ISO 265-1:1988 PDF

Overview

ISO 265-1:1988 - "Pipes and fittings of plastics materials - Fittings for domestic and industrial waste pipes - Basic dimensions: Metric series - Part 1: Unplasticized poly(vinyl chloride) (PVC‑U)" defines the metric series of nominal diameters and the formulae for calculating the common dimensions of PVC‑U fittings used in domestic and industrial waste systems. It covers fittings with spigot ends, socket fittings, and socket fittings with curved (swept) entries, and provides minimum laying lengths and calculation methods intended primarily to assist mould design.

Key topics and technical requirements

• Scope and materials: Applies to fittings made of unplasticized poly(vinyl chloride) (PVC‑U) for waste and soil discharge systems; excludes fittings fabricated from pipes.
• Nominal diameters (metric series): Defines permitted diameter selections (examples in the standard: 40, 50, 63, 75, 90, 110, 125, 160 mm) and allows supplementary diameters per ISO 161‑1.
• Fitting types covered:
  • Elbows (various nominal angles)
  • Branches and double branches
  • Eccentric reducers
  • All‑socket fittings and spigot‑end fittings with curved entries
• Angles:
  • Elbows: 15°, 22.5°, 30°, 45°, 67.5°, and 87.5°–88.5°
  • Branches/double branches: 45°, 67.5°, and 87.5°–88.5°
• Laying lengths (z):
  • Provides formulae and figures to calculate minimum laying lengths for spigot/socket insertion and for curved entries (swept entry radius, tangent angle, etc.).
  • Tabulated guidance (calculated using series B wall thicknesses per ISO 3633 and typical β angles) is provided as a design aid.
  • NOTE: laying lengths are intended to assist mould design and are not for quality control.
• Design limits & dimensional parameters: Uses dimensions D and emin in accordance with ISO 3633 and ISO 8283‑1; includes formulae for Dmax, di_max, radius r, tangent angle and related geometry for swept entries.
• Limitations: The standard does not supply every manufacturing dimension (for example, specific socket length or spigot length may be specified in future or related standards).

Applications and users

• Who uses ISO 265‑1:
  • PVC‑U fitting manufacturers and mould designers
  • Plumbing and drainage product designers
  • Specifiers, architects, and building services engineers
  • Standards committees and testing bodies referencing basic geometric rules
• Practical uses:
  • Designing moulds and tooling for elbows, branches and reducers
  • Defining nominal diameters and minimum laying lengths for product families
  • Creating product documentation and ensuring interchangeability in waste pipe systems

Related standards

• ISO 161‑1 - Thermoplastics pipes for the transport of fluids (nominal outside diameters)
• ISO 3633 - PVC‑U pipes and fittings for soil and waste discharge (specifications, wall thicknesses)
• ISO 8283‑1 - Dimensions of sockets and spigots for discharge systems (PVC‑U and PVC‑C)

Keywords: ISO 265-1, PVC‑U fittings, metric series, waste pipes, spigot ends, socket fittings, curved entry, laying length, elbows, reducers, branches.