Quick Answer: The Permeability Cup is a stainless steel cup used to measure how fast water vapour passes through a film such as paint, varnish, plastic or cellophane. A sample film is sealed over the opening and the cup is weighed over time.
Last updated: October 2026
Key Features
Made entirely of stainless steel
Holds a desiccant or a liquid, often water
Sample film is sealed across the cup opening
Weight change over a set period gives the vapour transmission rate
For films such as paints, varnishes, plastics, cellophane and protective coatings
About This Product
The cup is used to work out the water vapour transmission rate and permeance of a film. Comparing films lets students see how different binders, pigments or polymer structures change a coating’s resistance to moisture, which is useful in materials, coatings and packaging practicals. Laboratories and colleges in Mozambique, Dominican Republic, Sudan, Uruguay and Suriname can buy the Permeability Cup through an export order.
Frequently Asked Questions
How does the Permeability Cup measure permeability?
The cup holds a desiccant or liquid with the sample film sealed across its opening. The change in the cup’s weight over a set time gives the rate of vapour transmission, which is related to the film thickness to find permeability.
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