Mitigation begins with risk assessment and threat evaluation

Cable-supported structures are vulnerable to fire damage and have a varying degree of redundancy in their design. By implementing suitable engineering measures, the risk of failure as a result of the occurrence of hydrocarbon fire events, largely caused by tanker accidents or ship fires, can be mitigated.

While every project is different, our experience shows that the following general steps are typically undertaken in close collaboration with authorities and consultants:

  • A security specialist consultant conducts a risk assessment and threat evaluation, and determines the controlling risk scenario.
  • The consultant then performs an analysis to determine the effects of that hypothetical fire event – typically a hydrocarbon fire – on the structure and simulates the extent of the fire damage.
  • Results from this analysis, together with a structural vulnerability assessment and limiting cable properties, will reveal a specific set of requirements for the fire protection of the cables, including protected height, fire temperature and duration.

Design integration of the Fire Protection system

Following the risk assessment, VSL will then evaluate the specific requirements for the fire protection system. This is benchmarked against past qualification tests of other VSL Fire Protection projects, which will determine if requirements meet and/or exceed qualification standards.

The subsequent process is the design integration phase, where VSL’s stay cable specialists and fire engineers work together to adapt certain aspects of the Fire Protection system to the existing security measures on the structure.

Design integration is extremely important as other protection and security elements may be supplied by third parties or where the Fire Protection system is retrofitted to an existing structure. VSL works closely with other suppliers and project partners to ensure a seamless integration and cohesive protection for the stay cable system.

Qualification testing to ensure safety

Although mandated as a standard requirement for projects, qualification testing involves costs, which will ultimately impact bottom lines. The advantage of partnering with VSL is that our Fire Protection system has already undergone the required testing, so authorities, consultants and contractors can be assured of peace of mind.

We have conducted full-scale testing to some of the industry’s most demanding fire curves, different testing standards and international guidelines in line with the requirements of asset owners worldwide, including the US, Europe and Asia.

Fabrication stage of the Fire Protection system

Upon successful qualification testing, VSL commences the fabrication of the Fire Protection system.

Strict QA/QC measures are implemented during the fabrication process to ensure that the final product is fit for purpose. Full factory-based mock-ups of the installed Fire Protection system are included to check for fit and integration.

The final delivery of this stage results in Fire Protection blankets that are assigned unique product labels, which monitor movement through fabrication, logistics and finally implementation onto the stay cable system.

The manufactured fire protection system is in accordance with various ISO requirements including ISO9001:2008.

Ease of system maintenance

Fire Protection design and incorporation with the cable-stay system components allow for general maintenance and inspection procedures to be maintained. Specifically:

  • Our Fire Protection system is lightweight and can be moved together with the other elements of the outer cable envelope for inspection and maintenance interventions
  • Our system allows, together with the VSL Stay Cable System, strand-by-strand replacement and inspection
  • Components are modular for ease of replacement or removal, should this become necessary