An investigation of the water vapour resistance - the humidity detection sensor method in Versmaperm MkIV compared to the gravimetric method

This project has been performed at SP, Technical Research Institute of Sweden, in Boras. SP is a research institute where they are not only involved in different research areas, they are also able to provide quality assurance and certifications. Different companies turn to SP for those services and it is therefore important that those tests are reliable but also time efficient. This project will focus on one quality that the subgroup Polymer Technologies provide; the measurement of the permeability on polymeric building materials. Traditionally the permeability of polymeric building materials is measured by the well-established gravimetric method. This method tends to take a very long time, from weeks up to several months depending on the materials and in which humidities those are measured. It is therefore preferable to find alternative methods for those measurements. SP has recently invested in a new machine called Versaperm MkIV WVTR Meter, which measures the permeability using a RH-sensor based method, i.e. by measuring the relative humidity (RH) change. This RH-sensor based method is much faster than the gravimetric method. Those measurements can be done in some hours or in a couple of days, also depending on the sample and the RH. In the end one would like to find a correlation between those two methods. This thesis will include an investigation of the machine itself and Versaperm MkIV WVTR Meter turned out to have some limitations of how permeable materials that can be tested. The range of a material's water vapour resistance needs to be between 2:5 104 5:0 106 s/m to be able to give a result when measuring against a RH of 2% on the dry side. When measuring against a higher RH Versaperm will give a higher water vapour resistance than the gravimetric method which will give almost the same value in all conditions