Determining the potential consequences posed by facility operations is a necessary step in the process of developing a comprehensive safety plan. Facility siting studies are recommended or required by most regulatory bodies to analyze impacts from events resulting in explosion, fire, or toxic impacts to onsite and/or offsite personnel. Our professionals work in partnership with your team to analyze hazards and risks while taking into account your facility’s siting guidance protocols and project goals. Depending on your needs, BakerRisk can perform either detailed consequence-based or risk-based facility siting.
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Experience
A BakerRisk facility siting study helps you comply with regulations, as well as leverages our unique knowledge and skills to develop your facility’s overall safety plan. We can recommend upgrades for buildings, windows, and doors for hazard mitigation and perform building leak tightness testing to ensure your workers are protected from the hazards involved with your specific processes.
Leveraging our years of industry experience with extensive research and development programs, as well as our uniquely designed software tools such as SafeSite3G©, we can provide comprehensive solutions to address your facility siting concerns. BakerRisk is at the forefront of setting and maintaining facility siting study best practices.
Our professionals are well-versed in applicable recommended practice documents from around the world. We actively participate in several American Petroleum Institute (API) and National Fire Protection Association (NFPA) committees and are part of the committees that developed and updated API Recommended Practice (RP) 752, API RP 753, and API RP 756. BakerRisk also performed the full-scale testing program to help develop requirements for the placement of process plant tent structures under API RP 756, and is actively involved in other relevant NFPA committees, including NFPA 59A, NFPA 30, NFPA 68/69, NFPA 654, etc.
Process
BakerRisk facility siting studies are designed to collect extensive data and provide maximum value for you. Our methodology is grounded in robust research and development, which includes internally funded research as well as research funded by several Joint Industry Programs (JIPs), such as the Explosion Research Cooperative (ERC). We have also investigated thousands of notable industry fire, explosion, toxic, and structural collapse events worldwide. Lessons learned from investigating such incidents help us continue to improve and update our methodology and proprietary technology and provide you with practical information and recommendations necessary to protect your facility, personnel, and the public.
Our experts understand the importance of defining Maximum Credible Event (MCE) scenarios for a consequence-based approach to ensure that the consequences are not understated and your personnel are properly protected. BakerRisk’s industry-leading consequence analysis software SafeSite3G© goes beyond just determining the hazard endpoints to determine building response and indoor/outdoor occupant vulnerability. With the use of SafeSite3G©, BakerRisk professionals are able to evaluate hundreds of thousands of potential scenario outcomes in a typical study to produce results with the granularity to feed a quantitative risk assessment (QRA) and/or aid your decision-making process for risk mitigation.
BakerRisk documents each facility siting study in a comprehensive report that defines inputs, explains calculation methods, provides interim calculation results to allow verification and validation of the methods employed, and summarizes results in a range of meaningful forms. Composite contour plots of overpressure, flammability, thermal radiation, and toxicity define key endpoints and provide an overview of areas vulnerable to impacts from assessed hazards.
We compile facility siting study results in an extensive spreadsheet showing the maximum impact for each hazard scenario and each building assessed. In addition, results are presented in summary tables for easy tabulation of results. Consequence impacts to each building assessed are presented in terms of building damage level (BDL), flammable gas concentration categories, and fire/toxic occupant vulnerabilities.
BakerRisk’s proprietary software, SafeSite3G© enables us to evaluate the impact of changes to the facility – as well as potential mitigation measures – easily and efficiently. Combined with our unique knowledge and expertise, forged from years of industry experience and extensive research and development, BakerRisk assists clients with providing and evaluating practical, feasible, and proven solutions to address facility siting concerns.
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Discover the changes in Facility Siting Standards and the significance of API: 752, 753, & 756. Stay ahead and ensure operational safety in your organization.
Hydrogen is a key energy carrier for modern society. The breaking of the hydrogen bonds within traditional hydrocarbon molecules has been the primary mode of energy utilization since the industrial revolution. An increased focus on “net-zero” greenhouse gas emissions, specifically carbon dioxide and methane, has resulted in a global push for lower carbon energy vectors, including pure hydrogen. Accurately modeling the dispersion, fire and explosion hazards associated with new and existing hydrogen production, distribution and transportation networks, and consumption is a key component to the safe expansion of these networks.
Make the most of your next facility siting study with 6 smart practices to produce valuable, practical information.
This BakerRisk Best Practice document provides general guidance for performing an FSS to ensure that the consequences or risks to people posed by facility operations are thoroughly, accurately, and defensibly quantified and allow consequences or risks to be minimized to the extent practical.
Our team will be presenting several topics at the Texas/Louisiana EHS Seminar, June 9, 2022.
The results of a recently completed facility siting study (FSS) are sitting on your desk – now, what do you do with the information?
The purpose of this paper is to provide a case study that compares the results from a consequence-based facility siting study (FSS) limited to a specified release size as the maximum credible event (MCE) versus a risk-based study with a range of release sizes and associated frequencies. The results are intended to highlight potential differences in the building siting decisions made using a consequence-based approach with a limited MCE versus those made with a risk-based approach.
Our team is pleased to exhibit at this conference that provides such a valuable opportunity to advance process safety practices on a global scale.
Has facility siting identified a need for a hazard resistant building to mitigate your facility risk? Work with BakerRisk to identify whether a building upgrade, a new build, Rigid Pre-Engineered Metal Building, or a FORTRESS Protective Building LLC is the right solution for you.
Within the lifecycle of a capital project, it is common to conduct process safety reviews once the design and site layout have reached a mature state. This often leads to project team frustrations because at this advanced stage of design, mitigating hazards and risks is either difficult or costly due to the high level of rework associated with moving hazards/ populations to safer locations, layers of protections to be added to design systems, and ensuring the buildings are robust enough to protect personnel from identified hazards. One way to mitigate the frustrations associated with late stage changes is to introduce and effectively manage stage gate process safety reviews throughout the design phases. Note that it is critical that the stage gate process safety reviews align with the overall project schedule, so they can provide timely results and any recommendations can flow into the design process prior to progressing to the next stage.
One could be forgiven for being confused over what is meant by “facility siting.” The term was originally used to refer to the process by which a company decided where to locate a new operation (the city, state, etc.) and the evaluation was largely focused on the availability of workers, utilities, and other infrastructure in the area. There have been two editions of the AIChE/CCPS book “Guidelines for Facility Siting and Layout”1 (renamed for the second edition) that discuss site selection and arrangement of equipment and buildings within the site. In addition to industry available guidance documents, many companies have also established internal guidance documents for facility siting to ensure assets are reviewed in a consistent manner.
Facilities that handle hazardous materials above threshold quantities are required to assess the impacts due to postulated accidents involving releases of these materials, and to ensure that people are adequately protected from the associated fire, explosion, and toxic hazards. An analysis of these hazards can be based solely on consequences from maximum credible events or can incorporate the likelihood of the events to characterize results in terms of risk. The methods of performing these analyses may vary, but, regardless of the specific techniques used, fundamental principles of thoroughness and defensibility should be achieved. This paper describes best practices and basic requirements for consequence-based and risk-based facility siting studies (FSSs), also commonly referred to as quantitative risk analyses (QRAs), consistent with industry guidance. The fundamental objective of a consequence-based or risk-based FSS is to ensure that the consequences or risks posed by facility operations are minimized to the extent practical.
Facility siting methods to optimize the layout of industrial facilities for risk reduction have been evolving for decades from subjective views, standards, and guidelines to quantitative numerical analysis. The authors of this paper have tossed out the past, moved beyond the present, and taken out their crystal balls to provide a discussion around the future of facility siting by focusing on technology driven enhancements associated with three main themes: mainstreaming of current advanced analysis techniques into the base case methodology, incorporating company and/or site specific data trending and analytics to operationalize the studies, and the potential transformational change to machine learning-based predictive risk management. With technological advancements touching nearly every area of business, it is no surprise that it is also changing the landscape of consequence and risk-based facility siting approaches. As with all markets, the customers will be a key driver for the advancements of technical safety studies to suit their adapting needs. However, as this article will show, personnel conducting facility siting studies are also using technological advancements to challenge the status quo by improving data fidelity, increasing the robustness and depth of analysis, and providing improved insights to aid decision making.
Facility siting mitigation decisions should be made in a logical and defensible manner. This article provides a framework for making and justifying facility siting mitigation decisions beginning with presenting risk results in a clear manner prior to identifying practical risk mitigation strategies, highlighting potential source and location risk mitigation strategies, demonstrating how these strategies can be evaluated with examples, and ultimately to quantifying and optimizing the safety-benefit of each mitigation strategy / combination of strategies. The outcome of this process provides a defensible basis for prioritization and practicality of risk mitigation strategies, or a combination of strategies that reduce facility risk to broadly acceptable levels or as low as reasonably practicable while minimizing expense.
As organizations continue to adapt to challenges, we have noticed a trend in HSE and Operations professionals leveraging facility siting studies to support safety measures for their facilities.
Blast resistant modules (BRMs) have become prevalent at petroleum refining and chemical processing facilities over the last decade. A primary rationale for utilizing a BRM is to allow a building housing essential personnel (e.g., operators) to be sited near the process units for which they are responsible. BRMs are selected based on a pressure-rating and response level (typically Low, Medium, or High). A common misconception is that a BRM will be undamaged and reusable for a specified blast overpressure rating, and such buildings are often incorrectly referred to as “blast-proof”. In order to absorb blast energy, the walls and roof of a BRM are designed to undergo transient accelerations and displacements. The allowable displacements are dictated by the selected response level, and that stated response level does not directly communicate the hazard associated with wall deflection and non-structural debris.
This paper focuses on the consideration of an unbiased approach to assessing risk to push the industry towards proactively addressing risk rather than reactively allowing cognitive biases to drive process safety culture and personnel risk management solutions. Scientifically proven to affect the way we process and interpret the world around us, cognitive biases allow us to shortcut the complexities of the world when making decisions. In some cases, biases can be surprisingly accurate, while in other instances they can lead to making poor judgements and decisions based on the limited information available to us. Specifically damaging in the process safety industry are the availability heuristic and the confirmation bias, which together cause us to focus on information that comes to mind quickly, justifies our opinions, and favors our existing beliefs.
There are a variety of building design approaches that can be considered and employed to mitigate risks to building occupants. Although the preferred and safest approach is to design buildings for worst-case explosion, fire, and toxic events after completion of a consequence study, this can often be infeasible or cost-prohibitive. An alternative building design approach considers the frequency of each scenario and can be achieved through the use of frequency-consequence exceedance curves to determine a design accidental load (DAL) or by use of risk calculations from a Quantitative Risk Analysis (QRA). Using example case studies, the benefits and shortcomings of developing a building design basis employing frequency-consequence exceedance curves versus using a risk-based approach will be examined. Although a risk-based approach may require more complex modelling, additional effort and time compared to determining a DAL, it is important to consider each load (blast, fire, toxic) and the duration of each load to assess the vulnerability to occupants and fully quantify the effectiveness of a building design.
The design and construction of a new building is often a significant investment for capital projects. As a result, there are typically many competing design considerations, such as: land use, interconnectivity, access for operations personnel, building codes, personnel safety, cost, etc. To minimize the number of costly design iterations, it is vital that overall project goals for the building be firmly established, communicated, and implemented effectively. Unfortunately, many projects suffer from a misstep in one or more of these areas.
Ammonia and hydrogen represent opposite ends of the spectrum with regard to the potential blast loading resulting from an accidental vapor cloud explosion (VCE), although many in industry have expressed doubts as to whether either of these fuels actually pose a VCE hazard. Ammonia is some-times discounted as a VCE hazard due to the perceived difficulty in igniting an ammonia-air mixture and/or because of its low laminar burning velocity. Hydrogen is sometimes discounted as a VCE hazard due to the ease with which a hydrogen-air mixture can be ignited and/or because of its buoy-ancy. This paper presents results from ammonia and hydrogen unconfined VCE tests.
BakerRisk Facility Siting article published in the Journal of Loss Prevention in the Process Industries
Blast walls are frequently considered as a potential mitigation option to reduce the applied blast loading on a building or structure in cases where unacceptably high levels of blast damage are predicted. There are three general explosion types of interest with respect to blast loading: High Explosive (HE), Pressure Vessel Burst (PVB), and Vapor Cloud Explosion (VCE). The blast waves resulting from these explosion types can differ significantly in terms of blast wave shape and duration. The effectiveness of a blast wall depends on these blast wave parameters (shape and duration), as well as the blast wall parameters (e.g., height, width and standoff distance from the protected structure). The effectiveness of a blast wall in terms of mitigating the blast loading on a protected structure depends on the combination of the blast wave and blast wall parameters. However, little guidance is available on the effectiveness of blast walls as a mitigation option for non-HE explosion sources. The purpose of this paper is to characterize the effect of blast wave parameters on the effectiveness of a blast wall and to provide guidance on how to determine whether a blast wall is an effective and practical blast damage mitigation option for a given blast loading.
A common complaint when undertaking capital projects is the cost of engineered designs that must be added late in the project in order to mitigate hazards or risks. Due to the typical phasing of these project activities, the facility siting study (FSS) or other consequence or risk modeling is not completed until the layout of the facility has been established. However, when a site layout is already in a mature state, it can be extremely difficult to move hazards or populations to safer locations due to the substantial amount of rework that would be required. With mitigation through relocation thus limited or even unavailable, increasing the safety systems within the unit or adding layers of protection at the buildings of interest becomes the only option. Costs could be reduced and designs made safer if FSS or similar studies could be conducted earlier in the design process.
The first edition of American Petroleum Institute (API) Recommend Practice (RP) 753 - Management of Hazards Associated with Location of Process Plant Portable Buildings was released in 2007. Since that time, blast resistant modules (BRMs) have become a popular option for facility owners wanting to site portable buildings, but other options may also satisfy the API RP 753 requirements. This paper provides a systematic discussion of an example portable building siting analysis for blast loading using the requirements of API RP 753, including the detailed analysis requirements for siting a portable building within the API RP 753 Zone 2 boundary. In addition, this paper discusses a potential range of portable building options available to owner/operators seeking to comply with API RP 753, such as heavily-framed (e.g., 2”×6” or 2”×8”) wood trailers, retrofitted ISO shipping containers, and commercial BRMs. The paper also presents a brief discussion of the internal debris hazard associated with the blast response of two different portable buildings as observed during full-scale testing conducted with the BakerRisk® Deflagration Load Generator.
An open question with regards to facility siting studies, consequence analyses, and risk assessments for release scenarios involving very low laminar burning velocity (LBV) fuels (i.e., significantly lower than methane’s LBV) has been whether such releases pose an unconfined vapor cloud explosion (VCE) hazard. There are no reports of an accidental unconfined VCE with such fuels, and applicable VCE test data has not been published. One approach taken within industry has been to use methane as a reference for such fuels. This is clearly a conservative approach, as the flame speeds achieved with very low LBV fuels would be expected to be much lower than those achieved with methane in a VCE under the same conditions. An alternative approach taken by some has been to discount the potential for a VCE with very low LBV fuels.
The chemical process industry utilises many types of complex process facilities to generate a wealth of value added products. Management are faced with many different decisions ranging from the complicated, multifaceted corporate level decisions to the day-to-day facility operations decisions.
Portable buildings are gaining widespread use at refining and chemical processing facilities, particularly for facility siting requirements. Although trailers and blast resistant modules (BRMs) can be used for many modular applications, in certain situations fabric structures may provide a viable alternative. However, the blast response of fabric structures is neither clearly defined nor well understood throughout the blast design community.
Explosions in buildings produce large amounts of rapidly moving wall debris, particularly from the relatively lightweight, weak construction used for interior partition walls (typically wood stud or metal stud with gypsum sheathing). This debris has the potential to generate blunt trauma injuries to occupants impacted by pieces of studs or gypsum.
Facility Siting has received considerable attention in recent years. There are a number of generally accepted simplified methods for the prediction of vapor cloud explosion (VCE) blast loads, one of which is the TNO Multi-Energy Model (MEM). TNO has provided guidance for the application of the MEM based partially on the RIGOS, GAME and GAMES programs. However, the guidance involves physical parameters which can be hard to estimate, and to which the blast load predictions are fairly sensitive. The consistency with which different analysts can estimate these parameters is therefore a significant issue. This paper presents an approach to improve the consistency in TNO MEM blast load predictions by improving the consistency with which several key parameters are estimated.
Alkylation is a process that combines low value refinery by-product olefins with isobutane to form alkylate — a clean burning, low volatility gasoline blendstock used to increase gasoline octane rating. With changing fuel regulations and the global phase-out of leaded gasoline, alkylate continues to play an ever increasing role in gasoline formulations. Both hydrofluoric (HF) and sulfuric acids, which are used as catalysts in the alkylation process, are highly corrosive and hazardous if an accidental release occurs. Due to the lower boiling point of HF and its higher propensity to aerosolize into small droplets, releases of HF acid from HF Alkylation units are expected to pose a safety hazard at distances much greater than would be expected for comparable sulfuric acid units. As a result of industry and government sponsored research illustrating the impact potential from an HF release, there is a general perception that HF Alkylation units are high risk and sulfuric acid units are low risk. The author has conducted numerous Quantitative Risk Assessment studies of HF alkylation units along with potential risk reduction options that include passive systems, active systems, and inherently safer options. These studies have demonstrated that HF alkylation is not necessarily “high risk.” Furthermore, HF Alkylation units with effective risk mitigation strategies are compared with a comparably sized sulfuric alkylation unit for illustrative purposes. The lessons learned not only help address risks associated with HF alkylation units, but also can be applied to other highly hazardous processes.
The Center for Chemical Process Safety (CCPS) of the American Institute of Chemical Engineers has completed a project to update the book, “Guidelines for Evaluating Process Plant Buildings for External Fires, Explosions, and Toxic Releases.” The first edition of the guidelines book was published in 1996, based on the existing edition of API RP 752 at that time. This new second edition of the Guidelines book brings it in line with state of the art by addressing the newest version of API RP 752 [1], addressing portable buildings under API RP 753 [2], adding sections on toxic releases, and including recent technology and management system developments. Major changes to API RP 752 include the elimination of occupancy screening, requirements for more extensive documentation, and the requirement to address a Maximum Credible Event (MCE). The second edition of the book provides an up-to-date comprehensive and valuable resource to process safety professionals needing an understanding of how to evaluate and address building siting situations. A summary of the project objectives, status, and changes to API RP 752 that are addressed in the second edition of the book are presented here.
The Explosion Research Cooperative (ERC), a joint industry research program, was started by Baker Engineering and Risk Consultants, Inc. (BakerRisk) in 1993 and is now completing its thirteenth year. The ERC is funded by chemical, petrochemical, refining, and insurance companies interested in understanding and predicting explosion hazards and their consequences on buildings, process equipment and people, as well as preventing or mitigating explosions. Since January 2006, the ERC has been conducting a study on the blast capacity of portable buildings at refineries and chemical plants. The work summarized in this paper was performed by Baker Engineering and Risk Consultants, Inc. (BakerRisk). The work presented should not be considered an official guidance document or standard of the ERC or its member companies.
The choice of an optimum location for placing new structures in petroleum refining and chemical processing plants is subject to a host of considerations, of which the structure’s blast resistance is one of the most significant. The decision centers on defining an affordable structure that maximizes occupant safety. This paper discusses the considerations and alternative methods of assessing blast and structural response siting issues by using an example building. The assessment involves systematically defining potential blast loads, the construction details necessary to withstand those loads, and identifying locations that make the most of an existing facility.
The Baker–Strehlow–Tang vapor cloud explosion (VCE) blast load prediction methodology uses flame speed as a measure of explosion severity. In previous publications, guidance has been presented for selecting flame speeds as a function of congestion, confinement, and fuel reactivity. These recommended values were based on empirical data available from the literature. Over the last 5 years, a series of medium-scale VCE tests have been conducted through a joint industry program to better understand vapor cloud explosions and to allow a more accurate definition of the flame speed applicable to a given combination of congestion, confinement, and fuel reactivity. These tests have demonstrated that the previously published flame speeds are not conservative for all configurations for the case of no confinement (3-D flame expansion). This paper provides an overview of the tests along with an update to the flame speed table where the previously published guidance was not conservative.
Inherently safer design concepts can be applied to plant layout and facility siting. Passive and inherently safer plant layout design practices can lessen the adverse effects of accidental releases of toxic and flammable materials and runaway reactions, as well as minimize knock-on effects. The consequences of explosion, fire and toxic release hazards to building occupants can be reduced through building siting and design. Certain locations around process units are inherently safer than others. Likewise, certain types of construction and design practices make some buildings inherently safer than others. This paper will discuss appropriate inherently safer practices and illustrate with examples.
Past accidents have demonstrated that vapor cloud explosions (VCEs) are the most severe threat to refining and petrochemical industries. In order to estimate the air blast parameters at any given distance from a possible explosion source, a variety of prediction methods have been developed. A brief description of these of prediction methods will first be presented. Then, the focus of this paper will be on an engineering method based on blast curves, which is the most frequently used prediction method.
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