---
title: "Air-to-cloth ratio"
description: "Air-to-cloth (A/C) ratio is the volumetric gas flow rate divided by the total available filtration area of the filter bags, expressed as a velocity (m/min or ft/min). It is the primary sizing parameter for a fabric filter: higher A/C means a smaller, cheaper baghouse, but also higher ΔP, shorter bag life and greater blinding risk."
canonical_url: "https://sylio.co/glossary/air-to-cloth-ratio"
last_updated: "2026-06-28T02:29:24.336Z"
---

**Air-to-cloth (A/C) ratio** is the volumetric gas flow rate divided by the total available filtration area of the [filter bags](/glossary/filter-bag), expressed as a velocity (m/min or ft/min). It is the primary sizing parameter for a [fabric filter](/glossary/fabric-filter): higher A/C means a smaller, cheaper baghouse, but also higher [ΔP](/glossary/differential-pressure-baghouse), shorter bag life and greater [blinding](/glossary/bag-blinding) risk.

## Typical bands

<table>
<thead>
  <tr>
    <th>
      Cleaning system
    </th>
    
    <th>
      A/C ratio (m/min)
    </th>
    
    <th>
      A/C ratio (ft/min)
    </th>
  </tr>
</thead>

<tbody>
  <tr>
    <td>
      <a href="/glossary/pulse-jet-baghouse">
        Pulse-jet
      </a>
    </td>
    
    <td>
      1.0–2.5
    </td>
    
    <td>
      3–8
    </td>
  </tr>
  
  <tr>
    <td>
      <a href="/glossary/reverse-air-baghouse">
        Reverse-air
      </a>
    </td>
    
    <td>
      0.3–0.8
    </td>
    
    <td>
      1–2.5
    </td>
  </tr>
  
  <tr>
    <td>
      <a href="/glossary/shaker-baghouse">
        Shaker
      </a>
    </td>
    
    <td>
      0.5–1.0
    </td>
    
    <td>
      1.5–3
    </td>
  </tr>
</tbody>
</table>

## What pushes the design choice

- **Sticky or hygroscopic dust** — lower A/C (more bag area per unit gas flow)
- **High temperature** — lower A/C (preserve bag life)
- **Capex pressure** — higher A/C (smaller baghouse)
- **Strict outlet limits** — lower A/C (better filtration margin)
- **PTFE membrane media** — higher A/C tolerated (surface filtration not penalised)

## Why operators monitor effective A/C

If compartments are offline for cleaning or bag replacement, the *effective* A/C through the remaining online bags rises. A baghouse designed for 1.5 m/min can rapidly approach 2.0 m/min when two of eight compartments are isolated — which is one reason planned outages are sequenced carefully.

## Related terms

- [Fabric filter](/glossary/fabric-filter)
- [Filter bag](/glossary/filter-bag)
- [Can velocity](/glossary/can-velocity)
- [Bag blinding](/glossary/bag-blinding)
- [Differential pressure (baghouse)](/glossary/differential-pressure-baghouse)