What Are the Primary Applications for Thermography?
In the thirty years thermography has been used to solve building problems, a number of major applications have been developed.
These include: Insulation checks Moisture Intrusion Building Structural Verification HVAC Performance Electrical Overheating Air leakage location Rodents
Insulation checks Missing, damaged or non-performing insulation will stand out clearly in a thermal image when there is at least a 18°F (10°C) temperature difference between the conditioned space and the outside air. The inspection is done from both inside and outside, with the best results usually gained from inside where the thermal patterns are more distinct. When work is done in the daytime or early evening, the impact of solar loading must be considered. The effects of the sun can remain on a wall six to eight hours after sunset. Wind must also be reckoned with as it can quickly eliminate the thermal difference on an exposed surface. Keep in mind that wind can also enhance thermal patterns, especially those associated with poor performance of insulation. It is essential to know the type of insulation in the building as well as construction details, including how the insulation was installed. It is not unusual to find insulation in place but not performing up to specifications.
The costs of poor insulation performanceare numerous. In addition to excessive energy consumption, there may be health issues associated with mold growth and damage to roofs and interiors.caused by water intrusion. More and more insulation contractors are using thermographyto better understand the construction of existing buildings before they begin work or, in some cases, before they bid the job.
Thermal imaging provides us with a high-quality map of both the structural elements and any insulation that may already be in place. With this tool, a contractors work is more accurate and cost-effective. Contractors who inject foam insulation are finding thermographyallows them to see fill levels during installation, expediting their work and assuring it is of the highest quality.
Missing Insulation in Attic
Air leakage location Air leakage can account for up to half of the energy consumed to condition buildings. Of course, adequate air exchange is essential for health and safety, but most buildings have a far higher rate than is necessary. The root cause is poor design and/or construction, which allows air to move through the thermal perimeter. This can be as straightforward as a failed door weather seal or as complex as an air pathway through a plumbing chase in an interior wall or ceiling plenum. The leakage pathway is often complex and without infrared difficult to visualize.
Air leakage can be seen under natural building conditions, but the results can be confusing and incomplete. Inspections are best conducted when air flow is directed and controlled. This can be easily accomplished with exhaust fans, a blower fan door, or in larger buildings, by temporarily altering the HVAC system to create a negative pressure inside.
The first step in moisture problem remediation is to quickly and accurately locate and remove all sources of moisture. Infrared cameras instantly show you what's wet and what's dry. IR cameras can instantly find the ultimate source with little or no physical disassembly of the premises and minimal disturbance of inhabitants.
Before infrared technology that brown stain on the ceiling might be a leak in the roof, after infrared technology that brown stain,well, it just needs a little paint (because we verified using infrared powered technology that the leak is not active).
That is just one example of how the power of technology can literally save buyer and sellers thousands of dollars by getting them answers to their questions, rather than creating more questions. This has real implications for our businesses.
As building designs and techniques produce tighter thermal envelopes, moisture (from leaks or condensation) has created more and more problems. Locating moisture with thermographycan be simple because it has both a high thermal conductivityand a high heat capacitance. The growing popularity of buildings using Exterior Insulation and Finish Systems (EIFS) has been accompanied by numerous cases of moisture-related structural damage and health problems.
Although often attributed to the performance of windows, water typically intrudes where sealing or flashing systems were inadequate or have begun to fail. Sometimes this can occur around the windows, but there are many other possibilities. Once water intrudes, moisture is trapped under the relatively impervious foam. In warm climates, decay of structural wood elements can be shockingly rapid. Thermography is an invaluable tool to locate moisture in EIFS systems. Inspections are best conducted in the early evening from the outside after a sunny day with little or no wind. It may also be possible to locate moisture from inside during cooling or heating conditions.
In metal buildings and mobile homes, of Key West and the Florida Keys, moist air can bypass an ineffective moisture-retarder and condense in cooler wall and ceiling cavities. The water is typically mistaken for leakage. Damage includes structural deterioration, mold growth and reduced insulation values. In commercial high-rise buildings, similar problems can lead to brick spalling and fastener corrosion.
One of the fastest-growing new uses of the technology is in the restoration business. When buildings are damaged by floods, broken water lines or other sources, insurance companies are often involved in a settlement. Before the claim can be settled, all parties must be assured the building has been restored to a dry condition to prevent further damage from residual moisture, mold and decay. Thermography, often in conjunction with contact moisture probes, is being widely used to provide this documentation.
Moisture Intrusion Stucco Wall
HVAC performance HVAC systems can be plagued by design and installation problems resulting in excessive energy use and/or uncomfortable (or even dangerous) buildings. Thermography helps building specialists visualize the otherwise invisible impact of this poor performance as indicated by excessively hot or cold areas. Once these have been located, the root cause can be determined; these may include reversed or misdirected airflow or supply air short circuiting into return ducts.
Verification of Construction Detail No area of application is more important these days, particularly in commercial buildings, than the verification of construction details and performance. Thermography is being used with great success to verify bond beams and placement of reinforcement in concrete masonry unit (CMU) walls as well as structural elements of pre-cast, tip-up walls.
How? The solid portions of these walls change temperature more slowly than the rest. The inspection can be conducted anytime the wall is in thermal transition,typically in the early evening as it cools down. The inspection is conducted during construction, rather than after completion, allowing deficiencies to be corrected prior to occupation, often with minor inconvenience and cost.
Sick-building Syndrome When buildings are too tight or too moist, health-related problems quickly come to the forefront. Grouped together as sick building syndrome, these can stem from inadequate HVAC performance, moisture trapped in walls, mold growth on cold, damp surfaces and inadequate air change rates. Many of these present signatures that can be visualized and diagnosed, at least in part, with the aid of thermography.
Rodents Many unwanted animals can be detected. Boats Boat hulls and machinery can be analyzed for signs of failure. Electrical Overheating problems can be detected before they cause a breakdown, short or fire.
-Preventative / Predictive Maintenance
-Electrical current flowing through conductors generates heat
-Many electrical defects accompanied by temperature rise
-Rises may be present for weeks prior to failure
-Some defects cause component cooling
Electrical Breaker box overheating
Thermography, in Key West and the Florida Keys, perhaps now more than ever, continues to prove itself to be an invaluable tool for builders and building owners. Infrared inspections can not only save energy costs, but, in many cases, also save the building itself!
While building inspections may look simple, they are, in fact, among the most complex tasks a thermographermay ever face. It is essential that we understand building dynamics and construction as well as the basics of heat transfer and radiometrics.
The Snell Group Consumers Choice Property Inspections Inc.