The pressure field in fluid systems reflects the flow configuration. Measurements of the pressure along the perimeter of a slot ventilated room have been conducted for different room sizes. The momentum of the jet at the end of the room is decreased with increasing room length. The impingement region (region where the influence of the opposing wall is present) starts, independent of room size, when the distance from the supply device is about 70% of the room length. Corner flows could not be predicted by CFD using the linear eddy viscosity or standard stress models. However, these effects may be captured by using a second moment closure turbulence model with a new near wall approach now available in literature.