When you read the definition of dwelling unit in R202, what import do you place on 'independent'? I draw a very specific line that includes independent: electrical service, plumbing/water/sewer service; heating/mechanical/air circulation; and means of egress. In other words, dwelling units, as in a duplex, do not 'talk' to each other in any respect: i.e., there is no door between them, but there is a one-hour fire separation wall; and the heat, electric, plumbing, ventilation, etc., is independent one from the other. Am I putting too fine a line on this?