Baghouse Air-to-Cloth Ratio & Filter Sizing Calculator

Determine required filter media cloth area, total bag count, operating Air-to-Cloth (A/C) ratio, and interstitial can velocity per ACGIH guidelines.

Airflow & Particulate Service

Process Airflow (ACFM):

Gas Temperature (°F):

Dust Application / Material:

Target A/C Ratio (ft/min):

Filter Bag Specifications

Bag Diameter (inches):

Bag Length (ft):

Housing Inside Cross-Section Area (sq ft): Used to calculate interstitial can velocity

Filter Sizing & Operating Ratios

Required Filter Bags

-- Bags

-- ft/min actual A/C

Total Cloth Area

-- sq ft

-- sq ft / bag

Interstitial Can Velocity

-- FPM

Max 250 FPM

Recommended Tube Sheet Matrix: -- rows x -- bags

Bag Cleaning Type: Pulse-Jet Online

Differential Pressure Target: 3.0 - 5.0 in. w.g.

ACGIH recommends keeping interstitial can velocity below 200–250 FPM so dislodged dust cakes fall freely into the hopper instead of re-entraining.

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Frequently Asked Questions

What is the Air-to-Cloth (A/C) ratio in dust collector baghouses?

The Air-to-Cloth ratio (also called filtration velocity) is the volumetric gas flow rate (ACFM) divided by the total active surface area of the filter media (sq ft), expressed in units of feet per minute (FPM). Pulse-jet collectors typically operate between 3.0 to 6.0 ft/min, whereas shaker and reverse-air collectors operate between 1.5 to 2.5 ft/min.

What is interstitial "can velocity" and why does it cause bag blinding?

Can velocity is the upward superficial velocity of the gas stream flowing vertically through the open spaces between filter bags inside the baghouse casing. If can velocity exceeds 200 to 250 FPM, the upward aerodynamic drag overcomes gravity, re-entraining dislodged dust cakes and driving them back against the bags.

Why do metallurgical fumes require lower Air-to-Cloth ratios than sawdust?

Sub-micron metal fumes from laser cutters, plasma torches, or induction furnaces create dense, tightly packed filter cakes with very high specific flow resistance. Operating above 2.0 to 2.5 ft/min causes rapid pressure drop spikes and irreversible media blinding.