Elevator and design consultants are lauding a new elevator system from KONE Corp. that drastically reduces the weight of the hoisting cables—the bane of tall-building experts. The patented system, which replaces heavy steel ropes with lightweight carbon-fiber belts, increases the maximum feasible "nonstop" vertical run to one kilometer from about 600 meters. The system also significantly reduces elevator energy use, claims KONE, which is the world's second-largest elevator-escalator maker.

Jay Popp, executive vice president, international, for vertical transportation consultant Lerch Bates Inc., Denver, was at the launch of the system, called KONE UltraRope, in London on June 10. "It is a revolutionary new product," he says, calling it "breakthrough technology" that is going to make possible further advances in elevator design and tall-building architecture.

Weight reduction has been KONE's key aim, says Johannes de Jong, the Espoo, Finland-based company's head of technology for major projects. As buildings get taller, elevator "rope weight can mount up to 65% to 70% of the total moving mass when payload remains at below 10%," he adds.

With an eye on the high-rise market, KONE launched its system a day ahead of the Chicago-based Council on Tall Buildings and Urban Habitat's (CTBUH) 2013 international conference in London. The KONE technology is appropriate for all tall buildings, not just supertowers, says de Jong.

Building retrofits are also possible. Further, the system satisfies relevant European and U.S. codes, he adds.

The company will not divulge any cost information until it has orders but says there is a price premium over a conventional system. KONE is bidding on several projects and could sign a deal this year, says de Jong.

Essentially, KONE has replaced steel ropes with 2.5-centimeter-wide by 0.5-cm-thick belts comprising four cores of carbon fiber embedded in epoxy resin with a high-friction surface. In a 400-m-tall building with 10 elevators, the belts would reduce rope weight by over 90%, to under 12 tons. That weight reduction would save 130 MW-hours of electricity annually, claims de Jong.

Operationally, the system is less vulnerable to building sway in high winds, potentially eliminating the need to reduce elevator speeds during storms, says KONE. While steel ropes in elevator shafts tend to resonate with the swaying motion of tall buildings, carbon belts vibrate at higher frequencies. Consequently, uncomfortable movement is not an issue, de Jong explains.

Downtime also will be reduced by the elimination of oil lubricants and the extended working life of the carbon-fiber belts, which KONE claims is double that of steel's. The belts' reduced weight is expected to ease initial installation and periodic replacement.

KONE began developing the carbon-fiber system in 2004, collaborating with the Netherlands Liftinstituut, Amsterdam, says Guiseppi Bilardello, KONE's senior vice president for technology and research and development. The work included full-scale testing in a 333-m-deep shaft in a limestone mine at Lohja, some 40 kilometers west of Espoo.

One of the biggest challenges was simulating the material's behavior as it ages, Bilardello says. In the test mine, the system reached a speed of 15 m per second. De Jong figures the belts could handle much higher speeds.

"This technology will go a long way to reducing the first cost and overall energy use of a vertical-transportation system," says Marshall Strabala, the design partner for 2DEFINE Architecture, Shanghai. Strabala calls the technology "very important" to 2DEFINE.

Not everyone is as excited as Popp and Strabala. From a building-design perspective, KONE's technology is "interesting, but I wouldn't put it in the revolutionary category," says Julian Olley, global vertical-transportation design leader at Arup Group, London. The economic benefits likely will be "marginal in terms of the overall cost of the building," he adds.

While agreeing that UltraRope will significantly extend elevator travel heights, Olley thinks only a tiny fraction of future buildings will be mega-tall.

KONE is not concerned about that because the system is appropriate for all high-rises. De Jong cites CTBUH projections for numerous buildings above 200 m and several reaching 1 km.

There are no technical drawbacks to the system, says de Jong. "The biggest thing is to get market acceptance," he adds. "It will take a while."

De Jong predicts that adoption of the technology will start slowly, building up to account for the majority of the company's orders in a decade, mainly in the Asia Pacific region and the Middle East.

Popp says Lerch Bates is planning to investigate the system thoroughly. "Engineering test data suggest it does perform and gives you the opportunity to do things we haven't been able to do or that have been very difficult to do," he says.