Douglas W. Townsend, Ph.D., PE ::::
Case Synopsis: Plaintiff stepped through a doorway onto a fire escape on the floor above a neighborhood bar and grill. The fire escape railing opposite the door gave way and she fell into a concrete sidewalk and suffered paralyzing injuries. Some time before the incident, a four-foot section had been sawn out of the fire escape railing to facilitate removing a pay-for-play pool table from the building. Police photographs taken on the night of the incident showed pieces of rope tied to all four corners of the standing part of the fire escape where the section of the railing had fallen out. These photographs were taken from too great a distance from the railing to show if there were any broken welds. The bar owner and pool table owner asserted that the section of the railing had been welded back into place prior to the accident. Following the accident, the sawn out section of the railing had been welded back into position before the railing was examined by experts.
Engineering Analysis: A visual inspection of the railing was insufficient to show whether or not the U-section rails had been welded back into position prior to the accident. The re-attachment welds had rougher surfaces than the original manufacturing welds. A broken off piece of small diameter welding wire was stuck to one of the re-attachment welds which indicated that the re-attachment welds were made by a wire-feed welding machine. Some of the re-attachment welds were not completed on the vertical parts of the steel U-sections which left rusted saw cut surfaces. No mechanically broken welds were observed. To facilitate a detailed investigation, the railing was cut off of the fire escape and taken to a metallurgical laboratory.
A destructive examination was directed by defense and plaintiff metallurgical experts. Cross sections were cut through all four corners of the railing and through the corner posts to reveal both manufacturing and re-attachment welds and the remains of the saw cuts. Re-attachment welds, made after the incident, were observed to clearly bridge the saw cuts but had shallow penetration into the manufacturing welds and the top and bottom rails of the railing. Welding to re-attach the rails to the fire escape following the incident produced heat affected zones in the steel adjacent to the welds in the underlying steel rails and in the manufacturing welds. These heat affected zones could be observed after the cross sections were polished and etched by acid. The observed heat affected zones clearly matched only the manufacturing and re-attachment welds made after the accident. The heat affected zones showed that there had been no welding other than manufacturing welding and the welding to re-attach the top and bottom welds following the accident. The railing had not been re-attached to the fire escape by welding before the accident. (please contact Dr. Townsend at experts@forensicDJS.com)
Result: Verdict for plaintiff