Infrared thermal imaging is a diagnostic tool for buildings that can help detect a variety of building performance related problems such as air leaks, missing insulation, or thermal bridges. T.P Singh. Director-Sales (HH) at FLIR Systems India Pvt. Limited talks to Buildotech about this technology and its applications.
What are the salient features of thermal imaging technology?
Infrared (IR) inspection is a powerful and non-invasive means of monitoring and diagnosing the condition of buildings. An IR camera can identify problems early, allowing them to be documented and corrected before becoming more serious and more costly to repair. An infrared inspection within building diagnostics among other things help:
• Visualize energy losses
• Detect missing or defective Insulation
• Find moisture in the insulation, in roof & walls, both internal & outside
• Detect mold and badly insulated areas
• Locate thermal bridges
• Locate leaks in flat roofs
• Source air leaks
• Detect breach on hot-water pipe
• Detect construction failures
• Locate radiant floor heating faults
• Monitor the drying of buildings
• Detect electrical faults
• Find faults in supply line and district heating
What are the application areas for this technology in buildings?
Detecting Poor Insulation and Air Leaks
• Infrared thermography (thermal imaging) is an outstanding tool to locate building defects such as missing insulation, delaminating render and condensation problems and “see” energy loss. Thermography also helps assess flat roofs for damaged insulation and trapped moisture.
• Bigger office buildings often have an atrium in the middle and a glass roof above to let the sunshine in. These are water tight but not air tight. The air leak are detectable with thermal imaging.
• Large warehouses with well insulated prefabricated walls and roof too can experience energy loss from the joints between the parts.
The typical thickness of the insulation varies from country to country. In cold climates the insulation usually is thick. In countries with warmer temperate climates there is less thickness or nothing at all. On the other hand, in warmer climates cooling inside is often used which calls for thick insulation to take care of the energy. In using an IR camera, the rule of thumb is that it should be at least 10°C temperature difference between outside and inside temperature for the sides of the wall to get good and easy to see patterns. Using a camera with higher resolution and thermal sensitivity, the temperature difference can be less.
Detection of Air Leaks
It is not unusual to find air leaks through the envelope of a building. An air leak leads to higher energy consumption, often causing problems with the ventilation system, as well as causing condensation in the construction which makes the indoor climate poor. Ninety percent of air leaks are caused by the defect in the climate shelf. To detect air leaks with an infrared camera a temperature difference and a pressure difference over the construction are needed. The air itself is not possible to see. With an infrared camera however, you detect the characteristic patterns that occur when cold air is coming through a leak in the construction going along a surface and cooling it down. The infrared inspection should always take place on the side of the construction which has negative pressure.
Moisture damage is the most common form of deterioration for a house. Air leakage can cause condensation to form within walls, floors, or ceilings and wet insulation takes a long time to dry and becomes a prime location for molds and fungi. Scanning with an infrared camera can locate moisture that creates an environment conducive to molds – locations that may never be seen with the human eye. One might smell its presence, but not know where it is forming. An infrared survey will determine where inherently moist areas are located that promote potentially serious mold and health problems.
Moisture can be difficult to spot and the trick is to make the construction change temperature. Materials with moisture will then be clearly visible as they change temperature much slower than dry materials. While other methods only measure the temperature in one point, infrared covers huge surfaces in an instant.
A thermal bridge is an area with less insulation due to the construction; such as a metal fastener, concrete beam, slab or column. Heat will flow the easiest path from the heated space to the outside – the path with least resistance. Very often heat will “short circuit” through an element which has a much higher conductivity than surrounding material, which can be described as a thermal bridge. Typical effects of thermal bridges are:
• Decreased interior surface temperatures; in the worst cases this can result condensation problems, particularly at corners.
• Significantly increased heat losses.
• Cold areas in buildings.
Supply Lines and District Heating
In cold climates heating of pavements and gangways are used. It is also common with district heating, a system for distributing heat generated in a centralized location for residential and commercial heating requirements. A thermographic survey can easily detect any defects in heating systems under ground. Even if there is snow on the ground, the heating pipe lines are visible with an infrared camera.
One of the most common faults in buildings are electrical faults. Most of the time these electrical problems are invisible to the naked eye, but an infrared camera instantly makes hot spots visible on a thermal image. You can scan electrical cabinets, components and survey multiple wires, connections and get an instant picture of potential trouble. The problem area can be detected and repaired before real problems occur! Common electrical targets in the building industry are fuses, electrical panels, and lighting.
Challenges and potential of the technology in the Indian market
Being responsible for sales of handheld series of FLIR in India and India operations for FLIR- Commercial Systems, in my experience awareness of the technology among Indian design & engineering professionals is the key issue. Majority of designers and developers are not aware of the availability of such a technology at such an affordable price. These products start at the cost of INR 110,000/- plus tax and different models are available as per the requirement. FLIR Systems maintains highest standard of quality and gives 10 years warranty on uncooled detector of handheld range after product registration.
The potential is huge as thermal imaging product have application in almost all segments of the building industry. Infrared thermography is the easiest and quickest method to detect energy waste, moisture and electrical issues in buildings. An infrared camera shows exactly where the problems are and helps focus the inspectors’ attention allowing him or her to properly diagnose areas with energy loss.