Section 27-281. Construction class II-A

Includes heavy timber construction
  in which fire-resistance is attained by limiting the  minimum  sizes  of
  wood  structural  members  and  the minimum thickness and composition of
  wood floors and roofs; by avoiding concealed  spaces  under  floors  and
  roofs  or by providing fire-stopping protection for these spaces; and by
  using fastenings, construction details,  and  adhesives  for  structural
  members  as required by article seven of subchapter ten of this chapter.
  The minimum dimensions  for  framing  members  shall  be  prescribed  in
  section  27-623  of  article  seven  of  subchapter ten of this chapter,
  except that members which are protected  to  provide  a  fire-resistance
  rating of at least one hour need not comply with this requirement.