The traditional method of performing a roof inspection employs hand-held thermal imaging equipment or, when required, equipment mounted on manned aircraft. Irrespective of the method of data acquisition, the basic science of failure and detection can be described as follows:

• The substrate insulation on an industrial roof can be prone to degrade, which allows moisture to penetrate the roof in certain areas
• Areas with substantial moisture penetration lose the ability to insulate (the “R-value” essentially becomes zero) and causes energy (heat) to dissipate into the environment
• During the day, the roof is heated by the sun (Solar Loading)
• At night, the areas with dry insulation cool more quickly than the areas with wet insulation. The result is a visibly different thermal signature in the infrared (IR) spectrum, which enables inspectors to identify areas in need of repair
• A regular, accurate maintenance program minimizes heating and repair costs of the structure

Façade Inspection: Buildings consume energy – it is estimated that as much as 30% of all energy produced goes to commercial, industrial, or multi-unit residential buildings. Of this 30%, as much as 40% can be lost immediately, and 90% of this loss occurs within only 1% of the envelope. Put differently: a tiny fraction of the exterior of the building, generally at connection points between roofs and walls, is responsible for the vast majority of energy loss, and identifying/addressing these areas is critical.

The broader economic and environmental issues stemming from building energy loss are significant, and range from the carbon footprint from generation of “wasted” energy, to the impact on landfills of unsalvageable building materials which need to be replaced in the event of damage. Accordingly, governments have introduced legislation mandating periodic inspection. In the province of Quebec, Canada, Bill 122 mandates that, every five years buildings are inspected if they are more than five years old and over five storeys. Similarly, in Singapore they mandate commercial, industrial and institutional buildings must also be inspected in 5-year intervals.

Because the areas of energy lost tend to be small and hard-to-reach, UAS become the more economical and safe means of acquiring the necessary data. Moreover, the resolution of the data is critical: chipped bricks captured in a narrow field-of-view EO (visible light) image may be indicative of water ingress, and the precise overlay of a thermal image can help an inspector assess cause-and-effect. As with roof inspection, UAS can capture thermal imagery at 90 degrees to the façade, vs the oblique angles of handheld detectors on fixed-position lifts or harnesses. Thus, UAS technology ensures the highest accuracy thermal readings possible.

REQUIREMENTS

The building envelope inspection industry encompasses data capture of both roofs and façades (exterior walls). Both operations involve thermographic and electro-optical (daylight) imagery, with the thermography generally undertaken at night to ensure accurate data.

As well, reducing the time and resources needed for the inspections is a priority. For example, a roof with an area of 1 million square feet (equivalent to roughly 4 big-box hardware stores) takes a standard 2-person crew performing a night-time inspection 5-7 days under optimal conditions. Precipitation/inclement weather may force the project to be rescheduled to ensure consistent data collection across the roof.

When Industrial SkyWorks started the process of evaluating UAS, they focused on both a high standard of operating capabilities, as well as the broadest set of safety provisions within the UAS. Equally important was the operating stature of the provider of the UAS, particularly in an industry characterized by a lot of unproven technology from early stage companies.