NFPA Journal

See related article, photo gallery on creating technical rescue procedures for the world’s tallest observation wheel.

IT'S A BEAUTIFUL SPRING EVENING IN LAS VEGAS, and I’m finally being admitted to the hottest new attraction on the Strip. It’s not some high-wattage dance club or a poker table with a $100,000 buy-in, though—it’s the High Roller, an “observation wheel” built by Caesars Entertainment, essentially a giant Ferris wheel with enclosed cabins. Not just any giant wheel, though—at 550 feet (168 meters), it’s the world’s tallest, besting the Singapore Flyer by nine feet (three meters) and the London Eye by 107 feet (33 meters). It just wouldn’t be a Las Vegas attraction without a bit of world-beater hyperbole.

The wheel is the anchor attraction of The Linq, a new $550 million open-air pedestrian mall that Caesars announced in 2011. The opening of the High Roller on March 31, after two years of construction, signals the completion of The Linq, and I join a stream of visitors one night a couple weeks later to celebrate its arrival by traveling very high, very slowly, into the Nevada sky. We stroll the length of The Linq and enter a five-story “wheel building” for tickets and High Roller prep, which includes a big-screen video presentation on the two-year construction process. Attendants usher us up to the second-floor bar—champagne is a big seller—before sending us to the third floor and outside to the steel boarding platform.

As a local resident, I’ve watched the wheel take shape with growing anticipation. Other wheel projects had been floated for the Strip, only to come to nothing, but this one was different from the outset. When Caesars Entertainment announced it would tear down much of its O’Sheas Casino—which occupied a premium spot on the Strip, sandwiched between the Flamingo Las Vegas and the old Imperial Palace—to make room for, of all things, an open-air pedestrian mall, a lot of locals raised an eyebrow. We were used to dining and showrooms being a draw, but to actually bypass casino floors altogether seemed a strange proposition. Punctuating the mall with a giant wheel seemed like an exclamation point affixed to a possibly radical idea.

Standing on the boarding platform gives us an up-close sense of the wheel’s scale. Attached to the wheel’s rim are 28 enclosed cabins—each holds 40 guests, for a wheel capacity of 1,120—which slide slowly past the platform at the stately pace of just under one foot per second, or about 30 minutes for a complete revolution. Though the High Roller can be stopped to accommodate passengers who need assistance, the wheel is designed to keep moving, even as passengers board and exit the cabins along the 55-foot (17-meter) platform. Passengers must step across a gap of a few inches between the platform and the cabin, and the fact that motion is involved can make it a bit disorienting for some. “I really didn’t like that part,” says one of my cabin mates, Monique Bergam, who’s visiting with three friends from Boise, Idaho. She sits on a cabin bench, one hand grabbing a handrail, the other clutching a cocktail. “I’m actually a little afraid of heights.”

The cabin doors latch automatically, and a video screen lights up as our virtual guide encourages us to move about the 225-square-foot (21-square-meter) cabin. As we begin our almost imperceptible ascent, I ask the group if anyone has any safety concerns. A guy named Wade Denney, who’s celebrating his 40th birthday, says he feels more secure in the High Roller than he does taking the elevator to the top of a nearby hotel. “It’s all so smooth,” he says. “The thought of something happening never occurred to me.”

That’s precisely what the High Roller’s designers and local safety officials had in mind two years ago when they began poring over plans for the massive new wheel. They ensured the construction materials would minimize fire risk and worked out exactly how both operators and first responders would attend to passengers with medical issues. Fire officials asked for and got a number of design changes to make potential rescues go smoothly. Above all, their ultimate goal for keeping passengers safe was straight forward: Keep the wheel turning, no matter what.

“We’re essentially putting more than 1,100 people on a structure you can’t access,” says David Codiga, executive project director for The Linq. “There’s no staircase. No way for responders to walk into the cabins. No way for people to get themselves out.” The best way off was to step out of your cabin onto the boarding platform, and the only way everyone could do that was for the wheel to keep turning.

The people I spoke to about the High Roller pointed to the unusually strong relationship between fire officials and developers as the main reason such problems were effectively addressed, and why the wheel’s opening went relatively smoothly. “The High Roller doesn’t have to mean high risk,” says Robert Solomon, NFPA division manager of Building & Life Safety Codes. While there are no standards or codes that completely cover the important elements of such a project, Solomon says, “cooperation among the stakeholders allows you to look at different scenarios, apply the code provisions to a point, and fill in the gaps with engineering or operational solutions or, in this case, both. This is a characteristic case of performance-based design, and exactly the approach I’d want to see.”

Protecting the structure
In early March, a few weeks before the wheel’s opening, I visit the High Roller site, which buzzes with activity. Inside The Linq’s construction trailer, I’m joined by Codiga, along with High Roller project manager Randy Printz and Ed Kaminski, a fire protection engineer with the Clark County Fire Prevention Bureau. They pull out the document on failure modes and effects analysis prepared by Arup North America, the designer and engineer of record. It’s a hefty stack—76 tabloid-sized pages with tiny type. It’s the guiding document for ensuring the High Roller’s operations run smoothly.

All such plans cross Kaminski’s desk. He’s watched over the Strip’s high-rise properties since 2008 and previously served as a fire protection consultant to the casino and hospitality industries. He’s tasked with failure modes and effects analysis, which systematically outlines possible component failures, what could cause them, and what can be done through design and maintenance to mitigate or eliminate the failure risk. He also reviews the technical rescue team plans for “special amusement features.”

“We’ve seen some of these other projects come and go,” he says of some earlier wheel proposals. “Folks would come in and think they could bully their way through. The attitude was that they were above the fire department and knew more than we did.” The High Roller, he adds, “was a completely different experience.”

The Linq’s structures adhere to a number of NFPA’s codes and standards, but the High Roller itself is not considered a building. The wheel is set 25 feet (eight meters) away from the sprinkler-protected building housing its operations, connected by the steel boarding platform. In their fire protection report, Arup engineers wrote that, while structural fire protection of the steel wheel itself is not considered necessary, potential fire scenarios could develop involving vehicles or a ground-level retail kiosk near the wheel’s support legs. That’s why concrete fills the wheel’s four main support legs up to the level of the boarding platform level, providing two hours of fire resistance. The wheel’s fifth brace leg sits on a 24-foot-high (eight-meter-high) concrete plinth, situating it well above surrounding vehicle fire hazards.

Power redundancy is a key part of the Arup plan to keep the wheel turning. The primary system employs eight electric drive units that contact the rim just above the boarding and exit platform; at the hub, the wheel turns on two sets of spherical roller bearings, each set weighing nearly ten tons. Only six of the eight drive clusters are needed for normal operation, but the wheel can turn if just four are operational. The wheel’s primary power comes from the NV Energy electrical grid, and if there’s an outage, a backup diesel generator—located on the drive platform separate from the primary power control room—instantly kicks in, and deboarding begins immediately. The wheel would not resume regular service until primary power is restored.

The High Roller is the first attraction of its kind to have a completely independent backup system for moving the wheel. Printz notes that a 2008 fire in the control room of the Singapore Flyer knocked out both its primary and secondary power systems, trapping 173 people for more than seven hours. To help prevent that scenario, High Roller designers included a “manual mode recovery drive,” a diesel-powered system that uses hydraulic grippers to reach out, grab the wheel, and pull it around. “It’s the ultimate redundancy,” says Printz. “If all other means to move the wheel fail, we have something that Singapore and London don’t.”

The wheel’s cabins boast an array of innovative mechanical and safety features. The cabins are held to the High Roller rim by a fixed ring that houses what’s known as a slewing ring bearing; as the wheel turns, a motor slowly rotates the cabins within that bearing, keeping the cabin level in relation to the ground. “The cabin rotation is almost imperceptible,” Codiga says. “I don’t think most riders will really get how it is that they stay level.”

Cabin doors latch in place with upper and lower pins, further reinforcing the closure. Any sort of door fault will stop the wheel until the fault is cleared. During initial commissioning, software glitches routinely communicated false “door open” indications. “Our doors might give us some trouble because the [computer] logic involved is surprisingly complicated,” Codiga says. “But we also know we’ll have people wanting to base jump [from the cabins using parachutes] so we had to ensure they couldn’t be forced open.”

During the initial design phase for the High Roller, Codiga asked about equipping the cabins with fire extinguishers and got a resounding no. “They’re much more of a hazard with potential for malicious mischief and injury” than they are a help, Kaminski explains. “When people balk at the idea of no extinguishers, I ask them, ‘Have you ever been in a room crammed with people with no exits and no sprinklers?’ The answer is an airplane. The difference here is that there are also no combustible materials surrounding you.”

Each cabin has security cameras, and guests can communicate with operators through an intercom or by calling a posted phone number. There’s a smoke detector in each cabin along with a combination smoke-heat detector in the underfloor plenum. If smoke is detected, ventilation and emergency access hatches would pop, and a fan would ventilate the cabin. When a catering cart is wheeled on board for private functions, it’s equipped with an extinguisher and an employee trained to use it.

The wheel’s cabins were built to NFPA 130, Fixed Guideway Transit and Passenger Rail Systems. “That gave us the standards to follow in terms of materials and the separation between the floor and underfloor,” Prinz says. The noncombustible interiors are constructed of hard plastic, glass, and metal framing. Two hard-plastic benches curve out from the cabin rim to seat about eight people, but with 360-degree views through the floor-to-ceiling windows, most passengers seem to prefer to walk around.

“One lesson we learned from London is about security voids,” Codiga says. “Security cameras [in London] can’t see under the bench, so they can’t see if someone has left something there. Also, they placed that bench in the middle of the cabin, which is the worst location in terms of through-loading. We’re much more efficient, and safe, with our design.”

Emergency response
Arup identified five emergency response levels. In a Level 1 response, for something like the power grid going out, the backup power would keep the wheel speed steady to allow a full cycling out of passengers.

A Level 2 response calls for doubling the wheel speed and using both the entrance and exit sides of the platform for exiting. The most likely Level 2 scenario is a medical emergency that calls for the quick evacuation of just one cabin. In that case, all passengers would be notified that there is an emergency. The speed of the wheel would be doubled and only those in the affected cabin would be evacuated. The wheel would return to regular speed, and normal operations would resume.

If a passenger has an issue soon after boarding, the wheel’s direction can be reversed to return them to the platform faster. The longest it would take to return a cabin to the boarding platform is seven and a half minutes, when the affected cabin is at the 12 o’clock position atop the wheel and moving at double speed.

Level 3 emergency response would stop the wheel, with passengers in place, to accommodate a needed repair. Level 4 applies to a power loss involving both the primary and secondary drive systems, requiring the manual mode recovery drive. A full cycling out in this case would take between two and two-and-and-a-half hours.

Level 5 indicates a catastrophic failure and the wheel will not rotate. That’s when the technical rescue team would be called in to get all the passengers safely back on the ground.

Capt. Scott Province heads the technical rescue team for Las Vegas Fire & Rescue Department. He’s been a firefighter for 24 years and joined the technical rescue team when it formed 14 years ago. His team, along with one from the neighboring city of Henderson, would be called in should the High Roller stop rolling.

A quirky thing about Las Vegas is that much of the Las Vegas Strip is located outside the city proper, in Clark County, which is why Clark County Battalion Chief Eric Poleski, whose stations serve a section of the Strip and McCarran Airport, would be in charge of emergency responses at the High Roller. Four years ago, however, in the midst of drastic budget cuts and to curb overtime, the county dismantled its heavy rescue and hazmat teams and entered into cooperative agreements with the cities of Las Vegas and Henderson. The irony is not lost on Poleski, who pointedly notes that the Clark County Fire Department is the largest in Nevada “and we don’t have our own [technical rescue] team. I hope that changes again soon.”

In the meantime, Kaminski, Poleski, and Province have worked extensively with the Caesars team to ensure they’d be ready in the event of a Level 5 response. Shockingly, they say, no evacuation plans were in place and no rescue teams had practiced when the Singapore Flyer stopped for seven hours in 2008. Evacuation of the lower cabins had just begun when power was finally restored.

On vacation a year ago, Province rode the London Eye and stopped by the London Fire Brigade to discuss its heavy rescue training. He was told department personnel haven’t climbed it themselves. “These structures are so unique, so different from anything else we do, that I can’t imagine trying to wing it” in the event of an emergency, he says. “We started by doing a lot of research.”

The Ceasars team involved fire officials from the start. Province researched specialty equipment and brought in a gondola rescue expert to explain the nuances of the process. They agreed on what an emergency kit in each cabin should include: an automated external defibrillator, first aid supplies, bottles of water, cooling bandanas, and reflective sun shades, as well as “toilets in a bag” waste kits, tampons, diapers, wet wipes, and trash bags. Caesars flew Province to the cabin manufacturer in Colorado to ensure the heavy rescue team’s needs were being met.

The plan calls for seven of the lower cabins to be evacuated with the use of ladders or ladder trucks. Up to four more cabins would be evacuated by working with area construction crane companies. The remainder of the cabins would require a rope and harness rescue.

In the months leading up to the wheel’s opening, Las Vegas and Henderson technical rescue teams tested the plan. (For more detail, see “Develop, Test, Improvise, Adjust,” page 64.) Poleski says the process from time of arrival to lowering the first passenger has taken between two-and-a-half and three hours; the remainder of the rescue would proceed more quickly from there, he says. At full occupancy, he estimates a rescue taking 100 hours if just the heavy rescue shifts on duty were used; there are a total of 20 Las Vegas and Henderson rescuers on duty at any given moment. “We’d obviously call in all shifts and consider activating teams from Phoenix and Los Angeles,” he says. Helicopter assistance from Las Vegas Metro Police could also be used to speed the rescue process.

While a full-wheel evacuation is unlikely, say designers and safety officials, a somewhat more likely scenario would involve dispatching a rescue team to a particular cabin—for example, if the cabin’s floor stability system and its backup system should fail. “The probability of those two failures at the same time is very, very low,” Codiga says. “If it did, then we could manage very slow descent with the floor in gravity mode. But if we also couldn’t do that for some other worst-case reason, then we’d go to technical rescue.”

Some of the design changes that fire officials requested included adding ladders and anchor points along the wheel’s entire rim and around the cabins. They also changed the rung spacing. Inside the cabins, high and low anchor points were added to run main and belay ropes. “The ladders were more pronounced than we would have wanted, but this wasn’t a time to put the aesthetics before the function,” Codiga says.

Viva Las Vegas
My first ride on the High Roller is everything I’d hoped for. We reach the apex of the wheel as a spectacular desert sunset is in full glow, backlighting the mountain peaks to the west and bathing the glittering city around us in darkening shades of orange, bronze, and blue. As we begin to descend, the fountain show in front of the Bellagio lights up, far below us. “That’s exactly what we were hoping to see,” Bergam says. Minutes into the ride, she had left the security of the bench to snap pictures and toast her friends. “It’s so worth the price. I’ll do this every time we come.”

As a local, I’m somewhat inured to Vegas glitz, but the High Roller adds a majestic arch of color to our skyline—it is at once distinct from and integrated into the otherwise linear amalgam of the city’s architectural wonders. (It doesn’t hurt that more than 2,000 LED lights cast an array of colors on the cabins, transforming the wheel into an enormous jeweled ring.) Actually riding it makes me proud that, once again, the city has gone over the top. We’ll relish it for a long time to come.

Or at least for a couple of years, until the next world’s-biggest-wheel comes along. Developers of The New York Wheel (630 feet) on Staten Island and the Dubai Eye (689 feet) are working on that right now.