What makes this hard
Hydrogen sulfide is the routine hazard, not the exception
Sewer networks generate H₂S continuously from organic decomposition. It is toxic at low concentrations and it deadens the sense of smell at higher ones, which is precisely when it is most dangerous.
Spaces that are longer than they are deep
Utility tunnels, cable galleries and long culverts run for hundreds of metres. A monitoring arrangement designed for a compact vessel leaves the far end entirely unobserved.
Multiple access points under public roads
Work happens in the carriageway, under traffic management, with limited space at the surface for equipment and a crew that has to be in and out quickly.
Contract and utility teams in different locations
Maintenance may be performed by the municipality, a utility company or a contractor, each with their own procedures and records, on the same asset.
What we deploy
Municipal confined spaces are distributed across a city, entered from the street, and — in the case of tunnels and culverts — extend far beyond the reach of anything standing at the entrance.
- LSM3000 cascaded linear monitor for tunnels, galleries and long culverts — coverage to 1,000 m
- Entry monitoring station for compact spaces such as manholes, sumps and inspection chambers
- Four-gas monitoring with H₂S and combustible gas as the primary hazards in sewer networks
- Cabled data and power distribution along the tunnel, so no power is needed at the workface
- Personnel positioning and headcount along the full length of the run
- Emergency battery giving 6–8 h of operation after a mains failure
What changes on site
The far end is monitored, not just the entrance
Cascaded units extend detection, video and positioning along the run, which is the difference between monitoring the entry and monitoring the work.
Alarms reach the entrant without a network
Underground spaces have no mobile coverage. Internal units alarm locally and communicate over a cabled bus, so the warning does not depend on a signal that is not there.
Rapid setup under traffic management
The external unit is ready out of the crate and the internal units mount magnetically or on the wall, keeping the surface footprint and the time in the carriageway to a minimum.
Records that work across organisations
Entry, atmosphere and alarm records are held in one platform regardless of whether the crew was municipal, utility or contractor — which is what makes the asset history coherent.
Frequently asked questions
How long a tunnel or culvert can be covered?
The extendable data bus is rated for not less than 1,000 m in total, with 20 m per node as standard and up to 100 m per node where required. Units require power only at the entry point, which suits tunnels with no local supply.
What is the main gas hazard in a sewer network?
Hydrogen sulfide, with methane and oxygen deficiency close behind. H₂S is the one that catches people out because it deadens the sense of smell at the concentrations where it becomes dangerous, so you cannot rely on noticing it.
How quickly can a crew deploy for a short job in the carriageway?
The internal unit mounts magnetically or on the wall and the external unit is ready out of the crate; the two connect by a single cable. The surface footprint is limited to the external unit, which keeps the traffic management arrangement simple.
Can different organisations use the same records?
Yes. The platform holds the entry, atmosphere and alarm records for the asset regardless of which organisation performed the work, so the history of a tunnel or sewer section does not fragment between contractors.
Is it suitable for routine inspection as well as intrusive work?
Yes. Routine entry for inspection is often where exposure happens most frequently, precisely because it is treated as low risk and the monitoring is skipped. The same station is used for both.