Existing Building Retrofits

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Retrofit projects often pose the most difficult and complex construction challenges. Architectural and construction restrictions, available access, and radical-use changes all affect the mechanical system design. Norman S. Wright handles these challenges by working successfully with design, scheduling, and staging needs. The end result is optimal function with superior aesthetics: packaged rooftop mechanical systems, planar plenum fan arrays, skid-mounted pumping systems, and refrigerant-based multi-unit split systems.






  • Roseville, California
  • Acute care medical facility
  • 285 licensed beds
  • Level II American College of Surgeons verified Trauma Center


Norman S. Wright assisted a major Sacramento design-build contractor with the upgrade of existing fan system with a FANWALL TECHNOLOGY® system. The FANWALL® was installed to replace an aging fan in a location with poor access for rigging, disassembly, and reassembly.


Sutter Medical Center was very concerned about redundancy for 170 patient rooms. The 10-year-old fan system had served the hospital well with one vane-axial fan 138,000 CFM system at 8.2" static pressure, but its very congested and crowded location in the mechanical room made it very difficult and expensive to service. Figuring out how to retrofit and replace one larger vane-axial fan with a 250 horsepower motor while maintaining very short shut-down increments was a major challenge.


Offering expertise throughout the engineering and installation phases, Norman S. Wright worked closely with the mechanical and electrical contractors, the equipment manufacturer and hospital personnel. A fter many meetings with all involved parties, as well as many field visits and 3D modeling, the construction plan was implemented.

The FANWALL TECHNOLOGY® presented the only viable alternative and the ideal product for retrofit projects; either to replace plans in an existing Air Handling Unit (AHU) or to replace fans on large built-up systems. Being able to “stack” the fan cubes in place made a once unthinkable replacement a reality. Additional benefits included lower sound levels due to the built-in silencer as well as energy-efficiency improvements.

FANWALL® cubes were brought in cube by cube into a hole cut in the mechanical penthouse roof by an overhead crane. Large angle iron supports were built to hold and secure FANWALL® banks around existing ductwork. The FANWALL® system was installed and wired while the existing system continued to operate—a critical project requirement.


  • Built-in redundancy of 30 direct drive plenum fans
  • 9% additional capacity due to fan efficiency
  • Improved energy efficiency with 2.8” of system static pressure eliminated


  • FANWALL TECHNOLOGY ® system: (30) 18” fans with 10 horsepower motors built-up in (2) banks of (15) fans each