The University of Hartford College of Engineering, under the direction of Adjunct Professor Allan Penda, with a team of Senior year Mechanical Engineering students working as a Capstone Project, developed a test program specifically for TUTUS LLC as a case study of their new DOPS safety system – Dropped Object Solutions, a tool and debris containment wrap used on aerial lift vehicles. DOPS is a one-piece safety product made from small mesh netting, designed for field assembly using loop fasteners and one zipper. The assembled DOPS creates a re-usable five-sided enclosure that wraps around a work platform’s existing steel framework. As expected, the netting is prone to some degree of wind loading. Just how much was an unknown that needed to be solved. This is where the University of Hartford case study begins.
The TUTUS DOPS began with a fast-paced time line of ideas, development, testing, and prototype deployment – in two short years. DOPS founder and president Forrest Hester developed DOPS as an invention of necessity. As a trade worker in the gas and oil business of Texas and familiar with mobile aerial lift work platforms, Forrest was aware of the unaddressed need to keep tools and material contained in a small and frequently congested work area.
Often working with what can be sourced at a job site, Forrest like many others, was instructed to wrap their aerial lift platform with readily available extruded debris mesh, commonly used for light duty containment and perimeter marking. Assembled with zip ties, tape and rope, the wraps were one time use and were of dubious performance to contain much of anything.
Sketching and designing from home, and with the help of a sail maker, the idea grew into a series of workable prototypes. To bring the idea to production levels, Forrest reached out to a northeast safety net manufacturer, InCord. Together with a larger collaboration of ideas and assembly methods, the first production DOPS was assembled.
“IF IT CAN BE DROPPED, IT CAN BE STOPPED”
The UH case study began with a simple outline:
- Understand the design requirements, and the need for wind load testing.
- Research existing information regarding wind load on netting.
- Develop a test plan to evaluate wind load induced forces on the sample product.
- Conduct wind load testing and compare the results to expected results.
- Relate wind load results as a cumulative to known limitations of a relevant aerial lift vehicle.
- Relate results to Industry Safety Standards.
- Present conclusions and recommendations based on results and analysis. TUTUS, January 30, 2017 2-2
Three different materials supplied by manufacturer InCord were first analyzed and then electronically modeled and tested using existing case studies regarding porosity and drag coefficient for screens. This became the basis for later validating their test method as it related to synthetic netting. Predictions were made from calculated and available research to measure a pressure drop across the netting as it equates to an applied pressure – wind load, that is calculated by multiplying the pressure drop by the netting area. Wind tunnel testing at the UH test lab was performed and compared to calculated data. The results were nearly the same, validating the test method within six percent.
Analysis and Summary
The wind load testing up to 90 mph on three different materials produced results that were within the design requirements for DOPS. Each material had distinct characteristics, and each was proven suitable for use as standard and alternative material with the DOPS design. With solid test analysis, TUTUS could determine the safe working limits for each manufacturers’ mobile aerial lift platform that might use a DOPS platform wrap. To date, more than two-dozen mobile aerial lift platforms from three manufactures have been studied and matched with a TUTUS Dropped Object Protection System. Within 2017, the new aerial lift platform safety system will hopefully be deployed to worksites across the nation – saving lives and protecting property.
For more information on the study and the TUTUS DOPS, contact Forrest Hester Forrest@tutusdropprevention.com or visit their website www.tutussolution.com
TUTUS established in 2015 by Forrest Hester for the safety of his fellow co-workers and himself.