HHB Engineers was Prime AE for the replacement of AHU-27 and installation of desiccant outside air dehumidifier for AHU-22 and AHU-27. Original system was installed in 1977 and serves OR-1 through OR-10. Challenges included limiting OR downtime to two 2-day shutdowns. The $800,000 project included:
- Replacement of AHU- 27 during two 2-day shut-down. To accomplish this, new AHU was a roof mounted unit installed on roof of mechanical mezzanine. Roof structure modified with additional beams and bracing. After removal of old AHU-27, DOAS-27 installed inside penthouse. Wall opening closure using double exterior doors.
- AHU-22 was replaced in 2009 and was 100% outside air. System converted to re-circulating type by installing new return air duct from 2nd floor roof to 1st floor and up into bottom of OA plenum.
- New DOAS-22 installed at grade with new outside air duct to first floor then paralleling new return air duct..
- New DDC controls and re-heat control valves for all surgery rooms. And air handling units.
- Steam pre-heat and desiccant regeneration coils.
- All supply and return/exhaust ducts cleaned. (required two 2-day OR shut-downs, one concurrent with AHU-27 replacement)