How to use: pick a mode tab. Enter your Vmax, batch volume, and safety factor for filter sizing. Switch to Throughput for filtration time from area and flux, Scale-Up to go from a disc test to cartridges, or TFF/UF-DF for processing time. For diafiltration, set the concentration factor and the number of diavolumes. Use Membrane Guide to compare pore sizes and flux ranges.
Vmax Sizing
Throughput
Scale-Up
TFF/UF-DF
Membrane Guide
Product Type Preset ?
Vmax from Test (L/m²)?
Batch Volume (L)
Safety Factor ?
Filter Area (m²)
Batch Volume (L)
Flux (LMH)?
Membrane Type
Disc Test Format
Volume Filtered (mL)
Filtration Time (min)
Scale-Up Target
Scale-Up Mode
Batch Volume (L)
Initial Volume (L)
Concentration Factor ?
Diafiltration Volumes ?
Membrane Area (m²)
Permeate Flux (LMH)?
MWCO (kDa)
Application
--
m²
Required Filter Area
Detailed Results
Recommendations
Filter Format Reference
Format
Area
Use
25 mm disc
4.9 cm²
Screening
47 mm disc
17.3 cm²
Vmax/scale-down
10" mini cartridge
0.05-0.1 m²
Small batches
10" standard cartridge
0.5-1.0 m²
Pilot/production
10" large cartridge
1.0-2.0 m²
Production
20" cartridge
1.0-2.0 m²
Large scale
30" cartridge
1.5-3.0 m²
Large scale
Frequently Asked Questions
What is Vmax in sterile filtration?
Vmax is the maximum volumetric throughput (L/m²) a filter can process before it fouls completely, determined from small-scale constant-pressure filtration tests. It is used to size production-scale filters by dividing the batch volume (multiplied by a safety factor) by Vmax to get the required filter area.
How do I scale up from a 47mm disc filter to a 10-inch cartridge?
Calculate the throughput (L/m²) and flux (LMH) from your disc test. The 47mm disc has an effective area of 17.3 cm². Divide your batch volume by the proven throughput to get the required area, then select the appropriate number of cartridges. Maintain the same flux or throughput per unit area during scale-up.
What is TFF/UF-DF and when is it used?
Tangential Flow Filtration (TFF) with Ultrafiltration/Diafiltration (UF/DF) is used for protein concentration and buffer exchange. UF concentrates the product by removing permeate, while DF exchanges the buffer by adding fresh buffer while removing permeate at the same rate. See the UF vs DF mode-selection guide for sequencing and the canonical UF→DF→UF biopharma pattern.
What safety factor should I use for filter sizing?
A safety factor of 1.3-1.5x is standard for sterile filtration sizing. Use 1.5x for early-phase or variable feed streams, and 1.3x for well-characterized processes. Some applications with highly variable feeds may require 2.0x.
What membrane should I use for sterile filtration vs viral filtration?
Sterile filtration uses 0.2 µm (or 0.1 µm for mycoplasma) PES or PVDF membranes at typical fluxes of 500-5000 LMH. Viral filtration uses 20 nm parvovirus-retentive membranes (e.g., Planova, Viresolve) at much lower fluxes of 20-100 LMH due to the tighter pore size.
How do I calculate TFF processing time?
TFF processing time = total permeate volume / (membrane area × permeate flux). Total permeate includes concentration permeate (V_initial − V_final) plus diafiltration permeate (N_DV × V_retentate). Typical UF membrane fluxes range from 20-80 LMH depending on the MWCO and feed.
Can Vmax studies be applied to TFF membranes?
No. The Vmax method models dead-end (normal-flow) constant-pressure pore plugging, which does not describe tangential flow. TFF runs at a controlled flux and transmembrane pressure with a sweeping crossflow that limits cake build-up, so TFF membranes are sized from flux (LMH), membrane loading (L/m² or g/m²), and process time rather than from a Vmax number.
How do you calculate LMH (flux) in TFF?
LMH is permeate flux in litres per square metre per hour: LMH = permeate flow rate (L/h) / membrane area (m²). For example, 60 L/h of permeate through a 1.0 m² membrane is 60 LMH. Typical UF/DF operating fluxes fall in the range of about 20-80 LMH.