There are not categories of critical equipment but the uses of equipment might be critical. An IV pump could be delivering saline in palliative care to a terminally ill patient where it would not harm the patient if it were not to work for a couple of hours or the same pump could be delivering an inotrope that is keeping someone alive and might prove fatal if it stopped for a few minutes.
This is why I can see no point in the labels one sees on equipment saying its risk category.
Robert
