Structural strength: Gasketed vs non-gasketed flange joint under bolt up and operating condition

This paper presents results of an experimental study of the behaviour of the stress variation at the flange of a gasketed and non-gasketed flanged pipe joints during both the bolt up (pre-loading) and operating (internal pressure loading) conditions. Stress variations showing flange yielding, flange rotation, effects of joint tightening sequence, identification of the mode of response to loading (static or dynamic) is discussed. In addition the effects of re-tightening, importance of high quality bolting with proper surface treatment and use of proper tooling are also discussed.