The problem
Carbon monoxide gives no warning a person can perceive. It has no smell, no colour and no irritant effect, and the symptoms of exposure — headache, tiredness, poor concentration — are indistinguishable from a long shift. By the time somebody on the floor suspects CO, they have already been breathing it.
It is also the classic slow hazard. A partially blocked flue, a generator running in a space that has stopped ventilating properly, a forklift idling indoors — each produces a monotonic climb over tens of minutes. There is no spike for a threshold to catch, only a floor that keeps rising.
Which channels see it
Detection here is not one sensor reporting a number. It is several channels read at the same instant, where what one channel does NOT do is often as informative as what another does.
- Carbon monoxide — The primary channel. What matters is the sustained direction of travel, not the instantaneous value.
- Combustible gas — Stays flat during CO accumulation. If it moves too, the event is a fuel release rather than incomplete combustion.
- Air quality — Corroborates a general degradation of the air rather than a single-compound event.
- Ambient temperature — A furnace or flue problem often shows a small ambient rise alongside the CO.
- Sound level — A fan that has stopped is a fall on this channel — and a common root cause of CO building up.
How it is detected
The signature for CO accumulation is a monotonic rise on the CO channel with very little movement anywhere else. That is a genuinely distinctive shape in a twelve-dimensional space of rates of change: most channels near zero, one channel with a small, persistent, positive velocity.
This is the case that makes the argument for the whole approach. The absolute CO reading during the first twenty minutes of an accumulation may be well below any sensible alarm threshold, while the rate of change has already been positive and steady for the entire period. A threshold instrument sees nothing worth reporting; a derivative instrument sees a clear, sustained trend.
The prediction layer runs on top of this: from the current value and the slope, it computes a time-to-threshold — how long, at this rate, until the reading reaches the level you have said is unacceptable. That figure is what turns monitoring into something a shift supervisor can act on before the event.
What an operator gets
The output is meant to be actionable by somebody on shift, not interpreted by an engineer afterwards.
- An alert while the CO level is still climbing rather than after it has arrived, with the trend that triggered it.
- A time-to-threshold estimate, so the response can be scheduled rather than scrambled.
- The correlated channels — whether a fan stopped, whether ambient temperature moved — which usually contains the cause.
- A full history, so a recurring pattern tied to a shift or a piece of equipment becomes visible over weeks.
