quantity, and if they give off heat during testing), change-rate needs, standards you’re trying to reach, and ideal size of your chamber to find the solution that’s right for you.
Be certain you have the appropriate power levels. Whether you’re conducting cycling on a tight timeline or steady-state testing, having sufficient power is central. Outline all the test scenarios you’re likely to run and identify the necessary power levels for each. Again, a premier manufacturer will help you throughout the process to make sure you’ve thought through all relevant factors.
Don’t forget about the performance range. Similar to power, be familiar with all likely testing scenarios. Although each test chamber’s standard range may fit within your temperature or humidity requirements, that doesn’t guarantee it’s right for you. These ranges alone don’t fully account for instances where extreme temperatures must be maintained throughout testing.
While feasible for limited spans, most chambers aren’t designed to always operate near the extreme ends of their ranges. Consider adding more power to meet your demands. When in doubt, consult the manufacturer.
You have to have the proper space. Size is an obvious factor, even with a smaller chamber such as a benchtop. Do you have the desk space for it? Does it make more sense to stack a few smaller benchtops or to invest in a larger chamber, such as a walk-in? When considering lab space, think of power sources and how much room you might need to maneuver around the test chamber. In fact, it helps to work with a manufacturer that offers lab design consultation to optimize your space.
Got water? If you’re conducting humidity testing, you’ll need a water source. Examine your lab space to ensure your benchtop can easily hook up to your supply. Hoses can make the final location of your benchtop more flexible, but keep in mind the ways in which additional tubes can disrupt other workflows or create safety hazards. You’ll also need water if you choose a water-cooling option, a space-saving, albeit more expensive, choice.
Chambers are going to need service and maintenance. Chambers can last more than a decade, if well maintained. Much like that car you use almost daily, it’s easy to lose track of its maintenance and repair schedule. Partnering with the right manufacturer can ensure you routinely service your chamber, extending its life and improving the ROI on your new benchtop model.
So while benchtop test chambers have the advantage of size and relatively easy use, you need to consider many factors before making your purchase. Outline all likely testing scenarios to determine whether your new chamber meets testing requirements while adjusting to your specific lab space.
Once you’ve gone through this checklist, be sure to find a test chamber manufacturer that is willing to help you throughout the purchasing process and beyond.
Associated Environmental Systems carries benchtop test chambers, providing onsite service, repairs, and maintenance. Contact us today to receive a quote or learn more about which testing chamber options make the most sense for you.