Environmental Testing Considerations
Weathering the Process
18 May 2021
Every test has an informational goal and data is needed as an outcome for any number of reasons: conformity, R&D purposes, regulatory requirements, benchmarking, or general knowledge. It is always important to keep in mind the mechanisms you are testing and how you are achieving your testing goals. This is especially true in environmental testing, which can use a mechanism (such as thermal testing) to get multiple data points such as fatigue, stress, functionality, or performance. Knowing the data needed, the exposures to get it are important aspects of building an environmental test plan.
Take thermal testing, for example, which can be conducted using various ovens for steady state conditions, chambers for cyclic conditions or thermal shock chambers for rapid transients. Each method checks different types of information goals to answer different engineering and business decisions. Thermal testing can be combined with electrical or mechanical durability assessments, achieving checks on different information goals. It can be used to evaluate how equipment reacts to temperature, water submersion, salt, fog, corrosion, and harmful atmospheres (such as those with mixed flow gases). Thermal testing is required for a number of standards, each with various guidelines, requirements, and considerations. These can come from ISO, IEC, SAE or be specific to the original equipment manufacturers (OEM) based on their criteria, needs, and engineering or business decisions.
A big factor in thermal testing is what the product, equipment or component does within the environment. How does it function and why? What set points are needed for the item being tested? Remember, just because the test chamber reaches set points does not mean the product within it has also done so. The thermal mass of the item and its subcomponents must be considered when data is gathered, and results are identified.
To successfully conduct thermal testing, you need to note and include the following in your data: sample size; mass and materials; any hazardous materials involved; orientation; operating modes; actual temperatures; time notes such as ramp times, dwell times, and overall testing duration; number of cycles; equipment limitations; and perhaps most importantly, what results will constitute a pass or a failure.
These variations and factors apply to thermal testing and to assessments looking at humidity, climate considerations, aging, stress, and functionality/performance at extremes. Each of these will have multiple options for testing, their own considerations for how the test is conducted and what data is needed and what is being tested, making environmental testing quite complex.
It is important to start the test development process with the end-goal in mind: why are you testing? What information do you need? Is the information needed for an engineering or business decision? To assess a product to specific, set criteria? Are you conducting a failure analysis? Do you need to assess the life span of the product? The reason behind the testing will drive the test plan and data collection and, ultimately, analysis of the results.
From the testing setup and data collection to final results and their analysis, many considerations need to go into environmental testing to ensure its effectiveness. But paying attention to these details can help you to create the testing program, meet standard requirements, illustrate compliance, and, in general, help ensure successful testing and product development. Get more insights on environmental testing programs, including more details on various test types, in our webinar recording.
Global Director of Engineering
Alex Porter is a Global Director of Engineering at Intertek. With more than 20 years of experience in the testing industry, Alex has experience working with standards, materials, robotics and space station components. He has Bachelor's and Master's degrees in engineering from Western Michigan University, and has written several articles and a book on testing methods, particularly accelerated stress testing (AST).