By: Kristopher J. Seluga, PE
Tel: (203) 329-9909
Email: Technology Associates
There are over 100,000 ladder accidents annually in the U.S. requiring hospital emergency room treatment. Although many of these result from user misuse, such as an improper extension ladder lean angle against a wall causing it to slip outward, use of a damaged ladder, or failing to lock a step ladder's spreaders, many ladders fail due to design or manufacturing defects. Many are designed too flexibly and some extension ladders are equipped with inferior rung locks. Other defects can be introduced during manufacturing such as material flaws or improperly seated rivet attachments. In addition, the fine-print warnings and instructions, on most ladders, are hard to read.
We are active participants on the ANSI Ladder Standards Committee and have:
Through scientific analysis, we can help you answer pertinent questions such as:
Falls From Stepladders:
We have investigated numerous stepladder accidents involving unexplained falls where no obvious structural defect can be found. When a ladder is too flexible, a climber may inadvertently cause the rear legs to shift sidewise, raising one of the legs off the ground. Later, when the user shifts his weight, the raised leg suddenly strikes the ground causing him to loose his balance and fall. In several cases, we have demonstrated how modest side rail stiffness improvements can reduce this problem.
Extension Ladder Slips off Low Pitch Roof:
A handyman was repairing some siding on a split-level roof when the extension ladder he had placed on the lower roof slid out from under him. We demonstrated that the modest slant of the lower roof produced a significant tendency for the lower side rail legs to slide out, and that the posted warnings against such action were present on the incident ladder. This resulted in a successful homeowner's claim defense.
Kristopher J. Seluga, PE, is a Mechanical Engineering, Accident Reconstruction, Biomechanics, and Safety Expert with over 20 years of experience. He received his Bachelor's and Master's degrees from the Mechanical Engineering department at MIT where he worked on the development of novel three-dimensional printing technologies. Mr. Seluga is also a licensed Professional Engineer in New York and Connecticut, and has served as a member of the ANSI engineering committee for the Z130.1 and Z135 standards for golf cars and PTV's. His research interests and peer reviewed publications span the topics of Motor Vehicle Dynamics, Product Safety, and Biomechanics.
©Copyright - All Rights Reserved
DO NOT REPRODUCE WITHOUT WRITTEN PERMISSION BY AUTHOR.
7/31/2009· Accident Investigation & Reconstruction
Forensic Engineering Experts: Codes & Standards
Codes and standards specify criteria necessary to ensure that a product, material or process will consistently and safely perform its intended function. Although standards provide minimum design requirements, conforming to a standard is not always sufficient in preventing an accident.
7/22/2009· Accident Investigation & Reconstruction
Forensic Engineering Experts: Lighting & Visibility
A person’s interaction with his environment comes largely from visual cues. Without this information, a pedestrian can trip over an unseen object or a driver might not detect a dangerous situation. In order to avoid these hazards, a person requires adequate lighting and should be provided with appropriate illumination for a given task.
8/7/2009· Accident Investigation & Reconstruction
Forensic Engineering Experts: Airbags
Airbags are credited with reducing numerous injuries and saving many lives during vehicle accidents. However, there have been incidents where they do not function as intended, and have even caused injuries such as explosive powder burns, detached eye retinas, child suffocation and impact deaths.
