Industry and infrastructure

Why this matters

Factories and energy systems hold high-value assets that cannot simply be stopped. One failed solar module reduces the output of a whole string, an overheating line joint can black out an entire industrial estate, and a gas pipeline leak endangers lives. Inspecting by hand means climbing poles, shutting down equipment or walking kilometres of pipeline. Drones help a great deal, but inspection results only have value when they feed maintenance decisions, not merely when they produce thousands of images.

The whole course follows one hypothetical case: the utilities department of an industrial estate, responsible for a 1 MW solar farm, a 22 kV power line and a 3 km gas pipeline. All numbers are synthetic training data. The Python code for every module can be downloaded from /downloads/uat-362/.

Asset management

ISO 55000:2024 defines asset management as “coordinated activity of an organization to realize value from assets”, and ISO 55001:2024 sets the requirements for an asset management system. Inspection is therefore not an end in itself; it provides the information to decide whether to repair, replace or keep monitoring, and when.

A good inspection question starts from the decision, such as “which modules must be replaced before the hot season?” or “which spans need tree trimming before the rains?”, and then asks which defects must be seen, and with which sensor.

Motion blur and flight speed

Inspection uses a much finer GSD than mapping, so motion blur becomes a major issue. O’Connor and colleagues (2017) give the blur in pixels as the distance the drone travels during the exposure divided by the GSD, and advise keeping it below about 1.5 pixels.

BLUR_LIMIT = 1.5                                  # pixels
for gsd_cm in (0.5, 1.0, 2.0):
    speeds = [BLUR_LIMIT * gsd_cm / 100 * shutter for shutter in (250, 500, 1000)]
    print(f"GSD {gsd_cm} cm: max speed at 1/250 s {speeds[0]:.2f}, "
          f"1/500 s {speeds[1]:.2f}, 1/1000 s {speeds[2]:.2f} m/s")

GSD 0.5 cm: max speed at 1/250 s 1.88, 1/500 s 3.75, 1/1000 s 7.50 m/s
GSD 1.0 cm: max speed at 1/250 s 3.75, 1/500 s 7.50, 1/1000 s 15.00 m/s
GSD 2.0 cm: max speed at 1/250 s 7.50, 1/500 s 15.00, 1/1000 s 30.00 m/s

Patrolling linear assets

Pipelines and power lines stretch for kilometres. The US rule 49 CFR 192.705 is an example that requires gas pipeline operators to patrol the right-of-way for leaks and activities that could affect the pipe, allowing walking, driving, flying or other appropriate means. The frequency depends on the class location (module 3). In Thailand, the requirements of the regulator and the pipeline owner apply.

import math

ROUTE_M, SPEED, USABLE_MIN = 3000, 8.0, 20      # m, m/s, usable flight minutes per battery
fly_min = 2 * ROUTE_M / SPEED / 60               # out and back to the take-off point
batteries = math.ceil(fly_min / USABLE_MIN)
print(f"out and back {fly_min:.1f} min -> {batteries} battery per patrol")
for patrols in (2, 4, 12):
    print(f"{patrols:>2} patrols/year = {patrols * fly_min / 60:.1f} flight hours/year")

out and back 12.5 min -> 1 battery per patrol
 2 patrols/year = 0.4 flight hours/year
 4 patrols/year = 0.8 flight hours/year
12 patrols/year = 2.5 flight hours/year

Hazardous areas and stand-off distances

Industrial sites have specific hazards: high-voltage lines, magnetic fields near transformers that disturb the compass, areas with flammable vapour, and stacks with hot plumes. EGAT warns the general public to stay 4 m away from high-voltage lines, but that article does not set a distance for drones. Safe flying distances must therefore come from the asset owner, the risk assessment (module 5) and the CAAT announcements in force, some of which temporarily restrict flights around energy sites. ISO 21384-3 sets out drone operational procedures that can serve as a framework (a 2026 revision may be pending; check).

Module lab

Common mistakes

Summary

• Asset management (ISO 55000) realises value from assets; inspection informs decisions to repair, replace or monitor
• Choose sensors from the defects to be found, not from the equipment at hand
• Blur = v·t/GSD should stay below about 1.5 pixels; fine work needs slow flight or a fast shutter
• Safe distances and restricted areas come from the asset owner, the risk assessment and the rules in force

Check your understanding

1. At 1 cm GSD, a 1/500 s shutter and 5 m/s, how many pixels of blur occur?
2. Using question 1, what is the maximum speed for no more than 1.5 pixels of blur?
3. How does drone inspection relate to asset management?
4. How many minutes does a 5 km pipeline take out and back at 10 m/s?
5. Why can EGAT’s 4 m public warning not be used as a drone flying distance?