Answer:  Home Inspection rules apply to structures that have (or are intended to have) people living in them but have no more than 4 family dwelling units.  For instance, a 4 unit quad-home is a "home" that should be Inspected, individually or as a group, using the rules of a Home Inspection.  On the other hand, a 50 unit apartment building is a Commercial Building in the sense of an Inspection.  The gray area is something like a 10 unit townhouse complex.  Each townhouse is normally owned and occupied by an individual owner.  An Inspection of an individual townhouse unit is normally handled as a Home Inspection, even though the entire complex houses more than 4 families.   If the entire townhouse complex is Inspected as a single unit it should be handled as a Commercial Building.