Third party certification
and liquefied to produce liquefied natural gas (LNG). The new challenge here is that the performance of a fire safety product is not just determined by the product performance in the fire testing and approval processes. The reason for the physical behaviour is
that, as the temperature decreases, the ability of commonly used steel (low carbon) to exhibit plasticity is reduced. Therefore, in accidental cases, the steel will crack instead of plastically deform, which is the commonly expected behaviour in ambient and high temperatures. Considerably less energy is dissipated during cracking – in this case known as ‘cleavage’ – as compared with the plastic deformation. As a result, the cracks can grow very fast and can lead to collapse. This phenomenon is what makes the protection of low carbon steel to low temperatures a requirement, and the material used to achieve this is commonly referred to as ‘cold spill protection’ (CSP).
Passive protection
On the other side of the exposure are the protection materials used for hydrocarbon fires. They are known as passive fire protection (PFP) and are composed of numerous polymer chains, which obtain the characteristics of glass at sufficiently low temperatures, including its hardness and brittleness. In the event of a leakage of the cryogenic LNG, the fire protection can be damaged as cracks can
easily form and propagate. The resultant fractures will weaken the fire protection system before the ignition of the natural gas has occurred, and subsequently reduce the fire resistance performance. With this in mind, methodologies such as ISO 20088 need to be used to simulate thermal stresses and the deterioration damage that can occur in a real leakage scenario to obtain the cryogenic performance of the product. Ideally, the two systems, CSP and PFP, are combined or applied together to provide protection to cryogenic leakage followed by fire.
Installation quality
The performance of the protection system is also largely determined by the quality of the installation process. It is vital that the installation strictly complies with the manufacturer’s instructions and has been tested and approved. For example, in LNG facilities, the main structure or pipes can be subject to significant thermal expansion or contraction during operation or accidental leakage, which can lead to significant thermal stress and failure if the installation of the protection system deviates from the designed specification. Given the complexity of the installation
of most fire safety products, installation by competent contractors is essential, particularly in order to maintain the product’s integrity and warranty. It is recommended that a specialist
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www.frmjournal.com MARCH 2018
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