Measuring Fire-Damaged Breaches With Drones

Aerial measurement can give incident commanders a fast estimate of the width of a breach opening in a burning or recently damaged structure. A remotely piloted aircraft system (RPAS) can capture an elevated view when heat, smoke, unstable walls or falling debris make close access unsafe. The resulting evidence can support ventilation decisions, search planning, structural assessment and post-incident reporting.

For Australian fire and emergency services, the value lies in producing a defensible measurement rather than simply obtaining dramatic footage. A clear workflow should account for CASA requirements, radio coordination, privacy, thermal conditions and the limits of photogrammetry. Whether the job involves a warehouse in western Sydney, a rural property near Bendigo or a bushfire-damaged shed outside Hobart, accuracy begins with disciplined scene management.

Why Breach Width Matters During Fire Operations

A breach may be a window, door, roof opening, collapsed wall section or penetration created by fire spread. Its approximate width can help crews judge whether hose lines, search teams, ventilation equipment or rescue devices can pass through. It can also indicate how quickly a compartment is losing integrity and whether neighbouring parts of the structure are exposed.

A drone gives the incident controller a repeatable perspective from above and outside the hazard zone. In a large industrial building, an aerial image may reveal that an apparent wall opening is partly blocked by shelving, roofing sheets or vehicles. At a rural property, it may show that the breach connects to a secondary structure or lies close to LPG cylinders, tanks or overhead power infrastructure.

The measurement should be treated as operational intelligence, not a substitute for an engineer’s assessment. Fire, heat distortion, smoke and collapse can change the opening between flights. Crews should record the time of capture and relate the estimate to conditions on the ground.

Establishing A Safe Measurement Method

Before launching, the RPAS crew should agree on the measurement objective, the area of operation and the reference surface. A stable point near the breach—such as a known-length ladder, standard doorway, marked scale bar or surveyed feature—can provide a useful reference. Where placing a scale is unsafe, operators may use measured building elements visible in the imagery, while clearly recording the basis of the estimate.

A nadir image, taken as close to vertically above the opening as conditions allow, reduces perspective distortion. Oblique images are valuable for understanding depth and wall condition, but they should be paired with a scale reference before anyone reports a width. Photogrammetry software can create a model from overlapping images, although smoke, reflective roofing, moving hoses and changing light can reduce reliability.

Australian agencies should build the procedure around their local operating environment. CFA crews in Victoria may work around rapidly changing bushfire conditions, while NSW RFS teams can face long travel distances and limited mobile coverage. A launch site beside a suburban street may also require traffic control, spotters and coordination with police, SES volunteers and other responding organisations.

Choosing Sensors And Flight Profiles

A visible-light camera is usually the primary sensor for measuring an opening. High resolution, a fixed focal length and a steady hover can produce a sharper edge than a constantly moving orbit. Operators should capture several angles, keep the breach within the frame and avoid flying so close that turbulence, radiant heat or structural movement creates unnecessary risk.

Thermal imaging can identify hot edges, concealed fire and heat escaping through a gap, but thermal imagery does not automatically provide a reliable physical measurement. Emissivity, reflective metal, water streams and temperature gradients can blur the boundary. A thermal image should therefore supplement, rather than replace, calibrated visual imagery.

The flight profile must reflect the aircraft’s limitations and the scene. A small multirotor may be suitable for a short inspection in a suburban street, whereas a larger site may require a planned grid with exclusion zones. In Australia, the pilot must operate within applicable CASA rules and the organisation’s approvals, risk controls and emergency procedures. Crews should also consider wind, smoke, rain and the effect of hot air rising above the structure.

Recording Evidence And Maintaining Accountability

Each measurement should be stored with the original photographs or video, aircraft and sensor details, location, time, altitude, weather conditions and the method used to calculate the width. A short annotation can state whether the figure is an estimate, what reference was used and which edges of the breach were included. This makes the result easier for investigators, building professionals and later shifts to interpret.

Flight records support both technical reliability and fleet governance. Agencies should log pilot identity, aircraft, battery, mission purpose, launch and landing times, defects and maintenance actions; guidance on flight-hour records can help standardise that process. Consistent records are especially useful when footage becomes part of an insurance file, coronial inquiry or fire investigation.

Images may include residents, neighbours, vehicle registration plates or private interiors. Access should be restricted according to agency policy, retention rules and applicable privacy obligations. If footage is shared with the community after a major incident, agencies should remove unnecessary personal information and explain the public-safety purpose without exposing vulnerable people or sensitive locations.

Turning Measurements Into Operational Decisions

A breach-width estimate becomes useful when it is connected to a decision. The incident controller might use it to determine whether a search route is feasible, whether a wall requires isolation, or whether crews need a different entry point. In a post-fire inspection, the same measurement can help compare progressive collapse, document access for investigators and identify areas requiring temporary fencing.

Reports should distinguish between measured width, estimated width and visible width. For example, “visible opening approximately 1.8 metres wide at 1430 hours” is more defensible than presenting a single precise figure with no method. If smoke or debris hides an edge, that limitation should appear in the record.

Training should include realistic exercises using common Australian structures: corrugated-iron farm sheds, brick suburban homes, tilt-panel warehouses and bushfire-affected outbuildings. Fire and emergency services can run these exercises with local councils, structural specialists and community safety teams, ensuring that pilots understand how their imagery will be interpreted by people making high-consequence decisions.

Agencies that use drones for fire-damaged structures should adopt a written breach-measurement procedure, train crews against it and test the process during controlled exercises. Pair every reported dimension with its reference, time and uncertainty, maintain complete aircraft records, and share privacy-conscious information with the organisations responsible for safety and recovery. This approach turns aerial footage into dependable public-safety evidence when crews need it most.