The internal diameter of the tube is a major determinant of the run length. The larger the internal diameter, the longer the run length that can be achieved while maintaining uniformity.

The diameter of the tube also determines what size of connector to use. It also has an impact on the maximum pressure.

  • Nominal diameter – this is the industry terminology used to identify each specific drip tape/drip line. In general, the nominal diameter is the inside diameter for tapes and thin wall drip lines. Conversely, it is generally the outside diameter for heavy wall drip lines. Not all manufacturers align to the same terminology, and the cut-off between thin wall and heavy wall may vary. Therefore, you should check the internal diameter and outside diameter to confirm.

  • Internal diameter (ID) – the diameter of the tube within the tube. The Internal Diameter is the most important for hydraulic design, as this is the area that the water has to flow through.

  • Outside diameter (OD) – the diameter of the tube including the wall of the tube itself (the wall thickness).


A note regarding connectors

  • For tubes with connectors that are inserted into the tube (e.g. heavy wall barb fittings), the fitting needs to fit the ID of the tube.
  • For tubes with connectors that fit around the tube, the fitting needs to fit around the OD of the tube.
    Connector naming is not always consistent. Often it matches the nominal diameter name of the product category, but not always. Check.

Explore the next module, or search for a specific topic or issue.

Before using these modules, please familiarize yourself with the relevant disclaimers and additional safety and usage information contained within each module.

© 2023, Rivulis Irrigation Ltd, all rights reserved. 
Reproduction of this content in any form is prohibited without the written consent of Rivulis Irrigation Ltd.