In one of the NMR labs here we had O2 detectors installed when the
instruments arrived. In several other rooms with instruments we
have not done the same thing, but there is a much greater turn-over
of air in them and it was not deemed necessary to put them in (maybe
we should ?). The detectors come from GasTech Inc and have tested
out fine. Chemical cartridges need replacing (refurbishing) every
couple of years.
We don't vent He or N2 out of the lab.
All our magnets have had a removable fence installed around them. The
justification for this is that it keeps people (visitors and
janitorial staff) and objects (dewars, cylinders etc) at a safe
distance. It didn't occur to us that they could also serve the
purpose of keeping firemen from getting stuck to them!
Cheers,
Fred Morin