Much of the initial assessment of worst case environmental temperature effects on material toughness was carried out by the Welding Institute for application to pressure vessels. Much of this work formed the basis of the subsequent pressure vessel codes. Since that time, there has been an increased understanding of the effect of Joule Thomson (JT) cooling due to pressure reduction during routine and non-routine pipeline operations. To incorporate this latest thinking it is necessary to take account of the transient heat transfer from the pipeline and fittings to obtain a more realistic understanding of minimum temperatures to which they may be subjected.
The programme will define a clear and consistent rationale for specifying the temperature and toughness requirements for pipeline fittings.