Validating Zap-Lok Connectors for Subsea Use

Scope

Jee were tasked with evaluating a North Sea pipeline project where the adoption of Zap-Lok mechanical connectors may enhance commercial viability. In parallel, the client, were conducting a qualification testing programme for Zap-Lok connectors intended for subsea applications globally. Preliminary discussions with the Health and Safety Executive (HSEx) have indicated a pragmatic stance toward connector qualification, subject to the submission of robust supporting evidence.

To support this engagement, the client intended to present a qualification example to HSEx that validates the adequacy of their testing programme in line with regulatory and industry expectations. Jee were engaged to support the client in evaluating the qualification of 12” Zap-Lok pipeline connectors for potential use in the pipeline.

Solution

Jee broke down the problem into the following objectives:

Review of Qualification Test Data

Review available test data from the client’s ongoing qualification programmes, with a focus on data relevant to 12” Zap-Lok connectors intended for subsea service.

Standards Compliance Review

• Review applicable design and qualification requirements for mechanical connectors as specified in the following standards:
• BS PD 8010-2 – Pipelines on land: Subsea pipeline systems
• DNVGL- ST-F101 – Submarine pipeline systems
• ASME B31.4 – Pipeline Transportation Systems for Liquids and Slurries
• ASME B31.8 – Gas Transmission and Distribution Piping Systems

Comparison with Connector Testing Standards

     Compare client’s test data with the qualification testing requirements defined in:

• ISO 21329 – Pipeline transportation systems – Test procedures for mechanical connectors
• ISO 13679 – Procedures for testing casing and tubing connections

Gap Analysis and Justification

• Identify and assess any gaps between code requirements and the test data provided by client and/or publicly available sources.
• Where appropriate, develop technical justifications to support the acceptability of any such gaps, based on application-specific considerations or reduced risk profiles.

Assessment of Supplementary Data

• Evaluate whether any of the identified gaps can be addressed using available public domain data from NOV or its customers, related to testing of Zap-Lok or similar mechanical connectors.

The current test data provided by the client for the 12” Zap-Lok connector was not sufficient, on its own, to fully demonstrate compliance with the requirements of ISO 21329 or to conclusively prove equivalence to the strength of the adjacent pipe in key failure modes.

However, by focusing on demonstrating compliance with allowable stress criteria from relevant pipeline design codes, and supplementing with additional data, including historical performance records, smaller diameter test results, and publicly available NOV data, a comprehensive and compelling qualification case was developed by Jee for submission to HSEx.

For more information, visit www.jee.co.uk/design

To contact John French, email John.French@jee.co.uk.

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