Section 27-978. Definitions

For the purposes of this article: a. an existing
  building is one which is within occupancy group J-1, occupancy group J-2
  or  occupancy  group  J-3  and for which plans have been approved by the
  department on  or  prior  to  December  thirty-first,  nineteen  hundred
  eighty-one.
    b.  an  improvement  or alteration is a physical change in an existing
  structure  other  than  painting,  repairs  and  normal  replacement  of
  maintenance items.
    c.  a  building shall be deemed to have been substantially improved or
  altered if:
    1. the cost of improvement  or  alteration  exceeds  the  sum  of  one
  hundred fifty thousand dollars, or
    2. in either occupancy group J-1 or occupancy group J-2, fifty percent
  or  more  of  the  dwelling  units  or  square feet of the structure are
  improved or altered and the  cost  of  such  improvement  or  alteration
  exceeds the sum of fifteen thousand dollars per dwelling unit, or
    3. there has been a change in the occupancy or use of the structure.