Wireless sensor networks have been more andmore deployed for monitoring and controlling real environments. However, because of sensor nodes' limitations, their radios are more susceptible to noise and interference than in other wireless technologies. These are critical factors in the rigorous industrial environment, whose effects may not be the same on all channels of a sensor network. In this paper, we present some experimental studies about the characteristics of IEEE 802.15.4 channels in ISM band. We are particularly interested in the differences of implementing wireless sensor networks in academic and industrial environments. A common problem of wireless sensor network implementations is that most of them are purely academic or initially prepared in laboratory. Our study shows that it is very difficult to predict the quality and stability of the different channels in sensor networks, as the environment conditions greatly influence the network performance. Empirical approaches are suitable methods for choosing the appropriate channels to deploy WSNs in noisy environments. We conduct several tests in both laboratory and in a real world environment, particularly in an oil refinery as this is our case study in the context of the FP7 GINSENG project (Ginseng 2010).