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BS EN ISO 11296 — Plastics Piping Systems for Renovation of Underground Non-Pressure Drainage and Sewerage Networks
A series standard covering general requirements, close-fit lining, cured-in-place pipes and spirally-wound lining
📐 BS EN ISO 11296 is the British Standard series adopted by BSI from the European standard EN ISO 11296, which specifies the materials, design, installation and performance requirements for plastics piping systems used in the renovation of underground non-pressure (gravity) drainage and sewerage networks. Prepared by ISO/TC 138 (Plastics pipes, fittings and valves for the transport of fluids) together with CEN/TC 155 (Plastics piping systems and ducting systems) and entrusted in the UK to Technical Committee PRI/88/3, the series is classified under ICS 23.040.20, 23.040.45, 91.140.80 and 93.030. It supersedes the earlier BS EN 13566 series and is one of the most widely referenced European standards for trenchless rehabilitation of ageing municipal sewer networks.
📄 Scanned-version note: Part 7 of this series (BS EN ISO 11296-7:2013) is a scanned document (not machine-readable). This article summarises it from public domain knowledge of the standard’s subject area; the authoritative clauses are those in the BSI published version.
💡 In municipal drainage and sewerage maintenance, open-cut replacement is costly, disruptive to traffic and often damages adjacent structures. The various “lining” techniques specified in BS EN ISO 11296 restore structural performance and extend asset life without excavation.
1. Series Structure and Scope 📌
The BS EN ISO 11296 series is organised by “Part”. This batch covers four parts, each corresponding to a different trenchless rehabilitation technique:
| Part Standard | Technique Theme | ICS | Notes |
|---|---|---|---|
| BS EN ISO 11296-1:2011 | General | 23.040.20; 23.040.45; 91.140.80; 93.030 | General principles: terms, symbols, materials and design |
| BS EN ISO 11296-3:2011 | Lining with close-fit pipes | 23.040.20; 23.040.45; 91.140.80; 93.030 | Continuous plastic pipe folded or reduced, inserted and allowed to spring back |
| BS EN ISO 11296-4:2011 | Lining with cured-in-place pipes (CIPP) | 23.040.20; 23.040.45; 91.140.80; 93.030 | Resin-impregnated flexible tube inverted or pulled and cured by heat or UV |
| BS EN ISO 11296-7:2013 | Lining with spirally-wound pipes | 23.040.20; 23.040.45; 91.140.80; 93.030 | Profile spirally wound and locked in place, suitable for larger diameters |
⚠️ The series applies only to non-pressure (gravity) drainage and sewerage networks. Renovation of pressure pipes carrying water or gas is outside its scope and is governed by the appropriate pressure-piping standards.
2. Technical Requirements of Each Part 🔧
2.1 Part 1: General
Part 1 acts as the series framework, harmonising terminology, definitions, symbols and basic design principles across all parts. It clarifies concepts such as “renovation” versus “repair”, defines the long-term performance, chemical resistance and pressure-capability requirements of lining materials, and provides methods for establishing the design service life. Before work begins, the existing pipe must be surveyed and assessed in accordance with Part 1 to determine its residual structural capacity and the appropriate renovation approach.
2.2 Part 3: Lining with Close-Fit Pipes
Close-fit lining uses a thermoplastic pipe that is folded, flattened or radially reduced at the factory, inserted into the existing pipe on site, and then allowed to recover to its circular shape through heating, pressurisation or natural elastic recovery, so that it fits tightly against the original wall. No curing is required and installation is fast, making it suitable for pipes with a reasonable structural condition and no severe misalignment. The standard specifies pipe material (for example PE or PP), folding method, insertion pull-force control, the pressure and temperature parameters for shape recovery, and the required final wall thickness and ring stiffness.
2.3 Part 4: Lining with Cured-in-Place Pipes (CIPP)
CIPP is the most widely applied sewer rehabilitation technique: a flexible tube impregnated with thermosetting resin (unsaturated polyester, vinyl ester and similar) is inverted or pulled into the existing pipe and cured by hot water, steam or ultraviolet light, forming a tight “pipe-within-a-pipe”. The standard specifies the tube construction, resin impregnation, inversion/pulling parameters, the curing temperature-time regime, and acceptance criteria such as the cured wall thickness, ring stiffness, flexural strength and chemical resistance.
2.4 Part 7: Lining with Spirally-Wound Pipes
Spirally-wound lining suits larger bores (typically DN 600 and above) for manholes and main sewers: PVC or PE profiles are continuously spirally wound and interlocked inside the existing pipe by a dedicated winding machine, with the profile edges locking together to form an integral structure. Cementitious grout or resin may be injected into the profile cavities to increase stiffness. The process adapts well to the existing bore and can be carried out directly from a manhole.
✅ Each part requires site survey, CCTV inspection and pipe cleaning before work, and after installation calls for CCTV re-inspection, water-tightness (or air-tightness) testing and, where necessary, mechanical testing of samples to ensure a sound, leak-free liner-to-wall bond.
3. Key Technical Requirements and Acceptance Criteria 🧪
- Material performance: lining materials must meet resistance to internal and external pressure, ring stiffness, chemical attack and ageing; grade and formulation must comply with Part 1 and the relevant part.
- Structural performance: for CIPP, the cured ring stiffness, flexural modulus and thickness are core acceptance criteria; for close-fit lining, the recovered wall thickness, ovality and ring stiffness are the focus.
- Connections and sealing: the interface between liner and host pipe, and branch connections, must be sealed to prevent groundwater ingress and sewage exfiltration.
- Process control: pulling force, inversion pressure, curing temperature and time should be recorded throughout as a basis for traceability.
- Acceptance testing: after completion, CCTV inspection and water-tightness (or air-tightness) tests are performed, with mechanical tests on samples where required.
4. Engineering Practice 🛠️
- 🔍 Selection workflow: assess defect type and grade via CCTV → consider diameter, depth, traffic and ground conditions → choose close-fit, CIPP or spirally-wound lining → determine material and thickness to the standard.
- 🔧 Pre-treatment: high-pressure water jetting, removal of roots and sediment, and local repair of broken sections are essential to provide a clean, even base for the liner.
- 📊 Quality control: for CIPP, control resin impregnation uniformity and the curing regime to avoid wrinkles, voids and uncured zones.
- 📋 Compliance: contract and procurement documents should reference the applicable part and acceptance clauses, and manufacturers should provide material certificates and performance test reports.
5. Frequently Asked Questions ❓
❓ Q: How does BS EN ISO 11296 relate to BS EN 13566?
A: Each part of BS EN ISO 11296 supersedes the corresponding earlier BS EN 13566 part (for example 11296-1 supersedes 13566-1, 11296-3 supersedes 13566-3 and 11296-4 supersedes 13566-4) and is the currently effective renovation standard.
A: Each part of BS EN ISO 11296 supersedes the corresponding earlier BS EN 13566 part (for example 11296-1 supersedes 13566-1, 11296-3 supersedes 13566-3 and 11296-4 supersedes 13566-4) and is the currently effective renovation standard.
❓ Q: Can this standard be used for renovating pressure pipes?
A: No. The standard is explicitly limited to underground non-pressure (gravity) drainage and sewerage networks. Renovation of pressure pipes is covered by dedicated pressure-piping lining standards, for example for water and gas supply.
A: No. The standard is explicitly limited to underground non-pressure (gravity) drainage and sewerage networks. Renovation of pressure pipes is covered by dedicated pressure-piping lining standards, for example for water and gas supply.
❓ Q: What is the difference between CIPP and in-situ curing?
A: They are the same process. CIPP stands for Cured-In-Place Pipe, meaning a liner formed by curing in situ inside the existing pipe, and is the core subject of Part 4.
A: They are the same process. CIPP stands for Cured-In-Place Pipe, meaning a liner formed by curing in situ inside the existing pipe, and is the core subject of Part 4.
❓ Q: How do I decide which lining technique to use?
A: Consider diameter, depth, defect type, traffic and excavation conditions, cost and schedule. Generally, small bores with light defects suit close-fit lining; corroded or leaking medium and small bores commonly use CIPP; large, irregular bores or rapid repairs can use spirally-wound lining.
A: Consider diameter, depth, defect type, traffic and excavation conditions, cost and schedule. Generally, small bores with light defects suit close-fit lining; corroded or leaking medium and small bores commonly use CIPP; large, irregular bores or rapid repairs can use spirally-wound lining.