  The aim of this document is to define a Pyroclastic Density Currents (PDCs)
benchmark based on a large-scale experiment to be used with numerical models at
different levels of complexity. The document is organized as follows. Section 2
concisely describes the large-scale laboratory experiment setup and geometry,
and the relevant specific bibliography. Section 3 introduces the theoretical
framework to adapt the experimental dataset to numerical models at different
levels of complexity. Section 4 details the initial and boundary conditions. In
particular, Section 4.1 describes the inlet velocity that best reproduces the
experimental boundary conditions. Section 4.3 describes in detail the inlet
concentration and temperature profiles, respectively. Section 4.4 describes the
input grain size distribution. Section 5 gives the guidelines for consistently
presenting the numerical outputs in a model inter-comparison study. Section 6
is a summary to guide the reader through the data sets.
