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Pleated Filter Calculator

Initial Pressure Drop Model · Sothen & Tatarchuk 2009

ΔPT = ½ρ[(2KG)V₂² + (KC+KE+KP)V₃²] + AV₄ + BV₄²Seven-region flow model
Idelchik friction coefficients
KP = 0.11 · (FHD/FD) · (1/β)4/3
Model domainValidated for 20"×20" faces with depths 1–4", pleat counts 12–60, media thickness < 2 mm, face velocity < 1000 fpm. Extrapolations beyond these bounds are flagged below.
Total filter ΔP
Media area
Pleat pitch β
°
Pleat opening PO
in
Volumetric flow
CFM
Media velocity V₄
fpm
Pleat count (input)
pleats
Optimal pleat count
pleats
Optimal PPI
1/in
ΔP at optimum
inWC
KP (pleat coef.)

Pleating curve · ΔP vs. pleat count

U-curve · media + viscous + grating
ΔP breakdown by term

Fractional efficiency projectorPierce velocity-scaling · TSI 3160 data

How it worksPaste two fractional efficiency datasets at different face velocities. The tool fits each curve to Pierce's quadratic model (ln Pen = A(ln D)² + B ln D + C), back-calculates the velocity exponent N, and projects the penetration curve to the media velocity V4 computed by this calculator.
Mode
HEPA: single velocity exponent from U-curve fit (Pierce). Use for sub-micron 3160 data.
Face velocitycm/s
Face velocitycm/s
Ready · enter velocities, paste data, and fit