2006 New York Code - General Requirements.

 
    §  27-585  General  requirements.  For  purposes  of  this  code,  the
  structural elements of a building  shall  normally  include  all  floor,
  roof,   and   wall   framing   members  and  slabs  (but  not  including
  slabs-on-grade); all piers, walls, footings, piles, and similar elements
  of the foundation;  and  all  other  elements  of  both  foundation  and
  superstructure  which,  in engineering practice, are proportioned on the
  basis of calculated stress. Where doubt  exists  as  to  the  structural
  nature  of  an  element,  the  provisions  of  this  subchapter,  and of
  subchapter eleven of this chapter, shall be deemed to apply only  to  an
  element  in  which  the materials are stressed in excess of thirty-three
  and one-third per cent of the allowable stress values (without  increase
  for infrequent stress conditions) for such material in its proposed use,
  or to an element wherein public safety would be involved in the event of
  excessive distortion under the applied loads.