Monday, December 9, 2019

Train Your Kids in Proper Rigging - Not Like This!

     Pictured here is a load attaching method of hoisting an I-Beam some 250 feet in the air via a Tower Crane on a large industrial job site. The crane operator, about 275 feet away from where the beam is to be landed. He has little input as to  how the load is connected to “his Crane.” Yet, he and his Employer will feel the harmful effects of a dropped load, if someone should get hurt – it will be costly.

     The operations are 100% depending upon this rigger’s decisions; that will be made in a matter of seconds – based on his training and experience! He’s performed this “choker hitch,” a hundred times before (let’s assume) with no failures. The hitch may be the same – but are the working conditions that affect the outcome all the identical?

     What’s so wrong here that I am taking your time to “rail” about anyway? If I were testing someone in an entry-level Rigging 101 course, he would fail. Aside from the obvious of not running the eye through the yellow oblong link that re-duces wire wear and D/d ratio stress on the body of the sling, as the sling Manufacture intended. There is no kinking protection (softeners) between the beam/sling contact points. However, there is a much more important error.

     These experienced Ironworkers know that this thirty-foot, W 14 x 82 beam weighs about 2,460 pounds, (1,230 each end) is not going to break the 3/4" diameter wire rope sling they are using. So, they feel justified in abusing their employer’s equipment; after all, men will be men! So, bothersome soften-ers and sling body wear/stress is “kids stuff” not to slow down production and make this work harder than it is. There is some logic here, and I had witnessed an overuse of personal protection equipment (PPE), making things harder for the workers when no hazards existed, frustrating the people.

     The real “violation” here is the lack of control that could cause the beam to slip and fall from the choker hitch on its 250-foot journey over the heads of numerous workers - not the breaking of the sling. All manners of forces can occur to dislodge the beam along its route. To name a few; excessive swing speed, sudden starts/stops, beam caught on the obstacle, weather conditions, or setting one end down and releasing the “bite” allowing the beam to slip and fall. A bundle of metal studs from a single wrap choker hitch like this, occurred at a hotel under construction at Disney, killing one.

Corrected: Double Wrap, Softeners, and a Shackle in the “bite.”
     Simply a “double” wrap choker hitch would have provided all the necessary control, yes, a little more annoying for the riggers – but so much safer. A bad meth-od is a bad method no matter how many times you get away with it! And, it’s a terrible OJT example for the kids. These experienced riggers may have “fallen prey” to complacency.

     The camera is everywhere nowadays, catching us in the “act” as it were. Companies slogans like “Safety First, If you can’t do it right, don’t do it,” etc. will not stop an unsafe act, skills training helps. We ask ourselves why people take “short-cuts” why don’t people do it right all the time – oh yes, people were never made perfect!

As printed in the August 2018 issue of Wire Rope News and Sling Technology.

Dennis can be emailed at dennis@natlcrane.com.

Thursday, December 5, 2019

Synthetic Ropes, "to be or not to be " on Mobile Cranes - that is the question

     There is a long-established belief that “if it ain't broke, don’t fix it.” Steel wire rope has been used successfully on cranes since the 1800s. Now some are replacing steel ropes with synthetic ropes. At the last two conferences that I attended, held by the Crane Certification Association of America (CCAA), synthetic rope manufacturers (Samson and Yale respectively) gave presentations as to why replacing steel ropes with synthetic ropes on cranes makes sense.

     What the crane industry has experienced in the past is fiber roped being easily cut when they are used as slings, blocks, and tag lines. Fig. 1 There is an established “belief” this material is too soft to be used on multipart reeving. It’s said that facts and words do little to alter a belief, experiences are what one trusts. Crane owners have required the installed synthetic rope be removed from their crane based on this weakness belief. Yet, no evidence of damage was evident.


Fig. 1

     The popularity of synthetic ropes on cranes is growing just by the number of companies offering the product. They call it in sales terms, “market push” The Heavy Lift off-shore Oil industry is a major user of these products due to their reduced weight.

     The benefits of synthetic rope over steel are lighter weight, more flexibility, anti-spin, and no need for lubrication to prevent corrosion. Some synthetic rope manufacturers claim a fourfold increase in rope life, thereby reducing operating costs – a true advantage if proven. The benefit of reduced weight has caught the attention of the crane industry.

     Let’s do a little arithmetic. Let’s assume the weight of eight parts of 7/8” steel wire rope at 1.42 pounds per foot at a 100’ hook height (1.42 x 8 x 100 = 1,136 pounds) add a 3,800 pounds load block. Now have 4,936 pounds suspended over the crane’s boom point. Replace the steel rope with synthetic rope, as pictured in Fig. 2, will see a reduction of the weight of the rope by 80%. The weight of the block will also be further reduced because the overhaul weight requirement will be approximately 65% of its original weight. The new total weight in the hypothetical situation is approximately 1,352 pounds, a 3,584 pound reduction. This weight decrease really gets crane manufacturers excited, especially the ability to reduce weight at the boom point. Also, note the nylon point sheaves a further weight reduction over steel.


Fig. 2

     Synthetic ropes have been installed on utility truck winches used in the power industry for decades. Synthetic ropes are less conductive than steel wire ropes, an advantage when working around powerlines. For most operations, the synthetic rope on utility truck winches is used in a one-part configuration. Now we are looking at synthetic ropes being used as multi-part configuration on a mobile crane, greater wear.

     At various locations the Navy, Grove, and others have conducted trial tests of synthetic ropes on cranes, and the performance of the rope was reported satisfactory. I question how safe it is to trust a synthetic rope that can be cut with a knife, to lift 80-ton loads? Especially since I have witnessed synthetic ropes damaged when used for rigging slings and tag lines. How will the rope last in “real” job activities?

     When a crane is operated and used conservatively, the synthetic rope should be as reliable as steel ropes. That is the rub. When we factor humans into the equation, things get complicated, job pressures increase. What “predictable misuse” should be expected. I think of the ABBA song “Take a Chance on Me.” Do I take a change when not knowing if the crane will be properly operated and maintained some months down the line? I believe that synthetic rope needs the “test of time” to show the crane community how it survives in the real-world struggles of a modern job site.

As printed in the December 2019 issue of Wire Rope News and Sling Technology.

Dennis can be emailed at dennis@natlcrane.com.

Saturday, May 19, 2018

“Additive Manufacturing” of Hooks – Good Idea?


By: Dennis O'Rourke



Fascinated, when in 1984 I learned from a science magazine that a photo of a Statue Bust of Benjamin Franklin was taken in Cambridge, England and faxed to a laboratory in Massachusetts. Then, it was turned into a 3D CAD digital file which was loaded into a “molding printer” where it started to duplicate the bust of “Ben” - as a plastic replica, amazing.
Now in 2018, I learn of a comparable process of producing a crane hook, that caught my interest. This process forms an object layer on layer.  I thought it was a neat idea for ole Ben’s head but, for a crane’s load hook I have questions. As one who for about 45 years inspected and tested port cranes, I know that the hook supports all that is below it, no doubt critical to safety.
                                                               


History of 3D Technology

Well, why is it called 3D printing anyway? If you were to look at letters being typed on a page with a microscope you would see that the letters sit “on top” of the page, not stained into it. If you were to print over the same spot with different letters the area would build-up to form a three-dimensional object of a complex shape by the addition of each printed letter, letter by letter.

The “3D Printing” process technology started about 1981 and still is being performed using these basic steps.

1.  SCANNING - with 3D capabilities of making a virtual digital document of a drawing or object by locating digital points along it’s X, Y and Z axis, thus creating the digital copy of a solid object in a document file that can be distributed. A CAD file using a 3D-modeling program will create this file.

2. DIGITAL SLICING - this digital file is loaded into a computer having programs that turns the data into what could be thousands of thin cross-section digital layers. When the layers are stacked upon each other they will form the 3D replica. Then this digital message is loaded in an external “printer”.



3. PRINTING - Processes vary, a computer file then guides the printer’s robotic arm that lays on a liquid material in the prescribed pattern on a “product bed”, from the bottom-up, that instantly hardens the material forming a solid layer. The next layer is placed on top, layer on layer, till the object is duplicated per the digital instructions.




The 3-D printing started out in a laboratory using poly-based plastics that used very complex and expensive machinery at a university. Thus, ideas about how and where to use the new technology spread slowly throughout industry due to cost. The process, not only expensive but, the materials used were not strong and limited to “gadgets”.
                                    
These steps were at first three separate functions on different machines or even countries. Currently, all these functions are available in one low-cost unit suitable for the private-public to experiment.
Three major machine improvements took place through the years allowing many people to research with uses of the 3D printing process. Therefore, new ideas and products arose.
Now, products from plastics, cement, to the hardest steels are being used to manufacture structural components or gadgets at or below, current prices.

Current Process 3D “Additive Manufacturing”

Processes in printing of objects today to produce the 3D image and duplicate an object are evolving. The term Additive Manufacturing (AM) starts with a flat surface and builds up the object layer on layer. Developers feel this process of “adding” material more accurately defines the difference between taking a picture and producing an object (Ben’s head) vs. adding material to build-up an object (a hook). Additive manufacturing is only using the material you need, as opposed to Subtractive manufacturing, which involves cutting away what is not needed from a large casting.
In 2010 ASMT defined seven categories of Additive Manufacturing. Spray methods of building up material into objects are still used. To form plastic parts and decorative items. Structural concrete components for the construction industry use these spray methods.

Another method starts by spreading a thin layer of powered metal on a bed. Then using a laser, it welds the power into a solid layer of material on the bed, and then another layer is applied over that layer. The process is repeated until completing the object. There is a possible risk of the material not being fully fused during this “power” process.

Fusion welding which deposits metal to form 3D shapes by aiming a Plasma beam or Laser to achieve desired fusing results. Also, Wire & Arc using a GTAW or TIG power source are methods employed. This latest technique has replaced some casting/machining products manufacturing, ships propellers (wheel). At times in cast objects, 70% of the material is removed to form the item, a huge material cost. This savings is one major reason driving this method as well as the stronger objects (hooks) being made.
                                                
 The fusion zone and surface are subject to oxidation with some alloys and demand additional inert gas protection. Portal seals can be placed over the work area and filled with inert gas for protection against contamination.

Some draw-backs remain with “printing”. The process is not cost effective for some items; it cannot compete cost-wise with mass-produced items on the production line, yet.  Also, the smooth finishes necessary for some products are not achieved. Likewise, the variations in material types necessary are not available. Still, they are working on it, and the process is sprouting.



Steel Duplex hooks have been made by a Cast/machined process. A two-prong duplex hook cannot be forged as a Bowl hook is, they are cast and machined.
Cast Steel Hook
Forged Steel Hook 

A word about PLASMA, it is one of the four fundamental states of matter (plasma, gas, liquid, and solid). But plasma does not occur naturally on earth. It takes an electrical current or a strong magnetic field in a vacuum to strip or add electrons from an inert gas to place the molecules in the “Ionized” state, charged particular = plasma.  When these forces are removed the “freed” electrons emit light returning, and the molecule reclaims its normal state. However, plasma is familiar to us as in neon light tubes, the Northern lights in the sky, plasma TV or the “free” nitrogen released during a lightning strike.



When welding with a plasma beam (which is like a little rocket engine), the chamber inside the torch forms a vacuum heating the inert plasma gas that expands. The hot plasma ions gas rushes out the nozzle and can be precisely aimed. Because all this takes place inside the nozzle, there is no need for a vacuum chamber to produce the plasma state of the inert gas.

The process of building up steel by welding has been around for a while, in 1926, Baker-patented the use of depositing molten metal in superimposed layers to build-up objects. We all have seen multi passes welds on weldment to achieve the necessary strength in the structure.

World’s First 88-ton AM Duplex Hook


The Huisman Company, Netherlands accomplished the manufacturing and load testing of an 88-ton
WAAM Hook
Duplex Port Crane hook using a 3D printing technique. Termed “Wire & Arc Additive Manufacturing” (WAAM) process which utilizing a wire feed and plasma Arc to produce the midsize hook. WAAM process of Manufacturing is in some sense – special. The directions to the robot wheeling the Arc welder are the same as those in numbers 1 and 2 above. In step 3, the layering of the hook utilizes the Arc and Wire feed welding process which is hotter (10,000 to 20,000 degrees c) than carbon arc or laser to build-up the hook. This allows stronger materials to be used.


What’s next?

The Caterpillar Tractor Corp. is currently producing aftermarket parts using the AM method which are more cost-effective than starting up old production lines that no longer produced the part. One component which is manufactured new parts is a complex gas turbine nozzle which is used in their production equipment.
It is becoming cheap and easier to 3D manufacture metal parts, if widely adopted, it could change the way we mass-produce many products. Livermore National Laboratory announced they have 3D printing method for stainless-steel parts twice as strong as traditionally made one.
Markforged, a small startup, outside Boston, released the first 3D metal printer for under $100,000. Desktop Metal also in Boston, began to ship its first metal prototyping machines in December 2017 that are claimed to be 100 times faster than elder metal printing machines.
GE, which has long been a user of 3D metal Additive Manufacturing has a test version of its new metal printer fast enough to make large parts and plans to start selling them in 2018!
Even outer space is an option, NASA has challenged with a $250,000 prize to a company who can adapt 3D additive manufacturing technique for robots on Mars to build habitat designs to eventually house humans’ explorers on the planet! On the material side, they say the problem is solved. All we need now is a nozzle that is a little more “forgiving” to spray the material (may already have it). I guess, “the sky is the limit”.

3D HOOK MANUFACTURING CONCERNS

1.     The process of layering, how is 100% adhesion between layers assured?
2.     In use when loading/unloading flexes hooks, will layers delaminate?
3.     What type of NDE method would be appropriate?
4.     What visual inspection dimensions are assigned?
5.     Are the Hook Manufacturer’s data sheets available?


Saturday, September 27, 2014

OSHA extends operator's certification requirement for 3 years.



OSHA extends compliance date for crane operator certification requirements

 
WASHINGTON – The Occupational Safety and Health Administration today issued a final rule extending the deadline for crane operator certification requirements in the Cranes and Derricks in Construction final rule* published Aug. 9, 2010 by three years to Nov. 10, 2017. The rule also extends by three years the employer's responsibility to ensure that crane operators are competent to operate a crane safely. The final rule becomes effective Nov. 9, 2014.

During the three-year period, OSHA will address operator qualification requirements for the cranes standards including the role of operator certification. The final cranes and derricks rule required crane operators on construction sites to meet one of four qualification/certification options by Nov. 10, 2014. After publishing the final rule, a number of parties raised concerns about the Standard's requirement to certify operators by type and capacity of crane and questioned whether crane operator certification was sufficient for determining whether an operator could operate their equipment safely on a construction site.

The agency published a Notice of Proposed Rulemaking on Feb. 12, 2014, proposing to extend both the deadline for operator certification and the employer duty to ensure competent crane operation for three years. After publishing the proposed rule, a hearing was requested and held in Washington, D.C. Comments from the hearing are available at http://www.regulations.gov/#!docketDetail;D=OSHA-2007-0066. OSHA analyzed the comments to the NPRM and the hearing testimony and decided to extend both the crane operator certification deadline and the existing employer duty for three years. OSHA has already begun the process of developing a standard to ensure crane operator qualifications.

Under the Occupational Safety and Health Act of 1970, employers are responsible for providing safe and healthful workplaces for their employees. OSHA's role is to ensure these conditions for America's working men and women by setting and enforcing standards, and providing training, education and assistance. For more information, visit www.osha.gov.

Read More

Sunday, October 6, 2013

Inspection of Boom Ropes

     In a recent fatal crane accident in New York the crane inspector is being investigated for performing an improper and/or an “casual” inspection of the crane by authorities base on testimony  by the operator and other witnesses.


     The boom running rope on the Crawler Crane failed and dropped the boom. I don’t have any more info at this time, but the “experts” are investigating.
 
 
 
 
 

 
     From our experience in the certification business we know that boom ropes are;  

1.     Hard to inspect and a precise method is necessary to inspect them properly.

2.     Failure mode is usually “Crushing” on the Drum WHICH CAN BE SEEN and “Embrittlement” of the wires in the rope causing fatigue failures of the wires WHICH ARE HARD TO SEE.

  
 
 
 
     One reliable way of knowing your wire ropes are in good working condition is to keep track of the time the wire rope has been on the crane and the condition and maintenance of the wire rope. Gottwald Harbor Cranes have an hour meter on their hoist which shows the actual time the ropes have been spooled in and out on the drum which causes the damaging fatigue. Presently, they say to change the wire rope at 8,000 hours of operations. No other manufactures to my knowledge has given an hourly replacement criterion. 

ACTION

     The method we follow when making an inspection on the critical Boom Luffing Ropes is;
 

 
 
 
 
 
 
  1. Get the date the rope was installed, they don’t know, deficient.
  2. Get the Wire Rope certificates, must have.
  3. Check to see it’s the correct rope, if wrong, deficient.
  4. Boom must be put on the ground and ropes slack for inspection, if you can’t, deficient.
  5. Inspect per my presentation, which I will go over at out next newsletter.
 
      The “attentive” crane owner is well aware of the importance of inspecting the wire rope on his crane, but the problem is that some are becoming accustomed to having third party inspection companies perform their annual inspections, This is the only time the wire rope is thoroughly inspected. However, the new OSHA construction standard 1926.1413 requires written monthly wire rope reports completed by a “competent person” to be performed and documented. What does it mean to be competent?
     The definition of “competent person” in OSHA is thirty five words long! But what says is, someone who knows what there are looking for, and has a good track record of finding it!
     However, this written report is most often missing from the crane file when we (as required) review the files during our annual inspection. Let’s all try harder to improve ourselves in these inspections of this critical component, Boom Luffing Ropes.