Building 235 houses the NIST Center for Neutron Research and includes a working 20MW research nuclear reactor and reactor support spaces. Summer Consultants replaced all air moving equipment which had not been replaced in the past few years including a new air handling unit, five air conditioning units, seven heating and ventilating units and over 40 exhaust fans, including fume hood exhaust fans. New air handling and air conditioning units ranged in size from 5,220 – 22,000 CFM. In addition, all existing terminal units, both dual duct and variable air volume (VAV), within the wings were replaced and duct work was modified.
The replacement design of the existing controls system, including pneumatic, digital, and digital/pneumatic hybrids, was completed by Summer Consultants under a previous project and incorporated into this project, with modifications as required due to changes in the replaced equipment. All controls were replaced with a new direct digital controls system. In addition, cybersecurity concerns were also addressed.
A life safety study was completed for Wings A, B and E including an assessment of the fire alarm and fire suppression systems and compliance with local and federal codes. A return air corridor code violation was repaired by ducting returns in two wings and replacing louvered doors. Recommendations were also provided for improvements to the fire suppression system. In addition, new ceilings and upgraded light fixtures were provided in un-renovated portions of the building where terminal units were replaced.
Construction of the project was phased to be completed when the reactor is shut down for one year beginning in 2023 to provide fewer impacts on building occupants.