Modern technology is making great leaps forward in 3-D imaging, thermal scanning and measured photographs. Digital scans of buildings can be a valuable and less intrusive tool for Energy Advisors, Contractors and Renovators.

To best record what they find during their audit, an Energy Advisor is going to take lots of pictures. They will need at least one picture of the building face from a street view for filing purposes. From there, the EA will take photos of trouble spots and areas that will require special attention. In difficult to reach areas, a probing camera may be required to see behind walls or inside ductwork.

THERMOGRAPHIC IMAGES

Infrared cameras are commonly used to provide a heat-loss diagnostic in visual form. The camera picks up on warm and cool areas on a wall, floor or roof structure, creating an image with a temperature gradient represented by lighter and darker colours for hot and cold, respectively. This thermographic scan may show where insulation or air sealing is not installed properly, or where thermally conductive materials are located within an assembly.

The ideal conditions for thermography are exterior shots, early evening, on cloudy days in the fall season. With heating systems turned on, a variety of thermal images can be shot from all vantage points around the building.

LASER and LIDAR SCANS

Creating a very accurate virtual 3-D model of a building is now possible with laser and LIDAR scanning technology. Those scans can then load into computer aided design (CAD) and building information management (BIM) software to map out a plan for construction or retrofit.

LIDAR systems work like traditional radar, but uses the light from a laser to record the textures and dimensions of an object as they bounce off and return to the camera. The accuracy that professional grade laser scanners can achieve may be within millimetres, depending on the distance from the scan station to the building.

PHOTOGRAMMETRY

With a collection of photographs, it may be possible to gather enough information to create an accurate model of a building. This is what the science of photogrammetry is based on - from 2-D images, data may be extracted to realize a 3-D image. The information collected may include:

• Known distances measured parallel to the image, such as brick lengths, sidewalk blocks, etc..
  
• Stereo imaging that compares the same location taken from different vantage points.
  
• Benchmark measurements provided by placing markers in select photographs - tape measures or metre sticks, for example.
• Ground, aerial and interior photography combined to create an accurate representation of a structure.