ISO 4065:2018

Overview

ISO 4065:2018 - "Thermoplastics pipes - Universal wall thickness table" defines the standardized relationship between nominal wall thickness (en) and nominal outside diameter (dn) for solid‑wall thermoplastics pipes with a constant circular cross‑section. The third edition (2018) extends tabled diameters up to 3 000 mm and nominal wall thicknesses up to 150 mm, and standardizes S‑series (pipe series/SDR) values for pressure and non‑pressure applications. It is applicable regardless of polymer type, manufacturing method or intended application for pipes with smooth internal and external surfaces.

Key topics and technical requirements

• Scope and applicability: Applies to solid‑wall thermoplastics pipes of constant circular cross‑section (smooth internal/external surfaces).
• Universal wall thickness tables: Table 3 (main) lists nominal wall thicknesses en vs nominal outside diameters dn for preferred S series (SDR‑related). Additional non‑pressure series are provided in a separate table.
• Series S and SDR relation: Pipe series S is related to SDR by S = (SDR − 1) / 2. This connects conventional SDR designations to the S‑series used in the tables.
• Design and calculation rules:
  • Wall thickness may be computed from the nominal outside diameter and series: en = dn / (2·S + 1) (as used to derive table values).
  • S can be derived from design stress σs and nominal pressure PN by S = σs / PN, linking mechanical design inputs to table selection.
• Preferred numbers: S‑values and PN values are taken from preferred number series (R10 or R20) per ISO 3 and ISO 497 to reduce theoretical combinations to practical series.
• Deviations: Clause 6 allows limited deviations for special stiffness, temperature or other application needs; such exceptions should be minimized.

Practical applications and users

ISO 4065:2018 is essential for:

• Pipe manufacturers specifying standard wall thicknesses for thermoplastics pipes.
• Design and project engineers selecting pipe dimensions for pressure and non‑pressure systems (water supply, drainage, process piping, utilities).
• Specifiers, procurement and quality managers ensuring compliance with an internationally harmonized wall thickness table.
• Standards writers and testing organizations harmonizing dimensional requirements across product standards.

Using ISO 4065 simplifies product ranges, ensures mechanical compatibility, and supports consistent pressure‑rating design by linking nominal dimensions to accepted S/SDR series.

Related standards

• ISO 3 - Preferred numbers (R10 / R20 series)
• ISO 497 - Guide to selection of preferred number series
• ISO 161‑1 - Reference for selection of internal pressure and design stresses (used in calculations and selection of S)

Keywords: ISO 4065:2018, thermoplastics pipes, wall thickness table, nominal outside diameter, nominal wall thickness, SDR, pipe series S, design stress, PN, preferred numbers.