  An experimental study of the tracer dispersion in a complex structure is
presented. A point source of tracer (dyed salt) was placed inside a
multi-compartment structure embedded in water tank. This experimental setting
corresponds to a hazardous tracer release inside the engineering structure
(building, ship, aircarft etc). A system of conductivity sensors was deployed
to monitor the propagation of a tracer plume in the structure, including tracer
trapping inside some compartments and its release to the outside environment
through the external openings. The experimental data is processed by employing
the ideas of scaling and self-similarity of underlying transport processes. The
established and validated scaling laws provide a rigorous way to up-scale the
results of laboratory modeling to real operational scenarios and can be used as
an important step in the development of risk-assessment models for the first
responders to hazardous releases. Keywords: hazardous plume, tracer dispersion,
diffusion and advection, confined environment, water tank, structure
