Over the past 25 years, the National Institute of Standards and Technology (NIST) has developed, augmented and improved an important computational tool for fire investigators – the Fire Dynamics Simulator (FDS) code. FDS is a flow, heat, and chemistry modeling application that is utilizes Computational Fluid Dynamics (CFD) to model fires and other flows that … Continue reading Large Eddy Simulation →

 Engineering investigators are obliged to utilize the “Scientific Method” when conducting an investigation into a product failure. The basic elements are: Observe, Hypothesize, Test, and Conclude. Occasionally, an investigator will obtain sufficient information from the “Observe” phase, so that only one hypothesis is plausible. In such instances, the “Test” phase is not explicitly necessary, and … Continue reading A Spectrum of Hypotheses →

 When a consumer product fails thermally, customers may get “steamed” and demand their money back.  When the failures are frequent enough that the Consumer Product Safety Commission receives dozens of complaints about “melted plastic” and “first degree burns” a few weeks after the initial launch of the product, they may require the seller to pull … Continue reading Statistical Inference and Product Failure Analysis →

 News reports about fires involving Tesla Motors’ “Model S” electric vehicle have played a role in the company’s recent stock price decline.  However, these fires should be viewed in perspective because they share a common root cause.  Two of the three fires occurred right after the driver accidentally ran over a dangerous road hazard, and … Continue reading Road Hazards and Vehicle Fires →

 When I was a teenager, I remember my Dad occasionally becoming frustrated with my reluctance to rake leaves and pull weeds.  Thinking myself a modern-day Tom Sawyer, I once suggested to him that my interest in weeding and raking would go up tremendously if I could have a couple of friends over to assist.  In … Continue reading No Fuse At All →

 Unintended water release in a residence is a frequent cause of damage (and insurance claims). Often, the water released is caused by a worn-out washing machine hose that ruptures, or an ice-maker supply tube that flexed one too many times and sprang a leak. These failures can result from a hose or tube defect, but … Continue reading Ice Begets Water Damage →

 A fire that originated inside a restaurant in a strip mall became the subject of litigation almost three years after the date of the fire. An adjacent tenant in the mall was pursuing a claim against the restaurant owner seeking recovery for his losses. Subsequent to the fire, but before we were retained by the … Continue reading Photogrammetry →

 Portable cookstoves are used by caterers and campers to bring the convenience of a “kitchen appliance” to places where such appliances are normally not available. Some cookstoves are fueled with liquefied propane that is supplied in 1-lb canisters (first photo) or 20-lb containers (second photo). Others utilize liquefied butane that is supplied in aerosol-like cans … Continue reading Portable Cookstove Defects →

 Most people know that water boils at 212°F (100°C) at sea level. They also know that if the pot is open (i.e., not a pressure cooker), the bubbling, steam-water mixture will not exceed 212°F. While this observation is generally true, there is another aspect of boiling that many people are not familiar with – “superheating”. … Continue reading Exploding Chicken Soup →