Thermal inspection of the former Temple of Annunziata

Thermography is increasingly meeting the needs for the preservation of Italy's architectural heritage. However, when a building also holds historical and cultural significance, investigations aimed at preserving its integrity become even more crucial and important, not only for professionals in the field but also for the community as a whole.

We spoke with Danilo Mei, a professional thermographic operator, about his experience in Camerino. Danilo was called to conduct a thermographic inspection at the Former Temple of Annunziata, a historical monument dating back to the late 15th century, which holds significant cultural importance for the local community as well as the Marche region.

Danilo chose to use the Hikmicro SP60 thermographic camera for the inspection, providing an interesting case study in both the execution phase and the results achieved from the inspection. Keep reading to discover the activities carried out and the outcomes of the investigation.

Demand

More and more often, Engineers, Architects, and Restorers have the necessity to have a deeper knowledge of the built environment. In recent years, thanks also to modern instrumentation, the awareness of the professional has matured, and demands to know as much as possible about the structure in question. This request then makes the processes of design, execution, direction, and accounting of the works much easier and often prevents problems from arising.

Among the investigations, thermography completely fulfills this task. It is able to examine large surfaces quickly, non-destructively, in a repeatable manner, and at an affordable cost. It requires professional equipment and specialized thermographic operators with specific experience in the field of application.

The specific case study concerns an investigation carried out by Diemmeservices of Danilo Mei, commissioned by Unilab Sperimentazione srl, at the former Temple of the Annunciation in Camerino, a church from the 1500s rendered unusable due to the earthquake of 2016, currently the subject of surveys and investigations for the subsequent drafting of a repair project.

Specifically, thermographic investigations were carried out to identify thermal anomalies indicating the wall texture, the possible presence of systems, and detachment or bulging in the vaults.

The areas under investigation were heated using a hot air cannon, constantly monitoring the environmental conditions of temperature and humidity. The heating of the investigated area made it possible to highlight thermal anomalies indicating potential detachments and bulges, lesions and microlesions, wall texture, technological systems, and different layers of plaster.

Procedure

The operation was carried out by heating modest wall areas, approximately 40-50㎡, and then collecting a Thermogram. During the heating phase, the HIKMICRO SP60, placed on a tripod, constantly monitored the area under investigation, to immediately detect and record any anomalies that occurred. 

In the Thermogram, the infrared image was overlaid with the visible one for better positioning of the thermal anomalies, and an infrared photomosaic of the investigated areas was created. This allowed for an efficient highlighting of the detected anomalies.

Result

The analysis made it possible to clearly identify structural anomalies, lesions on the wall fabric, and plaster detachments, effectively pinpointing the areas for intervention.

Similarly, it was possible to discover the areas where relatively recent interventions had been made, with visible changes through thermography, such as the installation of electrical systems or differences in material texture, indicating the use of a different material from the original.

The Instrumentation

The thermographic camera used in this investigation is the HikMicro SP60, a high-performance tool equipped with a 640x480 resolution sensor and a thermal sensitivity (NETD) of less than 30 mK.

These features allowed for the discovery of very interesting details about the texture and layers of the plaster.

Flexible and easy to handle, its large 5-inch LCD Touch Screen display is adjustable and detailed, allowing us to immediately detect any anomaly, no matter how small. The focus is fast and precise, and temperature adjustment is done with a touch directly on the image, at the point to be analyzed.

The battery life is remarkable, with approximately 6 hours of continuous use. With the two included batteries, a full day of investigations is easily covered.

Another important feature is the quality of the visible image, 3264 × 2448 (8 MP), which allowed for further time savings during analysis for the visible/IR overlay and report generation.

The SP60 has proven to be an excellent IR camera, with quality capable of detecting remarkable details of the wall texture with very low noise in the thermograms. Its features also allow us to focus on the investigation without getting lost in lengthy settings or menu navigation: everything we need is right on the display.