Green roofs and green facades inspection using thermal imaging camera and drone

Green roofs and green facades inspection using thermal imaging camera and drone

Modern concept of green roofs has been established for over 100 years and they have been become one of the key elements in urban area in the past few decades. Many scientific researches and environmentalists focus on its cooling performance. [1]

Nowadays, the world leader in green roof technologies is Germany, where more than 10% of houses have installed green roofs (Köhler, 2006). Köhler (2006) reported that the first wave of constructing green roofs in Germany came at the end of 19th century. It only covered less than 1% of roofs in Germany during this boom. [1]

Green roofs are suitable for retrofit or redevelopment projects as well as new buildings and can be installed on small garages or larger industrial, commercial and municipal buildings. They effectively utilize the natural functions of plants to filter water and treat air in urban and suburban landscapes. [3]

Green roofs improve and reduce energy consumption. [4] They can reduce heating by adding mass and thermal resistance value, also can reduce the heat island 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] A 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 roofs construction

The green roofs and facades are not only a visual building element, but also a functional construction that has indisputable advantages over a conventional flat roof. However, for this the correct function of the individual layers of the green roof is essential. The structure of the green roof is quite complicated. Lets name the most important components (individual layers may vary): soil, water storage panel, the waterproof and anti-root membranes; the protection, filter, and drainage layers; the substrate; and the vegetation. An example of the composition of the green roof is on the figure 1.

Green roofs as well as green facade elements are also often equipped with automatic irrigation systems. Irrigation system installation depending on their 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 roofs and facades inspection using WIRIS Pro thermal imaging camera

Green roof maintenance is required. For that purpouse thermal imaging camera used in cooperation with UAV could be a key tool. The thermal imager can check the entire function of the green roof very quickly (in about 25 minutes) and comprehensively.

Overview aerial photo – thermogram provides an overview of irrigation system functionality, water stress of plants and functionality of individual layers of green roof. The possibility of measuring the exact temperature distribution on the green roof surface then objectifies the proper functioning of the flat roof and its impact on the nearest surroundings (microclimatic influence).

Figure 2.: 3D thermal model of the LIKO-S areal composed from data acquired by Workswell WIRIS thermal imager and created in Pix4D software. Captured by Vertical Images company

Figure 4.: 3D thermal model of the LIKO-S areal in RGB spectrum. Captured by Vertical Images company.

Why Workswell WIRIS Pro

 We offer something very special, without which the creation of the 3D models and  is literally suffering. This is Workswell ThermoFormat. Great software that allows you to mass edit hundreds of thermograms at once. Changing the emissivity or temperature range of a large number of images is a matter of minutes. Nobody else will offer you similar software like Workswell Thermo Format!

But i tis now only about software, but also hardware. Workswell WIRIS Pro could offer high resolution thermal imaging camera with resolution 640×512 px. However, other parameters are also very important: highest thermal sensitivity, really low temperature drift even during long flight and very high homogeneity in thermogram.

Thanks to these properties it is possible to assemble large orthophotomaps in the temperature spectrum. The problems can then be clearly and transparently localized and identified. Here, more than elsewhere, a picture says more than 1000 words.

Typical problems we are able to detect

Typical problems that could be on green roofs (and facades) detected using Workswell WIRIS Pro:

  • Vegetation is stressed due to drought.
  • Plant cover is less than 90%.
  • Vegetation is wilting, discolored, or dying due to disease, pests, or stress. 
  • Vegetation needs to be controlled through manual removal or mowing if specified by manufacturer.
  • Standing water is present.
  • Gullies or other evidence of erosion are observed.
  • Waterproof membrane is cracked or Leaking

LIKO-S – “living buildings” pioneer

LIKO-S is a Czech family run manufacturing and construction business based in Slavkov near Brno city. Company pioneers 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 using Smart Insulation. [2] The company cooperates with a number of research organizations in the Czech Republic and abroad.

Workswell WIRIS Pro thermal imaging system help the LIKO-S company in the development, maintenance of green roofs and facades, increasing the efficiency and durability of these structures. Vertical Images company is a aerial service provider for LIKO-S.

The first thermal imaging camera we bought from Workswell in 2014 and another (WIRIS) in 2016. Today we expanded our sensory equipment with 2xWIRIS Pro cameras. Since the previous version, this is a major advancement in utility software, RGB camera, 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