Large-Scale Explosion Consequence Modeling West, Texas Fertilizer Plant Case Study

Modeling Software for EH&S Professionals
Large-Scale Explosion Consequence Modeling:
West, Texas Fertilizer Plant Case Study
Prepared By:
Brian Holland – Senior Scientific Specialist/Meteorologist
Stephen Koch – Senior Software Developer
Qiguo Jing, PhD – Senior Software Developer/Consultant
Weiping Dai, PhD, PE, CM - Director of BREEZE Software and China Operations
BREEZE SOFTWARE
12700 Park Central
Drive, Suite 2100
Dallas, TX 75251
+1 (972) 661-8881
breeze-software.com
October 28, 2014

Trinity Consultants | LARGE-SCALE EXPLOSION CONSEQUENCE MODELING 1
Abstract
The West, Texas Fertilizer Company plant explosion on April 17, 2013 has highlighted the
number of similar facilities whose potential hazards had been previously overlooked in part due
to limited government and small-industry resources. This paper presents a preliminary case
study of the event using BREEZE ExDAM (Explosion Damage/Injury Assessment Model), and
examines the utility of such a model for quantifying these overlooked hazards.
BREEZE ExDAM is a software tool designed to perform explosion consequence modeling
(ECM) using a phenomenological approach which is computationally more sophisticated than
simple blast radius methods and computationally less sophisticated than physical modeling
methods (e.g. CFD). Damage/injury levels of different structure/people types are derived from
structure material properties and peak incident pressures/impulses adjusted for shielding effects
using a dipole flow-field algorithm. Such a tool might provide cost-sensitive local governments
and smaller industrial facilities with a comparatively simple but meaningful tool for assessing the
risks posed by a West-style incident.
The methodology used in this case study, to quantify peak incident pressures and subsequent
damage/injury levels while accounting for different structural materials and shielding effects, is
discussed. Predicted damage/injury patterns are compared to publicly-available information.
The particular strengths and weaknesses of the ExDAM model are discussed and compared to
CFD models.
Introduction
On April 22, 2014, more than one year after the April 17, 2013 West Fertilizer Company plant
explosion in West, Texas, the Chemical Safety Board (CSB) presented its “preliminary findings”
[1, 2] which included the following observations (bold emphasis ours):
1. “14 fatalities, 226 injuries, and widespread community damage.”
2. “We found 1,351 facilities across the country that store ammonium nitrate
[AN]. Farm communities are just starting to collect data on how close homes or schools
are to AN storage, but there can be little doubt that West is not alone and that other
communities should act to determine what hazards might exist in proximity.”
3. “The investigation notes other AN explosions have occurred, causing widespread
devastation. A 2001 explosion in France caused 31 fatalities, 2500 injuries and
widespread community damage. In the United States, a 1994 incident caused 4 fatalities
and eighteen injuries. More recently a July 2009 AN fire in Bryan, Texas, led to an
evacuation of tens of thousands of residents. Fortunately no explosion occurred in the
Bryan, Texas, incident which highlights the unpredictable nature of AN.”
4. “The CSB’s investigation determined that lessons learned during emergency responses to
AN incidents – in which firefighters perished -- have not been effectively disseminated
to firefighters and emergency responders in other communities where AN is stored and
utilized.”

5. “The CSB has found that on April 17, 2013, West volunteer firefighters were not
aware of the explosion hazard from the AN stored at West Fertilizer”.
6. “At the county level, McLennan County’s local emergency planning committee did not
have an emergency response plan for West Fertilizer as it might have done under the
federal Emergency Planning and Community Right to Know Act. The community
clearly was not aware of the potential hazard at West Fertilizer.”
7. “The Chairperson called on states and counties across the country to take action in
identifying hazards and requiring the safe storage and handling of ammonium nitrate.”
In its earlier June 27, 2013 “Written Senate Testimony” [3] the CSB made additional
observations (bold emphasis ours):
1. “The ammonium nitrate, a granular solid, was stored in the facility’s fertilizer warehouse
building in wood-framed bins with wooden walls. Both the warehouse building and the
bins were constructed of combustible wooden material, and the building also
contained significant quantities of combustible materials such as seeds stored near the
bins of ammonium nitrate.”
2. “Over time, many residences, a nursing home, an apartment complex, a high school,
and an intermediate school were constructed within a 2000-foot radius of West
Fertilizer.”
3. “Although the firefighters were aware of the hazard from the tanks of anhydrous
ammonia as a result of previous releases, they were not informed of the explosion
hazard from the approximately 60 tons of fertilizer grade ammonium nitrate inside
the warehouse.”
4. “Residents of the West Rest Haven nursing home were severely affected, and according
to nursing home officials 14 patients have passed away since the April 17 explosion,
dying at twice the expected rate. The nursing home itself was destroyed, as was the
apartment complex across the street. Two large schools – the high school and the
intermediate school – were structurally damaged beyond repair and will be torn down,
and a third school was also badly damaged. Because of the hour of day, all the schools
were unoccupied. Had the explosion taken place during the day, severe casualties
could have occurred in the intermediate school, which was devastated by both blast
and fire. Post-explosion damage assessments indicate that it would have been difficult for
children and others to escape from the building. The CSB is currently evaluating the
vulnerability of this structure, to understand the potential consequences if the
explosion had occurred when children were present and to inform future siting
decisions.”
5. “Nearly 200 homes were severely damaged or destroyed, a sizeable fraction of all the
houses in West. Financial damage is still being assessed, but the cost to rebuild the
schools alone will reportedly approach $100 million. Some reports suggest total
damages to the town may exceed $230 million, an unimaginable blow to a town of just
2800 residents – more than $80,000 for each man, woman, and child living in West.”

6. “Ammonium nitrate has historically been involved in some of the most severe chemical
accidents of the past century, including disastrous explosions in the United States,
Germany, and France. Two of these accidents – in Oppau, Germany, in 1921 and in
Texas City, Texas, in 1947 – each killed 500 or more people.”
7. “In September 2001, for example, a large AN explosion occurred at a factory in
Toulouse, France, killing 30, injuring thousands of others, and damaging up to
30,000 buildings.”
8. “The explosion at West Fertilizer resulted from an intense fire in a wooden warehouse
building that led to the detonation of approximately 30 tons of AN stored inside in
wooden bins.”
9. “Although some U.S. distributors have constructed fire-resistant concrete structures for
storing AN, fertilizer industry officials have reported to the CSB that wooden buildings
are still the norm for the distribution of AN fertilizer across the U.S.”
10. “No federal, state, or local standards have been identified that restrict the siting of
ammonium nitrate storage facilities in the vicinity of homes, schools, businesses, and
health care facilities. In West, Texas, there were hundreds of such buildings within a
mile radius, which were exposed to serious or life-threatening hazards when the
explosion occurred on April 17.”
11. “West reported the presence of up to 270 tons of ammonium nitrate, as well as
anhydrous ammonia, at the site. The company did not provide the LEPC or the West
Fire Department with an ammonium nitrate MSDS indicating the material’s
hazards, nor does EPCRA automatically require that information to be provided.”
12. “Combustible wooden buildings and storage bins are permitted for storing AN
across the U.S. – exposing AN to the threat of fire. Sprinklers are generally not required
unless very large quantities of AN are being stored or fire authorities order sprinklers to
be installed. Federal, state, and local rules do not prohibit the siting of AN storage
near homes and other vulnerable facilities such as schools and hospitals.”
On August 1, 2013, in response to these and many other issues, President Obama issued
Executive Order (EO) 13650 - Improving Chemical Facility Safety and Security [4].
Subsequently, in May 2014, the EO-established Chemical Facility Safety and Security Working
Group, tri-chaired by the EPA, DOL, and DHS, released its first “Report to the President” [5]
stating in their initial “Message from the Working Group Tri-Chairs” (bold emphasis ours):
“The Working Group, its member agencies [EPA, DOL, DHS, DOJ, DOA, DOT], and
the broader community of stakeholders have practices, operations, protocols, and policies
that address chemical facility safety and security but all recognize that improvement is
necessary and requires a shared commitment from all stakeholders. Emergency
responders, in particular, have needs to be addressed and capabilities to be
strengthened so that they can better manage threats and hazards in their
communities.”
Considering the ‘current events’ presented above, there is a fundamental need, directly within the
emergency responder community and their local supporting agencies, to not only ‘identify’ but to

quickly and accurately ‘quantify’ the life and economic consequences of potential explosions.
There are numerous software tools available for predicting human injury and structural damage.
However, most of these tools require prohibitively extensive human expertise, computing
resources, and project development/processing time.
This paper first briefly describes the ExDAM/HExDAM (High Explosive Damage/Injury
Assessment Model), a comparatively simple less-resource-intensive method for explosion
consequence modeling, and then demonstrates how the model can be used to quickly and
accurately replicate, analyze and predict the consequences of the West, Texas event.
Most generally, the objectives of this paper are two-fold:
1. Propose and demonstrate an alternative approach for addressing some of the CSB’s
suggestions regarding the West, Texas event (highlighted above):
a. Provide tools to “take action in identifying hazards”.
b. Quantify, analyze, prepare for, and mitigate potential consequences: “fatalities”,
“injuries”, and “widespread community [financial] damage” (e.g. “1,351 facilities
across the country that store ammonium nitrate”, some or most with “wooden
buildings” and some or most “in the vicinity of homes, schools, businesses, and
health care facilities”).
c. Help “firefighters [be] aware of the explosion hazard”.
d. Provide tools to “effectively disseminate [lessons learned] to firefighters and
emergency responders in other communities where AN is stored and utilized”.
e. Help “the community [be] aware of the potential hazard” and the “local
emergency planning committee [prepare] an emergency response plan”.
f. Determine whether “severe casualties could have occurred in the intermediate
school” “had the explosion taken place during the day”.
g. Provide tools for “evaluating the vulnerability of [the intermediate school], to
understand the potential consequences if the explosion had occurred when
children were present and to inform future siting decisions.”
2. Solicit cooperation from government, industry, and academia to evaluate and further
develop ExDAM’s phenomenological approach for providing a practical (i.e. simple, fast,
and accurate) solution for a variety of conventional explosion safety/security-related
problems such as:
a. Explosion Consequence Analysis (ECA)
b. Emergency Response Planning (ERP)
c. Event Reconstruction and Forensics Analysis
d. Consequence Mitigation Design & Testing
e. Event/Facility Planning & Security
f. Facility Siting Analysis & Regulatory Compliance
g. Overpressure Exceedance Analysis (OEA)
h. Quantitative Risk Assessments (QRA)
i. Security and Vulnerability Assessments
j. Force Protection Modeling, Simulation and Analysis
k. Perimeter Analysis (Standoff Distance Determination)

Large-Scale Explosion Modeling with BREEZE ExDAM
The modeling of large-scale explosions, involving numerous/complex structures and numerous
gathered/dispersed people, is a daunting challenge. In most cases, the primary objective is to
predict the distribution of structure damage and human injury due to one or more explosions.
Damage levels are typically reported in four categorized: no damage, slight damage (useable,
requiring minor repairs), moderate damage (partially usable or temporarily unusable, requiring
major repairs), and severe damage (permanently unusable, irreparable). Injury levels are
typically reported in six categories: no injury, walking wounded, needs minor surgery, seriously
injured requiring major surgery, unlikely to reach hospital alive, and deceased.
Computationally, local damage and injury levels are a function of incident pressures and
impulses which are a function of the blast wave/energy passing through air, reflecting off less
damaged structures, and passing through more damaged structures. CFD modeling methods
simulate these physical processes over time and space. Unfortunately, for large-scale projects
with limited resources CFD modeling can be prohibitively expensive. However, for complex
structure scenarios, any alternative modeling method must provide a mechanism to compute
incident pressures/impulses due to blast waves passing around and through structures.
ExDAM’s explosion models, HExDAM and VExDAM (Vapor Cloud Explosion Damage/Injury
Assessment Model), provide this mechanism using a unique ‘shielding’ algorithm which acts to
reduce incident pressures/impulses behind shielding structures using a dipole-flow-field
distribution.
To facilitate this shielding algorithm, ExDAM structures (See Figures 1, 2) are composed
exclusively of ‘blocks’. Complex block structures can be quickly created within ExDAM’s 3D
window using an extensive set of basic block editing operations (e.g. cut, stretch, copy, rotate,
translate) and advanced shape editing functions (e.g. extrude/interpolate/extrapolate,
cylinder/sphere, building with walls/floor/ceiling/windows/people). Structure editing is further
facilitated with options to import images (e.g. satellite images, floor planes, building profiles),
import 2D/3D line/surface models (e.g. CAD data, Google 3D Buildings), and import any
number of structures from other ExDAM projects recursively (e.g. urban scenario project…
imports parking garage project… which imports numerous car/truck projects).
Figure 1. ExDAM UI with Example Block Structures Figure 2. Structure with Floor Plan
Structure blocks are each assigned a material. Derived from empirical (i.e. observed
phenomenological) data, ExDAM’s structure materials directly correlate incident

pressures/impulses to percent damage/injury values with default damage/injury thresholds of
slight/moderate/severe set at 5%, 30%, and 75%, respectively. Material selection is quite simple
for macro-level analyses (i.e. modeling structures located large distances from blasts). However,
material selection can become critically important and relatively more complicated for projects
requiring micro-level analyses (i.e. modeling complex structures in close proximity to blasts).
Examples of whole-structure materials include:
a. Multistory Reinforced Concrete Bldg With Concrete Walls
b. Multistory Steel-Frame Office, Earthquake Resistant
c. Bldg W/ Med Weight Pre-Eng. Metal, Ltwt Walls & Roof
d. Bldg W/ Tilt-Up Concrete Wall, Lightweight Roof
e. Bldg W/ Reinf Concrete, 25 Cm. Walls, Reinf Concrete Roof
f. Bldg W/ Reinforced Masonry, 20 Cm. Walls, Light Roof
g. Ind Bldg W/ Heavy Frame (St Or Con), Unreinf Masonry Walls
h. Res Bldg W/ Wood/Steel Stud Wall, Ltwt Joist Or Truss Roof
i. Res Bldg W/ Multistory Wall-Bearing, Brick Apt House
j. Res Bldg W/ Wood Frame, House Type
Examples of structure component materials include:
a. Brick Wall Panel, 20 Or 30 Cm., Non-Reinforced
b. Concrete Or Cinder-Block Wall Panels, Non-Reinforced
c. Glass Windows, Large And Small
d. Steel (Corrugated) Paneling
e. Wood Siding Panels, Standard House Construction
When explosions are located close to buildings, such that the incident blast pressures/impulses
passing across the structure vary significantly, complex structure geometries composed of
numerous component blocks (e.g. column, beam, wall panel, floor panel, door, window) are
typically created and assigned a variety of different materials. For this type of ‘micro-level’
damage assessment, structure materials (i.e. structure vulnerability parameters) can be derived
directly from pressure/impulse (PI) data. For example, ExDAM structure vulnerability
parameters can be generated from VASDIP (Vulnerability Assessment of Structurally Damaging
Impulses and Pressures) [6] pressure/impulse (PI) data which includes a variety of structure
component types such as:
a. Reinforced Concrete Beams
b. One/Two-Way Reinforced Concrete Slabs
c. Reinforced Concrete Exterior Columns (Bending)
d. Reinforced Concrete Interior Columns (Buckling)
e. Reinforced Concrete Moment-Resisting Frames
f. Steel Beams
g. Metal Stud Walls
h. Open Web Steel Joists (Tension Failure in Bottom Chord)
i. Open Web Steel Joists (Web Buckling)
j. Steel Corrugated Decking
k. Steel Exterior Columns (Bending)

l. Steel Interior Columns (Buckling)
m. Steel Frames
n. One/Two-Way Unreinforced Masonry Walls
o. One/Two-Way Reinforced Masonry Walls
p. Masonry Pilasters
q. Wood or Timber Walls/Roofs/Beams
r. Wood or Timber Exterior Columns (Bending)
s. Wood or Timber Interior Columns (Buckling)
To produce a sampling (i.e. distribution) of human injuries, the interior spaces and exterior
grounds of structures are typically populated with arrays of people (See Figure 3). People are
composed of 19 unique and 28 total body components (See Figure 4). The material properties of
the 19 different body components are derived from empirical data, some sensitive to
overpressure (e.g. ears, lungs, GI system) and others sensitive to dynamic pressure or impulse
(e.g. ribs, long bones, vertebrae). People types include Man, Woman, and Child.
Figure 3. People Arrays within Structures Figure 4. People Body Components
After creating structures, assigning materials and placing arrays of people HExDAM projects
only require two more things before executing a model run: the placement of one or more high
explosives (with a specified TNT equivalent mass) and the optional placement of a
pressure/impulse sampling grid (i.e. an XYZ-bounded volume with a user specified resolution).
ExDAM model runs typically take minutes (at most a few hours) to execute on a conventional,
relatively low-end laptop computer. Model runs produce results files typically less than 10MB
in size. Results files contain a backup copy of the project file and are, therefore, completely
independent of the source project file. Model run block results (i.e. peak incident
pressures/impulses, percent damages/injuries) are displayed in the 3D window with a variety of
color coding options. By default, low values of pressure/impulse/damage/injury are displayed
with a blue color, moderate values progress to a yellow color, and high values progress to a red
color (See Figure 5). Block results for user-selected blocks/structures are also displayed in a
variety of HTML table formats (See Figure 6). Block results for complex multi-block structures
(i.e. total percent damage and average incident pressures/impulses) are typically reported using
volume-weighted averages. Sample grid results (i.e. peak pressure/impulse distributions within
the bounds of an XYZ grid) are displayed using contour planes, iso-surfaces, and volume
rendering (See Figures 7, 8, 9). The same user-adjustable color coding options are used to
display low/moderate/high pressure/impulse values.

Figure 5. Block Damage/Injury Figure 6. Block Damage/Injury Tables
Figure 7. Grid Contour Planes Figure 8. Grid Iso-Surfaces Figure 9. Grid Volume Rendering
West, Texas Project Development
An aerial/satellite image of West was first obtained from Google Earth, placed at ground level
and scaled to size. The geometry and construction characteristics of the various structures (i.e.
fertilizer plant, apartment building, nursing home, high school, middle school, residential houses,
commercial buildings) (See Figures 10 through 19) were then determined using Google Maps
Street View and various online aerial and street-level images from the extensive media coverage.
Interior details were included in the apartment building and nursing home. The schools,
commercial buildings, and residential houses were left hollow with no additional interior
walls/floors. All totaled the project structures are composed of 13880 structure blocks,
subdivided into 46148 blocks to increase sampling/computational resolution.

Figure 10. Satellite Image Figure 11. All Structures
Figure 12. Apartment Buildings Figure 13. Nursing Home w/ Roof Figure 14. Nursing Home w/o Roof
Figure 15. High School Figure 16. Middle School Figure 17. Commercial Buildings
Figure 18. Fertilizer Plant Figure 19. Residential Houses

The following materials (i.e. construction types) were assigned to the structures:
Structure Material Description
Apartment Building Res bldg w/ multistory wall-bearing, brick apt house
Nursing Home Res bldg w/ wood/steel stud wall, ltwt joist or truss roof
Middle School Bldg w/ reinforced masonry, 15 cm. walls, light roof
High School Bldg w/ reinforced masonry, 15 cm. walls, light roof
Residential Houses Res bldg w/ wood frame, house type
Commercial Buildings Ind bldg, lt steel frame, 4.5 mt. crane capacity
All of the structures were internally populated with over 340 people, evenly dispersed with
higher concentrations in the apartment building, nursing home, and intermediate school (See
Figure 20). A sample grid encompassing the entire scene and a 12.6 ton TNT high explosive
(~30 tons of AN using an R.E. facture of 0.42) was placed inside the fertilizer plant storage
building. All totaled, project development was completed within two working days.
Figure 20. Project Structures with Over 340 People Displayed at X20 Scale

West, Texas 12.6 ton TNT (30 ton AN) Explosion Simulation Results
Model runs took ~55 minutes on a conventional business PC (i.e. Dell Latitude Intel® Core™
i7-2760QM CPU @ 2.4GHz) producing results files ~7MB in size. The project’s structure
names and groups are defined in Figure 21.
Figure 21. Structure Names, Locations, and Groups
A contour plane located five feet above ground (See Figure 22) provides a quick idea of peak
incident over pressures. Notice how structures provide shielding to other structures (e.g. the
middle school provides significant shielding to the neighboring houses to the south west). Also
notice, the 1 and 0.5 psi lines are 1350 ft (0.26 mi) and 2225 ft (0.42 mi) from the explosion
center.
Figure 22. XY Overpressure Contours @ 5 ft Above Ground

Figure 23 displays color-coded structure incidence overpressures from 0.5 psi to 5 psi.
Figure 23. Structure Incident Overpressures
Figure 24 displays color-coded structure damage levels none, slight, moderate, and severe.
Figure 24. Structure Damage Levels

Figure 25 combines the overpressure contour plane (5 ft above ground) with color-coded
structure damage in a perspective view of the nearest, most exposed structures.
Figure 25. Perspective View of Overpressure Contour Plane 5 ft Above Ground with Color-Coded Structure Damage
Structures nearest the explosion were exposed to overpressures greater than 5 psi. Figure 26
provides a first visual comparison of predicted damage levels to actual.
Figure 26. Visual Comparison of Predicted vs. Actual Structure Damage

Figure 27 and Figure 28 display the incident overpressures and consequent injury levels to the
people closest to the blast. For a better view, the structures are hidden and the people are scaled
by a factor of 20.
Figure 27. Incident Overpressure to People Closest to the Blast
Figure 28. Injury Levels to People Closest to the Blast

Table 1 and Table 2 provide general information about incident pressures and average/maximum
damage/injury levels.
Table 1. Average(Maximum) Damage/Injury/Pressure/Impulse
Table 2. Damage & Injury Summary

From the above color-coded 3D images and corresponding results tables the following
observations and conclusions can be made:
A. Apartment Buildings (see Figures 29, 30, 31, 32) - The apartment building structure is
hit with a maximum of 5.07 psi and an average of 3.07 psi. By volume, 81.2% of the
structure is severely damaged, 13.0% moderately damaged, and 3.3% slightly damaged.
Assuming one person located in the middle of each apartment (i.e. 24 apartments
stretching from front to back of building, not 48/50 apartments as reported), on average
they experience 3.68 psi and at most 4.32 psi. Moderate injury due to high dynamic
pressures of up to 0.436 psi causing bone fractures (e.g. ribs, vertebrae, long bones) is
predicted.
Figure 29. Injury to 24 People in Apartment Building
Figure 30. Injury Table for Person Identified in Figure 29
Figure 31. Apartment Building - Comparison of Predicted to Actual Damage

Figure 32. Apartment Building and Neighboring Structures - Comparison of Predicted to Actual Damage
B. Nursing Home (see Figures 33, 34) – The nursing home is initially hit with almost 3 psi.
The average incident pressure throughout the entire structure is 1.31 psi. Average
structure damage of 32.3% is in the moderate range (i.e. over 30%) with 9.9% severely
damaged, 40.9% moderately damaged, and 10.1% slightly damaged. People located
behind windows nearest the explosion experience maximum overpressures of 2.4 psi and
maximum dynamic pressures of 0.14 psi. Injury levels to the people behind windows
nearest to the explosion are slight, consisting of ear drums due to overpressure and long
bones (e.g. ribs, vertebrae, long bones) due to dynamic pressure.
Figure 33. Injury to 64 People in Nursing Home
Figure 34. Nursing Home - Comparison of Predicted to Actual Damage

C. Middle School (see Figures 35, 36) – The middle school structure is hit with almost 3 psi
and experiences average overpressures of 1.43 psi. By volume, 23.4% of the structure is
severely damaged, 45.0% moderately damaged, and 19.6% slightly damaged. Occupants
experience overpressures as high as 1.85 psi and on average 1.05 psi. Overpressures and
dynamic pressures as high as 0.082 psi again produce slight ear and bone injuries.
Figure 35. Injury to 14 People in Middle School
Figure 36. Middle School - Comparison of Predicted to Actual Damage
D. Houses North of Apartments (Figure 37) - The houses north of the apartment building
are hit with up to 3.75 psi overpressure and 0.329 psi dynamic pressure producing mostly
moderate and severe damage. Slight injuries to ears and long bones are predicted.
Figure 37. Houses North of Apartments - Comparison of Predicted to Actual Damage

E. Houses North of Fertilizer Plant (Figure 38) - The nearest houses directly to the north
of the fertilizer plant are hit with up to 3.04 psi overpressure and 0.218 dynamic pressure.
Mostly moderate/severe damage and slight injuries are predicted.
Figure 38. Houses North of Fertilizer Plant - Comparison of Predicted to Actual Damage
F. South West Houses (Figure 39) – The houses directly south of the nursing home are hit
with up to 2.59 psi and 0.159 psi dynamic pressure, enough to generate moderate/severe
damage and some slight injuries.
Figure 39. Southwest Houses Hit with 6 psi Overpressure
G. Commercial Buildings - The commercial buildings toward the west are hit with up to
1.31 psi and an average of 0. 86 psi overpressure. Though there is no severe damage,
39.1% moderate and 50.1% slight structure damage by volume is predicted. No injuries
are predicted.
H. High School, South Houses - The high school and houses located directly south of the
fertilizer plant are hit with roughly 1 psi and experience average overpressures of roughly
0.5 psi. Slight damages of 55.7% and 77.4% by volume, respectively, and no injuries are
predicted.
In addition to images and tables ExDAM ECM results are typically reported using numerous
animation and video capture options. A preliminary video of this project, produced shortly after
the event, is available on YouTube [7] and an updated video for this specific conference paper
will be available on the Breeze ExDAM YouTube channel [8].

Conclusions
The explosion consequences in West, Texas (i.e. structure damage and human injury) are no
mystery to explosion experts. With a few simple calculations, an expert can accurately predict
the pressures incident on various structures and then, from experience, make reasonable
predictions about the damage and injury levels. Numerous software tools are available to help
facilitate such tasks. Scenarios for which blast pressure/impulse distributions pass around and
through numerous and/or geometrically complex structures (e.g. industrial plants, suburban/rural
cities, or downtown urban scenes with high-rise buildings) require more sophisticated software
tools to adequately assess/predict damage/injury levels.
The West, Texas ECM presented in this paper attempts to propose and demonstrate a fully three
dimensional simulation process easy, reliable, and affordable enough to be used by trained
technicians within the ranks of local emergency responders and/or their local community support
agencies. With ExDAM’s simple block structure modeling and fast phenomenological
computations, projects like West, Texas can be performed in hours or days using commonly
available computing resources. This process not only provides a means to quantify the
magnitude of threats but also helps to foster and sustain awareness of the threats by providing an
effective means to communicate the threats to all stakeholders (e.g. colorful multi-media 2D/3D
images/videos are typically more effective than stapled stacks of paper full of numbers).
As with all types of threats (e.g. hazardous release, fire, and explosion), investigations of past
events, such as West, Texas, seem to suggest that access to expertise and analytical tools for
consequence analysis are only part of what’s needed by local emergency responders and other
responsible community support/management agencies. The consensus seems to be that local
agencies not only need to identify and quantify potential threats to their communities but they
also need to “take action” so that adequate/prudent mitigation measures and emergency response
preparations can be designed, implemented, and maintained.
More alarmingly from an academic perspective, in the case of West, Texas, the CSB reports [1,
2, 3] clearly indicate that basic threat awareness, mitigation, and preparation measures are simply
being neglected across the U.S. Aside from the complicated political aspects, perhaps these
problems will be solved from the bottom up by developing and disseminating effective and
affordable (i.e. fast, easy, reliable) tools which naturally engage/induce/help emergency
responders and their support agencies to investigate, analyze, learn, communicate, educate,
organize and, ultimately (because all stakeholders understand, appreciate, and agree that there’s a
threat), take action to prevent and/or prepare for the threat.
In addition to on-going academic/government/industry testing and evaluation, ExDAM needs
access to any and all available blast vulnerability data (e.g. PI data such as the USACE CEDAW
[8]) so that users have a more complete set of structure materials to choose from. TCI is also
looking to collaborate with other organizations to continue the West, Texas analysis (or other
forensic/calibration/validation projects) to thoroughly test and evaluate ExDAM/HExDAM’s (or
VExDAM’s) overall process efficiency, effectiveness, and accuracy compared to actual event
damage/injury data and other predictive methods/processes. An Academic License Agreement is
available for qualified students/faculty/researches at educational/governmental institutions. TCI
is also looking to partner with local emergency responders and their supporting city/county/state

agencies to test, evaluate, and develop threat identification, analysis, communication, mitigation,
and preparation processes.
References
1. U.S. Chemical Safety Board, Preliminary Findings of the U.S. Chemical Safety Board from
its Investigation of the West Fertilizer Explosion and Fire, April 22, 2014
2. U.S. Chemical Safety Board, West Fertilizer Explosion And Fire Public Meeting, April 22,
2014
3. Testimony of Rafael Moure-Eraso, Ph.D., Chairperson, U.S. Chemical Safety Board, Before
the U.S. Senate Committee on Environment and Public Works, June 27, 2013Obama EO
4. The White House Office of the Press Secretary, Executive Order - Improving Chemical
Facility Safety and Security, August 01, 2013
5. Executive Order 13650 Working Group, Report for the President - Actions to Improve
Chemical Facility Safety and Security - A Shared Commitment, May 2014
6. BREEZE VASDIP (Vulnerability Assessment of Structurally Damaging Impulses and
Pressures) - Software Description Page Link:
(link broken - look for repaired link in http://www.breeze-software.com/exdam/ page)
7. BREEZE ExDAM West, Texas Explosion Analysis - Video Link:
(https://www.youtube.com/watch?v=45zetN2x6r4&list=PLwcBWH-
mGjwPsKQpSlPMKfAb6NjZLsAs-)
8. BREEZE Software - Video Channel Link:
(https://www.youtube.com/channel/UCh_3pHnt6zqZexFqBhCWKiA)
9. USACE CEDAW - Software Description Page Link:
(https://pdc.usace.army.mil/software/cedaw/)

Large-Scale Explosion Consequence Modeling West, Texas Fertilizer Plant Case Study

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