An experimental study was conducted using two different designs of volute casing of a centrifugal blower with backward blade shrouded impeller. The volute casing designs were based on the principle of "constant angular momentum" and "constant mean velocity". For both design of volute the flow fields were studied at various angular, radial and axial locations in the volutes. The experiments were conducted with full throttle open condition at inlet. Analysis was done with the help of three-dimensional probe, which gave flow parameters such as stagnation pressure, static pressure and flow directions. Based on the experimental data, analyzed results were presented for the pressure recovery coefficient and loss coefficient. (C) 2011 Elsevier Ltd. All rights reserved.