~ Summary ~
In July 2020, a fire at a loading docks Grain Store required a 13-month thermal imaging monitoring project. Using drone-based and ground-level thermography, we monitored residual heat, supported fire suppression efforts, and provided critical data for insurance assessments. Our expertise in Level 3 Certified Thermography helped prevent reignition, validate the liquid nitrogen extinguishing method, and ensure a safe, controlled resolution of the incident through detailed thermal analysis and long-term monitoring.
Introduction
Industrial fires pose significant challenges, especially in storage facilities containing combustible materials. This project involved a grain store explosion and fire, which persisted for over 13 months, creating long-term fire risks, structural concerns, and environmental hazards. The nature of the stored grain insulated the fire, making conventional suppression efforts largely ineffective. With internal hotspots smoldering undetected beneath the surface, ongoing thermal monitoring was critical to track fire activity, prevent re-ignition, and guide firefighting efforts.
Traditional firefighting methods struggled to contain the deep-seated heat sources, as water and foam were unable to penetrate the compacted grain mass effectively. The fire persisted beneath the surface, with heat spreading through convection within the stored material. Ground-based inspections using handheld infrared cameras proved limited in scope and accuracy, unable to safely capture the full extent of the smoldering fire. To overcome these challenges, a drone-based thermal imaging solution was deployed, allowing for frequent aerial surveys and high-resolution radiometric thermal data collection.
The collected thermal data was used to identify hidden heat sources, track temperature changes over time, and assess the effectiveness of different fire suppression techniques. The ability to capture comprehensive thermal readings from a safe aerial vantage point provided emergency responders and structural engineers with the data needed to make informed, real-time decisions. This case study highlights the critical role of thermography in industrial fire monitoring, demonstrating how drone-based thermal imaging can significantly enhance fire management strategies.
Industrial Fire Monitoring, Drone Fire Surveillance, Thermal Imaging for Fire Detection, Fire Suppression Thermal Analysis, Liquid Nitrogen Firefighting, Smouldering Fire Thermography, Drone Heat Mapping, Industrial Safety Fire Prevention, Fire Risk Thermal Inspection, Emergency Fire Monitoring
Task & Objective
The primary objective of this project was to implement a long-term thermal monitoring strategy to assess fire progression, suppression effectiveness, and structural risks. Given the scale and complexity of the fire, it was necessary to continuously track heat zones using aerial thermal imaging.
Unlike traditional ground-based thermography, which relies on static or handheld infrared cameras, drone-based thermal surveys allowed for regular, large-scale assessments with high accuracy. This continuous monitoring approach helped firefighters and engineers identify critical zones, ensuring targeted and efficient fire suppression efforts.
By capturing thermal data from an aerial perspective, we were able to:
Data Analysis and Fire Suppression Evaluation
Once the thermal imagery was collected, it was processed and analyzed to identify fire trends, temperature fluctuations, and suppression effectiveness. The fire’s progression over time was monitored to detect patterns in heat distribution and track the emergence of new hotspots. These findings enabled site managers and fire crews to fine-tune suppression efforts, ensuring resources were allocated efficiently to the most affected areas.
The analysis provided valuable insights into:
Liquid Nitrogen Fire Extinguishing Trials
Given the complex nature of the fire, alternative fire suppression strategies were explored and tested. One innovative approach involved the use of liquid nitrogen as an extinguishing agent. Unlike water or foam, which may fail to reach deep-seated heat pockets, liquid nitrogen is capable of rapidly cooling materials and displacing oxygen, cutting off the fire’s ability to sustain combustion.
Thermal imaging was instrumental in evaluating the effectiveness of this method:
- Pre- and post-treatment thermal scans were conducted to measure temperature reduction rates.
- Comparisons between nitrogen-treated zones and untreated areas revealed the cooling efficiency of liquid nitrogen.
- Long-term monitoring assessed whether nitrogen effectively prevented re-ignition.
These trials provided groundbreaking data on the viability of liquid nitrogen for industrial fire suppression, offering potential applications for similar fire scenarios in the future.
Effectiveness of Liquid Nitrogen as a Fire Suppressant
The introduction of liquid nitrogen as a suppression method offered promising results, with thermal imaging confirming rapid and effective cooling in targeted areas.
- Post-nitrogen treatment scans showed an immediate and significant temperature drop, compared to areas treated with traditional firefighting methods.
- Some zones required multiple applications, as heat from surrounding materials caused re-heating.
- Thermal data indicated liquid nitrogen was particularly effective in confined areas, where conventional methods struggled to penetrate.
These results provided valuable insights into alternative fire suppression strategies, demonstrating the potential for future use of nitrogen in industrial firefighting scenarios.
Key Findings
Persistent Underground Heat Sources
One of the most significant challenges of this fire was its long-term persistence, as heat remained trapped within the grain storage for months despite continuous firefighting efforts. Unlike open-air fires, which are easily extinguished, deep-seated smoldering fires can reignite without warning, posing an ongoing safety risk.
Key findings included:
- Thermal scans revealed stable heat zones in areas where the fire was believed to be extinguished, proving that smoldering continued beneath the surface.
- Some hotspots migrated over time, requiring continuous monitoring to track shifting fire zones.
- Deep-seated fires were resistant to traditional suppression efforts, as heat retention within the grain caused slow-burning combustion.
By tracking these thermal changes over time, fire crews were able to refine their intervention strategies, directing resources to areas most at risk.
Effectiveness of Liquid Nitrogen as a Fire Suppressant
The introduction of liquid nitrogen as a suppression method offered promising results, with thermal imaging confirming rapid and effective cooling in targeted areas.
- Post-nitrogen treatment scans showed an immediate and significant temperature drop, compared to areas treated with traditional firefighting methods.
- Some zones required multiple applications, as heat from surrounding materials caused re-heating.
- Thermal data indicated liquid nitrogen was particularly effective in confined areas, where conventional methods struggled to penetrate.
These results provided valuable insights into alternative fire suppression strategies, demonstrating the potential for future use of nitrogen in industrial firefighting scenarios.
Long-Term Fire Risk and Structural Concerns
The prolonged nature of the fire raised concerns over structural stability and material integrity within the grain store. Sustained heat exposure can cause material degradation, leading to instability and potential structural failure.
Thermal imaging played a crucial role in identifying:
- Areas with significant heat-related structural damage, where high temperatures weakened load-bearing elements.
- Heat migration patterns, highlighting where the fire had spread beyond its originally affected zones.
- Potential re-ignition risks, ensuring continued surveillance of high-risk areas.
By integrating fire monitoring with structural assessment, the project provided a holistic risk evaluation, supporting long-term site management and safety planning.
