Section 27-707. Timber piles

(a) Materials. Timber piles shall conform in
  quality to class A or B of reference standard RS 11-7.
    (1) SIZE OF PILES. Piles shall be  of  adequate  size  to  resist  the
  applied  loads without creating stresses in the pile materials in excess
  of twelve hundred psi for piles of southern pine, Douglas fir,  oak,  or
  other  wood of comparable strength; or eight hundred fifty psi for piles
  of cedar, Norway pine, spruce or  other  wood  of  comparable  strength.
  Except as provided in paragraph two of this subdivision, for piles forty
  feet  or  more  in  length  and  of  thirty  tons  capacity or less, the
  following sizes or classes of piles shall be deemed to be  adequate  for
  considerations of stress in the pile material:
    a.  Piles  of  twenty-five to thirty tons capacity--Class A or minimum
  eight inch tip with uniform taper.
    b. Piles of less than twenty-five  tons  capacity--Class  A  or  B  or
  minimum six inch tip with uniform taper.
    (2)  PILES  DRIVEN  TO  END  BEARING.  All timber piles, regardless of
  capacity, driven to end bearing on soils of classes  1-65  through  5-65
  shall  be  class  A or shall have a minimum eight inch tip and a uniform
  taper.
    (3) SPECIES OF WOOD. Any species of wood may be used that conforms  to
  the  provisions  of  reference  standard RS 11-7 and that will stand the
  driving stresses.
    (4) PEELING. Unless treated, piles need not be peeled.
    (b) Limitations on use. Where timber piles are to  be  driven  to  end
  bearing  on  soils  of  classes  1-65  through  5-65 by use of an impact
  hammer, the installation of each such pile shall be under  the  personal
  supervision  of  an architect or engineer, and the operations of driving
  such  piles,  the  observations  of  penetration  resistance,  and   the
  operation of the equipment shall be so conducted as to terminate driving
  directly  when  the pile reaches bearing on the hard material. A report,
  prepared by  the  architect  or  engineer,  describing  the  procedures,
  equipment,  and  precautions  followed  to  prevent injury to the piling
  shall be submitted to the commissioner.
    (c) Lagged and inverted piles. The use of  lagged  or  inverted  piles
  will  be  permitted. Double lagging shall be adequately connected to the
  basic pile material to transfer the full pile load from the  basic  pile
  material  to the lagging without exceeding values of allowable stress as
  established in subchapter ten of this chapter. The connection for single
  lagging shall be proportioned for half the pile load.  The  diameter  of
  any  inverted timber pile at any section shall be adequate to resist the
  applied load without exceeding the stresses indicated in  paragraph  one
  of subdivision (a) of this section, but in no case shall it be less than
  eight inches.
    (d) Installation.
    (1)  All  broomed, crushed, or otherwise damaged materials at the head
  of the piles shall be removed before capping.
    (2) Any sudden decrease in driving resistance  shall  be  investigated
  with  regard  to  the  possibility  of breakage of the pile, and if such
  sudden decrease in driving resistance cannot  be  correlated  to  boring
  data  or some incident in the driving, and if the pile cannot be removed
  for inspection, it shall be considered as adequate cause  for  rejection
  of the pile.