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.