Section 27-871. Chimney connection

In entering a flue in a masonry or metal
  chimney, the chimney connector shall  be  installed  above  the  extreme
  bottom  to  avoid  stoppage  and  in  such manner or by such means as to
  prevent the chimney connector from entering so far as  to  restrict  the
  space  between its end and the opposite wall of the chimney. The chimney
  connector shall be firmly attached or inserted into a  thimble  or  slip
  joint  to prevent it from falling out of place. All connectors shall fit
  tightly. Chimney connections to any flue shall be limited to one  floor.
  Two  or  more  chimney  connectors  may be joined to a single connection
  provided that the chimney connectors are on one floor level and the flue
  is of sufficient size to serve all  of  the  equipment  thus  connected.
  Chimney  connectors  shall  be  inspected  at  the  time  of the initial
  installation by the commissioner  or  by  a  duly  authorized  insurance
  company as provided in section two hundred four of the labor law.