SUBROGATION OF FIRE LOSSES
Most common Construction Defect Repair issues we have
Investigated regarding Fires
Pyrolysis: The Result of Improper
Fireplace Installation or Lack of Maintenance
When
combustible objects are placed too close to a heat source at temperatures of
212°F or more for a long period of time, a chemical breakdown or decomposition called
pyrolysis can occur. Pyrolysis is a
major cause of fires throughout North America. Every year many tragedies and fires are caused
by pyrolysis and yet most people don’t know what it is or the importance of
preventing it. Understanding the
potential presence of the threat is where prevention of this little-known
danger begins.
Materials
break down chemically as they dry out due to exposure to extreme heat. Essentially the ignition temperature of the
material is lowered so that they ignite much more easily than it was possible
before. Severely pyrolyzed wood can
ignite at only 212 degrees F, while it would normally have a catch-fire
temperature of about 500 degrees F, before it had any exposure to intense
heat. Eventually the pyrolyzed wood will
ignite, and a direct flame is not required for the fire to start. All that is required for pyrolysis to occur is
heat and oxygen.
METROPOLITAN’s
fire investigators say that of all the solid fuel-related fires they have
investigated are caused by pyrolysis over 86% of the time. About 10% of the fires they have investigated
were caused by improper installation or failure of the seals, connectors,
appliance, piping, valves, or chimney.
Another 4% of the fires have been caused by careless use or improper
maintenance of heating systems.
What
Causes Pyrolysis?
Pyrolysis
is practically an inevitable event when fireplaces, fireplace inserts,
solid-fuel stoves and furnaces are installed improperly or the system is not
maintained to prevent the escape of hot gases into the combustible components. The tragedies resulting from pyrolysis are
completely preventable. All that needs
to be done is to ensure that the amount of space between a wood-burning stove,
stovepipe, and other heating appliances is at least the minimum recommended by
the manufacturer.
It is also very common to see fires caused by pyrolysis in the latter years of a fireplace, when the system has deteriorated with time, allowing gases to escape through small gaps in the liner, failing mortar joints, etc. The numerous freeze-thaw cycles that all chimneys in the north America have been subjected to, will eventually cause the chimney structure to fail, and the liner to be cracked. A cracked liner puts the home at risk for a dangerous housed fire due to the effects of the pyrolysis. It may not happen in one year or ten years – but eventually the wood will be catching fire from the escaping gases through the small cracks in the liner or other places of the fireplace.
It is also very common to see fires caused by pyrolysis in the latter years of a fireplace, when the system has deteriorated with time, allowing gases to escape through small gaps in the liner, failing mortar joints, etc. The numerous freeze-thaw cycles that all chimneys in the north America have been subjected to, will eventually cause the chimney structure to fail, and the liner to be cracked. A cracked liner puts the home at risk for a dangerous housed fire due to the effects of the pyrolysis. It may not happen in one year or ten years – but eventually the wood will be catching fire from the escaping gases through the small cracks in the liner or other places of the fireplace.
It is
common for unprotected furnishings, walls, and other combustible structural
components to be placed too closely to heat sources. Because everything seems fine for months or
even years, homeowners fail to realize that the process of pyrolysis is
occurring and could unexpectedly result in a fire at any time.
Pyrolysis
is also caused by a damaged chimney liner. Even the smallest amount of
deterioration in the chimney liner or the deterioration of seals and joints or
the lack of sealants can cause nearby combustibles to catch fire from the
escaping gases.
Insufficient Clearances between
Fireplaces and Combustible Materials.
Insufficient
clearances between fireplaces and combustible materials can be a serious
construction defect. The construction,
placement, chosen material, and other aspects of fireplaces have to adhere to
certain regulations and building codes. These
regulations and building codes are in place to look out for the safety of the
inhabitants of a building. They can be strict but they do serve a public
purpose. Not being compliant with these restrictions can result in a hazardous
situation. Insufficient clearances between fireplaces and combustible materials
are fire hazards.
Clearances to
combustibles is something they didn’t worry about in the old days. It is quite
common to see wood beams or 2x4s right against the masonry of a chimney. When there are fires in old homes, it’s also
common to find that some of this wood ignited. Oddly enough, the process of
pyrolization takes place over many, many years. The unscientific definition of
that is that the ignition temperature of wood gets lower over time. In other
words, it takes less heat to catch it on fire 50 or 100 years later than when
it was new.
Use of Non-Approved Decorative
Chimney Terminations.
Use of
non-approved decorative chimney terminations is a common problem that many
homeowners may have, unbeknownst to them. A construction defect like this may
only become evident to a homeowner when there are some obvious issues, such as
excessive smoke collection or when products of combustion are venting into the
dwelling. If you are having issues with the functioning of your fireplace and
chimney you may need to verify that use of non-approved decorative chimney
terminations is not the issue.
Non-manufacturer approved
accessories installed into fireplace.
Due to
the strict requirements and testing process, all manufacturers require that
only manufacturer approved parts be used in conjunction with their fireplaces.
By using aftermarket glass doors, refractories and other fireplace components
that aren’t approved by the original manufacturer, there is a risk of voiding
the UL listing and the warranty, creating a liability issue for the person or
person(s) providing the services or even for the homeowner.
The chimney structure or flue or
connections to the fireplace have become settle, separated or disconnected
Based on
our forensic investigations, we see that gaps have been created around the
chimney structure or around the liner or the firebox. This resulted in hot gases escaping the
fireplace and drying out the wood around it.
As we stated earlier, the process of pyrolization takes place over many,
many years. And one fatal year, the wood
finally burns and causes extensive damage and loss of life.
There
are many reasons this shifting or disconnection can happen. At times, it could be a construction defect,
or installer error. Many times we
observe inadequate mortar or missing mortar due to lack of maintenance or
installation of incorrect type of mortar.
It is not uncommon to observe lack of seal between the firebox and the
lintel at the top of the firebox – this is a common construction defect leading
to fires as the escaping gases will slowly pyrolize the wood framing.
Other
times, the flue may have shifted in an earthquake, or a metal strap supporting
a bend in the system could have failed. At other times, the chimney moves due to
severe weather (excessive freeze-thaw cycles, heavy winds, erosion, flooding,
and so on). There are also instances
where a chimney sweep unfamiliar with prefabricated metal fireplace systems may
have disconnected the flue in the process of cleaning the flue, or removing the
cap.
Leaking Gas Connections had led to
Fires
After gas
line is connected, it is a code requirement
that each appliance connection, valve, valve train, shall be checked
while under normal operating pressure with either a liquid solution, or leak
detection device, to locate any source of leak. Tighten any areas where bubbling appears or
leak is detected until bubbling stops completely. DO NOT use a flame of any kind to test for leaks.
Leak test
with a soap solution after installing or servicing with main burner on. Coat pipe and tubing joints, gasket etc. with soap
solution. Bubbles indicate leaks. Tighten
any areas where the bubbles appear until the bubbling stops completely.
Before
performing any service on the appliance, ensure the gas has been completely
shut off, the unit cooled, and the electricity shut off to the appliance. The burner and valve control compartments
must be cleaned annually. A vacuum with
a brush attachment works well. The logs should be cleaned gently with a soft
bristle brush. The logs are fragile and are easily damaged.
Miscellaneous Fireplace Construction
Defects
Several
times we have observed missing or blocked out cleanout pits. Oftentimes during renovation of old homes, we
see that the fireplace ash pits are covered to create a finished room. This has created fire hazards as the ash
inside the pit will ignite when enough of it accumulates inside the ash pit.
At
other times, the valves inside the fireplace will get clogged with debris (pet
hair, ash, dust, etc.). Sometimes these
valves are improperly installed and they leak, creating fire hazards.
Finally,
we often see that manufacturer’s instructions are not followed during fireplace
installation. The key point to make here
is that all equipment and appliances and instruments have a certain operating
range that if exceeded due to improper construction or installation or
maintenance, these components will fail causing property damage and loss of
life.
As we noted earlier, if subrogation is contemplated, it
is important to notify potential responsible parties to inspect the scene,
prior to evidence removal and storage, in order to avoid spoliation claims.
SUBROGATION ASSOCIATED WITH LOSSES
CAUSED BY VENTLESS FIREPLACES
Ventless
fireplaces have resulted in a number of losses caused by design failures, as
well as failures caused by lack of regular maintenance or abuse. These fireplaces can be inspected for the
following defects or hazardous conditions:
• A gas leak. During
production, installation or servicing, a leak can be created;
• plugged burner
ports. The contractor may accidentally plug the burner ports while spreading
ceramic tile over the burners, or they may be painted over at the
factory. The resulting unbalanced burn will create excessive carbon
monoxide;
• a clogged burner.
Dust, carpet lint and pet hair can gradually choke off the fireplace’s air
supply, leading to incomplete combustion and high amounts of carbon monoxide that
are vented into the living space;
• high gas-input
rate. Excessive carbon monoxide ventilation or overheating of the unit will
result from firing the gas higher than the input rate set by the manufacturer’s
specifications. This can be caused by high gas-supply pressure, an incorrect
orifice drill size done at the factory, or if the installer gives the
customer's unit a larger flame for aesthetic reasons;
• the fireplace is
oversized for the square footage of the area to be heated.
• a cracked burner.
The gas burner may develop a crack over time and function erratically,
producing high levels of carbon monoxide;
• the fireplace
contains items other than the artificial logs designed for the unit. Problems
caused by the incineration of firewood or other flammable items will be
immediate and extreme. A more likely and less obvious hazard is created by
adding pebbles, lava rocks, and other non-combustible aesthetic touches to the
fireplace, as their exposure to flames will cause an unsafe rise in levels of carbon
monoxide; and
• a missing or
defective oxygen detection sensor. As
these components may fail, it is advisable to install a carbon monoxide
detector near a ventless fireplace and, ideally, in other rooms, as well.
In summary, ventless fireplaces, while attractive and portable, suffer from a design flaw that may allow dangerous gases to enter the living space.
As we noted earlier, if subrogation is contemplated, it
is important to notify potential responsible parties to inspect the scene,
prior to evidence removal and storage, in order to avoid spoliation claims.
SUBROGATION
SERVICES AT METROPOLITAN
METROPOLITAN
has broad experience handling subrogation claims arising from water, fires,
explosions, construction defects, product failures, energy and oil release
claims, and boiler and machinery failures. Our cases range from highly complex commercial
losses to smaller scale business and personal lines claims. Claims we handle include:
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We
routinely involve our teams of origin and cause investigators; civil,
structural, geotechnical, electrical, mechanical, metallurgical, materials, and
automotive engineers; combustion scientists; fire protection specialists;
certified fraud examiners; accountants; law enforcement; and coverage counsel
in the underlying claim to analyze and determine the causes of losses and
accidents. We work with outside or
insurer counsel to ensure thorough analysis, proper evaluation of losses, and
to exhaust and/or eliminate alternative theories. We, along with the team of lawyers, develop
non-destructive and destructive testing protocols, coordinate transfer of
evidence and preservation of evidence.
Metropolitan Engineering, Consulting & Forensics (MECF)
P.O. Box
520
Tenafly,
NJ 07670-0520
Tel.:
(973) 897-8162
Fax:
(973) 810-0440
E-mail:
metroforensics@gmail.com
Web
pages: https://sites.google.com/site/metropolitanforensics/
https://sites.google.com/site/metropolitanenvironmental/
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