Section 27-859. Chimney heights and locations

(a) Low temperature chimneys.
  Low temperature chimneys shall extend at  least  three  feet  above  the
  highest  construction, such as a roof ridge, parapet wall, or penthouse,
  within ten feet of the chimney outlet, whether the  construction  is  on
  the  same  building as the chimney or on another building. However, such
  constructions do not include other chimneys, vents, or  open  structural
  framing. Any chimney located beyond ten feet from such construction, but
  not  more  than  the  distance  determined  in  subdivision  (d) of this
  section, shall be at least as high as the construction.
    (b) Medium temperature chimneys.  Medium  temperature  chimneys  shall
  extend  at least ten feet above the highest construction, such as a roof
  ridge, or parapet wall or penthouse within twenty feet  of  the  chimney
  outlet,  whether the construction is on the same building as the chimney
  or on another building. However, such constructions do not include other
  chimneys, and vents. Any chimney located beyond  twenty-feet  from  such
  constructions  but  not more than the distance determined in subdivision
  (d) of this section, shall be at least as high as the construction.
    (c) High temperature chimneys. High temperature chimneys shall  extend
  at least twenty feet above the highest construction, such as roof ridge,
  parapet  wall,  penthouse, or other obstruction within fifty feet of the
  chimney outlet, whether the construction is on the same building as  the
  chimney  or  in  another  building.  However,  such constructions do not
  include other chimneys, vents, or open structural framing.  Any  chimney
  located  beyond  fifty feet from such construction but not more than the
  distance determined in subdivision (d) of  this  section,  shall  be  at
  least as high as the construction.
    (d)  Formula.  The following formula shall be used for determining the
  distances referred to in subdivisions (a), (b) and (c) of this section:
 
                              D = F (sq.rt.) A
 
  where: D = Distance, in ft., measured from the  center  of  the  chimney
               outlet to the nearest edge of the construction.
         F = Value determined from table 15-1.
         A = Free area, in sq. in., of chimney flue space.
 
           Table 15-1  "F" Factor for Determining Chimney Distances
  ========================================================================
                                  --------------"F" Factor--------------
                                  Low Temp.    Medium Temp.    High Temp.
  Type of Fuel                     Chimney       Chimney        Chimney
  ------------------------------------------------------------------------
  Gas ..........................     2             2               3
  No. 2 Fuel Oils ..............     2.5           2.5             3
  No. 3, No. 6 Fuel Oils,  Solid
  Fuels and Incinerators........     3             3               3
  ========================================================================