  We consider the transport of gas in long pipes and pipeline networks for
which the dynamics are dominated by friction at the pipe walls. The governing
equations can be formulated as an abstract dissipative Hamiltonian system which
allows us to derive perturbation bounds by means of relative energy estimates.
As particular consequences, we obtain stability with respect to initial
conditions and model parameters and quantitative estimates in the high friction
limit. Our results are established in detail for the flow in a single pipe and
through the energy-based modelling they naturally generalize also to pipe
networks.
