Expertly Speaking


Sprinkler Piping Installation – Code NFPA 16D Violation

James J. Shields, P.E., Mechanical Engineer ::::

Case Synopsis – A housing development company began a large multi-dwelling housing construction project at a site in Southeastern Pennsylvania. The development company hired a General Contractor to design and construct the site along with the erection of hundreds of homes. The project was planned by the development company to require several years for completion. As a first step in the process, the General Contractor obtained a building permit and produced a set of overall design drawings for the entire site, along with a set of design details for home construction. As is commonly the case, the General Contractor was responsible for the hiring of all sub-contractors. In addition, before commencing the work, all sub-contractors were required to sign a construction agreement with the General Contractor.

Approximately one year after the housing project had begun and certain housing sections had been completed, the housing developer and a prospective homeowner entered into an Agreement of Sale. The homeowner moved into the home about six months after signing the Agreement and lived in the home uneventfully for close to nine years. However, at that time, a severe water leak emerged from behind the drywall in the second-floor master bedroom. The water deluge from the leak was so great that it flowed through the wall, flooding the second story floor and pouring down two floors to the basement before the source of the water leak could be located and isolated. A vertical section of drywall was removed to expose the source of the water, which appeared to be originating from the sprinkler piping, although the exact location of the leak was still unknown. When the sprinkler system valves were shuttered the leak stopped, although, by then the volume of water released had created significant damage. The water was being supplied from the Township Water System, and the shutoff valves were able to isolate the home sprinkler system from the water supply.

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Cargo Barrier Failure in Armored Car

John R. Yannaccone, PE, Senior Mechanical Engineer ::::

Case Synopsis: On a dark and foggy morning an armored car, occupied with a driver and guard, was transporting assorted monetary cargo. The guard was situated in a seat located in the rear cargo area. As the armored car was traveling down the road, the driver failed to see a stopped tanker and drove into its rear. Upon impact, the cargo in the rear of the armored car shifted forward and impacted the rear of the guard’s seat, driving him into the bulkhead separating the cargo compartment from the driver’s area. The guard sustained serious injuries resulting in partial paralysis.

Expert Analysis: Inspection of the armored car revealed that the damage to the guard’s seat was consistent with it being loaded from behind and deforming it forward. There was a small bar, intended to serve as a barrier, to prevent the cargo from shifting, which was heavily deformed and had separated from its mounting points, allowing the cargo to move forward during the crash. In addition to the inadequate strength of the barrier, the basic design of the low bar was not sufficient to prevent heavy cargo from getting to the guard seated in the cargo area.

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Drone Documentation Technology

Catch Up on the Latest DJS News

DJS Associates’ newest drone pilot, Andrew Latzko, Field Investigator, is “cleared for takeoff” by the FAA after receiving his license to fly commercially on May 28th. Andrew is the 8th licensed pilot on DJS’ fleet and looks forward to assisting clients with their documentation needs.

Please join us in welcoming our 2019 Summer Engineering Research Interns! From left to right we have: Samantha Guest, a Mechanical Engineering student at the University of Rhode Island; Tim Primrose, a recent graduate of Bloomsburg University with a Bachelor’s Degree in Digital Forensics; Kevin Donnelly, a Mechanical Engineering student at Temple University; and Emma Angotti, a Biomedical Engineering Student at Penn State University, back for her 3rd year and taking on a new role as the Intern Manager. We look forward to learning as much from our interns as they learn from us!

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Event Data Recorder

The Importance of Event Data in Low Speed Collisions

Robert T. Lynch, PE, Principal Collision Reconstruction Engineer ::::

All model year 2013 and newer vehicles equipped with an event data recorder (EDR) that are sold in the United States need to adhere to the requirements set forth in 49 CFR Part 563 of the federal standards.

Part 563 establishes minimum requirements for an EDR. In particular, an EDR must record an event if the vehicle experiences a Delta-V (change in velocity) above 5 mph from any direction: front, rear or side. When a vehicle sees a Delta-V greater than 5 mph, the EDR will record 5 seconds of pre-crash speed, braking, and acceleration data, as well as severity data for the impact itself.

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Vehicle Operator Fatally Burned While Napping

R. Scott King, BSME, Principal Automotive / Mechanical Engineer ::::

A vehicle operator was fatally burned when the parked, but running, vehicle she had been sleeping in caught fire. Eyewitnesses reported hearing the vehicle’s engine racing before the fire began. Physical evidence revealed the fire originated in the area of the engine compartment supporting the witnesses’ observations.

The expert for the deceased’s estate postulated that the fire occurred because the occupant depressed and held the accelerator pedal long enough to allow the engine and its exhaust system to overheat, thus igniting nearby combustibles. The expert also opined that the engine speed control system, which was a fully electronic one, lacked safeguards that would have detected the abnormal condition of holding the accelerator pedal applied on a stationary vehicle and should have reduced engine speed to prevent the overheat condition. Examples from defendant’s discovery materials demonstrated that the vehicle was designed with the ability to self-regulate engine speed during a variety of driving situations, many of which were used to safeguard the engine from catastrophic damage. This, combined with examples of prior, similar claims, provided the basis for the opinion that the manufacturer knew of the risks that became manifested in this case, and had the technology and means to eliminate it.

R. Scott King, BSME, Principal Automotive / Mechanical Engineer with DJS Associates and can be reached via email at or via phone at 215-659-2010.

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Infotainment Expert Witness

Phone Data and Infotainment

Robert S. Kinder Jr., MS, Mechanical Engineer ::::

Even though cell phones are physically small, their data storage capacity is quite large. The infotainment system storage capacity in newer cars is also large and includes data from cell phones if it has been connected via Bluetooth or USB. An infotainment system refers to a vehicle system that provides entertainment and information to the end user. The systems include audio and video interfaces, touchscreens, and other features to enhance the user experience. Most newer vehicles are equipped with an infotainment system that assists users with various tasks such as hands-free calling and a rear-facing camera for reversing.

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