This benchmark is taken from the paper "Large-Scale Linear Systems from Order-Reduction", by Hoang-Dung Tran, Luan Viet Nguyen, and Taylor T. Johnson.
Description from the paper: "The building model is a model of the Los Angeles University Hospital with 8 floors, each of which has 3 degrees of freedom. This system has 48 state variables in which we are mostly interested in the twenty-fifth state x_25(t), which is the motion of the first coordinate."