The failure mode is not equipment that stops working. It is equipment that is switched on, visibly running, and delivering nothing. These are the four habits we go through at handover, because in each case the installation looks complete.
One unit at the hatch, no sampling points inside
The unit at the hatch governs whether data gets out; it does not know what the atmosphere is doing inside. Gas is not distributed evenly along the depth of a tank — a low pocket or a dead corner can already be hazardous while the hatch reading looks normal. The workable arrangement is a collecting unit at the hatch and sampling points distributed along the depth inside, with extra attention where residue accumulates.
One test before entry, then work to the end of the shift
A pre-entry test answers whether the space is safe to enter now. It cannot answer whether it will stay safe for the next several hours: activity inside, grinding and descaling, coating work and any interruption to ventilation all change the atmosphere again. GB 46768-2025 requires a reading every 15 minutes during the job and a fresh test after a break longer than 30 minutes — neither is covered by the readings taken at the start.
Readings displayed inside the space
A display mounted inside the tank shows the readings to the people who are busy working, while the attendant has to lean in or enter the space to see them — which is itself a new risk. The output belongs at the hatch, with gas curves, headcount and the camera view converging on the unit at the entrance so the attendant follows what changes without moving. On board, that means a split internal and external arrangement: the LSM3000 monitoring station keeps the external unit at the hatch and pushes the same data to the management platform.
Treating the equipment as a substitute for permits and attendance
The equipment covers what cannot be seen and cannot be watched continuously. It does not cover responsibility. Permit approval, ventilation and purging, the safety briefing, the attendant staying at the post and emergency drills cannot be delegated to a device — and an inspection looks at more than the equipment list: it checks whether the permit record, the gas data and the entry log agree with one another.
Ask what the installation proves. For each of the four points, the question is the same: if an inspector asked to see the last shift, would the data show the job, or only the equipment?