Fall from a Multi-Story Building

A woman attending an event at a hotel went over a railing on a spiral staircase, resulting in a three-story fatal fall to the basement. Eyewitness testimony was inconsistent regarding whether her initial location was at the very top of the staircase or several steps down. ESi needed to evaluate the physical evidence of the geometry of the staircase, the railings, and her final location to determine what fall scenarios could be consistent with the laws of physics.

ESi used a 3D laser scanner to document the scene, capturing the unique geometry of the staircase which included a landing on the level immediately below the top railing.  In order to travel through the vertical clear space of the stairwell to a final position on the basement level, someone falling from the top railing must travel outward almost five feet and over the lower landing railing.

To determine likely initial speeds, human surrogate testing was performed in the laboratory to measure body velocity while falling from a railing mockup.  Surrogate anthropometry was also evaluated to document how a person of that height would interact with a railing with the subject dimensions. It was determined that the surrogate’s standing center of mass was lower than and would have been contained by a railing of that height.

ESi performed kinematics analyses utilizing the gathered data. Based on the laws of physics, ESi showed that it was not possible for her to start at the top of the staircase, inadvertently fall, and land where the physical evidence indicated. The laser scan data was used not only for obtaining the necessary measurements for this analysis but also served as educational trial exhibits to orient the jury to the unique scene, giving perspectives not possibly obtained using simply inspection photos.