Stephen Ternullo & Associates, Inc. P: (586) 868-0220

Stephen Ternullo & Associates, Inc.


The season is upon us when the report of chimney fire damage is one of the primary claims submitted by the insured. Over 26,000 house fires each year are associated with chimneys connected to wood and coal burning heating appliances (stoves, fireplace inserts, and fireplaces).

Two of the most common causes of chimney fires are improper inspection/cleaning on a periodic basis to remove accumulated creosote, and improper installation. Usually these units are installed too close to combustibles, are improperly vented or are improperly assembled to the flue. This also includes the improper installation of wood stoves and fireplace inserts into pre-existing fireplaces. These may be unlined or may have mortared joints that have deteriorated between the bricks, allowing hot flue gases, flames, or glowing embers to escape into the enclosed structure.

The cause of the increase in chimney fires in the more modern appliances is linked to their efficiency in burning the wood/coal fuel. Most of these appliances are designed to be thermostatically controlled so that the fuel is not consumed quickly and the most efficient heat is attained. Unfortunately, this results in an incomplete combustion by-product, known as creosote, which forms on the interior surface of the firebox, flue pipe and chimney. Normal fire temperatures in the firebox are between 600 and 1100 degrees Fahrenheit during the free burning process. However, if the temperature of the chimney and flue pipe is below 1000 degrees, the creosote will begin to accumulate. The ignition temperature of creosote is 863 degrees Fahrenheit. This usually occurs when the homeowner starts a fresh fire in the fireplace or opens the air draft to allow a free burning fire which quickly elevates the temperature to 1000 degrees. The resulting ignition of the creosote causes a fire in the chimney just above the area where the flue pipe enters through the thimble. If the uncontrolled fire in the chimney continues, temperatures will elevate to 2000 degrees Fahrenheit, significantly affecting surrounding structural components. These temperatures will also damage the stainless steel pre-manufactured chimneys and chimney liners.

The best prevention of chimney fires is proper installation, maintenance and operation. The safety of these heating systems is predicated on the education, good habits, thoroughness and vigilance by the owner.

Depending on the type of chimney, repairs can be as simple and inexpensive as replacing a few liners and blocks (for an exterior masonry block chimney) at a cost of several hundred dollars, including labor. Or, it could cost several thousand dollars to completely rebuild a masonry chimney inside a residence (more than two stories in height) or install a pre-manufactured metal UL approved chimney.

Many incidents of chimneys believed to have been cracked during fires are reported at the end of the summer or early fall when chimney sweeps begin their annual cleaning. It is true that cracked chimneys may be the result of a chimney fire; however, it has been our experience that the majority are due to two other common causes: the cleaning process and the neglect of chimney maintenance which results in cracking due to expansion and contraction during weather and seasonal changes.

If a homeowner is using a fireplace or wood stove as a primary heat source during the six to eight month heating season, proper inspection and cleaning are required at least once a month, and frequently more often. The location of the cracks and the general appearance of the chimney liner are both indicators of the cause of cracks and/or deterioration. Cracked liners originating just above the fire box of a fireplace or the thimble where a flue pipe enters are the most common origins of chimney fire. White "hot spots" burned off areas with some creosote still adhered to the corners are good indicators of a chimney fire's origin. In contrast, cracks found in a chimney and spalling of a surface near the top of the chimney are more commonly caused by the expansion and contraction of these liners. This is due to moisture accumulation from poorly maintained chimney caps or tops. The moisture absorbs like a sponge into the masonry material and in the cooler weather expands, causing cracks. When heated they contract, further damaging the liners and blocks or bricks.

By: Babar Khan, P.E., I-ENG-A of New Hampshire


It is estimated that more than a million deer vehicle crashes occur each year in the United States. According to the 2003 report by State Farm concerning their claim statistics, Pennsylvania experienced more deer vehicle collisions (DVCs) than any other state. The report cites the states with the highest number of DVCs were Pennsylvania, Michigan, Illinois, Ohio, Georgia, Minnesota, Virginia, Indiana, Texas, and Wisconsin.

Yet, research by Keith K. Knapp, P.E., Ph.D., Assistance Professor at the University of Wisconsin reveals that data related to DVCs can only be "grossly estimated" due to a lack of data consistently collected. However, in an effort to obtain accurate information, the Deer-Vehicle Crash Information Clearinghouse (DVCIC) was started in 2001 to collect and manage data for a 5 state region. This same report, which studied the upper mid-west states, reported 67,760 accidents alone in the State of Michigan in 2003 causing 1,913 injuries, 11 deaths and over $115.2 Million in vehicle damage. Yet due to inaccuracies in reporting, the actual deer-vehicle crashes may be at least twice as large as those reported.

The good news is, according to a State Farm report published in 2011, for the 3rd consecutive year, the number of DVCs in the US has dropped. While State Farm is still estimating over 1 million in collisions between July 1, 2010 and June 30, 2011, that is 9% less than three years ago and 7% fewer than one year ago. And, they claim the downturn is accelerating.

According to the claims data in conjunction with the Federal Highway Administration, State Farm reports, for the fifth year in a row, West Virginia as the top state where a driver is most likely to run into a deer. The odds are 1 in 53 for a 12 month period. This is an improvement from one year ago when the odds were 1 in 42. Iowa remains second on the list, with the likelihood of a driver hitting a deer in this state within the next year at 1 in 77. South Dakota (1 in 81) moved up one place to third. Pennsylvania (1 in 86) jumps two places to fourth. Michigan (1 in 90) dropped from third to fifth. Montana is sixth, followed by Wisconsin and Minnesota. North Dakota and Wyoming round out the Top 10. In eight of the top ten states (MN and WY are the exceptions), the rate of DVCs per driver went down from a year ago.

Precautions for motorists include:

By: Arianne Ciarlo, Investigative Engineers Association

Sources:,,,, University of Wisconsin, Defining the Deer-Vehicle Crash Problem in the United States: National Estimates, and Regional Data Collection; and Results of Recent Deer-Vehicle Crash Information Clearinghouse Activities Keith K. Knapp, P.E., Ph.D.


The latest residential-fire loss estimate data from the Consumer Product Safety Commission, "U.S. National Estimates of Fires, Deaths, Injuries, and Property Losses from Unintentional Fires", published in July 2011, reports the total number of fires from the most recent three years of data. According to this report the total number of residential structural fires has declined each year from 390,900 fires in 2006 down to 389,200 fires in 2007 and down further to 378,800 fires in 2008. Although the number of fires has declined, the property losses in dollars increased from $6.30 billion in 2006, up to $7.69 billion in property loss in 2008. This report categorizes the types of fire causes in residential structural fires and also reports on fire death and injuries.

Among the types of fires reported, the greatest contributor of fire causes is from cooking equipment (149,500). The majority of these losses are from range and oven fires. Electric ovens account for more than four times that of gas ranges (on aver- age 12,000 as compared to only 2500).

The second leading cause of fires is from Heating and Cooling Equipment fires (56,500 fires). The majority of these fires is due to chimneys, chimney connectors and fireplaces at 26,400. Fires as a result of chimneys and fireplaces increased each year from 26,400 in 2006 to 27,200 in 2008.

The third leading cause of residential structural fires is from electrical distribution system components (e.g., installed wiring, lighting) (12,300), with the majority of these fires having been caused from installed wiring (5,000 on average).

The fourth group of leading structural fire causes is from 'other selected equipment such as audio/visual equipment, clothes dryers, washing machines, refrigerators, and garden tools (10,000). The majority of the fires in this category are from clothes dryers which includes almost 75% of this category is approximately 7,000.

The full report may be viewed here

Stephen Ternullo & Associates
P: (586) 868-0220
F: (586) 868-0221