This paper presents the results of some dispersion experiments of liquefied ammonia in the presence of peacock tail water curtains. The aim of this paper is to evaluate the effectiveness of water barriers to counteract a weak release of ammonia under pressure (0.25 kg/s). The dissolution of ammonia in the water curtain is rather poor (about 15%), but at 10 m behind the curtain the effectiveness can reach levels as high as 90%. The results of the effectiveness obtained with ammonia releases of 0.25 kg/s are compared with results from those obtained from a release of ammonia half the size.