Hydrogen jet flames resulting from ignition of unintended releases can be extensive in length and pose significant radiation and impingement hazards. Depending on leak diameter and source pressure, the consequence distances can be unacceptably large. One possible strategy to reduce exposure to jet flames is to incorporate barrier walls around hydrogen storage equipment. While reducing the extent of unacceptable consequences, the walls may introduce other hazards if not properly configured. An experimental and modeling program has been implemented to characterize barrier wall effectiveness at risk mitigation. The experimental approach is described and results are presented for various barrier configurations. The configurations include a vertical and inclined wall (2.4 x 2.4 m square) and a three-sided wall. A hydrogen jet flame issuing from a 3.175-mm diameter nozzle impinges upon the wall. Six gas cylinders at an initial pressure of 137 Bar supply the hydrogen. Typical test durations were 250 seconds, with maximum hydrogen flow rates of 80 gm/sec. The measurements include flame deflection using standard and infrared video, high speed movies (500 fps) to study flame propagation, ignition overpressures, wall deflection, radiative heat flux, and wall and gas temperatures. The barriers are evaluated in terms of their mitigation effectiveness for various hazards. The results show that barrier walls are effective at deflecting flames in a desired direction. While barrier walls can result in increased overpressures and radiative heat flux in the vicinity of the wall, they can also attenuate the effects of these hazards in surrounding areas if properly implemented.