What is a composite repair to ISO 24817?
In a composite repair (laminating), a damaged component — pipework, tank or vessel — is restored with a fibre-reinforced polymer laminate of glass or carbon fibre and epoxy resin. The design is calculated in accordance with ISO 24817 (or ASME PCC-2, Article 401) so that the component regains its original design parameters for strength and temperature. Properly engineered and installed by qualified installers, the laminate is a recognised permanent repair — carried out in operation, without welding, without a hot-work permit.
Sequence of a laminating project
- ▸1. Data basis: questionnaire, site visit, isometrics and safety data sheets.
- ▸2. Engineering: calculation to ISO 24817 or ASME PCC-2 with certified software; you receive the complete engineering report for review or submission to the inspection body.
- ▸3. Execution: surface preparation (typically blasting to Sa 2½), laminate build-up in the calculated number of layers, curing — without a hot-work permit; the plant does not have to be shut down. The process is designed for work in Ex zones.
- ▸4. Documentation: comprehensive protocol, product certificates, proof of the qualified installation company; photo documentation with an Ex-proof camera on request.
Technical data and application limits
| Parameter | Value |
|---|---|
| Operating temperature | up to 303 °C depending on the system |
| Pressure | up to several hundred bar (system-dependent) |
| Design life | engineered case by case to ISO 24817, up to 20 years; warranty up to 20 years, extendable by up to 10 years after an on-site inspection |
| Repairable damage | external/internal corrosion, wall loss, cracks, dents, through-wall leaks |
| Components | pipework (incl. bends, tees), tanks and tank roofs, vessels, steel structures, bridges |
| Materials | glass or carbon fibre fabric with epoxy matrix; glass barrier layer under carbon on steel against galvanic corrosion |
| Response time | from damage identification to code-compliant repair typically hours to days |
Standards, systems & qualification
- ▸ISO 24817:2017 (German edition: DIN EN ISO 24817:2018-03): qualification of repair systems, design calculation, installation, testing; new edition announced. Parallel code: ASME PCC-2, Article 401.
- ▸Repair classes with design life — from temporary (≤ 2 years) to permanent (up to 20 years).
- ▸ISO 24817 requires qualified installers and supervisors — HSOS is a certified installation company with all leading system manufacturers (incl. Henkel Loctite, Clock Spring|NRI, HJ3) and selects the suitable system manufacturer-neutrally.
- ▸Certified specifically for laminating work: SCC (VCA-P) and WHG/AwSV; products/engineering certified by TÜV, Lloyd’s Register or DNV.
When composite instead of welding?
A weld repair requires a hot-work permit, often a shutdown, flushing/gas-freeing — and on thin-walled corroded lines welding is frequently no longer permissible at all. The composite laminate, in contrast, is applied cold: no ignition source, no intervention in the base material, repair possible under operating pressure. In addition, the laminate acts as corrosion protection. The method reaches its limits at very high temperatures outside the system approvals and where the calculation shows insufficient reinforcement — then we recommend replacement or other methods.
Typical applications
- ▸Tank repair: extensively corroded tank shell/roof — the laminate restores structural integrity without taking the tank out of service.
- ▸Pipework with external corrosion (incl. bends): wrapped laminate over the damaged section, designed for full operating pressure.
- ▸Leaking nozzle/flange area: encapsulation with laminate as a documented repair until the next shutdown or as a permanent solution.
Frequently Asked Questions
When is a composite repair preferable to welding?
Whenever hot work must be avoided (Ex zone, ongoing operation), the component is too thin-walled for welding due to corrosion, or a shutdown would be disproportionately expensive. The laminate is applied cold and engineered to ISO 24817 so that the original strength is restored.
What does ISO 24817 require?
The standard demands three things: a qualified repair system (tested material properties), a documented design calculation for the specific damage case (pressure, temperature, defect size, design life/repair class) and installation by demonstrably qualified installers/supervisors with subsequent testing and documentation. That is exactly what we deliver, including the engineering report.
For which media and pressures is the repair approved?
That depends on the qualified system — the range extends to several hundred bar and, depending on the system, up to approx. 300 °C. As we work certified with several system manufacturers, we select the product qualified for your medium and demonstrate suitability in the engineering report.