Chapter 3

3.2.5 Iris valve - circular

An iris valve, iris control valve or diaphragm valve, is used in a circular air transport system to measure, control and/or adjust air flow rates.

Material quality and thicknesses
For normal comfort ventilation, iris valves are manufactured from the following materials:

  • Casing: Sendzimir galvanised steel;
  • Diaphragm valve: Sendzimir galvanized steel;
  • Adjustment nut and lever: plastic;
  • Other choice of material, depending on theapplication, in consultation with the supplier.

The iris valve has circular connections, fitted with a rubber sealing ring for an airtight connection to the air duct system.

The available nominal dimensions of the intermediate iris valves are standardised to NEN-EN 1506 (circular connections) and can be selected as indicated in the tables for standard dimensions, as mentioned in this guide under chapter (circular connections). They refer to internal dimensions with a tolerance of +0 to -5 mm. The dimensions depend on the manufacture.

Assembly instructions
Iris valves must be installed in accordance with the regulations of the Manufacturer, if present and at least meet the requirements of section 3.1.4.
A minimum distance from or to a bend, ventilator, valve, etc. must be taken into account. For iris valves a minimum distance of 1 x the connection diameter is advised.

Sustainability aspects
Iris valves, fitted with rubber sealing rings, can be efficiently connected to air ducts and contribute to the airtightness of the air duct system, if the fittings have sufficient airtightness in accordance with NEN-EN 1751.
An iris valve, unlike standard adjustment valves, does not have a continuous axis, making it easy to clean the ductwork without removing the valve.
Due to the fact that iris valves can be cleaned more efficiently than standard control valves, savings can be made on maintenance.

Iris valve - circular

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