Pinemarten,
Sorry to just "bump you off" like that!.
Yes, I would imagine that the approval is for the Smoke detection part of the unit.
Carbon Monoxide(CO), as it is, is heavier than air, therefore it stays around the floor level, just the same as a Propane leak!.
Anyone that installs Smoke Detectors, should know that there are a few Golden Rules about fitting these simple, but essential bits of household equipment:
  • Keep all smoke detectors at least 500mm from a wall!. (any FF worth thier salt will tell you that within 400mm of an upright wall and ceiling, there is a Dead Air Space, that will render a smoke detector null and void.
  • Never wall mount a smoke detector, anyone who has told you to do this, is an idiot, smoke detectors work on vertical heat and smoke currents!.
  • If you have a 2+ storey house, make sure that you have a smoke detector at each landing in the stair wells, as this will be the areas where a fire will spread quickest.

Need anymore advice?, just ask away!.
Cheers,
Trumpy. [Linked Image]