ISO 8773:2006

Overview

ISO 8773:2006 - "Plastics piping systems for non‑pressure underground drainage and sewerage - Polypropylene (PP)" - defines requirements for polypropylene (PP) pipes, fittings and systems used for non‑pressure buried drainage and sewerage (soil, domestic/industrial waste and surface water). The standard covers buried pipework and piping buried within building structures, materials (including PP-HM higher modulus grades), jointing methods, dimensional ranges (DN/OD 110 mm up to 1 600 mm), appearance, colours and the test parameters required to verify performance.

Key topics and technical requirements

• Scope & use: Non‑pressure underground drainage and sewerage systems; industrial discharges require separate chemical/temperature assessment.
• Materials: Base material must be polypropylene (PP); limited use of reprocessable material generated during production is allowed, but external recycled material is not permitted.
• Melt mass‑flow rate (MFR): General MFR limit MFR(230/2.16) ≤ 1.5 g/10 min. Materials for butt‑fusion are grouped into MFR classes A–D (A: ≤0.3 … D: ≤1.5 g/10 min); only same or adjacent classes may be fused.
• Mechanical and long‑term tests: Specifies test parameters (e.g., internal pressure long‑term test at 95 °C under 2.5 MPa hoop stress for 1 000 h, per ISO 1167) and reference test methods for dimensions, ring stiffness, impact resistance and longitudinal reversion.
• Jointing: Covers push‑fit joints with sealing rings and butt‑fused joints; sealing rings may be retained with non‑PP polymers. EN and ISO test methods for elastomeric ring leak tightness are cited.
• Geometry & sizes: Gives mean outside diameters and nominal sizes (110 mm to 1 600 mm) and refers to universal wall thickness tables and standard dimension ratios.
• Appearance & colour: Pipes/fittings must be smooth and free from defects; coloured through the wall. Recommended colours: orange‑brown, black or dusty grey.

Practical applications and users

Who uses ISO 8773:

• Manufacturers of PP piping and fittings for buried drainage
• Design engineers and specifiers creating sewerage and stormwater systems
• Installation contractors and site inspectors verifying product conformity
• Testing laboratories and certification bodies assessing MFR, ring stiffness and long‑term performance
• Regulators and procurement teams specifying compliant materials for infrastructure projects

Typical applications:

• Buried non‑pressure soil and waste stacks, branch connections, collector sewers
• Drainage systems embedded within building structures
• Surface water conveyance where non‑pressure PP systems are suitable (industrial chemical compatibility assessed separately)

Related standards

Standards referenced in ISO 8773 include ISO 1133 (MFR), ISO 1167 (resistance to internal pressure), ISO 3126 (dimensions), ISO 9969 (ring stiffness), ISO 2505 (longitudinal reversion) and EN 1401/EN 1277 for related PVC and joint leak‑tightness testing. These are useful cross‑references when specifying or testing underground drainage piping systems.

Keywords: ISO 8773, polypropylene PP pipes, non‑pressure underground drainage, sewerage systems, PP‑HM, MFR classes, push‑fit joints, butt‑fusion, pipe dimensions, ring stiffness.