NREL’s Field Test Laboratory Building (FTLB) houses more than 40 labs, including Lab 105. For this retrofit, 360 Engineering provided both prime consulting and mechanical engineering services. Undertaken so the existing two-story space could house new custom lab equipment, the project involved plumbing and mechanical design and modification. The mechanical scope involved providing a new air handling unit (AHU) to connect to the existing heating water, chilled water, and energy recovery loops within the building. The new mechanical system designed introduces additional makeup air into the building, with an energy recovery unit and associated exhaust fans. The laboratory makeup air and exhaust air systems now handle air change rates per NREL lab standards and the additional heat generated by the new equipment. To accommodate a chemical hood, seven gas cabinets, and several snorkels, the team designed a new variable volume supply system and variable air volume (VAV) exhaust system. The system includes Venturi air valves to maintain proper differential pressure with the adjoining spaces. A new plumbing system includes an acid-resistant sump pump beneath a laboratory sink that routes lab waste to a central processing tank within the building. Seven independent gas lines were installed to support the lab hood and lab equipment operations.