Serving the St. Louis Region, Mid-Missouri and Metro East

Serving the St. Louis Region, Mid-Missouri and Metro East

Air Masters completes HVAC and controls upgrade inside the Gateway Arch in St. Louis

IFS_Gateway Arch
ST. LOUIS – Air Masters has completed the first-comfort HVAC upgrade inside the Gateway Arch in St. Louis. The 50-year-old HVAC dual duct boxes and pneumatic controls in the national monument’s 630-foot legs were replaced with new boxes and computerized controls to ensure the comfort and safety of tram passengers on their way to the Arch observation deck.

“Visitors from all over the world tour the Jefferson National Expansion Memorial and ride the trams up the Arch legs to the observation deck. With the harsh weather conditions in St. Louis, proper comfort conditioning is extremely important for everyone passing through the Arch legs,“ said Gary Tidwell, project manager for Air Masters.

Without proper comfort conditioning, the temperature inside the stainless and carbon steel legs of the Arch could climb to dangerous highs in the summer and freezing cold in the winter, Tidwell said.

Air Masters worked closely with National Park Service staff to develop and implement special safety protocol as they worked inside the Arch legs to keep trams operational, workers safe and visitors comfortable. Simply moving equipment, materials and workers inside the monument was uniquely challenging. Every worker was tied off to prevent falls. Tools and equipment also were secured, safety nets were installed and magnets were used to contain hardware and prevent anything from being dropped down the Arch leg. As a result of the extensive safety precautions, Air Masters logged zero workplace accident or injury incidents on the complex project.

Working inside the narrow, curved structure also created logistical challenges. Air Masters field measured each of 20 separate worksite locations high within the Arch, then pre-fabricated sheet metal and steel support pieces off-site.

“Every aspect of this job was a special, out-of-the-ordinary challenge and required careful daily planning of how to move men, material and equipment,” said Tidwell. “We also knew from the beginning that the National Park Service schedule had priority over the construction schedule, so our work hinged on the needs of their staff, Arch visitors and tram usage.”

Twenty dual-duct terminal units for warm and cold air were disconnected and removed one at time. New support steel was installed, followed by new dual-duct VAV boxes with 12” and 14” round duct connections adapted to the original 28” and 30” main duct connections. Air Masters also installed Direct Digital Control (DDC) sensors and control wiring for Automatic Controls Equipment Systems (ACES).

“We’re proud to have been part of the effort to modernize the Arch for the next 50 years,” said Tidwell.

Air Masters has been named a Construction Keystone Award finalist by the Associated General Contractors (AGC) of Missouri for their work on the Gateway Arch. The AGC Construction Keystone Awards honor firms that exhibit excellence in providing solutions to unique obstacles and challenges specific to their project. Winners and finalists will be announced this November.

Air Masters Corporation is a full-service HVAC, plumbing, piping, building automation and energy conservation firm with more than 200 professional and trade employees. Established in 1966, Air Masters delivers mechanical engineering, construction, installation, service/maintenance and facility management services. Air Masters advocates for sustainable solutions designed to ensure occupant comfort, improve systems efficiency and reduce facility operational costs for the life of the building. Air Masters serves clients in Missouri and Illinois, with offices in St. Louis, Columbia and Rolla. For more information, call (636) 680-2100 and visit, and

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©Photos courtesy Gateway Arch

Media Contact
Rachel Brown

Source: IFS – Synergy