What is an environmental test chamber?
The purpose of an environmental testing chamber is to examine the effects of a variety of climactic, physical, and other unique conditions on a product. They are designed to create environments that a product may encounter during its use. Researchers rely on them to provide controlled conditions that can be manipulated, such as humidity, temperature variances, and high or low pressure, to test and examine the features of a product.
Environmental testing ensures companies of the quality of their products. Samples are subjected to various tests to measure their reliability and performance. Results can determine if a product has the potential of corroding and rusting or if it produces some form of emissions.
How does an environmental test chamber work?
To create a range of conditions, test chambers use heaters and refrigerator systems to increase or decrease temperatures. Humidity is created by steam generators to either add or remove moisture. Air dryers can add to humidity ranges to significantly lower the humidity range. Salt water environments are created with a salt spray solution that is forced into the chamber from a compressed air tank.
There are multiple types of temperature testing with a different chamber for each type. Steady testing chambers maintain the same conditions over a long period of time. They have precise temperature control to ensure accuracy of the final readings.
Thermal cycling chambers cycle through preset temperatures to test an item at a number of different temperatures. The cycling process eliminates the need for an operator to adjust and change temperatures as well as prevents any uncertainty in the test results. Since the rate of change is crucial, thermal cycling chambers give researchers the ability to design temperature gradients.
A key feature for environmental test chambers is the range of temperatures it can create. Most chambers have temperatures that range from -80o C or -112o F to +300o C or +672o F. Precision and accuracy in temperature settings is important and has to closely approximate the desired testing temperature.
Applications of environmental testing chambers
Environmental test chambers test products for a variety of industries including the auto, electronics, medical, construction, cosmetics, and many others. They are essential to the food, cosmetics, and pharmaceutical industry since those industries are required to abide by FDA regulations.
In microbiology and biology, chambers enable researchers to monitor the effects of humidity, light, heat, and other conditions on plants, insects, bacteria, and other microorganisms. Cells, tissues, organs, and plant growth can be closely examined for climatic influences.
Aerospace uses chambers to test products in a thermal vacuum and create conditions to approximate outer space. This allows producers and scientists to know whether instruments can withstand the absence of an environment and extreme pressure. A critical part of aerospace testing is astronaut support systems such as oxygen supply. Cryogenic equipment can test the effects of extreme low pressure and great heights.
The auto industry tests the effects of hot roads and extreme exposure to the sun. They use driven chambers to create real world conditions of humidity, wind speed, and temperature to check cars under normal and extreme conditions.
A key factor for food products is their shelf life. Test chambers are able to accelerate shelf life conditions by simulating degradation rates and stability changes that are typical in storage conditions. Chemical, microbiological, and physical changes are measured at time intervals until the product degrades. Test chambers can identify food safety and storage conditions to eliminate problems in product development and the viability of packaging.
Types of Environmental Testing Chambers
There is a wide range of testing chambers that are designed to create the requirements of specific environments. The most common types of test chambers are humidity and temperature, which can be separate or combined. Some of the other types of chambers are agree, altitude, climate, cryogenic, Halt and Hass, pressure, remote, spray, vacuum, and stability to name a few.
Below are types of environmental testing chambers:
Agree chambers combine temperature and humidity testing with vibration testing. They create rapid temperature changes with varying humidity. The vibration test measures a products reaction when being shipped or moved to determine if a product can endure being transported.
The aircraft industry uses altitude chambers to train pilots and give them the experience of oxygen deprivation or hypoxia. The chambers help improve training sessions since protective attire is not required and removes the need to take trainees to high altitudes, which saves money on training. Altitude chambers, hypobaric chambers, can create pressure and gas conditions at different altitudes to determine adjustments and changes to a product’s design.
Climate chambers create different climatic conditions to see the effects on products. They can prepare a product for further testing or do the test. Climate chambers create conditions such as thermal shock, extreme temperatures, altitude, humidity, radiation, corrosion, and many others. They can be small enough to set on a counter or large enough to walk in and use video feeds to observe the test sample during the testing process.
As the name cryogenic implies, cryogenic chambers create conditions with extremely low temperatures. Using liquid nitrogen or helium, a normal cryogenic chamber can reach temperatures as low as -238o F or -150o C. Use of a cryogenic chamber is time consuming and costly since the temperature has to be lowered very slowly to avoid products experiencing thermal shock.
Dry rooms, sometimes called dehumidification dry rooms or are a type of environmental test chamber. Inside dry rooms, humidity levels do not rise above a dew point of 14? (-10?), or humidity levels down to less than 1% relative humidity. They are insulated, hermetically sealed and do not allow for any leaks. Because they are hermetically sealed, they consistently maintain not only a low humidity but also good particle filtration. Dry rooms are most commonly used in: the fabrication of medical devices, lithium battery manufacturing, automotive hybrid manufacturing and pharmaceutical manufacturing and packaging.
Environmental chambers, also frequently called environmental test chambers and sometimes called climatic or climate chambers, are test chambers that assess product quality and reliability. In order to do so, chambers replicate certain environmental conditions within an enclosed space, where they monitor and evaluate the long term impact of these conditions on the product inside. Common environmental conditions that chambers simulate include normal and extreme pressures, altitudes, temperatures and humidities. By subjecting products and equipment to extreme environmental conditions and changes, manufacturers are able to catch and correct weaknesses and flaws before they are sent on to their chosen markets.
Environmental testing is the measurement of the performance of equipment under specified environmental conditions. The chambers simulate a full range of temperature testing and humidity testing conditions. Some chambers even account for corrosion through the introduction of salt spray into the chamber. Environmental testing chambers include salt spray test chamber, high and low-temperature test chamber, constant temperature and humidity test chamber, ultraviolet aging test chamber, xenon lamp aging test chamber, ozone aging test chamber and ovens. The main function of an environmental test chamber is to see how products handle operating in various environments.
HALT and HASS Testing Chambers
HALT and HASS testing is performed to determine design weaknesses, improve product reliability, and reduce life cycle costs. The names of the testings are anagrams for Highly Accelerated Life Testing (HALT) and Highly Accelerated Stress Screening (HASS). During a HALT test, a product is stressed beyond its design parameters to identify weaknesses and flaws during the design phase. It is normally repeated several times and the product is exposed to a wide assortment of environments. HASS testing is done during the production phase to determine flaws in manufacturing methods using the same stress tests that are used during HALT testing.
Humidity chambers create humid conditions to determine a products possible corrosion, warping, biological growths, and cracking potential. The data gained from the tests allows designers to develop reliable and cost effective solutions. A wide range of humid conditions can be created from 10% to 100%.
Pressure chambers test products under varying forms of extreme pressure and are able to withstand high and low pressure conditions. The operation of the chamber has to be monitored carefully to avoid explosions and malfunctions. They can simulate static and changing pressures at high altitudes and pressure at various ocean depths. Atmospheric pressures in the chamber can reach as high as 60,000 psi or be reduced to create a vacuum.
Since test chambers are a long way from a used car, they require a meticulously detailed process to make them sufficiently capable of performing their functions. When a chamber is refurbished, it is cleansed of any chemicals, liquids, and hardware, actions that are designed to guarantee safe transport and provide a first assessment for the refurbishing team. The data collected is helpful in determining the viability of the used chamber. A refurbished test chamber is much less than a new one and provides the same type of data.
Remote conditioners are designed to reach large products or ones that are hard to reach. They have flexible temperature settings for use in secluded locations. As with many chambers, remote conditioners can create temperature variations and humid conditions as well as cost effective testing solutions.
Salt spray Chambers
Salt spray chambers, known as salt fog testing, test the corrosion resistance of the sample. A test item is placed in the test chamber and subjected to highly corrosive solutions applied by a pressure nozzle. The purpose of the testing is to provide data regarding the durability of a surface or a product’s coating. The longer a product lasts without corroding, the more durable it is. Regardless of the severity of salt spray testing, the results of testing cannot be used to predict a product's reaction to an actual environment.
Stability chambers provide a stable, controlled environment where all variables are held constant as others are modified to test specific effects. They are primarily used to test temperature and humidity ranges but can do shelf life testing.
Temperature chambers are the most common type of environmental testing chamber. They create various temperatures to simulate the types of temperatures a product will encounter as well as gauge and evaluate the product’s reaction to different temperatures. A temperature chamber may also be used for storage for products that require a stable environment.
Test Chamber Repair
A testing chamber, regardless of its size, is a very precise and delicate piece of equipment that needs to be maintained and repaired in order to provide accurate and complete data. A purchase agreement for most testing chambers includes a schedule for regular maintenance and upkeep. During each cycle, a trained technician does a full assessment of the chamber as well as an evaluation of its components and readings. These timed repairs enable the technician to assess the need for upgrades or replacement of components.
The term “test chamber” refers to any type of contained space within which different products are placed and tested for their responses to and the long-term effects of any number of changes. Generally, test chambers replicate environmental conditions that a product will likely encounter at some point while working in its intended setting. In this way, they allow a manufacturer to evaluate the product’s durability and general quality, and to recognize and correct potential malfunctions and flaws before the product reaches the consumer market. In addition, through the use of test chambers, manufacturers can gauge and increase the lifespan of their products. Test chambers are popular in a number of industries, including, but not limited to: aerospace, automotives, consumer products, electronics, packaging, pharmaceuticals and telecommunications.
Thermal shock Chambers
Thermal chambers are a form of temperature chamber. Their purpose is to simulate conditions that have sudden or drastic changes in temperature and measure the amount of stress and strain such conditions produce on a product. Liquid or air are used to create temperature variances. Test items can be immersed in non-toxic, noncombustible, and low viscosity liquids or placed between compartments to produce temperature variations. The three zone method returns the item to room temperature between testings. The type of method depends on the product.
Vacuum chambers remove air and pressure from a sealed compartment to evaluate the effects of a vacuum on materials. The testing of products in a vacuum is a requirement of regulations related to aerospace and defense industries. Spacecraft engineers use vacuum testing for the electronics, circuits, lenses, filters, and structural materials of a spacecraft. Vacuum chambers are also used to remove air bubbles from plastic resin that is about to be inserted into a mold.
Walk in Chambers
Walk in test chambers are designed for the testing and storing of large products. They are large enough for a person to walk inside and vary significantly in size with some being the size of a small closet while others can be as big as a room. Walk in chambers can perform any of the functions of other environmental testing chambers from thermal shock and salt spray to humidity and temperature testing.
Welded chambers are welded together to provide a better seal and be able to withstand higher humidity and temperature ranges and high altitude conditions. They are more expensive than typical chambers because of the extra construction.
Reach in Chambers
Reach in chambers are a common form of remote conditioners. They are portable and can simulate any form of environmental conditions.
Components of an environmental test chamber
The first consideration when choosing an environmental testing chamber is selecting one that will last, which can be ensured by having an understanding of the chamber's internal components. Since different types of chambers perform different functions, there can be a variation in the types of features and structure. Regardless of these differences, all test chambers must have certain basic components to meet regulatory requirements.
Internal walls need to be seam welded to reduce any chance of leaks. Riveted walls do not completely seal and will leak heat and humidity.
The door should have some form of gasket. The best and most common form is silicone based since silicone can withstand changes in humidity and temperature, which is important when carbon dioxide and nitrogen are used.
The outer body of the chamber should be welded using cold rolled heavy gauge steel since steel maintains its shape and is durable. To increase the chambers longevity and endurance, a powder coated finish should be applied, which will protect against rust and corrosion.
The chambers’ intended applications affect the type of heaters, coolers, condensers, evaporators, controllers, sensors and other modules used depending on the kinds of environments to be produced. Heaters, compressors, refrigeration units, dryers, and other equipment have to comply with the regulations established by the International Standards Organization (ISO) as well as national regulatory agencies.
The inner and outer walls of the chamber vary according to the application but have to be insulated. The insulation material should have a very low K factor of fiberglass or mineral wool and be fire retardant, non-corrosive, and meet health and safety standards.
Sensors and monitors:
Older testing chambers have a simple on and off switch. All recent models have digital monitoring sensors and data recording equipment. Digital controllers allow for manually creating set points and making adjustments, which correct errors and disruptions. Sensors should be resistance temperature detectors or 100 ohm platinum ones for the most accuracy.
The computer interface allows for a Mbyte data transfer rate. Circular chart recording offers real time data collection and documents regarding the testing process and is connected directly to the controller.
Each testing chamber should have a set of safety features that include high temperature failsafe control, mechanical heat fuse, high temp limiter, a noise reduction system, and an alternate power source.
Benefits of an environmental testing chamber:
Environmental testing chambers have become commonplace in modern manufacturing. They provide producers with data to ensure that the products they put on the market meet the needs of consumers. In space exploration, environmental pollution, and air travel, testing chambers provide valuable data for the protection of people and the environment. Listed below are some of their other benefits.
Ensures that a product will perform in a normal environment. It is specification driven and can be completed in the R and D phase of product design to produce a robust product.
Testing guarantees that the product meets the requirements, specifications, and regulations for which it is intended.
ESS (Environmental Stress Screening)
Defects and errors in a product are discovered early in the design phase to prevent disastrous product failure.
Product life cycle testing
The product is placed in real world conditions to predict its life span.
A product may be produced to match the conditions of the manufacturing environment but not meet climactic conditions outside those conditions. The convenience of testing chambers makes it possible to create all varieties of environments of any location in the world.
The modern consumer demands that products have endurance and last. To prevent product failures and recall, testing chambers can put a product through the most extreme conditions to guarantee it will last.
The worst possible situation for any producer can be finding out that their product is unsafe and dangerous. Such occurrences can be a public relations nightmare. By using a testing chamber prior to production, violations of safety standards can be caught at the early stages of product development and prevented.