Forensic Engineers and Consultants

Tag Archive: The Warren Group

  1. In a Flash – The Transfer of Energies in Our Global Electrical System

    Leave a Comment

    According to published weather data for the year 2019, 2.35 billion lightning strikes were recorded across the world, with 223 million of these in the United States.  The movement of atmosphere causes electrical charges to build up between clouds.  A tipping point is reached where the insulating properties of the air cannot withstand the level of energy and a discharge occurs.

    Image Credit: Charleston Post and Courier. A lightning strike over Charleston, SC on July 3, 2019.

    Such discharge is rapid, lasting between a fraction of a second to just a few seconds.  With voltages between 40kV to 120kV and currents from 5kA to 200kA, each discharge can transfer up to 10 billion watts of power.  Such large bursts of energy can cause significant physical damage to structures and people.  The sudden expansion of moisture in a tree can cause it to be ripped apart and pieces thrown a significant distance from the base.   Wires can be melted as the energy is conducted to the ground reference of the earth.

    Using technology that came out of detecting nuclear weapon discharges, lightning is tracked around the globe.  Distributed sensor networks measure the intensity of lightning strikes and triangulate the precise locations.  This information is collected and made available to support the investigation of lightning claims.

    Nearby, non-direct lightning strikes can also cause damage.  Significantly high voltages can be induced through the soil to cause damage to electrical components nearby.  A good example of this situation is an inground well pump.  The high voltages induced can degrade insulating materials on conductors that in turn can cause an electrical failure.  The electrical properties of wiring can be tested to determine if lightning is a cause of a failed device.

    Protecting against lightning can be difficult and costly.  Lightning protection systems can be designed and implemented to help mitigate the effects of a lightning strike to a structure.  The National Fire Protection Association (NFPA) Standard 780 is a standard that guides the selection and installation of lightning protection systems (LPS).  Annex L of the NFPA 780 standard describes a method of performing a risk assessment to determine if a structure would significantly benefit from an LPS.  Factors in the assessment include physical properties about the structure, terrain considerations, geographic location, and neighboring structures.

    The selection and installation of surge protection devices is another means of reducing damages from the power of lightning.  These devices will be discussed in detail in an upcoming blog.

    Tom Kelly has a Bachelor of Science in Electrical Engineering and a Master of Science in Electrical Engineering from Florida Atlantic University, Boca Raton, Florida, along with a Master of Business Administration with emphasis in strategic leadership from Winthrop University, Rock Hill, South Carolina. Tom’s 30 plus year career in electrical engineering includes forensic engineering investigations involving industrial electrical accidents, electrical equipment failure analysis, control system failures, robotics and automation components, and scope of damage assessments.  He has conducted investigations for fires, arc flash incidents, electrocution and electric shock accidents and lightning strike evaluations.

  2. Improper Hearth Extension Leads to Structure Fire

    Leave a Comment

    The fire service affords you the opportunity to witness and observe things that a lot of engineers and even most people do not get the chance to see.  An example of this is the situation where extended elevated temperatures combined with poor construction techniques to result in a structure fire.

    I have personally observed several occasions where a structure fire was initiated due to improper construction of the fireplace hearth extension.  The most recent one followed a multi-day cold snap, at least by South Carolina standards.  The thermometer read 17 degrees F as I drove to the call of smoke in a residence (more…)

  3. Roadway Defect Scavenger Hunt for Collision Evidence

    Leave a Comment

    Not too long back, I was on the scene of a collision case where a roadway defect was blamed for the loss of control that led to a single vehicle collision which resulted in major damages and serious injury.  The collision was several years old, and the roadway had not changed over the time passed.  My assignment was to inspect the roadway in the area of the crash, document it (by photographs and 3D scanning), and identify if there was a roadway issue that potentially led to the loss of control.  What happened next was the result of going to the collision location and looking for more than what was to be expected.  These things can help the case tremendously and make a huge difference in resolution. (more…)

  4. The Pavement Tells the Story: Reading Evidence from a Motorcycle Crash

    Leave a Comment

    What can be determined from a motorcycle’s skid mark and the roadway evidence it left behind? The obvious, that the motorcycle crashed; but what more? From a recent case, starting with the pre-impact skid mark, a lot was determined about the driver’s (and passenger’s) input into the crash. A single skid mark started at the beginning of the collision location, a common piece of evidence at a motorcycle crash. Taking that mark and analyzing it, several things were determined. (more…)

  5. Heat Exchanger Failures Will Shut Your Process Down

    Leave a Comment

    Heat exchangers, as the name implies, are used to bring a process stream to a desired temperature.  They can heat or cool either gases or liquids. They are fairly intricate in their construction, therefore not the cheapest piece of equipment to purchase.  For that reason, facilities don’t keep “spare” exchangers lying around, so when they fail catastrophically, the entire manufacturing process goes down with them… and stays down until they are fixed or replaced. Ow!

    (more…)

  6. Proper Construction and Maintenance Can Prevent Deadly Chimney Fires

    Leave a Comment

    There are few things as comforting to me during the winter months as a warm fire burning in the fireplace.  And in this case, I am talking the real deal, the kind that warms you multiple times; from cutting, splitting and stacking the firewood until finally lighting a fire in the fireplace.  However, just like your parents taught you, fire can be dangerous.  And having an actual fire in your home fireplace comes with some required maintenance to ensure you can safely control the fire and keep it where it belongs. (more…)

  7. Major Causes of Wood Truss Failures

    Leave a Comment

    Wood truss failures can vary and identifying the cause requires visual inspection as well as a working knowledge of the structural loads and building codes. These truss systems must transfer the gravity and lateral loads to the foundations. Consequently, the framing system and the foundation provide strength and stability for a structure. The most common type of wood-framed construction uses roof trusses, exterior and interior load-bearing walls, beams, girders, posts, and floor framing to resist the gravity and vertical loads. This type of wood-framed construction engages a system of horizontal diaphragms (roof and floors) and shear walls (vertical exterior sheathed walls) to resist the lateral loads. (more…)

  8. Stress Corrosion Cracking of Stainless Steel in Marine Environments

    Leave a Comment

    Stress corrosion cracking involves the slow growth of small, often microscopic, cracks through a metal part in a corrosive environment.  The cracking can continue to the point that the part fails suddenly and unexpectedly even though it still appears new and in good condition.

    My first experience with stress corrosion cracking happened in the Charleston harbor when the stainless steel rudder suddenly separated from a sailboat during moderate winds. What had been a pleasant evening sail turned instantly into being in a difficult to control boat in the middle of the busy shipping channel. The rudder remained attached only (more…)

  9. Residential Structure Fires

    Leave a Comment

    The winter season is well underway in the United States, with the Christmas and New Years holidays behind us and the depths of cold weather here for the duration.  With winter, many people spend more hours indoors as compared to the summer when outdoor activities ramp up.  With more time spent indoors, it is somewhat intuitive that the use of electricity would increase as well.

    Electricity is one of the most influential utilities in our daily life.  Much of what modern societies rely on to get through a normal day requires electricity.  Have you ever been in a slight panic looking for an electric outlet when your cell phone is below 10% charge?  Or how many times do we all attempt to turn on a light switch when we enter a room during a known power outage from sheer habit?  Even our personal transportation which has relied on gasoline for roughly 100 years is shifting toward electric automobiles. (more…)

  10. Heating System Losses, Part One

    Leave a Comment

    When fall and winter arrive and temperatures drop, it is a great comfort to have a heating system to warm your home or office. Several categories of heating equipment exist to provide both primary and secondary heating. Primary heating systems include fuel gas/fuel oil/electric forced air furnaces, heat pumps, hydronic heating/steam systems and even wood-fired heating systems.  Secondary heating equipment includes electric, gas and kerosene space heaters of both fixed and portable design, and fireplaces. Each of the different types of heating systems have unique hazards that, uncontrolled, can result in fires, explosions, burn injuries, and carbon monoxide poisoning.  (more…)

Type ofLoss

Not sure what you're looking for?
Browse All

Select Loss Category