Section 27-862. Materials other than metal for construction of chimneys

Materials other than  metal  for  the  construction  of  chimneys  shall
  include the following:
    (a) Clay, concrete, or shale bricks, laid in a full bed of mortar.
    (b)  One hundred per cent solid masonry units, or hollow masonry units
  having the cores filled with mortar or  grout,  laid  in  spread  mortar
  covering the entire cross-sectional area of the unit.
    (c) Concrete cast in place and adequately reinforced where required.
    (d)  Natural  stones  that  have been sawed, dressed, or have a tooled
  finish, laid in spread mortar.
    (e) Perforated radial brick. Such brick shall be laid in spread mortar
  equal to type M, of reference standard RS 15-3, and shall be  shaped  to
  the circular and radial lines of the various sections so as to form even
  joints.
    (f) Other equivalent materials or combination of materials.