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
September 23, 2016
September is already upon us and our next educational conference is just around the corner. I would encourage each and every one of you to attend this next exciting training program. The Training Committee is hard at work developing an amazing program that will walk you through the process of data collection, scene investigation and report writing. This program will include separate tracts for law enforcement and private fire investigation. Whether you are a seasoned professional or just starting out on your career, you will greatly benefit from this program. Please visit our website for more details www.arson.org. I hope to see you there.
Another great benefit that we receive from the conference is the chance to visit with old friends and make new ones. I really enjoy spending time with each and every one of you, so please take a moment to stop and say hi. I realize that the Board Members and Volunteers will be very busy but we are never too busy to stop and speak with our members. We value your input and welcome your suggestions.
As a Member, you have the right to voice your opinions and provide suggestions. However, the most effective method of improvement is personal involvement. If you desire change or would like to participate in the direction of your Association, I would respectfully request that you get involved. There are many committees and projects that could use your assistance. Another suggestion is to run for office. We are looking for level headed individuals that can complete tasks on a reasonable schedule and enjoy the true value of working with others. If you have any interest, please contact our election committee Chair, Tom Pierce at 661-619-3702.
And last but not least, I would like to thank each and every one of you for your support and assistance as I navigate through my presidency. Being the CCAI President is like being an engineer on a train. I may drive the train but it takes the hard work of others to ensure that there is fuel in the engines, the cargo is secure, and the tracks are true. Without this team, we could never deliver our training. These individuals are the Office Staff, the Board of Directors, and many strong Volunteers who make our Association run smoothly.
I personally thank those who participate in any way… regardless of the amount of assistance, as without this help…CCAI could not exist as we know it. I would also like to thank those who have helped in the past and those that are considering any form of future participation. This Association is built on the backbone of good people who know how to serve others. We are wired to help and I am proud to be part of this incredible group.
Thank you again for your support and trust in my abilities.
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