Grille balancing

Enter each grille's design CFM, pick RVA or capture hood for that grille, then enter the prelim and final readings. The page works out CFM and % of design. Nothing is saved on this page.

Job (optional)

Unit / location (optional)

Tech (optional)

Number of grilles

Final tolerance (± % of design)

Area (add area served, type, and size for a full sheet)

Grilles

Pick RVA or Capture hood on each grille. RVA: type the Ak (from the submittal or a field Ak) and the average FPM; CFM = Ak × FPM. Capture hood: type the prelim and final CFM straight from the hood.

#	Area served	Type	Size	Design CFM	Method	Ak (sq ft)	Prelim FPM	Prelim CFM	Prelim %	Final FPM	Final CFM	Final %

% of design = reading CFM ÷ design CFM × 100. Totals % = total reading ÷ total design, never an average of the grille percents. Ratio method: the grille with the lowest prelim % is the key grille; leave its damper wide open and damper the closest grilles to about the same % (within 2%), then adjust the fan and take finals.