“FLACS is widely recognised as one of the oil and gas industry’s leading computational fluid dynamic (CFD) explosion models,” said Hansen. “The technology, which is considered to be the standard in its field, forms a crucial part of a range of safety studies on assets, such as on offshore platforms and FPSOs. For the offshore oil and gas industry, a typical explosion study will be a probabilistic model in which hundreds of ventilation, dispersion and explosion calculations are performed.
“Using FLACS, consequence studies are also performed for refineries, petrochemical plants and other facilities where flammable gases may accumulate and be ignited. An important feature of CFD models like FLACS is that it can be used to evaluate the benefits of a number of mitigation methods (such as water deluge) or layout modifications on explosion risk.”
A lesser known strength of FLACS is its ability to model gas dispersion. For many years the technology has been used as a preferred CFD tool for helideck studies, exhaust studies, gas detection optimisation studies and flammable gas dispersion studies at offshore installations. In 2011, US Department of Transportation accepted FLACS as the first CFD tool to model liquefied natural gas (LNG) dispersions according to the NFPA-59A standard. The approval included a thorough validation and evaluation process. A transient pool model for LNG-spills makes it even more attractive to study advanced pool spill scenarios using FLACS.
“FLACS is also a powerful tool to study the release of toxic chemicals – such as ammonia and chlorine – and hazards from toxic vapours emitted by oil and gas industry operations,” Hansen added.
“In many situations, dense gases are vented from an elevated stack, such as CO2 in connection to carbon capture and storage or oil tank vapours containing H2S or benzene on FSOs or FPSOs. On calm days – and more frequently nights – dense vapours may fall to the ground, trigger gas alarms, and violate occupational safety exposure limits . FLACS users can evaluate the potential problem in such situations and propose how to mitigate or eliminate it.”
Despite implementing safety measures - incidents, near misses and sometimes accidents can happen. To maximize the learning from such events and prevent it from repeating, it is important to properly understand what happened. For many release, dispersion and/or explosion scenarios, the best way to properly understand these aspects is to simulate the event, to vary unknown input parameters, compare predictions with observations, and use FLACS to understand what went wrong. Such a study can estimate the potential severity if an incident had escalated, and identify how detection and mitigation systems can prevent similar incidents from escalating in the future.
GL Noble Denton’s expanding FLACS capability marks another step in the company’s continued investment in growing its safety and risk services to Norwegian clients. The company has also recently announced a new strategic partnership with Stavanger-based consultancy XAFE; a cooperation that will allow both businesses to meet a growing demand for risk analysis, technical safety, and HSE management services from companies operating in the North Sea.
If studies as described above could be of interest, please do not hesitate to contact us to discuss. Olav Roald Hansen’s telephone number is +47 91 17 1787 and his email is firstname.lastname@example.org.
A typical oil platform explosion study may consist of more dispersion simulations to predict cloud size distribution than explosion simulations to predict consequences