An environmental test chamber, also known as EGCG, is a type of testing instrumentation used to evaluate different environmental conditions. It is generally used by contractors to evaluate the physical properties of materials and/or infrastructure before construction is started. The equipment is designed to simulate the effects of adverse conditions that could be encountered on site. The conditions that can be tested include: heat, moisture, wind, electromagnetic radiation, vibrations, salt spray, sun exposure/UV decay, and chemical precipitation.

A typical environmental test chamber has four major components: a chamber for forming the test samples, a collector for collecting the test specimens after they have been formed, a control for operating the machinery during the evaluation process, and a readout device for reporting results. Prior to testing, the material to be tested is placed inside the chamber and sealed to prevent contamination. Before the material is placed inside, it is thoroughly cleaned with water to remove particles and dust. A special solution containing calcium thioglycolate is also sometimes used to remove organic contaminants and to improve the electrostatic charge of the sample.

Most environmental test chambers are designed to accommodate varying temperatures. The test specimens are placed inside the chamber at different temperatures to evaluate their suitability for various types of conditions. Some of these conditions include accelerated deformation, extreme cold, direct sunlight, and high humidity. Most of the chambers available for aerospace applications are temperature-controlled. To achieve this, most environmental test chambers are electronically controlled.

In most cases, the temperature of the environmental test chamber will be controlled using a thermograph device. This device will measure the temperature level and range over the entire testing chamber. It will allow the contractor to easily determine the compatibility of different materials with each other. For example, aerospace manufacturers often require that their samples match exact specifications because some metals will form stiffer at specific temperatures. By using a steady test chamber, the manufacturer can more precisely control the metal's temperature range so that it is as close to the specification required.

High humidity is another major concern in many industries. High humidity has many negative effects on materials and the working environment. To help ensure superior performance, high temperature chambers come with humidity control features. This feature will ensure that the environmental test chamber maintains the right humidity level for the specific material being tested.

Some Environmental Test Chamber offer multiple pass rates for different types of tests. These pass rates allow different testing procedures to be carried out on the same type of material repeatedly. These chambers also come in various sizes. They are mainly used for medium to large-scale projects. The majority of walk-in chambers have a fixed pass rate of one percent.