Vytenis Babrauskas, Ph.D
Arc mapping was first introduced in the 2001 edition of NFPA 921 and was subsequently expanded so that in the recent editions it constitutes one of the four main methods for determining the origin of a fire. Careful consideration of engineering principles and large-scale experimental studies on the subject indicates that the relevance and prominence of arc mapping as a leading indicator of fire origin is greatly overstated. The technique is valid and applicable only in some very limited scenarios. Yet it has seen very extensive use in recent years by investigators preparing fire reports. In many cases, such attempted use of arc mapping is based on incorrect and invalid hypotheses, which are often implicitly assumed to be true instead of being explicitly stated. The following are myths: (i) An abundance of arc beads at a given locale means that fire originated in that area, while a paucity of arc beads indicates that it did not. (ii) When multiple arcs are present on a circuit, the direction of arcing will necessarily proceed upstream towards the power source. (iii) If an appliance is the victim of a fire, internal arcing will be primarily near the exterior of the unit, while arcing deep inside indicates a fire origin at that place. NFPA is urged to revise NFPA 921 to eliminate arc mapping as one of the four main methods for establishing fire origin, and to subsume it under the more general category of “fire patterns.” In addition, it is important that NFPA 921 reduce the implied general utility of the method and provide more explicit information on its interpretation and its limitations and on the circumstances under which it may be a valid method for assisting in the determination of the fire origin.
Vytenis Babrauskas, Ph.D.
Short circuits to building wiring can happen due to electrical mishaps, or as a result of fire impinging on the wiring. In either case, this may cause arcing. It is sometimes erroneously assumed that this must produce signs of ‘electrical activity,’ which is a term often used by fire investigators to mean discernable arc marks or arc beads. While such artifacts may indeed be produced, it is shown that it does not necessarily happen in every case. Shorting and arcing (whether due to fire or due to an accident) may occur without leaving physical evidence that is discernable as an arc bead. Ejecta also may, but do not have to be produced. Some variables have been identified which can influence the size of arc beads, when arc beads are produced. But stochastic aspects dominate, and no predictive correlations can be expected. It is also shown that there are no prediction methods available to establish if an arc locale will result in severing or welding together of conductors.
From Out of the Abyss...
This week’s article from the past is titled Incendiary Fires Can Be Spotted and was written by Benjamin Horton, CPCU, who was President of the National Adjuster Traing School in Louisville, Kentucky.. It is taken from the Decembe 1968 Vol. XVI No.5 issue.
Incendiary Fires Can Be Spotted
In the new issue of NFPA Journal®, President Jim Shannon said the Association will focus on the leading causes of home fires, including cooking. "We also need to continue to push hard for home fire sprinklers. That's still a large priority for NFPA, and we plan to work very aggressively in 2014 on our residential sprinkler initiative," he said.
From: The Desk of Scotty Baker
To: The CCAI Training Committee
Over the last several training seminars, even as an old hand, I have learned new information concerning fires and how they do what they do.
Get started today
The focus will be on Report Writing, Arc Mapping and Ignition Sources, Social Media as an Investigative tool, Fundamentals and more.
Register now online or Fill out the registration form and email, mail or fax it
Cathleen E. Corbitt-Dipierro
Stonehouse Media Incorporated
Smartphones are quickly taking over the US cellular phone hardware market — iPhone, Droid, Blackberry, Palm, just to name a few brands. With their advanced computing capability, smartphones are enabling users to perform more and more tasks on their phone than just the simple calling and texting. This computing power is harnessed by “apps,” which are application software programs used on smartphones.
For the fire investigator, the smartphone can become a handy tool in your daily work, but only if you know how to outfit it. This article highlights some of the core apps that fire investigators can use every day to assist in managing their investigative and administrative work. One caution before we begin: the investigator should be aware that any investigative information kept on your smartphone is not secure and also may be discoverable in a future legal proceeding. For that reason, we’ve confined the discussion of apps in this article to those where case-based investigative information is not stored or shared. At all times, exercise the utmost caution with investigative information.
Most weather apps have auto location based on the GPS signal from your phone, meaning that the app knows where you are and provides the weather data for that location. You can also lookup weather for a different area and program a favorites list for different locations you travel to repeatedly. Mapping Mapping applications, many of which are GPS-based, have both administrative and investigative value. Using the GPS in the phone and the mapping app, you are able to:
Mapping can also be used in other apps that help you find traffic, tides, mass transit, or parking information.
Remember that any information gleaned from one of these apps should be verified with another source. Roads change, streets are temporarily closed, and other events occur that may make the situation on the ground not the same as it is in a published map.
Administrative Management There are a wide variety of management and productivity apps that can help you organize your daily tasks, including:
Take a little time to think about the administrative tasks you do every day and then search the available apps for your device to see what’s out there to help you manage and streamline the administrative process. Incident Management There are several Incident Command System apps that can help the investigator handle large incidents, including the National Incident Management System (NIMS) components, concepts, and planning forms. Some of the ICS apps also provide an interactive look at the chain of command structure, which can assist with proper reporting at the scene. Scene Safety There are a number of apps available, and more are under development, that assist the investigator in working safely at the scene. Some examples of currently available scene safety apps include:
These apps can assist in identifying hazards at the scene and provide information on how to respond to the identified hazard.
Locators There are a number of locator apps available that can help the investigator find businesses nearby. Some locator apps also provide ratings and reviews for these businesses. A locator app works by using the GPS in the smartphone to determine your location, and then searching a database of nearby businesses that fit the criteria you enter, which is typically a category of business or government, and sometimes augmented with additional search filters, such as distance, price, or number of “stars.” These locator apps can be extremely helpful when you are not familiar with the location and can assist you in both physical comfort and investigative ways.
Some examples of what you can find with locator apps include:
There are also people locator apps, including offender and sex offender locator apps.
You should be aware that the locator app databases may not be definitive or complete and any information should always be confirmed with another source.
There are thousands of apps and more are being released every day. Set aside some time to browse through the apps available for your smartphone and think through how they might assist you in the field. Be sure to keep your apps up to date and periodically look for new apps that have been released and may be beneficial to you. Put your smartphone to work for you and you can work more efficiently, safely, and thoroughly.
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