Search for confined space monitoring equipment and the first thing that comes back is usually a gas detector. A detector is one layer of a working setup, and it is not the layer that decides whether the job is under control. Three layers have to be in place — measurement inside the space, entry and exit control at the opening, and monitoring worn by the person doing the work — because each one answers a question the other two cannot.
Inside the space: measuring the atmosphere at the workface
The gas detection dome camera sits near the workface and samples by pump, covering oxygen, carbon monoxide, hydrogen sulfide and combustible gas as the standard four. When a concentration crosses its limit the unit alarms locally with sound and light and pushes the reading to the entry point and the remote platform at the same time. Because it also carries a camera and two-way audio, whoever is watching the dashboard can speak to the crew the moment the picture changes, rather than waiting for a phone call that may never be made.
At the opening: controlling who goes in and out
The entry and exit monitor is split into an internal and an external unit. The internal unit mounts inside the opening, magnetic or wall-mounted; the external unit sits outside the opening, works straight out of its case and carries a 10.1-inch touchscreen. A standard network cable links the two — 8 m as standard, up to 100 m — and a built-in backup battery keeps the external unit running for six to eight hours through a power cut. Wristband check-in and check-out and the registration of tools carried in and out both happen here, and anything left behind raises an automatic reminder.
On the worker: vital signs, and a button that works when nothing else does
Each entrant wears a smart wristband that records heart rate and blood oxygen continuously and alarms on abnormal readings. In an emergency the SOS button notifies the on-site attendant and remote management at the same time. The wristband talks to the internal unit wirelessly, with a line-of-sight range of at least 200 m, at least 24 hours of battery life and an IP67 rating — the layer that covers the person, not the space.
Three layers, three questions
The layers answer three different questions: is there toxic gas in the space, did people enter and leave by the rules, and can the person inside physically hold out. Fit only one layer and the other two questions stay unanswered for the whole shift. That is also what an inspection reads: gas data on its own is not enough — it has to reconcile with how many people went in and whether every tool came back out. GB 46768-2025, the safety technical specification for confined space operations, sets clear requirements for testing before entry and for monitoring while the work is under way. Fitting all three layers is what turns those requirements into records that can be pulled up afterwards.
Check the configuration, not the catalogue. Ask what answers each of the three questions on your site — gas in the space, people at the opening, and the condition of the worker inside. A quotation that covers only the first layer is a detector purchase, not a monitoring system.