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Environmental Test Chambers



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Environmental test chambers expose products to one or more environmental conditions (e.g., temperature, humidity) in order to determine reliability. They are used widely in the industry to test myriad products and systems. A notable example is electronic components. By testing your product in an environmental test chamber you can:

  • Reduce Product Development Time
  • Increase Customer Confidence
  • Ensure Product Quality and Reliability
  • Forecast Life Expectancy
  • Reduce Costs
  • Increase Profitability
  • Reduce After Sales Service

Environmental test chambers may subject test samples, components, or products to:

  • Extreme temperature
  • Thermal cycling
  • Humidity
  • Vacuum
  • Microwaves
  • Various forms of radiation (other than temperature)


Under carefully controlled conditions, environmental test chambers may be used to monitor:

  • Acoustic (sound) radiation
  • Thermal radiation
  • Light and spectral radiation
  • Gas emissions: e.g. exhaust internal combustion engines; bacterial/biological growth

Some environmental test chambers are application specific. For example, a chamber designed to measure corrosion may monitor the effects of variables such as:

  • heat
  • humidity
  • salt fog
  • salt spray
  • rain spray

Before investing in an environmental test chamber, determine:

  • How large the chamber needs to be.
  • What exactly will be tested in the chamber. And whether there be more than one product or type of product that needs to be tested.
  • What temperature range(s) is/are needed for test(s).
  • If the environmental test chamber needs to air- or water-cooled.

Chambers for electrodynamic and mechanical vibration testing of machinery are also available. See our article on Shock and Vibration Testing for more information.

List specifications for environmental test chambers may include:

  • temperature range (full-scale value)
  • temperature control accuracy (measured in degrees or as a percentage of a full-scale output or reading)
  • humidity range (full-scale value)
  • humidity control accuracy (percentage)
  • chamber capacity


Environmental Test Chambers: Types and Sizes

  • Reach-In Chambers: from 0.5 f3 to above 70 ft3. Almost all environmental conditions may be created in these chambers: altitude (pressure), solar and UV, temperature, rain and humidity, vibration, etc.

  • Walk-In Chambers (aka Environmental Rooms): size range from just big enough to step into to large enough to park a vehicle in. There are two major types of walk-in chambers:

    • modular: made from preformed panels with urethane foam insulation, much like walk-in freezers found in supermarkets and restaurants. Maximum high temp for modular walk-ins: 100 C - 121 C. Humidity range for modular walk-ins: normally limited to 70 C and 95% RH
    • welded: these walk-ins are like giant reach-in chambers. The internal chamber is welded together to stand up to more extreme humidity and temperature ranges. This type of walk-in environmental chamber may also withstand altitude conditions. Welded walk-in environmental chambers are usually more expensive than modular walk-ins, due to additional labor required for their construction.

  • Thermal-Shock Chambers: are available in various sizes and configurations and can change the exposure temperature (from one extreme to another) in seconds. This rapid transient thermally shocks and stresses a product or system.
Chamber types may also be denoted by lesser-used terminology:

AGREE chambers, Portable Temperature Chambers, Temperature Chambers, Expendable Refrigerant Temperature Chambers, Altitude Chambers, Temperature/Altitude Chambers, Temperature/Humidity/Altitude Chambers, Universal Test Chambers, Temperature/Humidity Chambers, Klearview Temperature Humidity Chambers, Portable Temperature Servos, Environmental Stress Screening, Thermal Shock Chambers, Salt Fog Chambers, Humidity Chambers, Portable Liquid Chillers, Thermal Shrouds, and Space Simulation Chambers.


What is an AGREE environmental chamber?

For years AGREE chambers have been the workhorses of the environmental test chamber industry. AGREE can produce fast temperature changes. These chambers usually have removable floors and integrate with a variety of electrodynamic shakers for vertical and /or horizontal vibration. Temperature and /or humidity environments are also simulated in conjunction with vibration.

Originally created to meet military test standards (specific series of temperature, humidity, and vibration tests conforming with MIL-STD 781 and 883) their flexible design has made them suitable for a wide variety of applications.

Fast temperature changes of 5 to 40°C/m. are possible, even with significant loads. The chambers have a removable floor, allowing integration with vibration test systems. Custom designs are common, allowing configuration to meet your exact requirements. Other features may include:

  • Slide-out floor with Teflon guides and manual clamps
  • Heated door frame prevents gaskets from freezing
  • Special models can interface with both vertical and horizontal vibration systems
  • Hinged service doors
  • Touch-screen programmer which may have Military-Standard tests preprogrammed

AGREE chamber
above: An AGREE test chamber from ESPEC

AGREE from Thermotron
above: An AGREE test chamber from Thermotron


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Updated: Friday, 2007-11-16 17:40 PST