Jensen Hughes

Blacksburg, VA, United States

Jensen Hughes

Blacksburg, VA, United States
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Borggaard J.,Virginia Polytechnic Institute and State University | Lattimer A.,Jensen Hughes
Proceedings of the American Control Conference | Year: 2017

Reduced-order models based on the proper orthogonal decomposition are important tools in modeling and control of nonlinear distributed parameter systems. However, the global support of the reduced-basis functions and basis orthogonality provide challenges for applications such as combustion and fire models. This is due to the fact that all basis functions, except the first, have regions with different signs. Thus it can be challenging to simultaneously constrain coefficients to preserve positivity while ensuring an accurate representation of the full-order model. In this paper we introduce a logarithmic transformation that allows us to maintain both features though introduces its own issues. We consider a simplified Arrhenius reaction model to illustrate the transformation and the bases that are obtained. Imposing a conservation constraint is easy when the bases are coupled, but the logarithmic transformation forces us to decouple the models. This method is compared to a standard POD-Galerkin model, which predicts negative densities. © 2017 American Automatic Control Council (AACC).

Global Congress on Process Safety 2017 - Topical Conference at the 2017 AIChE Spring Meeting and 13th Global Congress on Process Safety | Year: 2017

Human reliability analysis (HRA) is defined as a structured approach used to identify potential human failure events (HFEs) and to systematically estimate the probability of those events using data, models, or expert judgment. HRA is most commonly performed as part of a larger quantitative risk assessment (QRA), but can also be performed as a part of incident investigation to evaluate the root causes for the incident and attempt to prevent their recurrence. There are several pieces to the risk assessment and risk management that allow facility operators to evaluate and measure what is actually occurring in their facilities, including the review of processes, procedures, and events to assess human reliability. This paper will discuss the process for evaluating human errors by obtaining process-specific information used for qualitative and quantitative HRA. Copyright © (2017) by AIChE.

Collins E.P.,Jensen Hughes | Amico P.J.,Jensen Hughes
Global Congress on Process Safety 2017 - Topical Conference at the 2017 AIChE Spring Meeting and 13th Global Congress on Process Safety | Year: 2017

Performance indicators have proven to be a key to successful performance-based management. They establish clear goals for objectively measuring achievement of program objectives without constraining the performer with prescriptive requirements. This paper documents an assessment of safety performance indicators as a tool for measuring the safety performance of process facilities. A number of candidate performance indicators covering the broad range of safety aspects of facility operation are identified, including a blend of both leading and lagging indicators.

Floyd J.,Jensen Hughes | McDermott R.,U.S. National Institute of Standards and Technology
Fire Safety Journal | Year: 2017

The evaporation of sprinkler droplets is an important phenomenon in fire simulations both for heat removal from the gas and for heat removal from surfaces. In this paper, we address the problems of potential numerical instability and super-saturation that may occur in explicit time integration of the droplet equations. Two novel numerical approaches are developed and evaluated. The first is based on an analytical solution that relaxes the cell composition and temperature toward the equilibrium values. The second method is an implicit solution to the droplet equations. The two approaches are implemented in the Fire Dynamics Simulator (FDS) and verified and validated using both single droplet and practical sprinkler calculations. Ultimately, the implicit approach is deemed the most cost effective for practical fire simulations. © 2017 Elsevier Ltd.

Hayner G.,Jensen Hughes
18th Process Plant Safety Symposium, PPSS 2016 - Topical Conference at the 2016 AIChE Spring Meeting and 12th Global Congress on Process Safety | Year: 2016

This paper will examine and discuss the challenges faced by the U.S. nuclear industry after 9/11 and the Fukushima accident, the process to determine the appropriate path to success, and the solutions themselves. It will show that the solutions were effective, useful, and cost-effective. It is possible the fuel and petrochemical industry may glean valuable lessons from the experience of the nuclear industry regarding security and risk mitigation. Copyright © 2016 Retained by Authors, April, UNPUBLISHED.

5th Process Safety Management Mentoring Forum 2016, PSM2 2016 - Topical Conference at the 2016 AIChE Spring Meeting and 12th Global Congress on Process Safety | Year: 2016

Investigations of recent proceb incidents have identified multiple proceb safety management deficiencies that led to the accident. Furthermore, audits of the Safety and Environmental Management System (SEMS) program under the U.S. Department of the Interior's Bureau of Safety and Environmental Enforcement (BSEE) have shown that the "management of risk" elements such as Hazards Analysis and Management of Change (MOC) are not consistently implemented as tools to manage risk. In addition, the requirement to perform hazards analysis is frequently documented and often referenced as a corrective action, rather than as a "system driver". There are several pieces to risk abebment and risk management that allow facility operators to evaluate and measure what is actually occurring in their facilities, including the review of historical event data to identify what went wrong and for near mibes, what almost happened. This paper describes techniques that have been used in the commercial nuclear power and other industries to collect and apply historical experience data to improve safety and operability. An approach using accident sequence precursor analysis of incident data and risk analysis techniques is recommended to identify potential accidents before they occur as part of a comprehensive treatment of historical data. Copyright © 2016 by AIChE.

Beitel J.J.,Jensen Hughes
ASTM Special Technical Publication | Year: 2016

This paper addresses the current code requirements for the use of exterior insulation and finish systems (EIFS) specified in the 2015 editions of the International Building Code and the International Residential Building Code. A description of the code sections of interest and the fire performance requirements embedded in those sections is provided. These code requirements and their referenced standards have become significant because they now form the basis for the appropriate use of EIFS. In particular, the fire performance of EIFS is addressed and the various fire tests for the components and the EIFS assemblies are described. This includes information concerning EIFS' fire performance in NFPA 285, Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-Load-Bearing Wall Assemblies Containing Combustible Components. This is the primary fire test to allow the use of EIFS on exterior walls of Types I, II, III, or IV construction. A brief history and description of the test method is provided as well as EIFS' fire performance in this test method. Additionally, the fire performance of EIFS in several actual fire events such as the Monte Carlo fire, the Palace Station fire, and the Luxor fire is discussed. These fires have vividly demonstrated the issues surrounding the use of decorative features applied to or incorporated onto EIFS wall assemblies. Information concerning the appropriate construction and materials for these decorative features is provided. EIFS are among the most extensively fire-tested exterior wall assemblies used in the United States. As such, lessons with respect to EIFS' construction, fire performance, applicability, and use have been developed and addressed. © Copyright 2016 by ASTM International.

Crowley M.A.,Jensen Hughes
Consulting-Specifying Engineer | Year: 2015

NFPA 99-2015 establishes criteria for levels of health care services or systems based on risk to patients, staff, or visitors in health care facilities to minimize the hazards of fire, explosion, and electricity. Here's what's in the current code and what engineers need to know once their authorities having jurisdiction enforce this version. © 2015, Reed Business Information (Cahners). All rights reserved.

Anoba R.,Jensen Hughes
International Topical Meeting on Probabilistic Safety Assessment and Analysis, PSA 2015 | Year: 2015

Probabilistic Risk Assessments (PRAs) are increasingly being used as a tool for addressing seismic hazards at nuclear power plants. The selection of structures, systems, and components (SSCs) for Seismic Probabilistic Risk Assessment (SPRA) is a critical element for determining the scope and the resources required to perform the analysis. A Seismic Margins Assessment (SMA) is another approach that can be used to address seismic hazards. The seismic margin methodology is designed to demonstrate sufficient margin over the safe shutdown earthquake (SSE) to ensure plant safety and to find any "weak links" that might limit the plant's capability to safely withstand a seismic event larger than the SSE. The selection of equipment for a SMA can be based on a set of shutdown equipment required to safely shut down the plant during a seismic event. The SMA methods used to select and screen SSCs for a SMA, are directly applicable to the development of a SPRA. Some of the insights derived from recent SMAs can be used to guide the development of future SPRAs. For example, the "rule-of-the-box" (ROB) principle is often used to group subcomponents with a primary component or a panel. A control room panel containing 50 subcomponents that would not usually have to be seismically evaluated individually. Based on the ROB principles, with the exception of essential relays, only the panel is seismically evaluated. However, in locations of high seismicity, the panel may not screen, and the subcomponents may have to be seismically evaluated. This, of course, results in an increase is scope of the SSC selection process and the SMA walkdowns. The purpose of this paper is to summarize current SMA SSC selection insights and to review the applicability of these insights to the development of the system models for a SPRA.

News Article | March 23, 2016

As the 2016 Laboratory Design Conference approaches, we will continue to make more exciting announcements about what you can expect at this annual gathering of those involved in planning, designing, engineering, constructing and operating laboratory facilities. For now, get to know the professionals who will be delivering the conference's feature presentations. Simon Goodhead, PE, is a code consultant/fire protection engineer and the director of Jensen Hughes’ Atlanta office. Simon oversees engineering operations and designs fire suppression, detection, and alarm systems. His project management responsibilities include reviewing architectural and engineering documentation for compliance with codes and standards, preparing comprehensive fire protection and life safety programs for new and existing buildings, and interfacing with local, state, and federal officials. Simon is one of the first to apply coupled analysis of egress models to fire models within the commercial consulting industry, which enables owners to see, for the first time, how fire and smoke could affect occupants within their buildings during a fire event. After earning his engineering degree in England, Simon worked as a fire protection engineer for four years before moving to Atlanta to work for Harrington Group, and subsequently Jensen Hughes. Simon, Fire Protection Engineer and Director at Jensen Hughes, will be speaking on the topic of “Complexities with Fire—New, Additions, and Adaptive Reuse.” Click here for the full conference agenda. Laboratory Design recently spoke to Simon about his background, professional experience and personal interests. Laboratory Design (LD): How did you first get into your field? Simon Goodhead (SG): When I was three, my Mum (British spelling) tells me I threw a piece of Duplo on the fire. This gassed the whole house and forced us to evacuate. Later, when I was 17, I interned with a Fire Investigator and that sealed the deal—I was going into Fire Safety. Following college, I worked with a couple of consulting engineering firms as a Code Consultant and have been in the built environment ever since. The most recent seven years at Jensen Hughes have been the most interesting. I have developed fire protection approaches for BSL3 and 4 labs, flammable and explosive materials, and toxic materials—all difficult topics that have unique solutions tailored for the specific use. The codes do a good job at getting a baseline, but tailoring a solution will always result in a better, more rounded design. LD: Do you speak at other conferences or trade shows? What are you most often asked to speak about? SG: I do—the most recent was a regional conference and the topic was parking structure fires. In May I will be in Warsaw, Poland speaking about benchmarking comparative Performance Based Designs (a way to design fire safety in buildings with lower construction costs or better aesthetics). Houston will be a blast—especially if barbecue is involved. LD: What was your favorite college class? Was it related to your current career? SG: I really enjoyed Management Strategy as part of my Graduate Degree. Taking complex problems and developing solutions is an integral part of my work, so applying those skills to a business setting was great fun. LD: What do you like to do in your spare time? SG: All of my spare time is spent balancing playing princesses with our 3 year-old and feeding our 6 month-old twins. BT (“Before Twins”) I enjoyed driving, particularly mountain roads in North Georgia. The twins meant the fun car was exchanged for an SUV to fit three car seats … one day I’ll get back to the mountains, but I’m enjoying zonal marking at the moment. LD: Have you ever been to Houston? Do you plan to explore the city in your spare time? SG: I have. Oddly it was for a project that needed a balance between U.K. codes and U.S. codes—as the former British guy I got pulled in. Fortunately, I was rewarded with a tour of the historic area of downtown, barbecue at Goode Company and pecan pie. I had a terrific time and look forward to doing it again!

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