A significant amount of hydrogen may be released inside the containment of water-cooled nuclear power reactor under postulated accident conditions. Its distribution in the multicompartment containment geometry must be known to manage and mitigate the local hydrogen concentration in combustible pockets. An experimental study to characterize the behavior of a lighter gas (helium in place of hydrogen) in a multicompartment containment studies facility (CSF) has been pursued. Helium distribution experiments have been performed in CSF by varying important accident parameters like helium release rate, injection duration, injection area, and injection direction. The experimental studies performed in CSF depict helium stratification in the upper dome region. Stratification in terms of stratification/effective stratification factor has been determined for a range of experiments. The present experimental studies are important for understanding hydrogen distribution characteristics in multicompartment containment geometry and for benchmarking computational fluid dynamics (CFD) codes. Based on these studies some important prevailing practices for recombiner placement were endorsed.