View A Video on Environmental Test Chambers - A Quick Introduction
Environmental chambers evaluate product quality and reliability, and identify manufacturing flaws and weaknesses in those products before they are released to the general market. Common tests undertaken in environmental test chambers are extremes of temperature and sudden variations of temperature in
temperature chambers and
cryogenic chambers, the effects of humidity and moisture in
humidity test chambers, and
salt spray test chambers which record the degrading effects of salt water on objects for manufacturer analysis. Other types of chambers include:
AGREE chambers,
altitude chambers,
thermal shock chambers and
vacuum test chambers. Causal environmental conditions such as airborne and structural vibrations, shock, dust and sand, electromagnetic and UV radiation are further tests carried out in test chambers to evaluate a product's reaction to the elements. As the nature of the tests which environmental chambers perform is widely varied, the common sizes of the chambers are also as broad.
Test chambers can range from simple, smaller
benchtop test chambers which can be used to test a small component, to a variety of sizes of altitude chambers, to the larger, more complex
walk-in test chambers, and even drive-in chambers for vehicles and aircraft.
The validity of environmental test results is important as it is these results that future product modifications and improvements are based upon. Therefore, design and construction of the environmental test chamber has to be carefully considered. As it is a process test, chambers typically have a means of viewing and monitoring the testing procedure either through a viewing hole, or through a video feed. In some cases, an environmental test chamber will have a reach-in capability in order for the testing engineer to handle the product or material being tested. The method of process control is another consideration to be undertaken as control panels can be either analog or digital, fed by a computer or the web etc. The consistency with which an environmental test is performed is crucial to the reliability of the results, therefore it is wise to refrain from including unnecessary man-made interference with the process to keep it as uniform as possible. Each element of the test and testing conditions has to be taken into consideration - such as already existing environment and climate, the potential addition of interior chamber lighting and thus extra heat, and the variations that already exist between products and materials. Strict control during the process will yield the most accurate and useful results from the tests.
Test chambers are designed with the capacity to replicate not only normal, but also extreme environmental conditions. Temperature chambers can typically reach temperatures above 1000 degrees Fahrenheit, and cryogenic chambers produce temperatures on the other end of the scale achieving lows of -200 degrees Fahrenheit, or even lower with the help of liquid nitrogen. In addition to temperature variations which can be further tested by thermal shock chambers, humidity and air moisture content can be replicated with humidity ranging from 10-100% in most humidity chambers. These are basic tests which are commonly carried out on most products. Altitude chambers simulate extremely high altitudes to test the effects of pressure and air change, and routinely 10-8 Torr levels are achieved in vacuum environmental chambers. Means must be implemented to record the data of the product response to these tests for analysis, verification and future development and adjustment planning. Therefore, there is a two areas of focus within a testing chamber - that of producing the controlled conditions for the testing of the object or product, and the accurate recording of the results of that testing.
Industries which use environmental testing include: automotive, engineering, construction, medical, pharmaceutical, food processing, packaging and consumer. Everyday products such as car parts, cigarettes, make-up, medicines and kitchen appliances undergo testing by manufacturers to ensure their durability and effectiveness in certain environmental conditions. An important reason for the process of environmental testing is that it finds flaws and weaknesses in product design and lifespan before it reaches the public market. These findings allow for production adjustments and result in a better quality product arriving on the market. Once a product is tested and approved in extreme circumstances, there will be lower warranty claim expenses from replacement and repair, and this saves manufacturer expenditure. Without testing products in a variety of environmental conditions, it is a high risk for a manufacturer to sell the products under warranty. Customers are increasingly demanding longer warranties on products and goods, and it is imperative that a manufacturer has tested the product that he or she is guaranteeing to avoid high reimbursement costs. Testing can take many hours and can be a costly procedure depending on the size and process undertaken, and yet it is a wise manufacturing choice to undergo environmental testing, especially in terms of long-term expenditure and future benefit.
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Environmental Test Chambers
and Environmental Test Chamber Manufacturers Image Provided by ESPEC
North America, Inc. |
Environmental Test Chambers
and Environmental Test Chamber Manufacturers Image Provided by Hastest
Solutions |
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Environmental
Test Chambers and Environmental Test Chamber Manufacturers Images
Provided by Russells
Technical Products |
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Environmental
Test Chambers and Environmental Test Chamber Manufacturers Image
Provided by Cincinnati Sub-Zero Products, Inc. |
Environmental Test Chamber Types
- can produce fast temperature
changes of 41-104˜F (5-40°C)
per minute, even with large loads. Vibration test systems can be
integrated within agree chambers,
as they have removable floors.
- test the effects of low
pressure on an object and are capable of replicating low-pressure environments
found at altitudes of
up to 200,000 feet above sea level.
- reduce test time
when testing small items.
- Cryogenic chambers replicate extremely low temperatures from -238 degrees F to absolute zero.
- accommodate large items,
such as vehicles, and are useful when performing batch testing.
- change
the temperature of a product at a highly accelerated rate through high
air velocity conditioning.
- replicate environmental conditions for engineering tests.
- replicate
environmental extremes that an airplane typically endures when in operation.
- are
able to simulate a variety of humidity conditions in order to test
the effects of humidity on an object. Used for specific testing in industrial
and biotechnology applications.
- are
used to expose electronic equipment to a mixture of pollutant gases in
an
environment in which the temperature
and humidity are controlled.
- often contain shelves
and other amenities for easy storage and user convenience.
- test
the corrosion resistance of an object. The object usually hangs from
a rod while the
chamber introduces a salty
residue, which creates a foggy atmosphere, although the object remains
visible throughout the process.
- test
the effects of temperature on an object. Temperature cycling is performed
alone or in conjunction with other tests, such as altitude and vibration
tests.
- involve
the subjection of an object to extreme changes in temperature within
a single chamber
in which the temperature alternates between cold and hot for a given
number of cycles.
- Test Chambers are enclosures designed to provide controlled environments for tests and experiments.
- initiate automatic
changes between two compartments, in which one compartment contains an
extremely cold environment and one
compartment contains an extremely hot environment. The rapid transference
of the object between these two compartments of extreme temperatures
causes a shock to the object.
- are used for thermal
and dynamic testing and have shock and vibration capacity.
- are chambers from which
almost all matter, especially air, has been removed.
- apply
shock vibrations of varying frequencies to an object, including the
bumping, shaking and
bouncing of an object, and
can be administered in conjunction
with temperature and humidity testing. Vibration chambers have sensors
that perceive and monitor the object's
reaction to the vibration.
- vary in size and can usually accommodate one or more persons.
Walk-in chambers are useful when testing large objects and performing batch testing.
Environmental Test Chamber Terms
- The amount of water vapor,
or moisture, in a unit of air.
- The measurement of an object's vibration
in comparison to a fixed point in space.
- The subjection of a product to stress
during the development phase in order to gauge the quality of the product.
The stress applied to the product often exceeds that which the product
would sustain during normal use.
- The subjection of a product to stress
after production in order to identify production flaws before the product
reaches retailers and consumers.
- The process of applying greater stress to
an object than that which the object would sustain during normal use,
the purpose of which is to identify guidelines by which the product may
be used.
- Also called "two-zone thermal
shock," this process is the transferring of a product from a hot
chamber to a cold chamber or other sudden changes of the air temperature.
- The given temperature and humidity content
of an indoor (internal) or outdoor (external) environment.
- The amount of force the atmosphere exerts
upon the earth's surface, measuring 14.7 psi at sea level.
- A test procedure in which multiple items are tested
at the same time.
- The hastening of a product's aging process through
the continuous operation of the product, usually at higher than moderate
temperatures, in order to evaluate product quality.
- The process of comparison between the current operation
of an object or a system and the operating standards of that object or
system. Calibration determines the efficiency of an object and identifies
errors and the manner in which the system can improve.
- The gradual deterioration of a metal caused by oxidation
or chemical reaction.
- The frequency level at which point the destruction
of the object subjected to such frequency begins.
- Decrease in the vibration of an object.
- The temperature of a given unit of saturated (containing
the maximum amount of water vapor) air.
- An environmental chamber in which the humidity level
remains below a 14° F/-10° C dew point.
- The internal and external conditions, regardless
of the source, which affect a given object. The environment includes
temperature, humidity, electricity, precipitation, etc.
- The determination of the working
efficiency of an object or system through the identification of the effects
of thermal changes upon the object or system.
- The rate of movement, measured in cycles, of a wave
within a set time frame, usually one second. Frequency is often measured
in hertz (Hz), which equals one wave cycle per second.
- A test that assesses the
lifetime of a product, reduces its development cycle time and increases
confidence in the life-cycle reliability of the product.
- Product reliability test
in which an object is subjected to high temperature, humidity and pressure.
HAST has also come to be called Autoclave or Pressure Cooker Test (PCT).
- The airtight sealing of an object.
- The subjection of a product to stress comparable
to that which the product will sustain during use in order to determine
product quality.
- Alternately immersing an object
in hot and cold liquids.
- The recovery time of a physical product
after it has been subjected to testing. Product recovery time is dependent
upon the location of the sensor in the load.
- Unit that measures the amount of
pressure applied to an object.
- The ratio of the current amount of water vapor
in a given unit of air at a given temperature to the greatest amount
of water vapor the unit of air could hold at that temperature.
- The measurement of an object's vibration
in comparison to a fixed point on the object.
- The maximum amount of water vapor a given
unit of air can hold at a given temperature. Air becomes saturated when
relative humidity reaches 100%.
- Condition or force applied to an object that may impair
the object's quality and performance.
- Product reliability test
in which an object is subjected to high humidity under a constant temperature.
Test time greatly exceeds that of HAST test time.
- Subjecting an object to extreme changes in temperature
within a single environmental chamber.
- Stress sustained by an object as a result of rapid
temperature changes.
- Moving
the object from a hot to a cold chamber and vice versa, with an intermediate
step of exposure to room
temperature.
- The amount of time it takes for an object to be
moved from one chamber to another.
- Also called "downstream recovery
time," this is the time required for the air temperature to recover
in the new zone. Upstream recovery time can be measured in the air stream
prior to or following the test load.
- Motion of an object around a position of equilibrium.
