LR issues guidance note on cryogenic spill analysis
Lloyd’s Register said it has launched guidance note providing a methodology to establish risk-based cryogenic exposure based on a probabilistic approach.
Accidental release of cryogenic liquids such as LNG poses a significant risk to personnel and assets on oil & gas installations, LR said in a statement.
The new guidance note is applicable to any unit where hydrocarbon and refrigerant cryogenic hazards are relevant but offers special guidelines on how to handle leak scenarios specific to LNG plants.
Joar Dalheim, Vice President Technology in Lloyd’s Register’s consulting team said, “Given the large quantities of cryogenic materials present on a floating LNG facility, there is a serious risk of extensive damage in the event of cryogenic failure of critical components. As the estimation methods currently available are granular, we see a need for a more inclusive approach.”
The guidance note describes two different methods for cryogenic risk quantification: the Initial Cryogenic Risk Analysis (ICRA) and the Advanced Cryogenic Risk Analysis (ACRA).
The ICRA method relies on 2D models to estimate cryogenic liquid and vapour hazard zones. While this is the most common approach, it offers certain limitations as it cannot incorporate platform specifics, such as equipment, walls, deck and other structures, and thus necessitates strong conservative assumptions. The ICRA is therefore mainly suitable for cryogenic risk quantification at the early design stages.
The more advanced ACRA risk method is based on 3D Computational Fluid Dynamics (CFD) models and has been developed to incorporate detailed facility specifics (e.g. confinement and congestion) in the risk assessments. LR said.
“Integrating 3D analytical tools in the cryogenic risk analysis removes many of the uncertainties and limitations involved when relying on 2D analyses alone. This increases the accuracy of the hazard predictions and eliminates the need for arbitrary assumptions,” ascertains Dalheim.
Image: Lloyd’s Register