Drone-Mounted Thermal Imaging Camera Inspections of Green Roofs and Facades

Drone-Mounted Thermal Imaging Camera Inspections
of Green Roofs and Facades

While modern, the green roof concept is over 100 years old. Köhler (2006) reports that the first wave of green roof construction in Germany came at the end of the 19th century, yet by the end of this early boom, less than 1% of German roofs were green. [1] Nowadays, the world leader in green roof technologies is still Germany, and more than 10% of German houses have installed green roofs (Köhler, 2006). In fact, these verdant ‘crowns’ have been one of the key elements of urban design in recent decades. Green roofs are suitable for retrofit or redevelopment projects as well as new buildings, and they can be installed on small garages or larger industrial, commercial and municipal buildings.

In addition to the pleasant aesthetic that green roofs offer, many scientific researchers and environmentalists focus on the cooling effects of these leafy installations. [2] They effectively utilize the natural functions of plants to filter water and treat air in urban and suburban landscapes. [3]

Furthermore, green roofs improve efficiency and reduce energy consumption. [4]  They can cut heating costs by adding mass and thermal resistance value, and even reduce heat islands by increasing evapotranspiration. [5] A 2005 study by Brad Bass of the University of Toronto showed that green roofs can also reduce heat loss and energy consumption in winter conditions. [6] Another modeling study found that adding green roofs to 50 percent of the available surfaces in downtown Toronto would cool the entire city by 0.2 to 1.4 °F (0.1 to 0.8 °C). [7]

Green Roof Construction

Green roofs and facades are not only a visual building element – they constitute a functional construction that has indisputable advantages over more conventional flat roofs. However, to fulfill their potential, green roofs must be layered properly. This can be tricky, for their structure is quite complicated. To name just the most important components (individual layers may vary), we have: soil, a water storage panel, the waterproof and anti-root membranes, the protection, filter, and drainage layers, the substrate, and the vegetation. An example of green roof composition can be found in figure 1.

Green roofs and green facade elements are also often equipped with automatic irrigation systems. Irrigation system installation depends on type (intensive, semi-intensive, or extensive) and plant species selection.

Figure 1.: An example of the composition of the green roof. [8]
Figure 1.: An example of the composition of the green roof. [8]

Green roof and facade inspections with the WIRIS Pro thermal imaging camera

If they are to function properly, green roofs require maintenance. That’s where thermal imaging cameras used in cooperation with UAVs can play a vital role. With a drone-mounted thermal imaging camera, a thermal imager can check the entire function of a green roof quickly (in about 25 minutes) and comprehensively.

An overview aerial photo – thermogram provides important information about irrigation system functionality, plant water stress, and the health of individual green roof layers. Measurement of the exact temperature distribution on a green roof surface clarifies the proper functioning of the flat roof and its impact on the immediate surroundings (microclimatic influence).

3D thermal model of the LIKO-S area composed from data acquired by the Workswell WIRIS thermal imager and created in Pix4D software. Captured by Vertical Images.

3D thermal model of the LIKO-S area in the RGB spectrum. Captured by Vertical Images.

Why Workswell WIRIS Pro

 We offer something very special, without which it is virtually impossible to create a useful 3D model. This is the Workswell ThermoFormat – software that allows you to mass edit hundreds of thermograms at once. ThermoFormat makes it easy to change the emissivity or temperature range of a large number of images in a matter of minutes. Nobody else can offer you software like Workswell ThermoFormat!

Of course, software isn’t the only thing that matters – great hardware is critical. The Workswell WIRIS Pro offers high-quality thermal images, with a resolution 640×512 px. Other parameters are also important, and they include high thermal sensitivity, minimal temperature drift (even during long flights), and very high thermogram homogeneity.

Thanks to these properties, Workswell makes it easy to assemble large orthophotomaps in a given temperature spectrum. The problems can then be clearly and transparently localized and identified. Here, more than anywhere, a picture is worth a thousand words.

Workswell wiris pro detects Typical Green Roof Problems

Typical green roof (and facade) problems detected with Workswell WIRIS Pro thermal camera include:

  • Vegetation stresses due to drought.
  • Plant cover of less than 90%.
  • Wilting, discolored, or dying vegetation due to disease, pests, or stress. 
  • Vegetation in need of maintenance, removal, or mowing.
  • Standing water.
  • Observable gullies and erosion.
  • Cracked or leaking waterproof membrane.

LIKO-S – “living buildings” pioneer

LIKO-S is a Czech family-run manufacturing and construction business based in Slavkov, near the city of Brno. The company has pioneered the concept of “living buildings” based on natural thermal stabilization. LIKO-S assemble Living Buildings – storage halls, production halls, inhall units, and ventilated and green façades. LIKO-S insulate buildings with Smart Insulation. [2] The company cooperates with a number of research organizations in the Czech Republic and abroad.

The Workswell WIRIS Pro thermal camera helps LIKO-S develop and maintain green roofs and facades, increasing structural efficiency and durability. Vertical Images is an aerial service provider for LIKO-S.

We bought our first thermal imaging camera from Workswell in 2014, and our second (WIRIS) in 2016. We have just expanded our sensory equipment with 2x WIRIS Pro cameras. Compared to the previous version, this is a major advancement in the utility software, RGB camera, and communication with various control units. We thank Workswell for the fast delivery and long-term support. Workswell thermal imagers are one of our basic working tools.“, Petr Lněnička, Vertical Images, CEO

References

[1] Li, W.C. and Yeung, K.K.A.- A comprehensive study of green roof performance from environmental perspective

[2] https://www.liko-s.com/en/liko-s-introduced-the-world-s-first-living-hall-liko-vo

[3] https://en.wikipedia.org/wiki/Green_roof

[4] Li, W. (2013). A scenario planning approach for school green roofs to achieve stormwater management benefits: A case study of Brier’s Mill Run Subwatershed

[5] Santamouris, M. (2014). Cooling the cities – A review of reflective and green roof mitigation technologies to fight heat island and improve comfort in urban environments. Solar Energy, 103(Supplement C), 682–703.

[6] “University of Toronto – News@UofT – Green roofs in winter: Hot design for a cold climate”. 17 November 2005. Archived from the original on 11 April 2008. Retrieved 10 June 2008.

[7] Reducing Urban Heat Islands: Compendium of Strategies, Green Roofs. Available from:https://www.epa.gov/heat-islands

[8] Syumi Rafida Abdul Rahman, et al., Perception of Green Roof as a Tool for Urban Regeneration in a Commercial Environment: The Secret Garden, Malaysia, Procedia – Social and Behavioral Sciences, Volume 170, 27 January 2015, Pages 128-136