Inspect Without Sending Anyone Down
Shafts, sewers and tunnels are among the most dangerous confined spaces to enter. Hydrogen sulphide, methane and low oxygen build up in them, and a fall or a collapse far below ground is hard to rescue from. Under Singapore's Workplace Safety and Health (Confined Spaces) Regulations, every entry needs a permit to work, gas testing, ventilation and a standby team, which takes time and money before anyone even looks at the asset.
A confined-space drone removes the need for a person to go in. It is launched from the opening, flies down the shaft or along the tunnel, and records what an inspector would have seen, often more, because it can hold position close to a surface for as long as it takes.
What We Inspect
| Asset | Typical owner | What we look at |
|---|---|---|
| Sewer and deep tunnel shafts | PUB and its contractors | Shaft lining, penstock gates and guide rails, benching, baffle walls, debris |
| Sewers and large-diameter pipes | PUB and its contractors | Crown corrosion, joints, infiltration, sediment and blockages |
| Drainage culverts and box drains | Agencies, developers, estates | Cracks, spalling, exposed reinforcement, silt, obstructions |
| Cable and utility tunnels | Power and utility operators | Lining condition, water ingress, cable tray and support condition |
| Pump sumps, wet wells and chambers | Plant and facility owners | Walls, inlets, pipework, ladders and fixings |
| Vertical shafts in buildings | Building owners and MCSTs | Lift and service shafts, risers, brackets and wall condition |
Two Platforms, Matched to the Job
No single drone suits every shaft and tunnel. We choose between two confined-space platforms at scoping, based on depth, length and how well a radio signal will carry.
| Flyability Elios 3 | ScoutDI Scout 137 | |
|---|---|---|
| Design | Caged and collision-tolerant, so it can touch walls and keep flying | Tethered, with power and data carried through a 60 m cable |
| Link | Radio, which needs a line of sight back to the pilot | Through the tether, so there is no radio link to lose |
| Flight time | About 9 to 12 minutes per battery | Unlimited, with no on-board battery |
| 3D mapping | On-board LiDAR builds a point cloud as it flies | Point cloud of the space for geometry and position |
| Best for | Tunnels, culverts, chambers and shorter shafts | Deep shafts, live sewers and anywhere radio drops out |
Safety and Permits
Neither drone is certified for explosive atmospheres. The space is gas tested and ventilated under the confined space permit before we fly, and the work runs under the owner's or main contractor's permit to work. Nobody from our team enters the space; the crew stays at the opening.
For each job we provide a method statement and risk assessment covering the launch point, gas readings, flow conditions, lighting, retrieval and emergency procedures, so it can go straight into your safety submission.
What You Receive
- Condition report — a defect register with each finding located by depth or chainage, rated by severity.
- Annotated images and 4K video — every surface recorded under the drone's own lighting.
- LiDAR point cloud — an as-found 3D record of the space, for checking geometry such as shaft verticality or guide rail alignment.
- Recommendations — what needs repair, what needs a closer look, and what can wait.
The point cloud can also be turned into a model through our scan to BIM service.
Tunnel and Shaft Inspection Pricing
| Asset | Price range |
|---|---|
| Tunnel or culvert, per 100 m section | $3,000 — $6,000 |
| Deep shaft or complex tunnel system | $8,000 — $15,000 |
Prices include planning, the method statement and risk assessment, the crew and platform, and the report. Further shafts inspected in the same mobilisation are quoted at a lower rate. Every job is confirmed after a site survey, because access, flow and gas conditions change the scope.
Why Choose SG Drone Inspections
The Right Platform
We choose between a caged drone and a tethered drone for each job, instead of forcing one aircraft into every space.
Trained Confined-Space Crew
Our pilots are trained on the Elios 3 and plan every flight around the space's gas, flow and access conditions.
No One Inside
The drone does the entry. Your permit, rescue and standby arrangements cover the opening, not a person far below ground.
Measured, Not Just Filmed
A LiDAR point cloud comes with the imagery, so geometry and positions can be checked, not just looked at.
Frequently Asked Questions
Get a Tunnel or Shaft Inspection Quote
Send us the asset type, depth or length, access opening size and whether it will be live during the inspection. We reply with a scope and quote within 24 hours.