This time of the year we see a number of cause and origin (C&O) cases regarding property damages caused by heating, ventilation and air conditioning (HVAC) systems. Investigation and evaluation of these systems determines the cause of failure and damage, including whether or not there are sudden and accidental related causes or long term maintenance and age related conditions or some other cause. This blog addresses the results of some of the C&O investigations of these property damage claims.
The most common HVAC damage claims include: mold growth, water damage and air quality claims; carbon monoxide damage claims; theft or vandalism; lightning or power surge damage; improper installation or maintenance; hail/flood/fire/mechanical failure and other miscellaneous damage claims. This blog addresses the water damage/mold growth claims.
Mold Growth and Water Damage Claims
As the air conditioning system cools a building it produces a large amount of condensation. Without proper routine maintenance that condensation can lead to extensive water damage and mold growth. See Figure 1 for what can grow in the HVAC condensation pan, unless it is regularly maintained by the insured.
Figure 1. Mold growth collected from an HVAC drip pan. The insured complained about odor problems and stained or clogged air registers, but he never inspected the HVAC unit because it was located in the attic.
Depending on the humidity level, a central home air conditioner can produce from 5 to 20 gallons of water day. When the system is working correctly, this condensation drains off of the coil into a drip pan and is carried by a condensate drain hose into the sewer system.
Regardless of which system an AC system uses, almost all blockages occur in the small bend, called a trap. The trap system always holds a small amount of water that is there to keep fumes and other objects from backing in to the system. Over time, algae or gum builds up, the trap becomes clogged, resulting in a plugged condensate drain line. At other times, we see a kink in the hose, leading into water damage. Humidifiers can also add too much moisture to a house, leading to dampness and mold.
If for any reason (typically because of lack of maintenance or lack of proper operation or improper installation) the drain or the hoses become clogged, or the system is producing more water than the drain can handle, the result can be water damage and mold growth. The HVAC system then becomes a mold supper highway by recirculating air contaminated with mold spores and other contaminants throughout the building.
Depending on where the air handler is located, i.e. a basement, a closet or attic, if the water over flows it could go unnoticed for a period of time leading to extensive water damage and mold growth. See Figure 2 for a rusted air handler located in the crawl space. Lack of accessibility led to lack of maintenance, corrosion and water damage.
Figure 2. Rusted and leaked air handler located in the crawl space of this building.
Clogged drain lines are not the only cause of damage. There are other problems that can contribute to water damage such as excessive condensation and evaporator coils that are dirty or over worked. An overworked coil may freeze up and defrost over and over causing more water than the systems main drain can handle.
Many times, we have discovered that the HVAC ducts are leaking cold air that mixes with humid air in the attic or other non-conditioned area of the building; this causes condensation with subsequent water damage and/or mold growth. At other times, our inspections have discovered that the air leaks exist on the return side where the HVAC unit is drawing humid, un-filtered air into the blower and ducting, resulting in buildup of water and mold growth that in turn is released into the home. We oftentimes see mold growth on the ceilings around the air register. What is happening is that the builder often cuts the drywall opening too large and forgets or not properly seals the gap. The result is that humid and hot attic air enters the building through these openings and condenses, providing the moisture needed for mold growth.
Figure 3: Condensation formed on the exterior of the duct due to system leaks.
In many high rise constructions we have observed lack of return air ducting due to lack of space. This led to overworked HVAC systems, resulting in freezing, water leaks and mold growth. At other times we observed the ducts to be too bent, causing excessive energy use; the building owner then turned down the thermostat to compensate for the reduced system efficiency, causing duct sweating and mold growth. The building tenants complained that they were “breathing dust and mold”.
Figure 4. This is an example of a common problem we have seen with air ducts: they are bent by the installers too much trying to fit them in tight places. This has led to excessive energy usage, water damage and mold growth.
By far the most common area of mold growth in an HVAC system is associated with buildup of mold and dust inside the return duct. The buildup of mold and dust there will cause an accumulation of the same in the evaporator coils, leading to water damage and health issues inside the home. Regular maintenance of the air filters and the ducts will prevent such damage claims.
Figure 5 and 6: Dirty air filter and air duct (Fig. 5) due to lack of cleaning of the air filters and ducts. This resulted in dirty HVAC coils (Fig. 6), because there was lack of maintenance of the coils. The coils rusted, froze up and end up causing water damage to the insured’s property.
Overall, the overwhelming majority of the property claims could have been avoided with proper maintenance or replacement/repair of the failing HVAC components.
Metropolitan Engineering, Consulting & Forensics (MECF)
Providing Competent, Expert and Objective Investigative Engineering and Consulting Services
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/metropolitanenvironmental/
To unsubscribe from future technical blogs and announcements, please reply to this email with the word “unsubscribe” in the subject line.
Metropolitan appreciates your business.
Feel free to recommend our services to your friends and colleagues.
We know you need to process damage claims quickly and knowing the facts is now faster than ever – within 24 hours of site visit. Our Pegasos Forensic Investigation Services (PFIS) feature:
· Expert Forensic Investigators on-site.
· Defensible, Readable, Conclusive Reports.
· Fixed-Prices starting at $499 per chimney or roof inspection (volume discounts are also available). Flood loss assessments start at $999.0. HVAC equipment only inspections start at $299 for local (within one hour one-way drive) assignments.
· 10-State Coverage Area.
Metropolitan has extensive experience assisting in the evaluation of environmental factors. Our Certified Industrial Hygienists and Registered Professional Engineers have performed IAQ testing, mold testing, Chinese drywall corrosion investigations, water source evaluation and remediation design and oversight.
We perform Property Condition Assessments, Indoor Air Quality Evaluations and Environmental Site Assessments, including Indoor Air Quality