30-13 Steinway Street, Astoria

A small medical office on the second floor of an existing commercial building on Steinway Street, Astoria's main shopping street. The tenant wanted cooling and fresh air for a handful of small rooms — about 770 ft² of reception, a medical area, offices, a hall and two toilets — without ducting a separate system to each room, and without giving up the closet and storage space the practice needs. The condensing unit goes on the roof above the third floor, so refrigerant piping and power have to rise through the building. Every room needs its own thermostat. The design had to meet the NYC Department of Buildings code, ASHRAE ventilation standards and the 2020 NYStretch Energy Code. Like every New York project, the design also has to satisfy the NYC Construction Codes and the city's energy code requirements.

Mechanical: one 3.5-ton DX horizontal fan coil, FC-1, hung high in a closet so no storage floor is lost, delivers 1,250 cfm, with its condensing unit C-1 on the roof on a steel support with vibration control (39.9 MBH total cooling, 29.5 MBH sensible, 13 SEER). To give every room its own thermostat without a separate air handler, we zoned the office with seven single-duct by-pass dampers, each driven by a room thermostat: when a room is satisfied, its damper sends the extra air to the ceiling plenum return instead of overcooling the room. Supply air goes through 12 × 12 in. ceiling diffusers of 50 to 125 cfm, and return air passes through 24 × 24 in. ceiling transfer registers into the plenum. Fresh air comes through a 36 × 18 in. outdoor-air louvre (300 to 1,250 cfm) into a mixing box with motorized dampers, with a 36 × 18 in. relief louvre and barometric damper (225 to 1,175 cfm); the toilets have 75 cfm exhaust fans interlocked with the lights. We added a duct smoke detector, condensate drains and sequences of operation, and a COMcheck report for the 40 kBtu/h split system (13.0 SEER against 13.0 required). The six mechanical sheets cover the plot plan, notes and system description, the second-floor and roof plans, the equipment and diffuser schedules, and the details and sequences, with two energy sheets, issued in September 2024.