Water Vapor Barrier Property Test Method of Foam Glass

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As a new kind of inorganic heat insulating material, foam glass is featured with a structure of numerous pores. It is mainly made of glass added with adequate foaming agents after heating and baking in high-temperature tunnel furnace, then annealing and cooling. Because it well reserves the chemical stability of inorganic glass, it has the following features: low density, low thermal conductivity, vapor impermeability, no water absorption, incombustibility, protection from rat eating, high mechanical strength but easy to cut and able to bear all kinds of chemical erosions except the hydrofluoric acid.

With the outstanding features mentioned above, the foam glass is widely used for inside and outside wall heat-preservation material. If the moisture barrier property of the foam glass is inadequate, the water vapor may reach the inside wall through the foam glass and then damage the internal structure of the wall and the heating insulation function of the foam glass will be compromised. Therefore it is necessary for the foam glass manufacturers to control the water vapor permeability of their products by testing the water vapor transmission rate.

Figure 1. Foam Glass

There are mainly two categories of test methods for water vapor transmission rate i.e. gravimetric method (also known as cup method and divided into dry cup method and wet cup method) and sensor method (including electrolytic sensor method, infrared sensor method and humidity sensor method).

The testing instrument used in the tests mentioned in this article, Labthink W3/030 Water Vapor Transmission Rate Tester adopts gravimetric method, which is widely used in WVTR test of pharmaceutical packaging materials.

The foam glass specimens can be tested in the following way.

(1)  Cut 3 pieces, 75mm by 75mm specimen with sample cutter

(2)  Seal the specimen in the test dish with sealing wax. Place the test dish inside the test chamber. Close the door of the testing instrument.

(3)  Input test parameters including specimen name, thickness, test temperature, and test humidity, etc.

(4)  Turn on the gas supply and start test.

(5)  The test results will be displayed automatically after test.

The manufacturer or user of foam glass can determine whether the specimen materials can meet the requirements for use according to the test results obtained in water vapor transmission rate tests.

For more details about W3/030 Water Vapor Transmission Rate Tester, please visit www.labthink.com

About Labthink Instruments Co., Ltd:

Labthink Instruments Co., Ltd is one leading supplier of packaging testing instruments, which is headquartered in Jinan, China and operated in Boston, U.S.A.