Section 27-828. Fuel oil storage equipment

(a) General requirements for fuel
  oil  tanks. All tanks shall be designed and installed in accordance with
  the provisions for steel work in subchapter ten of this  chapter  or  in
  accordance with the provisions of this subchapter.
    (1)  All  fuel  oil  storage  tanks  shall be built of steel plates or
  sheets, made by the open hearth or  basic  oxygen  process.  Such  steel
  shall  be  free  from  physical imperfections, and shall be new, in good
  condition, and free from rust.
    (2) Tanks shall be welded, riveted and caulked, or riveted and welded.
  Flanges or other pipe connections may be welded. All caulking  shall  be
  placed with round nose tools and without damage to the plates. Filler of
  any kind between plates shall be prohibited.
    (3) Tanks to be buried shall be cleaned and then coated on the outside
  with  two  coats  of  red  lead,  or  equivalent.  They shall be further
  protected by a coating of hot tar, asphalt, or equivalent rust resistive
  material, applied at the work site.  Tanks  installed  inside  buildings
  above ground shall be coated with one coat of red lead, or equivalent.
    (4)  All  buried  storage  tanks  shall  be  constructed  of  at least
  one-quarter inch thick metal and shall  be  designed  to  withstand  any
  external loads to which the tank may be subjected.
    (5)  At  the  time  of  installation  all  storage  tanks shall bear a
  permanently-fixed plate, spot welded or equivalent, bearing the name  of
  the  tank  manufacturer,  the gauge of the material, and capacity of the
  tank.  Shop  fabricated  storage  tanks  shall  be   installed   without
  structural alteration.
    (6)  All openings shall be through the top of the storage tank, except
  that storage tanks of two hundred seventy-five gallon capacity or  less,
  located  above ground but below the lowest story, may be provided with a
  three-quarter inch opening for gravity discharge and a one inch  opening
  in the bottom for cleaning and protection against corrosion.
    (7) Tanks for no. 1, no. 2, no. 3 and no. 4 commerical grade oils need
  not  have  manholes.  However,  if  manholes are used for such oils, the
  manhole covers shall be bolted and made gastight. Tanks for  no.  5  and
  no.  6  commercial  grade  oils  shall  have  manhole  covers  bolted or
  otherwise secured to the tanks and kept  hydrostatically  tight  at  all
  times.
    (8)  Tanks  outside  of  buildings  shall  be electrically grounded in
  accordance  with  the  requirements  for  equipment  grounding  of   the
  electrical code of the city of New York.
    (9)  Tanks  shall be located at least seven feet, measured in the most
  direct manner, from any source of  exposed  flame  unless  protected  as
  provided  in paragraph two or three of subdivision (a) of section 27-829
  of this article and at  least  two  feet  from  any  surface  where  the
  temperature exceeds one hundred sixty-five degrees Fahrenheit.
    (b)  Construction  requirements,  cylindrical  tanks,  except vertical
  tanks  above  ground  outside  of  buildings,  more  than  two   hundred
  seventy-five gallon capacity.
    (1)  The  thickness  of  cylindrical  tanks, including oval, elongated
  oval, or obround tanks of more  than  two  hundred  seventy-five  gallon
  capacity shall be subject to the following requirements:
    a.  Tanks  thirty-six  inches  in  diameter and less--at least 1/4 in.
  shell and 1/4 in. heads.
    b. Tanks thirty-seven to seventy-two inches in diameter--at least  1/4
  in. shell and 5/16 in. heads.
    c.  Tanks  seventy-three  to one hundred twenty inches in diameter--at
  least 5/16 in. shell and 3/8 in. heads.

    d. Tanks over one hundred twenty inches in diameter  shall  be  of  at
  least  3/8 in. steel and shall be stiffened by angle rings or equivalent
  members so as to retain their cylindrical form.
    (2)  Dished  heads for such tanks shall have a curvature the radius of
  which is not greater than the diameter of the tank. Dished  heads  shall
  be  formed  with  an  adequate  cylindrical  extension  rim to provide a
  welding or riveting surface. If flat  heads  are  used,  they  shall  be
  braced  in the same manner as described for the bracing of flat sides of
  rectangular tanks.
    (3) Riveting in single lap seams shall not exceed a pitch as follows:
    a. Shell 1/4 in. thick 5/8 in. diameter rivets, 2 1/4 in. pitch.
    b. Shell 5/16 in. thick 5/8 in. diameter rivets, 2 3/8 in. pitch.
    c. Shell 3/8 in. thick 3/4 in. in diameter rivets, 2 1/2 in. pitch.
    (c) Rectangular tanks, of more than two  hundred  seventy-five  gallon
  capacity.
    (1) Plates for rectangular tanks of more than two hundred seventy-five
  gallon capacity shall be at least 5/16 in. thick.
    (2) Corners may be made up by bending the plates or by using angles.
    (3) Minimum rivet diameter in seams shall be 5/8 in., and rivets shall
  be spaced not more than 2 1/4 in. center-to-center.
    (4)  All  flat  surfaces  of  rectangular  tanks  shall  be  braced by
  structural members or rods.
    (5) When structural members are used, the rivet pitch shall not exceed
  six inches.
    (6) All structural members shall be designed in  accordance  with  the
  requirements of subchapter ten of this chapter.
    (7)  Connections  between  bracing  members  and the sides of the tank
  shall be designed so that the connection will not fail before the member
  will fail.
    (d)  All  tanks  except  vertical  tanks  above  ground,  two  hundred
  seventy-five gallon or less capacity.
    (1)  All oil storage tanks of two hundred seventy-five gallon capacity
  or less that are not buried shall have a minimum thickness of shell  and
  head plates of no. 10 manufacturer's standard gauge steel plate. Storage
  tanks  of  sixty  gallon capacity or less shall be similarly constructed
  but need not be thicker than No. 14 manufacturer's standard gauge.
    (e) Vertical storage tanks over one thousand gallon  capacity  located
  outside of building above ground.
    (1)  Vertical tanks located outside of buildings above ground shall be
  built of steel plates of the quality required for cylindrical tanks.
    (2) The minimum thickness of shell  or  bottom  plates  shall  be  one
  quarter  of an inch, and the minimum thickness of roof plates one-eighth
  of an inch. The  thickness  of  shell  plates  shall  be  determined  in
  accordance with the following formula:
 
                                  P x R x F
                           t = ------------------
                                    T x E
 
  where: t = thickness of shell plate in inches.
         P = head pressure at bottom of ring under consideration in psi.
         R = radius of shell, in inches.
         F = factor of safety (taken as five).
         T = tensile strength of plate, in psi as verified by mill
               test certificate.
         E = efficiency of vertical joint in ring under
               consideration.  E shall in no case be taken greater than one.

    (3)  Roof  plates  shall  have single lap-riveted or welded watertight
  seams, and the roof shall be built to shed water.  Bottom  plates  shall
  have  single  lap  riveted  or  welded seams. Shell plate seams shall be
  designed to develop the full strength of the plate.
    (f) Storage containers of six gallons or less.
    (1)  Oil  storage  containers used with burners or oil burning heaters
  and having a capacity of six gallons or less  used  in  connection  with
  burners  or  oil-burning  heaters shall be designed so as to withstand a
  hydrostatic pressure  test  of  at  least  five  psi  without  permanent
  deformation, rupture, or leakage, and shall be approved.
    (2)  All  storage  containers used with burners or oil burning heaters
  shall be installed with rigid metal fasteners for wall, floor,  or stand
  type installations, and shall be protected against mechanical damage.
    (3) Portable containers may be filled by a pump mounted on  a  storage
  tank, provided that the pump is approved.