Invitation to participate in NDT trials of ex-service engineered composite repairs


In January 2017, the Health and Safety Executive (HSE) initiated a Shared Research Project (SRP) on Engineered Composite Repairs. The technical work scope of the project consisted of five separate but inherently linked work packages. Work Package 2, ‘Inspection and Criticality of Defects’, proposed a series of inspection trials to evaluate the capabilities of non-destructive testing  NDT) techniques to locate and characterise defects. Trials were to be undertaken on ex-service and manufactured reference samples.

Recognising that a community of inspection service companies and equipment vendors already existed under the auspices of HOIS, HSE signed a collaboration agreement in December 2017. HOIS members were informed of the scope of the HSE trial programme on 16 July 2018.

HSE is in receipt of circa 100 ex-service repairs, representing a wide range of defects, geometries, thicknesses, diameter and material types. From these, HSE has selected nineteen ex-service samples to use in the trials. In due course (estimated to be September 2018), these will be supplemented with manufactured reference samples.

This article focuses on the inspection of ex-service repairs and provides pertinent information to assist inspection service companies and other interested parties in conducting the trials.

The ex-service repairs available for the NDT trials are shown in Appendix A. The aim of the trial(s) is to evaluate a range of NDT techniques by inviting NDT service providers to take part in a ‘blind’ inspection programme. Once the blind trials have been completed, where appropriate, HSE can then provide anomaly information such that ‘open’ trials can be performed.

NDT service providers will be asked to inspect three key areas that make up the engineered composite repair system:
  • Laminate – glass or carbon fibre-reinforced polymer (composite) material
  • Bond – interface between composite and pipework
  • Substrate – base material beneath the repair, for example pipework.

A ‘datum’ will be marked on each sample that will act as a reference point for the purposes of inspection and to facilitate comparisons between techniques. Once preliminary trials have been completed, consideration will be given to quantifying the effect of the transported media on inspection. This will take the form of filling pipework with fluids of different densities, e.g. oil and water. HSE requests that inspection service providers produce an inspection report for each specimen that they inspect.

All ex-service repairs are in an ‘as received’ condition. Whilst all have been checked and cleared for naturally occurring radioactive material (NORM), it is reasonable to assume that there are trace chemicals on the inside and, to a lesser degree, outside surfaces. HSE has sealed all accessible surfaces with a polymeric bagging material secured with tape.

It would be considered good practice and advisable to wear appropriate levels of personal protective equipment during the inspection trials. This is likely to mirror the measures taken when in an offshore environment.

Once the NDT trials have been completed and all potential techniques have been evaluated, HSE intends to remove the composite repairs to accurately evaluate the nature and size of the defect(s). HSE will then work with HOIS members (and any other parties) to review the outputs.

The trials are scheduled to take place during August 2018 and September 2018. Any NDT service providers interested in participating in the inspection programme should contact the following HSE representatives:

The ex-service samples are currently stored in Aberdeen. It is requested that NDT service providers contact HSE with a proposed trial slot as well as a list of the NDT techniques they would like to trial.
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