Page 24 - Wire Rope News & Sling Technology - June 2019
P. 24

useful, but not foolproof in all work lo-
                                                                               cations and weather conditions. Thus,
                                                                               there is controversy among crane own-
                                                                               ers, hazard analyzers, and lawyers.
                                                                               Much of this controversy is, in my opin-
                                                                               ion, among the unknowing  or vested
                                                                               interests – not to the improvement of
                                                                               hazard recognition for its own sake.
                                                                                 Next, the weight of the load is moni-
                                                                               tored on the cranes by load limiters.
                                                                               The crane is prevented from lifting
                                                                               more than 100% to 110% of the capac-
                                                                               ity. These crane capacities are based
                                                                               on the crane’s strength, not its tipping.
                                                                               The hoist motor stops hoisting when,
                                                                               on some cranes, the mast deflects the
                                                                               predetermined amount indicating  an
                                                                               overload. (Figure 9, page 26) Also on
                                                                               some cranes the trolley will stop when
                                                                               traveling out beyond capacity. It is
                                                                               critical  to safe  operations  that these
                                                                               devices function properly and are test-
                                                                               ed monthly. If safeties don’t work cor-
                                                                               rectly, then the old crane axiom “either
                                                                               the crane moves or the load moves” will
                                                                               prevail to horrifying outcomes.
                                                                                 To emphasize this point is a 2019
                                                                               New York City  regulation (fueled by
                                                                               accidents)  mandating “crane  event
                                                                               recorder”  installation on  all tower
                                                                               cranes working in the city. This device
                                                                               (labeled a Block Box) is to record any
                                                                               overload incident  and  status  of  limit
                                                                               switches.  The problem I see here is,
                                                                               say, the overload switch fails and the
                                                                               “Black Box” records the malfunction,
                                                                               would that stop overloading? No. But,
                                                                               it  would  help  in  the  “finger  pointing”
                                                                               after an accident.

                                                                               ERECTING OR
                                                                               CLIMBING/DISMANTLING
                                                                                  Manufacturing changes in the crane
         Fig. 7: Damage is seen at the site of a tower crane collapse at 91st Street and First Avenue in
         New York City on May 30, 2008, killing one person and damaging an apartment building on   design has lessened the “artistry” neces-
         Manhattan’s upper east side. Photo © Shannon Stapleton|Reuters        sary to perform raising or taking down
                                                                               the crane successfully. It had been years
         continued from page 22             dition has always been “basic” to crane   since the papers were reporting a cata-
         operators fall off these cranes.  Why?   safety. The operator could stop or beep   strophic tower crane accident in this
         Well, as one that has climbed all over   a horn, and is required to avoid carry-  country, until a recurrence in Seattle
         them, it’s my opinion  that we  know   ing loads over people to prevent a pos-  this year. Our society should respond to
         the risks, understand the safety equip-  sible accident – if he/she could see it   these devastating disasters since we all
         ment, do not need to be told to use it   coming! Some tower cranes now have   share the cost. The “big ones” in Cali-
         (kind of self-evident) and feel comfort-  remote controls that allow the opera-  fornia, New York and, Florida brought
         able with heights!                 tors to locate themselves closer to the   on  the  significant  OSHA  Construction
                                            “action”  thus  significantly  improv-  1926.550  rewrite  becoming  1926.1400
         OPERATION                          ing visibility. However, most cranes   (17 pages to 213 pages.) The extensive
            A problem with the tower crane opera-  don’t have remote controls, and to my   studies  conducted  after  the  2007-2009
         tion is, it’s always a long way between the   knowledge, luffing tower cranes (boom   tower  crane  accident  “spell”  exposed
         operator and where the load is being at-  type, versus a trolley for radius) are   root problem areas. A task force formed
         tached. Also, most operators don’t know   all cab operated. So, viewing the work-  in New York recommended needed ar-
         the load weight or how it is rigged; they   place is the signalperson’s duty via ra-  eas of change – and industry responded.
         depend on an overload device to stop the   dio or hand signals.       I’m sure the latest accident will be felt
         hoisting as well as a qualified rigger.   Two tech devices are now in use on   by the insurance companies who will
           The ability of the operator to see   tower cranes to help the operator “see”   pay out millions and feel the need to
         the load (some cabs could be 600 feet   the work area. These are video camer-  spread the cost to those they can! The
         away) and react to the unforeseen con-  as and anti-collision devices. Both are        continued on page 26

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