Surge of turbo compressors can cause large stepwise changes in flow and pressure, which can potentially damage the compressor and any equipment that is in direct connection with the compressor. Surge is usually avoided by an anti surge controller (ASC). However, in spite of the ASC surge cycles may occur. A more robust approach is therefore to design the compressor, piping lay-out and attached equipment such that surge cycles can be sustained. For the evaluation of the effect of surge on a new centrifugal compressor it was intended to apply a model that simulates the flow and pressure variations that occur during a deep surge cycle. In order to increase the confidence in the reliability of the model, experimental data from two existing compressor systems forced into surge were compared with the results of simulations. It appeared that the simulation results compared very well with the measurements. As a next step, the model has been applied to evaluate the forces that can occur on a cooling circuit in the driver.