Section 28-113.2.2. Alternative materials

Except as otherwise specifically
  limited by this code, the provisions of this code are  not  intended  to
  prevent  the installation of any material or to prohibit any alternative
  engineered design or method of construction not specifically  prescribed
  by  this  code,  provided  that the use of such alternative material has
  been previously approved by the commissioner and may be used only to the
  extent set forth in such approval. The use of an  alternative  material,
  design,  method of construction or equipment shall be approved where the
  commissioner finds that the proposed design is satisfactory and complies
  with the intent of the provisions of this code, and that  the  material,
  method  or  work  offered  is,  for  the  purpose intended, at least the
  equivalent of  that  prescribed  in  this  code  in  quality,  strength,
  effectiveness, fire resistance, durability and safety.