The emission of noise in the frequency range 10 kHz to 25.6 kHz from an experimental gas leak in a flanged joint has been experimentally investigated. The overall conclusion is that the emitted noise is almost frequency independent in level within the considered frequency range.A small PC program for estimation of the attenuation of sound during free field propagation outdoors has been developed and used for simulations. A number of curves of sound attenuation under varying temperature and humitidy conditions are shown. A crude overall estimate is provided.Computer simulations of the influence of the ground reflection on the received sound level have been carried out. These simulations have been carried out for the case of no wind and for one downwind and one upwind example. One of the conclusions is that the receiver should be located several meters over the ground in order to reduce the influence from upwind conditions.