DICA recently contributed to an article on the crane industry featured in the 2015 May-June issue of Lift and Access magazine. Authored by Tracy Bennet, the article highlights how non-metal materials are being applied in new ways to crane accessories. The developments in the crane industry have delivered new benefits but at times, also some confusion. The article can be read in it’s entirety below or by using the following link.
DICA is proud to be leading the way in the application of composite and synthetic materials in our outrigger pad and crane mat products. These developments are helping DICA to improve the reliability, durability and safety of outrigger-enabled equipment operations around the world. See the following links for more information on DICA Safety Tech Outrigger Pads and FiberMax Crane Pads or continue reading below to enjoy the article.
Can the Crane Industry Keep Up with Technology Changes?
Non-metal materials applied in new ways to crane accessories brings benefits, and also confusion.
By Tracy Bennett
Synthetic, plastic, nylon, composite are all terms commonly heard in relationship to non-metal materials for rigging gear and crane accessories. For about 20 years, operators and riggers have been using polyester round slings, nylon sheaves, and plastic outrigger pads. But according to manufacturers, many industry professionals use the aforementioned terms interchangeably. The more recent advent of composite and high-performance materials has further increased common misunderstandings of these products. Meanwhile, non-metal materials are also making their way into new applications, such as the introduction of composite spreader beams and synthetic hoist lines on mobile cranes.
While users don’t really need to know the materials science behind these products, they do need to know the performance limitations and the manufacturer’s inspection and usage guidelines.
Steve Fryer, Manager of Training for NCSG Crane & Heavy Haul, based in Edmonton, Alberta, admits that as much as his company tries to stay on top of changing technology, sometimes it changes faster than they can adapt. That’s partly due to a wait-and-see approach many in the crane industry take regarding the application of new products.
NCSG’s use of synthetic products has been largely limited to synthetic slings, which now has a proven track record. Outside of that, “We have entertained the idea of using other synthetic products such as crane hoist ropes, but are reluctant to do so without a clear history of use.”
However, he acknowledges the benefits. “Most synthetic products on cranes improve capacity due to much lighter weight than steel components. Boom and block sheaves are an excellent example. Some manufacturers have introduced carbon fiber boom pendants, although they have not been widely accepted in the industry despite being much stronger pound-for-pound than steel.”
While Fryer believes his company does have a clear understanding of the differences between various non-metal materials used in crane and rigging products, that is not universally the case.
Jeff Susman, President of Slingmax®, Aston, Pa., which pioneered the use of synthetic fiber round slings for rigging and overhead lifting applications, shared a recent encounter with someone who said they were using ‘carbon fiber belts’ for rigging. “I knew that carbon fiber is much too stiff and brittle to be used for a sling application. After some investigation, I discovered what he really had was a polyester round sling from which the tags had been removed and replaced with inaccurate information. This was a very extreme case of a customer not knowing what he was buying,” said Susman, who added that OSHA requires sling tags to be permanently affixed with legible information prescribed by the manufacturer.
In crane accessory applications, synthetic and plastic are typically used to mean any non-metal product. But the reality is that the material might actually be polyester, nylon, high density plastic, fiberglass, high molecular weight polyethylene, aramids, etc., some of which are considered high-performance fibers and materials. The list could go on and on.
“There’s a whole variety of synthetic fibers with specific applications and performance characteristics,” said Michael Quinn, Director of New Business Development for Samson Rope, Ferndale, Wash. “What’s more important is that the customer understand the various grades of the material, how it is tested and rated, and what the specifications are for the application,” he said. “For example, Samson’s published strengths for our ropes are spliced rope strengths. Almost all synthetic rope applications require a spliced termination. If your supplier is quoting ‘unspliced’ strengths, it may show a higher strength than the actual rope system in use.”
Asked where composite materials fit into all of this, Susman explained: “When two materials are combined so that the result is greater than the sum of its parts, that’s a composite.”
Kris Koberg, CEO of DICA Outrigger pads agreed with that definition. “Our SafetyTech® outrigger pads are often referred to as composites, but they are not. They are made of engineered thermoplastics. Whereas FiberMax® crane mats, a combination of resin and fiberglass, are a composite.”
On a practical level, Bill Steiner, President of Bigfoot Outrigger Pads, Woodstock, Ill., said price is always a factor when it comes to applying new materials to rigging and crane gear. “Just because you can design it, that doesn’t mean it’s cost effective.” Ironically, he shared a story to book-end the one from Susman about carbon fiber. This high-strength, low-weight material is often used in the design of racing cars. Bigfoot once looked into applying this material in the design of outrigger pads, a potentially good application for the material. “Availability and cost of the material ultimately affect design decisions, even if the material is a good one,” he said.
Which product is best?
Everyone interviewed for this article agreed that the purchase process is a custom one. In most cases, we are not talking about off-the-shelf products. Outrigger pads and crane mats must be sized based on the pressure and force being applied and the ground bearing capacity. “Our fitting consultants recommend options to customers for the area, material, construction, and thickness of the outrigger pad or crane mat,” said Koberg.
When it comes to slings, “There are simply different applications for nylon, which stretches more than polyester, than for high-performance fibers, which are as much as three times stronger. When a customer is faced with a heavy or complex lifting problem, then we work to provide a product that fits the application,” said Susman.
“It’s definitely not one size fits all,” said Quinn.
For outrigger pads, Steiner explained, “Nylon is not a factor in this application because it’s more susceptible to cracking, while fiberglass is expensive. UHMW plastic flexes rather than cracks.”
Acknowledging the confusion over terminology in the market, Steiner added, “Every part of the country has its own terms. The sales process is done one-to-one. After we talk to a customer and understand their application, we can help them select the best product for them.”
Compared to buying metal or wood products, there’s almost always a higher up front cost for synthetic products, but the list of advantages is long. These materials are lighter weight and higher strength, easier to inspect, and boast longer life cycles. “Lower operating costs and overall lower total cost of ownership provide significant value for users,” said Koberg.
Koberg made this comparison between synthetic and wooden outrigger pads: “Soon after wood pads are put into use they begin to deteriorate due to fiber stretching, water absorption, and exposure to the environment. The gap between functional failure and physical failure is very small. This means that your opportunity to react and take corrective measure is short. In the case of outrigger pads made of synthetic materials, the gap between functional failure and physical failure is large. If bending starts to occur, you have time to increase mat size, better prepare the ground, or move the crane to a firmer position. Because of the strength of synthetic outrigger pads you will rarely see a physical failure.”
These products are also less susceptible to degradation by the environment. They don’t rust like metal or decompose like wood, they don’t take on water or mask internal deterioration, he explained.
Citing information in a new book published earlier this year by David Duerr, P.E., 2DM Associates, “Mobile Crane Support Handbook,” Koberg also explained the life span benefits of synthetic products.
“The average life span of mixed hardwood timber mats is 1 to 4 years, whereas the life span of synthetic mats is over 20 years. You also have to think about the time it took to produce the tree the hardwood mats were made from. It’s a 50-year investment to replace that renewable product, which doesn’t have consistent engineered properties.”
A year ago, Samson and Manitowoc Cranes introduced Samson’s KZ™100 synthetic hoist rope on Grove RT770E rough-terrain cranes—a first in mobile crane history. With the same load pull and load chart as wire, KZ100 can be used with a 5:1 safety factor. It is 80% lighter than the wire it replaces, making for easy handling, reeving and installation. It does not rust and requires no lubing. “The torque neutral construction virtually eliminates load spin, cabling, and birdcaging which are common issues with traditional wire rope,” said Quinn. Because of the lighter weight of the rope, the potential exists to lengthen the boom of the crane, delivering greater capacity and longer reach without adding more size or weight to the chassis.
“Like all new ideas, the concept of using a synthetic material as a load hoisting rope was initially greeted with many negative comments,” said Michael Herbert, P.E., Global Product Director for Manitowoc’s Rough Terrain Cranes. “Because of that we had to be absolutely confident in the technology and reliability of our development. The design was truly a creation of two companies with a strong understanding of their industries coming together.
Just as synthetic slings faced opposition when they were first introduced, Manitowoc anticipated that synthetic hoist rope would face skepticism at first, but Herbert is happy to report that “as users fully begin to understand the benefits, they will start to embrace the technology and the product will catch on.”
Manitowoc reported that by early 2015, it expected to introduce KZ100 on Grove Yardboss Industrial Cranes, nearly all of the rough-terrain and truck crane models, and 40-ton and larger National boom trucks. Look for it to also be available on Grove all-terrain cranes, including GMK3060 and GMK4100, by the third quarter of 2016.
For under-the-hook applications, The Caldwell Group, Rockford, Ill., recently introduced Dura-Lite™ lifting and spreader beams, made of a composite material and available in ¼- to 3-ton sizes. The benefits of the lightweight material are lower transportation costs and less risk to personnel while handling the beams. When every piece of rigging must be accounted for in lift planning, composite lifting beams mean fewer load chart deductions.
Last year, DICA introduced FiberMax crane mats with maximum strength and rigidity, with a crush rating of up to 600 psi and a rated capacity up to 900,000 pounds. Bi-directional I-beam design originally developed for vehicle bridges, allows FiberMax crane mats to distribute concentrated loads over large areas to safely and effectively reduce ground bearing pressures. Since debuting at ConExpo-Con/Agg in 2014, FiberMax crane mats have been put to use under 100- to 600-ton capacity mobile cranes working in a variety of ground conditions.
“Chellino Crane uses FiberMax crane mats because they’re so lightweight compared to steel, making them easy to transport and move around the job site,” said Wesley Chellino, Operations Manager. In a crawler crane application in Florida, the U.S. Navy is using custom designed and constructed FiberMax crane mats where the supported load is as high as 769,000 pounds and the allowable ground bearing pressure is just under 900 psf.
Meanwhile, Slingmax just introduced Syn-Glide® Film, an accessory designed to reduce 70% of cover friction for riggers using Twin-Path Slings® by allowing the cover to glide over itself or a piece of hardware. It eliminates ‘bite’ in situations where the cover is resting on itself when the weight of the load is applied, and reduces wear to the sling.
And Bigfoot has upgraded the rope handle on its Ultra Pads, which are UHMW polyester outrigger pads made of post-consumer recycled materials. The new, stronger handle is rated for 7,500 pounds, compared to the previous rope, which was rated for 2,200 pounds. Bigfoot’s outrigger pads are suited for cranes rated for 100 tons or less.
What does the future hold? “Because of ever more complex lifts and more technologically demanding customers, we will continue to see an increase in the use of non-metal materials in crane and rigging applications,” said Susman. “We’ll also be using traditional materials in new ways and new materials will be developed for traditional applications,” he predicts.
In addition, Quinn believes there’s lots of opportunity for design improvements to cranes themselves. This thought was echoed by Koberg, who thinks the industry is just at the beginning. “We will continue to see synthetic materials used for weight reduction, increased strength, and increased safety in the crane and rigging market,” he said.
[sidebar] Inspection and Use: Rely on manufacturer guidelines
When new materials are introduced to an application, users are frequently concerned with proper use and inspection. How do you measure wear on a nylon sheave? How will nylon sheaves react to use with synthetic rope compared to wire rope? Several years ago FIRST Sling, Oklahoma City, Okla., introduced the Inspectable Roundsling® featuring a transparent cover to dramatically improve inspection processes. A revolutionary product–yet users asked whether these slings would react differently to UV exposure than slings made of other colors.
“It takes a long time for new materials to make their way into the industry standards,” said Susman. In the meantime, the best source for use and inspection is the manufacturer,” he said.
This is exactly the reason the Navy Crane Center, which sets inspection and maintenance policies for the 5,000+ share-based cranes the U.S. Navy uses around the world, decided to participate in Manitowoc Crane’s pre-production trials of the Samson KZ100 synthetic rope. The rope was retrofitted on two Grove rough-terrain cranes used for Navy projects. “This was a good opportunity for us to gain knowledge about how to inspect synthetic ropes in mobile crane applications before the product becomes readily available on the market,” said Mark Jaxtheimer, Director of Engineering, Navy Crane Center, Portsmouth, Va.
“Inspection of synthetic rope represents a complete shift in thinking compared to wire rope,” he said. There are no broken wires to count or rope diameter to measure. Instead, the process, which Jaxtheimer describes as “a bit subjective,” involves looking for abrasion and making a visual comparison with photos provided by the manufacturer. He notes that inspection is easier to do than with wire rope because there’s no lubrication to remove before inspecting. One new factor that the Navy Crane Center is keeping an eye on is potential UV degradation.
Among the performance benefits the Navy Crane Center hoped to achieve was reduced wear caused by mis-spooling on the drum. “Unlike wire rope, synthetic rope is more immune to the damage that spooling problems cause,” said Jaxtheimer. Another unexpected benefit: the orange rope is more visible to operators and crew during night operations.
Regarding synthetic rigging products, Fryer of NCSG believes the products have had a huge impact on the industry, but in at least one area, he believes the standards do little to address proper use, specifically regarding sling protection. “In my opinion, most sling failures are due to lack of appropriate sling protection, much of the damage being cumulative. Many in the industry equate abrasion protection with edge protection, and they are two very different products. Synthetic slings are much more prone to damage than their steel counterparts, especially when they are under tension. Some of the best new products on the market are in the area of sling protection, which unfortunately has not become as widely used as we would hope.”
“Customer and market education are critical to technology development and implementation,” said Quinn. Samson is addressing such questions regarding synthetic crane hoist rope by distributing a pocket guide through training organizations and associations such as the Associated Wire Rope Fabricators (AWRF). According to a Samson technical bulletin, “The need for a method to determine the state of a rope is more critical than ever before.” Currently no common, standardized language exists to describe synthetic rope wear in the same way that industry is used to for wire rope. However, Quinn reports that a new ASME B30.30 standard on ropes, currently in draft form, will include information relevant to both synthetic and wire ropes.
Tracy Bennett operates Mighty Mo Media Partners, Parkville, Mo., a marketing consulting firm specializing in technical writing, content marketing, public relations, and branding strategy for companies in the construction industry. She is a member of the Specialized Carriers & Rigging Association and the Construction Marketing Association. She can be reached at firstname.lastname@example.org.