Pressure vessels serve as vital components for the containment of liquids or gases in various industrial applications. The utilization of pressure vessels constructed from composite materials presents a significant advantage compared to conventional vessels crafted from metal alloys or those incorporating liners, specifically, in terms of weight reduction. This attribute holds particular significance in industries such as aerospace, where it is imperative to minimize weight. By applying composite materials in pressure vessel design, substantial gains in weight reduction can be achieved, thereby contributing to enhanced performance and operational efficiency in critical aerospace applications. This work presents the mechanical design, including experimental validation, of a permeability test setup, used to estimate the permeability of composite materials used in type V aerospace pressure vessels. The test setup includes two steel chambers, between which the composite sample is placed for evaluation. During the test, the gas that the pressure vessel will hold is introduced under pressure by the receiving chamber. The other chamber (measurement chamber) serves to measure the pressure variation by a pressure transducer. With the data collected by the pressure transducer, the sample permeability can be assessed. During the design process, alternatives were also considered during the design, and the justifications of each selected and implemented solution were presented. The test setup was fabricated, and the correct operation validated. The validation of the proposed setup was accomplished using materials with different permeability characteristics, and the respective data analyzed and compared between materials and values from the literature. Permeability tests were also carried out and the results obtained were analyzed. The validation stage was successfully completed, since the obtained results from the setup agreed with those found in the literature, and the test setup was created and it is currently operational.