HVAC Air Distribution case studies
HVAC Air Distribution · Put your knowledge to work in context.
This page is an independent study resource for candidates preparing for the NATE HVAC Air Distribution certification exam. NATE (North American Technician Excellence) is described on its website as "the nation's largest nonprofit certification organization for heating, ventilation, air conditioning and refrigeration (HVACR) technicians." NATE offers certification exams across HVACR specialties, including air distribution. The HVAC Air Distribution case studies are 5 cases and about 4,082 words.
1Interior VAV Zone Held at Minimum While Reheat Saturates
A ten-storey office building has an interior open-plan zone of 900 ft² with 12 occupants, served by one VAV box with a hot-water reheat coil. Design airflow is 1,200 cfm and the commissioning report set the minimum at 30% of design, 360 cfm.
824 words, about 4 min2Duct Static Sensor Ahead of the First Takeoff Starves Upper Floors
A six-storey office building has a 24,000 cfm VAV air handler with a variable-frequency drive and a duct static pressure sensor installed 10 ft downstream of the fan discharge, ahead of the first major takeoff. The setpoint is 1.5 in.
775 words, about 4 min3Laboratory Offset Three Times Design After a Constant-Volume Exhaust Mis-set
A 1,000 ft² chemistry lab in a research building uses a 100% outdoor-air VAV system with airflow tracking: supply follows exhaust to hold a design offset of −200 cfm, about −0.05 in. relative to the corridor.
836 words, about 4 min4Kitchen Makeup Air Shortfall Produces Hood Spill and Flue Backdraft
A two-storey restaurant has a 12-ft island hood rated at 200 cfm per linear foot (2,400 cfm) and a 6-ft wall hood at 300 cfm/ft (1,800 cfm), both ducted to rooftop upblast fans, 4,200 cfm total. The makeup air unit is a dedicated rooftop unit with a 3,000 cfm direct-drive fan, no heating coil, and four 2 × 2 ft ceiling diffusers over the cook line that blow horizontally across the island hood face.
833 words, about 4 min5Auditorium: Front-Row Draft and Rear Stagnation in the Same Room
A 400-seat university auditorium, 80 ft × 60 ft with a 14-ft ceiling over the seating, is served by a constant-volume air handler delivering 8,000 cfm at a 20 °F supply-to-room difference, through sixteen 4-way ceiling diffusers at 500 cfm each in four rows of four. Return air leaves through six ceiling grilles located in the first two rows.
814 words, about 4 min