NEBB Testing, Adjusting and Balancing Certified Technician (CT) case studies
NEBB Testing, Adjusting and Balancing Certified Technician (CT) · Put your knowledge to work in context.
The NEBB Certified Technician (CT) credential is an individual-level certification in the Testing, Adjusting and Balancing (TAB) discipline, offered by NEBB - an association established in 1971 that describes itself as "the premier international certification association for firms and their individuals that deliver high performance building systems." NEBB distinguishes firm certification from individual certification, and its disciplines are overseen by subject-matter committees, including a TAB committee. Candidates for the CT credential are typically field technicians who measure and document airflow, hydronic flow, pressures, temperatures, and rotational speeds, then adjust dampers, valves, fan drives, and pump trim to bring systems within design tolerances. The NEBB Testing, Adjusting and Balancing Certified Technician (CT) case studies are 5 cases and about 3,428 words.
1VAV System Starved at the End of the Run
You are balancing AHU-3 in a 12-story office building. Design supply is 12,000 cfm but the VAV terminal schedule sums to 12,600 cfm.
720 words, about 4 min2Chilled Water Coils Fighting Each Other on a Direct-Return Loop
A secondary chilled water loop serves three AHUs from a common supply main in a direct-return arrangement, with a manual balance valve at each coil. Design is 240 gpm per coil at 12 ft.
673 words, about 3 min3The Traverse That Doesn't Add Up
You must verify 10,000 cfm in a 24 in. rectangular supply duct.
676 words, about 3 min4Spec vs. Standard: Which Tolerance Governs?
Six exhaust terminals on a fume-hood manifold read 8–9% below design and cannot be raised: the associated exhaust fan VFD is at 60 Hz and the fan is at the end of its curve. The general contractor wants the report issued with a note that the NEBB tolerance is ±10% and the system therefore "passes." Separately, you notice the calibration sticker on your micromanometer expired six weeks ago, partway through the project.
667 words, about 3 min5Fan Laws vs. Motor Nameplate
AHU-7 has a belt-drive centrifugal supply fan rated 20,000 cfm at 2.0 in. The motor is 20 hp, 460 V, nameplate 27 A, service factor 1.15, on a VFD.
692 words, about 3 min