Abstract: The traditional quasi-steady friction models are proved to be inaccurate in transient pipe flow because they underestimate friction losses in transients. In the past few years, some unsteady friction models have been developed so as to depict waterhammer produced in pipelines more accurately. In this paper, the traditional methods of the computation of friction losses in transients and the main achievements in this field are summarized. On the basis of them, a new idea is suggested to extend the application of the more accurate unsteady friction models to other pipelines such as crude oil and products pipelines.