~ Summary ~

A thermographic survey was conducted on a high-rise commercial building with a glass curtain wall system to assess thermal performance, heat loss, and air leakage. Using UAV-mounted infrared imaging, the study identified minor efficiency losses at mullions, spandrel panels, and external doors. No critical defects were found, but minor air leakage and thermal bridging effects were noted. Recommendations included inspecting door seals and verifying Low-E glass coatings to improve energy efficiency. Regular monitoring is advised to optimize long-term building performance.

Thermography UK-Advanced Thermal Survey for a Commercial Glass Curtain Wall

Introduction

A recent thermographic inspection was conducted by our client on a high-rise commercial building featuring an extensive glass curtain wall system. The survey was undertaken to assess thermal performance, heat loss, and potential air leakage, ensuring that the facade functions optimally in terms of energy efficiency and structural integrity. The inspection aimed to identify areas of excessive heat transfer, highlighting inefficiencies that may contribute to increased energy costs or compromised occupant comfort.

By utilising UAV-mounted thermal imaging technology, the assessment provided a comprehensive thermal profile of the entire building envelope, pinpointing locations where thermal bridging, air infiltration, or material inconsistencies could be affecting performance. Conducting the survey at night allowed for accurate differentiation between internally generated heat and external environmental influences, ensuring that results reflected true building conditions rather than transient solar effects.

The findings from this study enabled stakeholders to make data-driven decisions on potential maintenance or retrofit strategies, reinforcing the building’s overall sustainability and energy management plan.

Project Subjects

"thermal imaging survey, UAV building inspection, glass curtain wall assessment, commercial building thermal analysis, detecting air leakage in glass facades, UAV thermography for energy efficiency"

Project Skills

Thermography Level 3, UAV drone

Certified Master Thermographer Level 3

Thermal Imaging Survey, UAV Building Inspection, Glass Curtain Wall Assessment, Commercial Thermography, Building Energy Efficiency, Heat Loss Detection, Air Leakage Analysis, Infrared Building Survey, Thermal Bridging Detection, Drone Thermography UK

Fire Thermal Imaging Monitoring
Grain Store Explosion and Fire Thermal Monitoring

Task & Objective

The primary aim of the thermal survey was to identify thermal anomalies within the glass curtain wall system, including heat loss at mullions, air leakage at spandrel panels, and door seal performance. The inspection aimed to provide quantifiable insights into the building’s energy efficiency, helping to detect areas where heat transfer inefficiencies could be optimised.

Key Objectives:

  • Assess the thermal performance of the curtain wall system.
  • Detect thermal bridging effects at mullion interfaces.
  • Identify air infiltration and seal integrity issues at doors and spandrel panel joints.
  • Provide actionable recommendations for enhancing energy efficiency.

Challenges

Conducting a large-scale thermographic inspection on a multi-story commercial building presented several challenges:

  1. Survey Conditions – The inspection had to be performed at night to eliminate solar heat gain, ensuring accurate thermal readings.
  2. Survey Distance – The UAV-based thermographic inspection required precise calibration to detect small but significant temperature variations at heights exceeding 20 meters.
  3. Emissivity & Reflection Issues – The glass curtain wall had Low-E coatings, which required careful adjustment of thermal imaging parameters to account for emissivity variations and external reflections.
  4. Environmental Variables – Wind speed, external ambient temperature fluctuations, and internal heat sources had to be considered when analyzing the results.

Approach & Procedure

The thermographic inspection was conducted using a high-resolution UAV-mounted thermal imaging camera, allowing for precise, non-intrusive data collection across the entire building facade.

Survey Methodology

  • Nighttime Inspection: The survey was conducted at midnight to ensure that all solar heat had dissipated, providing a stable temperature differential.
  • Infrared Imaging: A radiometric uncooled microbolometer camera was used to capture detailed thermal maps of the glass curtain wall.
  • Systematic Coverage: Each elevation was scanned methodically, ensuring that all mullions, spandrel panels, and door interfaces were assessed.
  • Baseline Temperature Calibration: Temperature readings were referenced against ‘known good’ areas to establish an isotherm threshold of +2°C for identifying thermal anomalies.
  • Environmental Data Recording: External conditions, including ambient air temperature (4.7°C), internal air temperature (19°C), and relative humidity (73%), were recorded to ensure accurate interpretation.

Key Findings & Conclusions

The thermal imaging survey revealed localised temperature anomalies at specific mullion junctions, spandrel panel connections, and door interfaces. However, all identified anomalies fell within expected performance tolerances for a modern curtain wall system.

Key Observations:

  • Mullions exhibited localised heating (2-4°C above baseline), consistent with thermal bridging from internal floor slabs.
  • Spandrel panel joints showed signs of air leakage, suggesting that seal integrity should be reviewed.
  • Certain glass panels exhibited unexpected temperature variations, which may indicate Low-E coating inconsistencies or glazing seal degradation.
  • External door interfaces consistently showed heat loss, likely due to seal deterioration or engineered air venting design.

Risk Assessment & Recommendations:

  • Thermal bridging at mullions: Within expected tolerances but could be optimised by verifying the thermal break design.
  • Spandrel panel joints: Potential air leakage, requiring seal inspections to improve performance.
  • Glass panel performance: Variations suggest the need for further verification of glazing specifications.
  • Door seal inefficiencies: High-priority maintenance checks recommended to reduce heat loss.

Final Conclusion

The survey concluded that the glass curtain wall system performed within expected tolerances, with minor efficiency losses identified at key structural joints and door interfaces. The findings support proactive maintenance efforts, ensuring that thermal performance is optimized and long-term energy efficiency is maintained.