Project Profile: Kimpton Cottonwood Hotel
A boutique reinvention of a landmark hotel in Omaha, Nebraska, which was designed and built over a century ago.
Engineering firm: LEO A DALY
2021 MEP Giants rank: 98
Location: Omaha, NE, United States
Building type: Hotel/motel/resort
Project type: Existing building retrofit
Engineering services: Automation, controls; electrical, power; energy, sustainability; fire, life safety; HVAC, mechanical; lighting; plumbing, piping
Project timeline: April 2018 to April 2020
MEP/FP budget: $437,867
“It’s a 105-year-old building that’s gone through a lot of changes. When you open up a wall, what’s behind it is not always you think.” – Senior Mechanical Project Engineer Dan Donahoe, LEO A DALY
The Kimpton Cottonwood Hotel is a boutique reinvention of a landmark hotel in Omaha, Nebraska, which was designed and built over a century ago. Engineering challenges centered on installing modern guestrooms, restaurants and amenities inside spaces designed in 1915. Simultaneously, to maintain the building’s historic status, designers could not penetrate the existing structure. They needed to use a “gentle touch,” a phrase borrowed from History Nebraska, the state agency that sanctions changes to historic buildings. New infrastructure needed to minimize impacts to existing features. For example, restoration standards mandated that even deteriorated remnants of original ceilings remain undisturbed, precluding the possibility of removing it. Consequently, new ductwork, pipes and conduits had to be routed below.
Pan-joist structural systems originally used for each of the building’s eight floors also created challenges for routing HVAC and plumbing risers. New risers were needed because original guestrooms used smaller lavatories than are used today, and guestroom layouts needed to change.
Limited overhead space drove innovation in the basement, which houses the meticulously recreated Cottonwood Room, a restored speakeasy cocktail bar, as well as a new steakhouse restaurant. A new kitchen, serving both the bar and restaurant, is equipped with four commercial ranges – each of which multiplies the ventilation demand. Commercial kitchens today require higher volumes of inbound fresh air than they did 100 years ago. And typical slopes for vent ducts could not be specified because of the original low ceilings.
Many challenges arose from a need for additional elevators. The original building accommodated only two elevators, both relatively small. Adding elevators necessitated a new structure, and any structure to a 100-year-old building comes with challenges. For example, excavation can vibrate foundations and cause cracking. Furthermore, the new elevator structure overlaps an original sub-basement that houses HVAC equipment. As with other aspects of the renovation, the building’s original framework restricted space available for electrical and technology infrastructure. The integrated design team of architects and engineers collaborated extensively to coordinate space for conduits.
Mechanical and Plumbing
The design employs a dedicated outdoor-air system to provide fresh air to each guestroom and all common spaces. Because the building had undergone commercial renovations over the years, many pieces of existing mechanical equipment could be reused – such as chillers, boilers, distribution pumps and the cooling tower – and they were kept in their existing locations. Hotel guests will enjoy quiet and efficient heating and cooling units rather than the noisier direct-expansion (DX) systems used in many residential and commercial designs.
With the historic building’s limited space behind walls and between floors, engineers worked with contractors to minimize potential conflicts with the structure by specifying multiple, smaller risers for plumbing, supply air and exhaust air. These smaller risers are carefully routed between pan joists that compose the original structure.
To accommodate commercial-kitchen infrastructure in the low-ceiling basement, ductwork for range hoods follow an undulating pattern rather than a traditional slope, and they are equipped with grease drains. Exhaust is provided through new, dedicated ductwork routed between the basement ceiling and first floor, along with ventilation ducts. The kitchen’s fresh-air and exhaust systems are controlled by automated ventilation demand. Monitors beneath the range hoods initiate ventilation adjustments to match cook-line operations. During light duty, the system operates at minimum air flow to conserve energy, and then seamlessly ramps up for the dinner rush.
Electrical and Lighting
Wherever possible, new lighting occupies original fixtures. In some cases, such as above landings on the original marble staircase, additional lighting was needed to meet code. Designers specified strip lighting to augment. Electrical systems will consume less energy than ever before, in part because all lighting is LED. And modern lighting-control systems create “zones” that allow precise refinement of color and brightness for enhancing mood and ambiance from space to space.
As with other aspects of the renovation, the building’s original framework restricted space available for electrical infrastructure. In some cases, flexible conduit was used to route cables around beams, pipes, ducts and light fixtures (as code allows). Hidden access panels in public corridors retain maintenance access for repairs and upgrades.
Exterior electric lighting highlights aspects of the hotel’s original architecture and aids in wayfinding. Low lighting around the courtyard fountain, for example, adds a dramatic focal point. Step lights around original outdoor terraces help create a light and airy atmosphere at night, casting patterned shadows from the wooden trellis overhead. Low-profile lights in the restored porte cochère beam down on people and luggage below while activating handmade replica terracotta columns and scrollwork.
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