The Museum at Gateway Arch National Park: IMEG design highlights

The renovated and expanded Museum at Gateway Arch National Park in St. Louis is designed to be approximately 20 percent more efficient than ASHRAE 90.1-2007 and has achieved LEED Gold. Highlights of IMEG’s design include:


  • High efficiency magnetic bearing centrifugal chillers at the Museum at Gateway Arch National Park

    Existing AHUs were decentralized and many were located in hard-to-access mezzanines, making maintenance difficult. Eleven of the existing 15 AHUs were removed. New AHUs were provided at ground level in mechanical rooms.

  • The two existing centrifugal chillers were replaced with two new high efficiency magnetic bearing centrifugal chillers and one heat recovery chiller.
  • There is no ceiling plenum in the addition portion of the museum and exposed ductwork was not architecturally acceptable.  It was decided to route ductwork and piping underground from the equipment located in the existing building to the addition.  A combination of a utility tunnel and direct buried ductwork and piping was used.  The utility tunnel allowed for maintenance access to equipment and valves.  Excavation at the site was expensive so the size of the utility tunnel was minimized through a highly coordinated design effort and using the tunnel itself as a return air path in lieu of having a return duct.
  • The addition features a new west entrance with walls and roof constructed entirely out of structural glass.  This presented a challenge to the design team to heat, cool, and prevent condensation from forming on the glass during cold outdoor conditions.  Two AHUs were required to meet the heating and cooling loads of the roughly 2,000-sf entrance.  A computational fluid dynamic (CDF) analysis was performed by a third party to help ensure the proper volume and temperature of air was being supplied at the correct locations so that condensation would not form on the glass.
  • Phasing plans required that certain utilities be kept operational during construction.  In order to help with construction cost and schedule, newly developed Victaulic couplings were used for the temporary low pressure steam piping.


  • The existing electrical service was completely overhauled.
  • The existing electrical service for the museum consisted of a 2000 Amp, 480/277 Volt switchboard fed from three 1000 KVA utility transformers. In addition, the existing electrical service combined both utility power and emergency power as well as two transfer switches in a single piece of switchgear. This meant that the existing electrical service was a potential “single point of failure” such that an event in either power system could interrupt power to the entire museum.
  • The new design corrected this situation by splitting the utility power and emergency power services into two separate distribution systems housed in two different electrical rooms. With this configuration, a failure in the utility power system would not impact the emergency power system or vice versa. To accommodate the renovation and expansion, the existing electrical service was replaced with a new 4000 Amp, 480/277 Volt switchboard and three 1500 KVA utility transformers.
  • The utility tunnel at the Musuem at Gateway Arch National Park

    The challenge associated with this new design was that the museum needed to remain operational during construction. In addition, the existing electrical service was located in the room that would eventually become the new emergency power distribution room.

  • To address these challenges, the new electrical service was installed in a new area of the museum and the existing electrical service remained operational until such time that all the existing electrical loads were migrated to the new electrical service. Once the existing electrical loads were migrated, the existing electrical service was removed to make room for the new emergency distribution gear.
  • The result was a completely new utility power distribution system and emergency power distribution system, each housed in separate electric rooms. This removed the potential “single point of failure” situation and provided redundancy as well as capacity for future expansion.


  • Most of the lighting for the museum was replaced with more efficient LED lighting.
  • The existing lighting system was broken up into three separate spaces (front of house, back of house, and exhibit space.) The front of house (tram lobby, museum store, theaters, etc.) and exhibit spaces consisted of a mix of incandescent and fluorescent lighting, controlled by an ASCO lighting control panel and toggle switches. The back of house space (office spaces, security offices, maintenance areas, etc.) consisted of a mix of fluorescent and incandescent lighting, controlled by standard toggle switches.
  • The renovated and new spaces consist of an energy-efficient LED system. The lighting controls for the tram lobby and entry plaza are accomplished via a centralized dimmer rack with adjustable time-of-day settings. The exhibit areas are controlled via DMX (Digital Multiplex) which can vary dimming, color temperature, intensity and other factors in the lighting system. The back of house lighting control systems consist of a mix of occupancy sensors and toggle switches.
  • The challenge associated with designing the new LED lighting system for the museum was that there were several lighting consultants on the project and multiple lighting control systems that required coordination.
  • IMEG was responsible for design of the back of house lighting and controls, as well as coordination of the DMX and dimming systems.
  • Through close collaboration with the architect, lighting designers, exhibit specialists and others, IMEG developed a new lighting system for the new and renovated spaces which created a unique experience for the visitors. Additionally, the lighting energy usage was greatly reduced by incorporating a more energy efficient LED lighting system.

    Fire alarm system

    • The existing fire alarm system was partially replaced and upgraded.
    • The existing fire alarm system had been upgraded a few years prior to the start of design for the museum renovation and expansion. Unfortunately, the existing fire alarm control panel was not capable of handling the new expansion and had to be replaced. Most of the existing initiating devices and all of the existing notification devices were replaced so as to be compatible with the new system. Of course, all of the fire alarm devices (both initiation and notification) for the expansion were new.
    • As with the electrical service, the fire alarm system needed to remain operational during construction. To that end, the existing fire alarm control panel was temporarily relocated to an area of the museum not immediately affected by the renovation. Wiring for the existing fire alarm devices was temporarily rerouted to the existing fire alarm control panel to maintain an operational fire alarm system during construction.
    • Once the museum expansion was to a point where it could be partially occupied, the new fire alarm control panel was installed in the new main electric service room, where it would be permanently housed. The existing fire alarm control panel remained operational until the existing and new fire alarm devices were connected to the new fire alarm system. Once this migration was completed, the existing fire alarm control panel was removed.
    • The result was a robust fire alarm system that provided full coverage of the new museum and was capable of future expansion as well as future upgrades.

      Watch a video about IMEG’s work at the Museum at Gateway Arch National Park.

      Read about IMEG’s other projects at Gateway Arch National Park.