Project Description:
To improve air quality, energy efficiency, and maintain mission-critical environmental controls at one of the nation’s highest-security production facilities, the United States Mint in Denver initiated a multi-phase replacement of their aging air handling infrastructure. The project spans two phases and includes the full replacement of six large-scale, custom-built AHUs serving key production and administrative spaces.
Phase 1 included the demolition and replacement of four major air handling units (AHU-2, AHU-3, AHU-4, and AHU-35). Each unit was engineered and factory-tested to stringent federal specifications and included direct-drive fan arrays, chilled water and steam coil integration, MERV 8 filtration, VFDs (ABB ACH580 series), and custom drain pans. Phase 1 also required advanced rigging logistics and phasing plans to ensure uninterrupted operation of Mint processes during construction.
Phase 2 extends the replacement scope to AHU-37, AHU-39 and AHU-41, which serve areas with unique humidity and pressure requirements. This phase introduces additional controls integration with the facility’s BAS, incorporates factory-installed instrumentation where feasible, and continues the use of Paragon outdoor airflow measurement systems for performance monitoring. Like Phase 1, AHU components are to be field-mounted on pre-installed housekeeping pads, with platforms, access ladders, and seismic anchoring systems installed to meet OSHA and Mint safety standards.
Midlands Mechanical, Inc. served as the mechanical contractor for both phases, coordinating closely with Cator, Ruma & Associates (engineer of record) and Nortek/Temtrol (equipment manufacturer). All work adhered to NFPA, UL, AMCA, and AHRI standards for federal installations.
Project Responsibilities:
- Removal and disposal of existing AHU equipment
- Installation of AHU-1, AHU-2, AHU-3, AHU-4, AHU-5, and AHU-35
- Chilled water and steam coil piping (with steam traps and drip legs)
- Stainless-steel triple-sloped condensate drain pans
- Custom VFDs with external harmonic filters
- Electrical coordination for 208V/3-phase power and short-circuit compliance
- Seismic anchoring, pressure testing, and SMACNA duct integration
- Airflow measurement stations (Paragon FE-1500 and FAATS 1000)
- BAS integration via Automated Logic controls (DDC)
- OSHA-compliant service platforms and access
- Factory and field commissioning including SMACNA Class A duct leakage testing
Design + Construction Team:
Mechanical Engineer: Cator, Ruma & Associates
General Contractor / Mechanical Contractor: Midlands Mechanical, Inc.
AHU Manufacturer: Temtrol (Nortek Air Solutions)
Owner/Agency: United States Mint – Department of the Treasury
