Air Masters Completes HVAC, Controls Upgrade Inside St. Louis’ Gateway Arch

Air Masters_1ST. LOUIS, Mo. — Air Masters has completed the first comfort HVAC upgrade inside the Gateway Arch in St. Louis, Missouri. 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_2Air 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 personnel 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 a time. New support steel was installed, followed by new dual-duct VAV boxes with 12- and 14-inch round duct connections adapted to the original 28- and 30-inch main duct connections. Air Masters also installed Direct Digital Control sensors and control wiring for Automatic Controls Equipment Systems .

Air Masters has been named a Construction Keystone Award finalist by the Associated General Contractors 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 in November.