August 5, 2019

We've all been there, happily going about our day, when bam the power unexpectedly goes out. The weather appears to be fine, so, what gives?

Aside from weather conditions, a standard power outage can happen for any number of reasons. Anything from a curious critter to human error could affect the power supply to your home. And while it is bothersome, it usually is not terribly detrimental. We have grown accustom to finding the flashlights, keeping the refrigerator closed and waiting it out.

Now, imagine if an establishment of much greater scale, such as an airport, goes dark. Lighting some candles isn't going to do the trick here.

This past December, Atlanta's Hartsfield-Jackson International Airport experienced a paralyzing power outage, leaving thousands of passengers stranded in dark terminals and sitting in planes on the tarmac. The outage lasted for nearly 11 hours and led to the cancellations of more than 1,000 flights in and out of the airport, disrupting air travel across the United States as a result.

An electrical fire in a tunnel beneath the airport caused the outage. Because the fire was in a tunnel adjacent to the backup cables, the redundant system, or fail-safe system, was also knocked out, exaggerating the fiasco.

In the event of a catastrophic failure, a natural disaster, or even a terrorist attack, airports are extremely vital parts of the region's infrastructure for obtaining urgently needed supplies and assistance. And while not in response to Atlanta's incident, O'Hare International Airport has made a major investment to ensure they have reliable systems in place.

Epstein is pleased to be providing engineering and architectural services required to replace and redesign O'Hare's emergency and standby power system generators, which airports rely on to make sure power is continuous in the event of an outage. Essentially, it is a backup power plant.

"It's a need, a necessity, for O'Hare," said Tom Smiles, PE, Epstein's Senior Vice President, Director of Engineering. "The airport's current system is antiquated and needed to be modernized. Since they're updating, the thought was not only to replace it, but also to enhance it."

While O'Hare's existing emergency backup system is operational, it utilizes technology from the 1960s. Furthermore, the equipment is so dated, parts for it can no longer be found. It is also mechanically based and mechanically controlled.

"Some of the systems Epstein is replacing are original to the airport construction. The system as a whole has lived and survived well beyond its usual life," Tom said. "That was the driving force behind O'Hare's decision to embark on this project."

The Epstein-designed replacement is more computer driven and digitally based. It increases the existing system capacity from 8-10 megawatts to 18 megawatts, which is enough to power several thousand homes. As a result, O'Hare will acquire greater system functionality and efficiency during emergencies in which normal operations have been impaired.

"O'Hare is a 24-7 operation that, just, cannot go down," Tom noted, adding, "Epstein is helping to bring the airport into the 21st century with newer, more reliable equipment, but more capability, as well."

Epstein is also responsible for the design of two new buildings to accommodate the replaced system: one to house the new generators and one to house the associated electrical distribution.

The generators themselves can be likened to diesel locomotive engines; they produce the power. The electrical distribution, or switchgear, dispenses the power throughout the airport. Typically, the two components exist in different rooms of the same building. Epstein's two-building approach, along with the internal design of the buildings and systems, are part of a compartmentalized method to minimize the chances of a catastrophic event taking down the entire system.

The generators are enormous, and there are six of them. Their building is split in two halves, with three generators in each half. Each half also houses a fuel tank, which feeds the generators with the thousands of gallons of fuel they require to continuously run at full-speed. Furthermore, the wall separating the two generator rooms is a 2-hour fire-rated wall; therefore, it can withstand a fire burning on one side for two hours before it starts to penetrate the other side. The walls separating the generator rooms from their tank rooms have a fire-resistance rating of four hours, an increase due to the nature of the fuel inside.

The switchgear building is designed in the same manner: split in two halves. There is also a 2-hour fire-rated wall separating those rooms. The fire-resistance separation walls are comprised of concrete masonry units, which are standard rectangular blocks used in building construction, and are eight inches thick.

"The separation provides inherent protection, and creates the redundancy. If there's a failure at one half, the other half can run completely independently," said Will Ernst, an Epstein Project Manager working within the Construction group. "At any time, if one side goes down, for whatever reason, the other side will still be available. That's key."

Originally, these buildings were planned to be in the back of the airport, near the airfield and out of sight. As the project evolved, however, it became clear a larger space was needed. Therefore, both buildings will now reside just north of the H&R Plant, which is a mechanical building on O'Hare's grounds that supplies all of the chilled and hot water for the heating and cooling systems throughout the airport; similar to a boiler room. The H&R Plant is where the existing emergency backup system is currently located.

As visitors are leaving O'Hare, passing Terminal 3 to go back out onto the expressway, the two buildings will be on the right.

"Now, that being a prominent location at the airport, we had to address the aesthetic component that, perhaps, wasn't quite as big of a concern before," Tom said. "It has to look good!"

Epstein was able to quickly adjust, and turned what could have been a standard utility building into more of a design project.

The final concept mimics the main two components of the H&R Plant - steel and glass. This approach ties all three buildings together, resulting in a unified look. The generator building is clad with black aluminum fins that resemble the steel components of the H&R Plant. And the switchgear building is a glass cube made entirely out of channel glass. The design also purposely plays off of the contrast between light and dark colors, creating a pleasing finish among them. The buildings will sit on a slightly elevated platform.

"We have these two distinct buildings, but they rest on one platform that brings it all into one cohesive project," Will said. "This was challenging. We had to promptly come up with an aesthetic design, while taking all of the technical details into consideration. Our solution allows those two components to work together, which, in turn, is a complete building design."

In order to ensure the system is in a constant state of readiness, monthly maintenance will take place. Similar to a car, after a certain period of time, or, in this case, a number of operational hours, the generators oil will need to be changed. Visual inspections and test runs will also be performed to make sure the system is working as it's designed to.

"This project is more than just the engineering behind it," Tom said. "We're providing expert engineering services for an extremely complicated, intricate system. And we're doing it when dealing with an operational facility that never shuts down. I don't know if many other firms would have the ability to do what Epstein did."