ABSTRACT
Any discussion of sealing must of necessity consider the converse of sealing: leakage. Leakage exists in all fluid (gas, vapor, or liquid) systems to one degree or another, and the amount of leakage that can be tolerated is a matter of choice. Technological advancements in manufacturing have enabled many fluid carrying systems to be unitized to eliminate separate components, thus reducing the number of joints that might leak. The oldest and least expensive way to plug the spiral leak path of a sealing thread is to use drying or nondrying dopes. To eliminate leakage from surface irregularities, the minimum sealing stress must be achieved, thereby ensuring that the gasket flows into all fange face imperfections. Straight threads are used where there can be justification of producing a separate sealing element outside of the thread. Fluctuations in temperature of a gasketed assembly create a variety of changes, all of which can affect sealing properties of that assembly.
