greater than the SWL of the wire rope, the test weight will be computed from the SWL of the wire rope or if the winch capacity is less than the SWL of the wire rope,  the  test  weight  will  be  computed  from  the capacity of the winch.    The winch capacity is either documented   on   the   load   charts   or   in   the manufacturer’s manual. The formula for computing the SWL for a hoist rope is the diameter of the rope squared multiplied by 8 or (D x D x 8 = SWL in tons). Example: The wire rope on a crane is 1/2 inch in diameter.  Compute  the  SWL  for  the  rope. The first step is to convert the 1/2 into a decimal number by dividing the bottom number of the fraction into  the  top  number  of  the  fraction:  (1  divided  by 2 = .5). Next, compute the SWL formula: (.5 x .5 x 8 =  2  tons).  The  SWL  of  the  l/2-inch  wire  rope  is 2 tons. The   next   factor   to   compute   is   the   breaking strength of the wire rope. On some wire rope spools, the  nominal  breaking  strength  of  the  wire  rope  is published;   however,   if   the   breaking   strength   is unknown, a break test can be performed on the wire rope. This is accomplished by cutting off sections of the wire rope and placing each section of the rope on a wire rope break test machine. The machine pulls the wire  rope  apart  and  computes  the  breaking  strength. By testing several sections of the wire rope, you can determine the average breaking strength for that type of  wire  rope. Overseas,  Public  Works  Centers normally have wire rope break test machines that can be  used  by  the  NCF. If  the  break  test  cannot  be performed,  the  rule  of  thumb  used  for  finding  the breaking  strength  is  to  multiply  the  SWL  by  5 (SWL x 5 = B.S.). For example, a l/2-inch wire rope with a SWL of 2 tons has a breaking strength of 10 tons  (2  x  5  =  10  tons). REMEMBER:   When   the single  line  wire  rope  end  connection  is  assembled with a wedge socket, the wedge socket only develops 70  percent  of  the  breaking  strength.  Example:  The crane is rigged with l/2-inch wire rope with a wedge socket   end   connection.   The   wedge   socket   only develops  seventy  percent  of  the  l/2-inch  wire  rope B.S.  of  10  tons,  which  gives  the  wire  rope  a  B.S. determined by an end connection of 7 tons. Swaged socket,  cappel  socket,  and  the  zinc  (spelter)  socket  all provide 100 percent of the breaking strength when properly  made. The next factor to compute is the AWL by using the factor of safety (F.S.). To compute the allowable working  load  (AWL)  of  a  wire  rope,  you  must  first understand  the  following  wire  rope  safety  factors: 1.  Rigging rope a. 5 to 1 under operating conditions b. 10 to 1 when used to lift personnel 2.    Pendants or standing rope a. 3.0 to 1 under operating conditions b. 2.5 to 1 when erecting the boom 3.  Ropes  that  wind  on  drums  or  pass  over sheaves a. 3.5 to 1 under operating conditions b. 3.0 to 1 when erecting the boom For the auxiliary line, use the F.S. of 3.5 for wire rope that winds on drums or passes over sheaves. The formula for the F.S. is the breaking strength (B.S.), determined by the type of end connection divided by F.S.  (Example:  B.S.  =  7  divided  by  3.5  =  AWL  of 2 tons.) The  next  factor  to  compute  is  the  test  weight. This is done by multiplying the AWL of 2 tons by 110 percent (2 x 110% or 2 x 1.10 = 2.2 tons). Your test weight for the l/2-inch wire rope is 2.2 tons. After the test weight is figured, you must remember that the hook blocks and rigging gear are weight that are part of the test weight. Leveling   a   crane   cannot   be   overemphasized. Cranes   must   be   set   up   as   per   manufacturer’s instruction, with the outriggers fully extended and the crane leveled. Crane capacity is lost when the crane is  out  of  level  by  a  few  degrees  (fig.  3-14).  Most Figure 3-14.-Crane capacity lost by crane out of level. 3-15