2006 New York Code - Jacks.

 
    §  27-1064  Jacks. (a) Marking. The rated capacity of every jack shall
  be legibly marked in a prominent location on  the  jack  by  casting  or
  stamping. The manufacturer shall designate the intended supporting point
  of  the  load  and  the  maximum  permissible  length of lever and force
  applied.
    (b) Overtravel to be limited. Every jack shall, where practicable,  be
  provided  with  a  positive  stop  to  prevent  overtravel; otherwise an
  indicator to clearly show overtravel shall be provided on the jack.
    (c) Maintenance. Lubrication  and  operation  of  jacks  shall  be  in
  accordance with the recommendations of the manufacturer.
    (d) Foundations. Jacks shall rest on a firm, level foundation adequate
  to support the load.
    (e)  Blocking required. When the object has been lifted to the desired
  height, blocking or cribbing shall be immediately placed under it.