Case Study – Fatal Stairwell Fall

Customer: Private Client

Case Overview

A male fell backwards down a flight of stairs, receiving fatal injuries. In order fully understand the limited information available regarding the cause of the fall, our client requested an analysis of the event to be carried out as it was questioned whether it was an accidental fall or an intentional push that resulted in the accident occuring.

Objective

The simulation model was developed to provide an insight into the impact locations and injury causation mechanisms for a range of initial scenarios. The main variable was the initiator of the fall, i.e. a loss of balance or an external push.

Solution/Methodology

From simple scene measurements of step height and pitch, a Madymo model of the staircase was created. A scaled Madymo Human Body Model was then carefully positioned at the top of the stairs, its stance having been specified by the client, based upon witness statements.

Initially the human was allowed to fall under gravity with no other external influence. As the model developed, external forces were applied to represent pushes of varying magnitude and points of application, e.g to the left shoulder, right shoulder, chest etc.

By examining the injuries and the impact locations during the simulated falls, it was possible to assess the influence of the fall in terms of the initial body posture and any additionally applied forces initiating the fall.

As an extension to the work, a brief study was carried out which examined the influence of stairway design on the likelihood of injury during a fall. This was achieved by varying the pitch (steepness) of the original staircase in the simulation and finally by implementing a ‘corner’ layout.

Results

By applying various initial inputs to the human, it was apparent that an external force was not required to match the physical evidence.

Conclusion

Advanced Simtech were on this occasion able to show that foul play was unlikely to have been a factor in the fatal stairway fall.

Furthermore,  via the flexibility of the simulation model created, it was possible to show the influence of changes in the staircase design on the likelihood of serious injury during a similar fall.  This lead to the publication of an article together with ARUP in  ”Hospital Engineering & Facilities Management’ a global publication for civil engineers and architects involved in the design and construction of public buildings.