---
title: "Flange standards (DN / ANSI)"
description: "DN (EN 1092 European nominal-diameter) and ANSI B16.5 (American National Standards Institute, with pressure classes 150 / 300 / 600 lb) are the two dominant industrial flange standards used for sonic horn mounting to process vessels."
canonical_url: "https://sylio.co/glossary/flange-standards-dn-ansi"
last_updated: "2026-06-28T02:29:35.016Z"
---

**DN** (EN 1092 European nominal-diameter) and **ANSI B16.5** (American National Standards Institute, with pressure classes 150 / 300 / 600 lb) are the two dominant industrial flange standards used for [sonic horn](/glossary/sonic-horn) mounting to process vessels.

## Common horn mounting flanges

<table>
<thead>
  <tr>
    <th>
      Horn size band
    </th>
    
    <th>
      Typical DN flange
    </th>
    
    <th>
      Typical ANSI flange
    </th>
  </tr>
</thead>

<tbody>
  <tr>
    <td>
      Small horn (75 Hz, 230 Hz)
    </td>
    
    <td>
      DN50–DN80
    </td>
    
    <td>
      2–3 inch 150 lb
    </td>
  </tr>
  
  <tr>
    <td>
      Mid-size (60 Hz)
    </td>
    
    <td>
      DN100–DN150
    </td>
    
    <td>
      4–6 inch 150 lb
    </td>
  </tr>
  
  <tr>
    <td>
      Large infrasonic
    </td>
    
    <td>
      DN200+
    </td>
    
    <td>
      8 inch 150 lb
    </td>
  </tr>
</tbody>
</table>

## Specification practice

European-market horns typically ship with DN flanges as standard, with ANSI options available. North American-market horns ship with ANSI 150 lb as standard. International projects sometimes specify both flange faces (e.g. ANSI weld-neck flange on the horn, DN flange on the vessel adaptor) — this is the integrator's problem to resolve.

## Related terms

- [Bell horn](/glossary/bell-horn)
- [Sonic horn](/glossary/sonic-horn)