Section 241. Partitions; fire-stopping

1. In tenements erected after April
  eighteenth, nineteen hundred  twelve,  wood  stud  apartment  partitions
  which  are  directly  over  each  other shall run through the wood floor
  beams and rest upon the plate  of  the  partition  below.  In  fireproof
  tenements  erected  after  such  date all partitions shall rest directly
  upon the fireproof floor construction and extend to the  fireproof  beam
  filling  above.  Apartment partitions within the meaning of this section
  are partitions crossing the floor beams at any angle and separating  one
  apartment  from another or any part of an apartment from any public part
  of the dwelling.
    2. In tenements  erected  after  April  eighteenth,  nineteen  hundred
  twelve,  apartment  studding  shall  be  filled  in  solidly between the
  uprights to the depth of the floor beams with incombustible materials.
    3. In non-fireproof tenements erected after  April  twelfth,  nineteen
  hundred  one,  in every wall where wood furring is used, every course of
  masonry from the under side to the top of any floor beams shall  project
  a  distance  of  two inches or more beyond each face of the wall that is
  not on the outside of the dwelling, so as to provide an  effective  fire
  stop;  and  whenever floor beams run parallel to a wall and wood furring
  is used, every such beam shall always be kept two inches away  from  the
  wall,  and  the  space  between the beams and the wall shall be built up
  solidly with brickwork from the underside to the top of the floor  beams
  so as to form an effective fire stop.