Importance of Standard Test Methods in Investigations of FRP Composite Ladders

Fiber reinforced plastic (FRP) composite ladders are used everywhere from household to construction sites. Ladder related falls can cause injury to the user as well as result in damage in the FRP composite material of the ladder. Often, the visual observation of the appearance of the fractured fibers and resin material found in the damage area of the ladder are used to speculate inadequate material properties of the FRP were the cause of the incident. In forensic engineering, thus, a need arises to determine if the FRP ladder was manufactured to meet the requirements of the industry standard and that the ladder was not defective in material, manufacturing, or design.

In this presentation, the importance of standard test methods in the evaluation of an FRP composite ladder material will be discussed. The investigation was performed to answer if the failure of the subject FRP ladder was due to lack of cure of the resin material, improper wetting of the reinforcement during pultrusion manufacturing, or ladder design. The test methods used in the investigation involved inspecting the subject ladder, reviewing the design data and relevant technical standards, conducting a functional test of the subject ladder, performing standardized mechanical testing to determine the mechanical properties of the FRP ladder material, and a critical review and criticisms of the non-standard test utilized by other experts. The use of proper standardized test methods allowed for clear interpretation of data and the applicability of the standard to which the ladders are designed. A standardized test method approach also provided factual scientific data and photographic evidence that was used to establish proper wetting of the fibers with resin during manufacturing. This methodology also proved that the failure of the subject ladder was not due to material, manufacturing, or design defects.