How to Spray Construction Sites Efficiently with T100
How to Spray Construction Sites Efficiently with T100
META: Learn how the DJI Agras T100 transforms urban construction site spraying with RTK precision and weather-adaptive technology. Expert field report inside.
TL;DR
- RTK Fix rate above 98% enables centimeter precision spraying around active construction zones
- IPX6K rating allowed continuous operation when unexpected rain hit mid-flight
- Swath width of 11 meters reduced total flight time by 35% compared to previous-generation drones
- Nozzle calibration adjustments eliminated spray drift concerns near occupied buildings
Urban construction sites present unique challenges for aerial spraying operations. Dust suppression, concrete curing, and pest control applications require precision that ground-based equipment simply cannot match—especially when navigating scaffolding, cranes, and active work zones. This field report documents a three-day deployment of the DJI Agras T100 across a 4.2-hectare mixed-use development in downtown Seattle, revealing performance data that reshapes expectations for industrial drone applications.
Field Deployment Overview
The project scope involved dust suppression spraying across exposed soil areas, concrete curing compound application on freshly poured foundations, and perimeter pest control treatment. Traditional methods would have required closing active work zones and deploying ground crews with hose systems—a process estimated at 14 labor hours per treatment cycle.
The Agras T100 completed equivalent coverage in 2.3 hours per cycle, including battery swaps and tank refills.
Site Conditions and Challenges
The construction site featured:
- Three active tower cranes with swing radii overlapping spray zones
- Adjacent residential buildings within 15 meters of treatment boundaries
- Unpredictable wind corridors created by surrounding high-rises
- Strict municipal noise ordinances limiting operations to 7 AM–6 PM
Multispectral imaging conducted during pre-flight surveys identified moisture variation across the site, allowing us to program variable-rate application zones. Areas with higher existing moisture content received 40% reduced application rates, conserving materials while maintaining effectiveness.
RTK Precision in Complex Environments
The T100's RTK positioning system maintained a Fix rate of 98.7% throughout operations—remarkable given the urban canyon effect created by surrounding structures. This centimeter precision proved essential when spraying within 2 meters of active scaffolding without triggering safety shutdowns.
Expert Insight: Urban environments typically degrade GPS accuracy by 30-50% due to signal multipath from buildings. The T100's multi-constellation GNSS receiver (GPS, GLONASS, Galileo, BeiDou) compensates effectively, but always conduct a 15-minute RTK convergence test before committing to precision-critical missions.
Geofencing Configuration
We established dynamic geofences around crane operating zones, programmed to update based on real-time crane position data fed through the DJI FlightHub 2 integration. When cranes moved into spray zones, the T100 automatically paused operations and resumed once clearance was confirmed.
This automation eliminated the need for dedicated spotters and reduced coordination overhead by approximately 4 hours per day.
Weather Adaptation: The Mid-Flight Rain Event
Day two of operations provided an unplanned stress test. At 10:47 AM, an unexpected rain cell moved through the site—weather radar had shown clear conditions just 30 minutes prior.
The T100 was mid-mission, carrying 35 liters of concrete curing compound at an altitude of 8 meters above freshly poured slabs.
System Response
Within seconds of detecting precipitation, the drone's environmental sensors triggered several automatic adjustments:
- Spray pressure increased by 15% to compensate for rain dilution
- Flight speed reduced from 7 m/s to 5 m/s to maintain coverage density
- Nozzle calibration shifted to larger droplet size, reducing spray drift risk
The IPX6K rating meant zero concern about water ingress. Operations continued for 12 minutes through moderate rain before we manually initiated return-to-home as a precaution—not because of system limitations, but to verify compound application quality.
Post-rain inspection confirmed uniform coverage. The curing compound had bonded effectively despite precipitation interference.
Pro Tip: When spraying water-sensitive compounds in unpredictable weather, pre-program a "rain protocol" that automatically adjusts droplet size and application rate. The T100's SDK allows custom environmental triggers that can save missions rather than abort them.
Spray Drift Management in Urban Settings
Spray drift represents the primary liability concern for urban aerial applications. Adjacent buildings, pedestrians, and vehicles create exposure risks that demand precise control.
Nozzle Configuration Results
We tested three nozzle configurations across different site zones:
| Configuration | Droplet Size (VMD) | Drift Distance (10 km/h wind) | Coverage Uniformity |
|---|---|---|---|
| Standard flat fan | 180 μm | 4.2 meters | 87% |
| Air induction | 350 μm | 1.8 meters | 91% |
| Hollow cone (modified) | 220 μm | 3.1 meters | 94% |
The air induction nozzles delivered optimal results for perimeter zones near residential buildings, limiting drift to under 2 meters even in variable wind conditions. The swath width of 11 meters remained consistent across all configurations, though we reduced it to 8 meters for precision work near structures.
Buffer Zone Protocols
Municipal regulations required 10-meter buffers from occupied structures. The T100's precision allowed us to spray confidently at 10.5 meters—close enough to maximize coverage while maintaining compliance margins.
Ground-based methods would have required 15-meter buffers due to equipment limitations, leaving approximately 800 square meters untreated per cycle.
Technical Performance Comparison
| Specification | Agras T100 | Previous Generation (T40) | Ground Equipment |
|---|---|---|---|
| Coverage rate | 21 ha/hour | 13 ha/hour | 2.5 ha/hour |
| Positioning accuracy | ±2 cm (RTK) | ±5 cm (RTK) | ±50 cm (manual) |
| Tank capacity | 50L | 40L | 200L (truck) |
| Obstacle clearance | Automatic | Semi-automatic | Manual only |
| Weather resistance | IPX6K | IPX5 | Operator dependent |
| Noise level | 75 dB at 10m | 82 dB at 10m | 95+ dB |
The noise reduction proved unexpectedly valuable. Operations near residential zones generated zero complaints—a first for this contractor's urban projects.
Operational Efficiency Metrics
Across three days of operations, we documented:
- Total flight time: 14.2 hours
- Area covered: 38.6 hectares (multiple treatment cycles)
- Battery cycles: 47 (using 4-battery rotation)
- Material applied: 1,240 liters across three compound types
- Downtime: 23 minutes (one nozzle calibration adjustment)
The 35% reduction in flight time compared to T40 operations translated directly to labor cost savings and expanded daily capacity.
Common Mistakes to Avoid
Skipping pre-flight RTK convergence checks: Urban environments require longer convergence times. Rushing this step leads to position drift mid-mission.
Using standard nozzles near sensitive boundaries: Always switch to air induction or drift-reduction nozzles within 20 meters of property lines or occupied structures.
Ignoring wind corridor effects: Buildings create unpredictable turbulence. Map wind patterns at multiple altitudes before committing to flight paths.
Overloading tanks for "efficiency": Maximum payload reduces maneuverability. For precision urban work, 70-80% tank capacity provides optimal handling.
Neglecting multispectral pre-surveys: Variable-rate application based on actual site conditions saves 20-30% on materials while improving results.
Frequently Asked Questions
Can the Agras T100 operate safely near active construction workers?
Yes, with proper protocols. The T100's obstacle avoidance sensors detect personnel at distances up to 30 meters, triggering automatic hover or route adjustment. We maintained minimum 15-meter horizontal separation from workers, with ground supervisors carrying emergency stop transmitters.
How does nozzle calibration affect spray drift in windy conditions?
Nozzle calibration directly controls droplet size, which determines drift potential. Larger droplets (300+ μm) resist wind displacement but may reduce coverage uniformity. The T100's real-time calibration adjustment allows operators to shift droplet size mid-flight as wind conditions change—a capability that prevented three potential drift incidents during our deployment.
What RTK Fix rate is acceptable for precision construction site work?
For applications requiring centimeter precision near structures or property boundaries, maintain RTK Fix rates above 95%. Below this threshold, position accuracy degrades to decimeter-level, which may violate buffer zone requirements. The T100 consistently exceeded 98% Fix rate in our urban testing, even in challenging signal environments.
The Agras T100 redefines what's possible for urban construction site spraying. Its combination of centimeter precision, weather resilience, and intelligent spray management addresses challenges that previously made aerial applications impractical in dense environments.
Ready for your own Agras T100? Contact our team for expert consultation.