Environmental testing

Environmental tests are used to verify a piece of equipment can withstand the rigors of harsh environments, for example:

• extremely high and low temperatures
• large, swift variations in temperature
• blown and settling sand and dust
• salt spray and salt fog
• very high or low humidity
• wet environments
• fungus
• vibrations (airborne and structural)
• accelerations
• solar radiation
• high and low pressures (especially for aeronautical and space equipment)

Carrying out Environmental conditions

Many products are manufactured in different climates to which the product will be used in. For example a mobile phone battery may be manufactured in the UK but may be sold to India therefore will need to survive a much higher temperature than in the UK.

Many industries use testing before their product goes to market

• Electronics
• Telecommunications
• Aerospace
• Automotive
• Defence
• Many others ...

Conditions that can be tested are

• Temperature
• Humidity
• Pressure
• Vibration
• Sand and dust
• Rain

Products that can be tested are

• Automotive components
• Avionics components
• Batteries
• Measuring devices
• Paint
• Missiles
• Weapons
• Electonic components

Humidity

Humidity is the amount of water vapor in the air. Relative humidity is defined as the ratio of the partial pressure of water vapor in a parcel of air to the saturated vapor pressure of water vapor at a prescribed temperature.

Dew point

The dew point is the temperature to which a given parcel of air must be cooled, at constant barometric pressure, for water vapor to condense into water. The condensed water is called dew. The dew point is a saturation point.

The dew point is associated with relative humidity. A high relative humidity indicates that the dew point is closer to the current air temperature. Relative humidity of 100% indicates the dew point is equal to the current temperature and the air is maximally saturated with water. When the dew point remains constant and temperature increases, relative humidity will decrease.

Combined

Combined testing is when two or more conditions are needed to test the product, for example movement and humidity may have to be tested at the same time. Combined testing can then be used.

Accelerated aging

Accelerated aging is testing that uses aggravated conditions of heat, oxygen, sunlight, vibration, etc. to speed up the normal aging processes of items. It is used to help determine the long term effects of expected levels stress within a shorter time, usually in a laboratory by controlled Standard test methods.

Stress screening

Environmental Stress Screening (ESS) is the process of exposing a newly manufactured product to environmental stresses in order to identify and eliminate latent defects introduced during the manufacturing process. It is part of the manufacturing process and is therefore performed on 100% of the items manufactured.

Thermal stress screening

Environmental stress screening (ESS) using thermal cycle testing is primarily intended to accelerate failure of weak or inadequate solder joints. It exposes the product to an environment that causes the "weak" elements of an assembly to fail. This is achieved by exposure to a relatively high rate of repetitive thermal transitions over the operating temperature range of the product. The transitions cause stress to build up in solder joints due to the mismatch of the thermal expansion co-efficients.

The next stage

When you have decided which condition you need to test your product at, you will need to find a suitable environmental chamber that can reach the temperature or humidity ranges that you require.

If you have several products that need testing the best option is to purchase a chamber. At ETS we can supply any range of environmental chamber from -80°C to + 220°C to. Click here to view our range of production brochure.

If you have a one off test then either hiring or using in house testing maybe more economical for your company. We have an extensive range of hire chambers ranging from -80°C to + 220°C with capacities ranging from 1580 liters to 15 litres.

If you decide to purchase a new chamber, the chamber would come with a warranty (warranties varies on different equipment) we can also offer calibration at an additional charge. After the initial warranty period calibration and maintenance would need to be carried out at your expense. Various options are available through service contracts.

If you hire or decide to use in house testing, calibration and maintenance would be included in your hire costs.

If you require any further information please contact Trevor Leake.