Measuring Water Permeation Through EPDM Rubber Hoses

Knowledge of the rates of water permeation through rubber hoses as a function of internal pressure, ambient temperature and relative humidity is important for designing water-cooled systems. The high-performance mainframe hardware, critical to cloud-computing, keeps shrinking, reducing the volume of space available for the cooling system, which, therefore, must shrink accordingly to fit in the tighter spaces in the frames. To determine the minimum size of the reservoir needed to replenish the water lost over the life of the machine, information on water permeations rates through rubber hoses is critical. The paper will present a novel technique for measuring water permeation rates using the concept of the water permeating out of a water-filled hose raising the relative humidity in a sealing box containing the hose. Results of permeation rate measurements through [1/4]-inch, [1/2]-inch, [3/4]-inch inch and 1-inch internal diameter EPDM hoses as a function of internal pressure and relative humidity at 40°C ambient temperature will be presented. The physics of water permeation through rubber hoses will be discussed.