EXCLUSIVE FEATURE: How are airports using green spaces to revolutionize the passenger experience?

More and more airports are bringing the outside in, using internal green spaces and even airside gardens to refresh and reinvigorate passengers.

Talking point, photo opportunity or just a place for passengers to relax – ‘indoor-outdoor’ spaces continue to take root across the aviation sector. From Singapore Changi’s luscious indoor forest featuring the world’s first waterfall inside an airport to LaGuardia’s ‘pocket parks’, indoor gardens and green spaces are a great way to create a sense of place and underline an airport’s environmental credentials.

“Our indoor-outdoor spaces are designed to provide moments of delight,” explains Peter Lefkovits, AIA design principal at Skidmore, Owings & Merrill (SOM), which recently led the design of the impressive gardens found within Kempegowda International Airport’s new Terminal 2 in Bengaluru, India (see Room to grow, January 2024, p34).

Hamad’s Orchard

In November 2022, Hamad International Airport unveiled an exclusive indoor tropical garden, which it refers to as ‘ORCHARD’, as a unique space for passengers to relax, rejuvenate and recharge. With a stunning water feature, the indoor garden sprawls across 6,000m2, and is surrounded by 65 of the airport’s 180 world-renowned retail and dining experiences, as well as a business-class lounge for passengers – all harmoniously set against a refreshingly lush green environment.

More than 300 trees and 25,000 plants were sourced from sustainable forests from around the world in its creation. A column-free, grid shell roof controls and filters the light, allowing trees and plants to adapt to the internal conditions and grow throughout the life of the airport. The same natural light creates a calming ambiance and sense of well-being for travelers.

“A special fertigation system is distributed to provide water and nutrients to the plants, supported with a soil moisture monitoring system to ensure optimal watering and sustainable management of irrigation water,” explains Michael McMillan, senior VP, facilities management, Hamad International Airport. “Additionally, we added advanced fogging systems, with more than 350 nozzles distributed across the indoor garden to maintain the humidity of the space and promote a rainforest ambience,” he continues.

“Considering the ORCHARD is located within the central concourse and is a busy environment, we introduced a tailored maintenance schedule to maintain the upkeep of the garden including introducing biological and safe pest control solutions that would cater to the plants and shrubs without impacting passengers and staff.”

“While travel can be stressful, we wanted to create an inspiring, uplifting and serene experience for passengers,” he continues. “The integration of landscaping, hanging gardens and skylights not only creates a calming oasis but also has sustainability benefits. In fact, these advantages – from user wellness to improved air quality – apply to all design typologies.”

Credit score

For Kempegowda, the green spaces also contributed to the airport’s LEED Platinum accreditation and even helped boost revenue. “The [LEED Platinum] certification is the result of a holistic sustainability strategy,” explains Lefkovits. “The extensive outdoor areas were designed to maximize wellness and play a pivotal role in this certification. For example, the abundant vegetation uses water that is harvested on-site, and the indoor waterfalls cool the interior environment. We also worked closely with the airport’s operator to create programming opportunities within these indoor-outdoor areas, including restaurants, cafés, galleries and other commercial offerings.”

Inspired by the ‘garden city’ heritage of Bengaluru, Bengaluru International Airport Limited (BIAL) originally proposed a simple yet captivating idea: to design a ‘terminal in a garden’. “The idea was to radically reimagine the travel experience by connecting passengers to nature along each step of passenger processing,” Lefkovits says.

“Upon check-in, passengers are immersed in hanging gardens; after security, passengers can find peace among soothing sounds of water and verdant plants. If time allows, passengers explore the ‘forest belt’ – a network of landscaped bridges and outdoor walkways en route to the gate. Our goal was to invert every expectation of how an airport should look and feel.”

Kempegowda isn’t SOM’s first foray into the great ‘indoor-outdoors’. “We have designed a series of integrated landscaping for other airport projects such as Chhatrapati Shivaji International [in India] – Terminal 2 and Singapore Changi International – Terminal 3,” notes Lefkovits.

“Most recently, we designed an exterior garden adjacent to the baggage claim at Kansas City International, which features a fountain that nods to Kansas City’s moniker as ‘the Fountain City’. While these examples highlight moments of ‘indoor-outdoor’ spaces, Kempegowda International Airport is the first time we have created a fully immersive landscape experience throughout the entire terminal.”

South Korea’s Incheon International Airport also boasts an iconic airport garden development featuring a rich mix of flowering plants, trees, ferns and bamboo, with smaller water, rock, cactus and pine gardens strategically located across the airport campus.

Cultural enlightenment

Tim Hudson, aviation practice leader at Gensler, oversaw the design of a series of enormous gardens and even aviaries within Incheon’s Terminal 2. “Key objectives were to create distinctive activities for passengers integrated into dynamic spaces that focus on the cultural layers of nature,” he says.

“Green spaces create a higher sense of relaxation and health” Tim Hudson, Gensler

High translucent roofs deliver an abundance of filtered, natural daylight inside the terminal through open, massive roof spans and further translucent panels within the building. This helps to nurture a diverse range of natural plants and trees, which grow as if in a greenhouse. Park-like settings and vegetation-lined avenues for pedestrian walking paths connect concessions, art exhibits and performance stages.

“Particular emphasis was placed on creating authentic passenger experiences rooted in local and national culture,” continues Hudson. “Green spaces create a higher sense of relaxation and health. They provide potential for increased revenue opportunities as people are more inclined to dwell in and around these parks and green spaces while enjoying a meal or reading a book. Trees and landscape elements can bring a sense of human scale to significantly high roof volumes, which helps reduce stress levels compared with terminals with low ceilings and crowded holdroom seating areas.”

SOM’s Lefkovits had to work equally hard to bring natural light into Kempegowda, without overloading the HVAC system: “We worked closely with our landscape architect, Grant Associates, and lighting designers, BPI, to balance the daylighting requirements of the plants and the energy loads of the building to create a natural interior environment. The skylights were then tuned to provide the perfect amount of filtered natural daylight to the interior spaces.”

Lefkovits believes that the most successful indooroutdoor experiences are fully immersive. “The goal is to make passengers feel like they are in a garden, or even in the middle of a forest,” he says. “Every aspect of the design, from a careful selection of plantings to holistic lighting strategies, must harmonize together to create a multisensory experience.”

Such a scenario awaits passengers in Kempegowda’s ‘forest-belt’ – a 90m-wide swathe of planted landscape between the gate concourses and the terminal building. “If time allows, passengers can traverse a network of bridges and outdoor walkways that provide a dramatic and immersive experience,” notes Lefkovits.

Gate garden

This year’s Passenger Terminal Conference will include a fascinating presentation from Fraport Bulgaria about its plans to create airside ‘gate gardens’ where passengers can relax and enjoy the view of the apron with a drink before boarding their flights directly. The operator will open gate gardens at two airports: a 1,600m2 area at Varna and an 800m2 space at Burgas.

“The Gate Garden is a garden-like outside area on the airside, equipped with gates, commercial offers and resting zones for passengers,” explains Dr Frank Quante, CEO of Fraport Bulgaria. “The idea started as a pure outside terrace, designed beautifully and used as a place to relax closer to nature, but airside.

“We then looked to increase functionality with the addition of commercial offers and finally the gates that allow passengers to stay outside and just walk to the aircraft, with no need to re-enter the building. For seasonal, tourist-driven airports like ours, this is an excellent solution. As this project was in parallel with the tender of our airside concessions, we also presented the idea to potential commercial partners – all of whom were hooked immediately and began contributing their own ideas.”

Fraport Bulgaria expects significant energy savings by taking gate space outside. “I estimate we’ll cut our energy bills by 40%, mainly due to the lack of HVAC systems for the common and operational areas,” says Quante. He also anticipates a drastic cut in capital expenditure, which is set to reduce to around €750 (US$820)/m2, as opposed to €3,000 (US$3,282)/m2 for a more traditional terminal extension.

“The Gate Garden will increase the operational area of the terminal in Varna by 35% and the commercial area by 45%. For Burgas, it is a 25% increase in operational area and a 35% increase of the commercial area. This outdoor approach has allowed us to handle the expansion of our traffic during our busiest period – the summertime. This passenger-centric initiative not only enhances the overall travel experience but also presents exciting avenues for commercial monetization, making the airport more than a transit point – a destination itself. Our projections show positive return on investment within a few years of operation, the result of optimized capex [compared with a fully enclosed terminal area] and opex, mainly by reducing HVAC operation in the summer, which is the high season for the airport.”

“I estimate we’ll cut our energy bills by 40%, mainly due to the lack of HVAC systems” Dr Frank Quante, Fraport Bulgaria

When designing the outside spaces for both airports, Aleksandar Georgiev, head of planning, engineering and design at Fraport Bulgaria, had to consider both operational safety and the passenger experience. “As summer holiday airports with most annual traffic between May and October, we did a thorough analysis of all the major factors in play with an open-air solution – starting with traffic heat map analysis through to solar diagrams, as well as historical precipitation data to wind considerations,” he explains.

“The design solutions are multifunctional, emphasizing a garden-like experience while providing operational flexibility. We also wanted to reduce our environmental impact – starting with the construction itself but also with procedures for the passengers, through savings on cooling and heating. We expect a win-win for our passengers, commercial partners, our company and the environment. Considering that the built environment generates nearly 50% of annual global CO2 emissions, we hope this project will help others reconsider the norms for construction and airport infrastructure and challenge us to deliver more – sustainable, people-oriented and efficient architecture.”

This article originally appeared in the April 2024 issue of Passenger Terminal World. To view the magazine in full, click here.