Exploratory room-temperature gasket leakage tests were performed on different types of asbestos-filled spiral wound gaskets. Under investigation were the following parameters: gasket pre-wetting, gasket width, spiral winding density, load cycling, and use of water instead of nitrogen as the pressurized fluid.The results indicate that the first three parameters have only a marginal effect on gasket leakage performance. Of major significance, however, is the fact that unloading-reloading the gasket from and to some intermediate assembly stress level does not affect its behavior at a higher assembly stress.A previously introduced tightness parameter has proved useful for interpreting the data.