ASTM International

Standard Test Method for Exposure of Membrane Switches to Temperature and Relative Humidity
 N F1596

Annotation

This test method covers a procedure for temperature and humidity cycling of membrane switches.

This test method is performed to evaluate the properties of materials used in the construction of membrane switch assemblies as they are influenced by the absorption and diffusion of moisture and moisture vapor. This is an accelerated environmental test, accomplished by the continuous exposure of the test specimen to high relative humidity at an elevated temperature. Absorption of moisture by many materials results in swelling, which destroys their functional utility, causes loss of physical strength, and changes in other mechanical properties. Insulating materials which absorb moisture may suffer degradation of their electrical properties.

Physical changes:

Differential contraction or expansion rates or induced strain of dissimilar materials.

Cracking of surface coatings.

Leaking of sealed compartments.

Deformation or fracture of components.

Chemical changes:

Separation of constituents.

Failure of chemical agent protection.

Electrical changes:

Changes in electronic and electrical components.

Electronic or mechanical failures due to rapid water of condensate formation.