Mitigation Assessment Team Report
Hurricane Charley in Florida
Observations, Recommendations, and Technical Guidance
FEMA 488
April 2005

Chapter 7. Conclusions

The conclusions presented in Sections 7.1 through 7.6 are based on the MATs 
observations; evaluations of relevant codes, statutes, and regulations; and 
meetings with state and local officials, building associations, contractors, and 
other interested parties. The conclusions presented in Sections 7.1 through 7.6 
are based on the MATs observations; evaluations of relevant codes, statutes, 
and regulations; and meetings with state and local officials, building 
associations, contractors, and other interested parties. These conclusions are 
intended to assist the State of Florida, local communities, businesses, and 
individuals in the reconstruction process and to help reduce future damage and 
impact from natural events similar to Hurricane Charley. Observed mitigation 
successes are presented in Section 7.7.


7.1 	General Conclusions

Hurricane Charley was a powerful hurricane when it made landfall as a strong 
Category 3 or borderline Category 4 hurricane in southwestern Florida. Although 
waves and coastal surge caused erosion and damage along the beaches of the 
barrier islands in Charlotte and Lee Counties (including the breach that was cut 
across North Captiva Island), Hurricane Charley will be remembered mostly for 
its winds and wind-induced damage. In addition to the estimated 145 to 155 mph 
(3-second peak gust) winds associated with the eye of Hurricane Charley as it 
passed over North Captiva Island, communities around Charlotte Harbor, including 
Port Charlotte and Punta Gorda, were impacted with winds estimated at 125 to 140 
mph (3-second peak gust) in densely populated areas. Hurricane force winds (with 
3-second peak gust winds as high as 105 mph) in densely populated areas of 
Orlando continued to induce damage across the peninsula of Florida until 
Hurricane Charley exited into the Atlantic Ocean near Daytona Beach, still 
categorized as a hurricane. 

The need for hardening, providing backup power, and data storage to the NOAA/NWS 
surface wind and weather monitoring system was demonstrated by Hurricane 
Charley. The assessment of the performance of buildings and infrastructure is 
tied to the estimates of wind speeds experienced throughout the area of impact. 
None of the Automated Surface Observing Systems (ASOSs) and other systems, as 
far inland as Orlando, that were impacted by the strongest winds continued to 
report wind information throughout the storm. In many cases, the ASOS operates 
more like an early warning system for hurricane force gusts (because the power 
is typically lost when wind gusts approach hurricane force) than as a reliable 
source of data on the winds during the heart of the storm. 

The categorization of the storm by a single hurricane classification also has 
limited use in the post storm assessment and may lead people in the impacted 
areas to draw incorrect conclusions about the event they actually experienced at 
their site and the strength of their building. The development of wind field 
estimates and resulting wind speed swath maps (Figures 1-4 and 1-5) are critical 
to the proper assessment of an event and its implications for building 
construction and code development.

The response of buildings to the high winds varied due to their location in the 
wind field, building code in effect at the time of construction, level of code 
compliance, quality of construction, and mitigation efforts implemented on the 
building. The most severe damage and structural failures occurred along the path 
of the eyewall of the hurricane, where most of the structural collapses and 
severe damage to the structural elements of buildings was observed. However, 
based on MAT observations, the number of structural failures from the winds 
associated with Hurricane Charley was generally less than has been observed 
during damage assessments following previous hurricanes with similar wind 
speeds. 

Performance of building envelope elements such as roof coverings, rooftop 
mounted equipment, unprotected glazing, soffits, and siding was generally poor 
and led to widespread damage to the interiors of residences, businesses, and 
critical/essential facilities. In the windborne debris regions (areas identified 
in the 2001 FBC with 3-second peak gust design wind speeds of 120 mph or 
greater), where glazing was not protected, debris often broke the unprotected 
glazing and resulted in damage to building interiors (and, in some cases, 
structural failure from an uncontrolled increase in air pressure). Damage to the 
contents of residential and commercial buildings, and critical/essential 
facilities is preventable, as are the resultant costly losses and claims.


7.2	Building Performance and Compliance with the Building Codes, Statutes, and
	Regulatory Requirements of the State of	Florida

Most structural failures observed by the MAT appeared to be the result of 
inadequate design and construction methods commonly used before the 2001 FBC and 
other modern building codes and standards were adopted and enforced; some 
failures may be explained by lack of maintenance or poor condition of the 
building and its structural elements. Code changes implemented in response to 
Hurricane Andrew in 1992, such as improvements to the SBC and the adoption of 
the 2001 FBC, can be credited with improving the wind resistance of buildings 
that have been designed and constructed over the past 12 years. In addition, the 
improvements in ASCE 7, including the addition of windborne debris protection 
requirements and the elimination of the one-third stress factors, are further 
refining the loads that new buildings must resist, thus ensuring better 
performance in wind events.

Buildings constructed in accordance with older codes were typically vulnerable 
to envelope and equipment damage, because older codes lacked or had inadequate 
criteria (refer to Chapter 2). Where buildings were designed and constructed to 
newer codes and standards (such as the FBC, the SFBC, or ASCE 7-98 or later) 
with improved building envelope and equipment design criteria, some of the 
observed failures were due to failure to comply with code provisions in both the 
design and construction phases. Other failures were the result of installed 
materials and systems that are known to lack the ability to perform under high-
wind loads (i.e., the use of unsecured soffit panels). These components either 
do not meet the new criteria or there is a lack of evidence, through either 
realistic laboratory testing or observed performance during hurricanes, that the 
product will work under high-wind loads. Because these components are not 
considered structural elements, their design and construction is often 
overlooked during design, permitting, construction, and inspection. Therefore, 
improvements are needed in the design requirements of the codes themselves and 
with enforcement and code compliance to ensure that components and cladding 
(C&C) elements are being engineered and designed per the code requirements. The 
MATs observations are presented in Chapters 4, 5, and 6, and provide details in 
support of this statement. 

The 2001 FBC and the recently completed 2004 FBC (to be adopted statewide by 
administrative rule effective July 1, 2005) include several improvements to the 
structural design of buildings and attached structures, as well as improvements 
for the design of building envelope and equipment provisions. Based on the 
observations outlined in this report, design guidance provided by the code with 
regard to the design and construction of the building envelope and attached 
structures and equipment needs to be expanded and improved. Guidance for some of 
these issues is provided by current model codes and standards, including the 
International Building Code/International Residential Code (IBC/IRC), NFPA 5000,  
and ASCE 7-02. 

Finally, performance of manufactured housing was also observed to be a function 
of age of the building and the regulations to which the units were designed, 
constructed, and installed. Widespread damage was observed to manufactured 
housing designed and constructed prior to the 1976 HUD regulations. The 
performance of units installed between 1976 when the first HUD regulations were 
enacted and the implementation of the 1994 HUD regulations was observed to be 
somewhat improved, but significant improvements in performance were observed in 
the units designed and installed to the HUD regulations implemented after 1994 
in response to Hurricane Andrew. Although some instances of structural failure 
were observed, the newer manufactured housing units typically sustained minimal 
structural damage and remained secured to their foundations when installation 
followed state requirements (e.g., enforced by the Division of Motor Vehicles, 
Department of Highway Safety and Motor Vehicles, etc.) of unit tie-downs 
(anchors) at 5 feet 4 inches on center (if no ancillary structures were attached 
to the unit). Much of this improved performance was difficult to observe due to 
widespread damage caused by the failures of improperly designed and constructed 
attached structures (including screen enclosures, carports, and accessory 
structures). The failure of these attached structures, in many places occurring 
where wind speeds were below the design wind speed for the area, resulted in 
extensive damage to roof coverings, siding, windows, and doors of the 
manufactured units, and generated significant amounts of debris. Very few 
manufactured homes had glazing protection and, as a result, numerous unprotected 
windows on units along the path of the eye of the storm were damaged and broken. 
Had the Zone II and Zone III homes  installed in areas where debris protection 
is required for site-built one- and two-family dwellings  been shipped with 
appropriate glazing protection, these homes would have been protected from 
windborne debris.


7.3 	Performance of Structural Systems (Residential and Commercial 
Construction)

Buildings designed and constructed to resist wind loads prescribed in the 2001 
FBC and to the requirements of ASCE 7-98 performed well and showed how 
improvements to the building codes have been successful in Florida. Structural 
damage, however, is still occurring during code level events such as Hurricane 
Charley.

7.3.1	Internal Pressures
Breach of the building envelope through broken windows, failed doors, or loss of 
sheathing led to rapid and uncontrolled increases of the internal air pressure 
in buildings, which sometimes resulted in structural damage or failure. Research 
suggests that internal pressures are affected by openings as small as 1 percent 
of the wall area and that the internal pressure generally becomes equal to the 
external pressure at the opening when the area of the opening reaches or exceeds 
5 percent of the wall area. Consequently, the loss of a large window, a sliding 
glass door, a double-entry door, or a garage door can expose the interior of a 
building to the full effect of the external wind pressure. When openings are 
breached on the windward face of the building by direct pressure-related failure 
or by impact from windborne debris, the internal pressure in the building rises 
toward and tends to follow the fluctuations in positive pressure that would have 
occurred on that window, door, or panel had it not failed. Because air is 
essentially incompressible at the wind speeds encountered in even the most 
severe wind storms, the pressure builds without the need for much wind flow 
through the opening. However, if other openings in the building are present, 
including panels covering ceiling access holes in attics, air pressure can 
escape from the building, but does so as rapidly moving air that whips through 
the building. Failures of windows and doors on the windward face of a building 
have been correlated with subsequent failures of partition walls, windows, and 
doors on side and leeward walls, attic access panels, roof sheathing, and even 
whole roof structures (refer to Chapter 4 for details of these types of 
failures).

The MAT found examples of all of these types of failures in Hurricane Charley. A 
number of newer homes had double-entry swinging doors that failed. Because these 
homes were built with reinforced masonry and had adequate roof strapping, the 
roofs remained intact, but the sliding glass doors on the leeward side of the 
homes came out of their tracks, opening the house to the hurricane winds. It was 
not uncommon to find furniture blown out of these homes. A church sanctuary in 
Punta Gorda was reduced to rubble when the entire roof separated from the walls 
and a house on Pine Island lost most of the roof over a central area with a 
cathedral ceiling when a window blew in on the windward side. The widespread 
failure of low-slope roof systems may have been impacted by the build-up of 
internal pressures after a window or door failed, but the roof was probably 
compromised and the internal pressure just hastened the failure.

7.3.2	Wind Mitigation for Existing Buildings
To minimize damage or prevent failure of older buildings (residential, 
commercial, and critical/essential facilities), mitigation to create a 
continuous load path from the roof to the foundation must be implemented. This 
type of mitigation can be expensive because it often requires demolition and 
replacement of interior building finishes, and may require displacement of 
occupants while the mitigation is performed. Justifying the cost may also be 
difficult because the building code or local ordinance may not require that the 
building be upgraded to current code requirements.

For homeowners, opportunities to perform mitigation retrofits that improve the 
buildings continuous load path would be optimal during renovation work or roof 
replacement projects, when significant invasive work is already being performed 
and the cost to install extra clips, screws, or nails to secure decking to 
rafters/trusses would be minimized. Access to the roof structure/top of wall 
connection is often made accessible during these projects, and clips and straps 
may be installed to help with the creation of a continuous load path. Additional 
anchorage of the bottom of the walls may still be required to develop a complete 
load path. Mitigation projects stated above would address the roof decking and 
roof structure failures observed after Hurricane Charley.

In commercial and critical/essential facility buildings, mitigation retrofit 
costs may be minimized if these types of projects are performed during tenant 
fit-out projects or major capital improvement projects. Prioritization can be 
given to mitigating space used for critical and essential functions. Public 
schools are examples of where these types of mitigation projects have occurred. 
As part of their efforts to increase safe public shelter space, FL DCA has 
evaluated schools, and sponsored structural and non-structural mitigation 
projects to strengthen buildings and provide debris impact protection to 
mitigate existing buildings once vulnerable to damage from wind and windborne 
debris. 


7.4	Performance of Accessory Structures/Attachments 

Historically, aluminum accessory structures have had little rigorous engineering 
applied to them because they have been regarded as auxiliary and even expendable 
structures. Since the mid-1970s, the design of aluminum accessory structures has 
been most often accomplished through the use of prescriptive guidelines 
promulgated by a few professional engineers apparently without adequate formal 
peer review or industry consensus. Consequently, the widespread failure of these 
structures observed after Hurricane Charley (refer to Chapter 4) was 
unfortunate, but not surprising.

Another issue affecting the survivability of aluminum accessory structures is 
that, in general, installers and building department personnel (plan reviewers 
or inspectors) may not be sufficiently knowledgeable about the design of 
aluminum accessory structures. Although attention has been given to the size and 
spacing of members, little effort seemed to be focused on the connection details 
between the members and anchoring. Field observations point to connection detail 
failures, inadequate bracing as being frequent initiation points, and 
overturning/sliding for the ultimate failure of these aluminum accessory 
structures.

In addition to the damage and failures of the structures themselves, damage 
occurred to the site-built and manufactured housing to which they were attached. 
The failure and destruction of accessory structures and attachments contributed 
large pieces of windborne debris that impacted the surrounding homes. 
Manufactured homes that had a collapse or partially collapsed attached 
structure, significant damages to roof covering, roof decking, and siding were 
commonly observed. Further, the widespread failure of these structures created 
large amounts of debris that had to be cleaned up and disposed.

Sound guidance for the design of these types of structures was developed with 
the preparation of the 2001 FBC. The Aluminum Association of Florida (AAF) 
commissioned research that involved wind tunnel testing of both screened 
structures with screened roofs and screened structures with solid roofs. This 
research established wind design pressures that should be applied to these 
aluminum structures and these results are included in Table 2002.4 of the 2001 
FBC. The AAF document, Aluminum Design Manual, referred to in the code in 
Section 2002.2, should be used by engineers and building officials to learn the 
engineering properties of the components that comprise a completed structure. 
The document does not deal with particular extrusions or assemblies of parts, 
but rather with the criteria for evaluating the connections. 

It is important to note that Table 2002.4 of the 2001 FBC (submitted by the AAF) 
does not address the issue of the particulars of the design, just the applied 
pressures. In recognition of the limited guidance available and in preparation 
for the 2004 FBC, the AAF Guide to Aluminum Construction in High Wind Areas was 
developed. Although it is not a consensus standard, this guide is based on wind 
tunnel testing and rigorous engineering that has been constructively peer 
reviewed, making it the best guidance available at the time of issuance of this 
report. Designs based on this guide would substantially address the shortcomings 
in the current way aluminum accessory structures are being designed and the way 
they will ultimately perform. The results contained in the AAF document have 
been incorporated into the 2004 FBC. However, because most attached structures 
and pool enclosures were constructed prior to the 2001 FBC code, the MAT could 
not determine if the industry has moved to fully support the guidance in the 
existing FBC code and the 2004 Edition.

In addition to the guidance from the aluminum structure industry, changes in 
wind loads for open and partially enclosed canopy roofs are set to appear in the 
next edition of the wind load section of ASCE 7 (2005). Furthermore, the ASCE 7 
standard has been revised to make it very clear that the one-third stress 
increase frequently used for short duration loads, such as wind loads, should 
not be applied unless it can be clearly demonstrated that the material capacity 
clearly increases as the load duration decreases. Thus, the common practice of 
reducing safety margins for metal or concrete structures by taking a one-third 
increase in allowable stress is no longer allowed. This should lead to stronger 
frames for screen enclosures and stronger carports and metal roof canopies in 
the future. 


7.5 	Performance of Building Envelope, Mechanical and Electrical Equipment 

Although structural system failures tend to be perceived by the public and the 
building industry as the dominant issue of concern, the greatly improved 
performance of houses built in accordance with the FBC 2001 and other model 
codes have, in general, resolved many structural performance issues. Now, the 
arena in which improvements can and must be made are those related to rain water 
intrusion and protection of the building envelope (refer to Chapter 5). 
Protection of the building envelope is important in minimizing losses and 
damages to building contents, but also because of the importance of the building 
envelope with respect to internal pressurization of a building.

Poor performance of building envelopes and rooftop equipment was common on 
residential, commercial, and critical/essential buildings. Envelope and 
equipment damage was more widespread and significant on older buildings, 
although new buildings were also damaged in many cases. Damage was noted 
throughout all areas observed. Ramifications of poor performance include:

--Property damage. Property damage was extensive, requiring repair and/or 
replacement of the damaged envelope and equipment components; repair and/or 
replacement of interior building components; and mold remediation and furniture 
and equipment replacement as a result of rain water and/or wind damage in the 
interior of the building. Even when damage to the building envelope or equipment 
was limited, such as blow-off of a portion of the roof covering or broken 
glazing, substantial rain water damage frequently resulted because of the heavy 
rains accompanying the hurricane and rains occurring in the following days and 
weeks. Rain water entered the buildings through the breaches in the building 
envelope.

--Loss of function. Depending upon the magnitude of the wind and rain water 
damage, repairs can take days or months. As a result, residents may not be able 
to return home, businesses may not be able to reopen, and critical/essential 
facilities may be incapable of providing their vital services. In addition to 
the costs associated with repairing the damage and/or replacing the damaged 
property, other financial ramifications related to interrupted use of the 
building can include rental costs of temporary facilities or lost revenue due to 
business interruption. These additional costs can be quite substantial.
 
7.5.1	Building Envelope 
Poor performance was a function of both inadequate wind resistance and damage 
from debris impact. Inadequate resistance to high-wind pressures on building 
envelopes and rooftop equipment was responsible for much of the damage caused by 
Hurricane Charley. In addition, windborne debris caused significant envelope 
damage (and virtually all of the glazing damage) that the MAT observed where 
wind speeds from the event were thought to be 120 mph 3-second peak gust and 
greater. Damaged and fallen trees, and failed building envelope components and 
rooftop equipment (such as roof coverings, gutters, HVAC equipment, and wall 
coverings) also became windborne debris that damaged the buildings they blew off 
of, as well as other buildings in the vicinity. 

7.5.1.1	Roof Coverings, Wall Coverings, and Soffits
Observations showed that roof coverings of all types continue to fail at 
unacceptable rates during hurricane events. Some of these failures were due to 
the age of the coverings (coverings that were never considered for their ability 
to resist what is now understood as design level wind loads) while other 
failures were due to design and construction related issues or debris impact. 
With respect to roof coverings, wall coverings, and soffits, the MAT concluded 
that

--Wind damage to roof coverings and wall cladding was widespread, even with wind 
speeds below design levels. Improved performance of roof and wall coverings was 
generally observed on the newer buildings and is likely due to improved codes 
and standards, product and test method improvements, a more educated designer 
and contractor workforce, and reduced detrimental effects of weathering (on 
newer buildings).

--Asphalt composition roof shingles continued to fail at or below design level 
winds. In general, it appeared that shingles installed within the past few years 
performed better than shingles installed prior to the mid-1990s. The enhanced 
performance is likely due to product improvements and less degradation of 
physical properties due to limited weathering time. In most cases, observed 
shingle failures were attributed to inadequate self-seal adhesive bond strength 
or installation that did not comply with recommended methods for resisting blow-
off in high-wind areas. Failures of shingle roof systems applied over previously 
installed shingles were frequently observed.

--Tile roof systems experienced varied levels of performance from complete 
resistance to wind to substantial loss of tiles. Variation in performance was 
primarily related to installation and attachment methods with mortar-set tile 
system failure most frequently observed as compared to foam set and mechanically 
attached tiles. Tile failures on roofs with foam-adhesive were observed, in most 
cases, to not comply with manufacturers installation recommendations. All types 
of tile (concrete and clay) are vulnerable to breakage from debris impact, 
regardless of installation methods used. Tiles lifted by wind or broken from 
windborne debris often lead to cascading failures. Tiles on hips, ridges, and 
edges of the roof were a frequent point of failure. Hip and ridge tiles rarely 
were attached using mechanical anchors.

--Aggregate roof surfacing continued to cause debris damage when aggregate was 
blown off the roofs by high winds.

--For all roof systems, inadequate attention was typically given to edge 
flashing, coping, and gutter/downspout design and installation despite being 
located in the roof areas subject to the highest wind pressures. Failure of 
these roofing components often initiated roof membrane lifting and peeling.

--Wall cladding of all types (EIFS, vinyl and aluminum siding, masonry, etc.) 
appeared to have typically received minimal attention during design and 
construction, and continues to be an initiation point for progressive failures 
leading to interior contents damage or pressurization of the building.

--In numerous buildings, wind-driven rain was driven into attic spaces because 
of soffit failures. Widespread loss of soffits was observed in residential 
construction. In many of these instances, water intrusion occurred from wind-
driven rain through areas where soffits were displaced or lost.

7.5.1.2	Windows, Doors, and Shutters
Windows and glazed doors can be protected in all wind regions using shutter 
systems, laminated glazing systems, and other means of opening protection. Large 
amounts of debris and loss of many unprotected windows and doors in areas along 
the path of the eye of Charley support the required protection of these openings 
in areas within the FBC windborne debris region. Further, many buildings in the 
areas outside the windborne debris regions would have benefited had the glazing 
been protected. Using glazing protection to prevent internal pressurization and 
wind-driven rain water intrusion protects interior contents from being damaged. 
Specifically; with respect to windows, doors, and shutters, the MAT concluded: 

--The benefits of shutters are two-fold. First, they minimize an inrush of air 
that might cause a building not designed for internal pressures to fail 
structurally and they protect against the intrusion of wind-driven rain that 
could enter an unshuttered broken window. Although the public generally 
understands the importance of minimizing the inrush of air that might damage or 
cause a structure to fail, it is not clear that the public appreciates the 
dramatic damage that can be caused by rain entering a residence. Code prescribed 
shutters capable of withstanding penetration by windborne debris and both 
negative and positive wind pressures would eliminate water intrusion that would 
otherwise result from broken windows.

--Many homes and businesses that experienced only contents damage could have 
prevented these losses if their openings had been protected. Success in 
designing the structural frame to resist wind loads and internal pressures was 
negated by significant losses to building interiors and contents.

--Most shutters observed on buildings performed well during Hurricane Charley.

7.5.1.3	Attached Equipment (Rooftop and Ground Level)
Much like the building envelope systems already discussed, rooftop and ground 
level equipment is not typically receiving the design, installation, or code 
attention needed. Design guidance in ASCE 7-02 provides basic information to 
calculate wind loads on these elements to determine connection and support 
anchoring systems, but detailed guidance is needed. The lack of design and 
installation attention caused displacement or damage to these units across the 
wind field of the hurricane. This not only resulted in the loss of function 
associated with the damaged units, but in many cases led to the loss of function 
of the occupied space due to rain water infiltration at displaced rooftop 
equipment.

7.5.2	The Need for High-Wind Design and Construction Guidance 
Designers, contractors, and building officials need additional education and 
resources to promote wind-resistance design and construction. Although many 
successes of design and construction were observed across the path of Hurricane 
Charley, it was apparent that the load path concept was not fully understood in 
all cases. It was also clear that many designers, contractors, and building 
officials do not fully understand the devastating effects that hurricanes can 
have on envelopes and equipment. It was common to see fasteners spaced too far 
apart, fasteners that were too small, and weak connections. Enhanced details 
were seldom seen. In contrast, there were numerous examples of failure to follow 
well established basic construction practices such as minimum edge distances for 
fasteners. Unless wind resistance issues are understood by designers, 
contractors, and building officials, envelope and equipment failures will 
continue to occur. In part, the envelope and equipment problem is due to lack of 
high-wind design guides for various envelope assemblies and various types of 
rooftop equipment. 


7.6 	Performance of Critical and Essential Facilities (Including Shelters) 

Critical and essential facilities must remain operational before, during, and 
after significant hazard events, such as hurricanes, to serve their communities. 
As stated in Chapter 6, buildings that were considered critical and essential 
facilities were EOCs, fire and police stations, hospitals, schools, and 
shelters.

In general, buildings functioning as critical and essential facilities did not 
perform any better than their commercial-use counterparts. Despite codes of the 
past 10 years that require high design loads be used in the design of these 
facilities, the same flaws in construction, such as poor wall cladding, poor 
attachments of roof covering, and improper anchorage of rooftop mechanical 
equipment, were observed in critical and essential facilities. As a result, the 
operations and response at many critical and essential facilities discussed in 
Chapter 6 were hampered or shut down and taken off-line after the hurricane. In 
Charlotte County alone, over a half-dozen fire stations, three hospitals, 
numerous police stations, and the county EOC were significantly damaged and some 
were unable to respond in the days, weeks, and sometimes months after the event.

Most critical and essential facilities (shelters excluded) were housed in older 
existing buildings and most, if not all, apparently were not mitigated to resist 
known hurricane risks. If these critical and essential operations were housed in 
buildings constructed to the 2001 FBC, the 2004 FBC, or the model codes such as 
the IBC or NFPA 5000, designs for the structural and building envelope systems 
(including debris impact resistance) are required to provide levels of 
protection from wind and windborne debris. As a result, these design 
requirements may have prevented enough damage to allow these buildings to remain 
operational after the event. Alternatively, if key areas of the building had 
been mitigated or retrofitted for wind and windborne debris design requirements 
that are specified in the current code, building damage and loss of function 
would have most likely been reduced. 

Widespread damage to large rolling and sectional doors and roof systems at fire 
stations is preventable. If these older buildings had been designed or mitigated 
to the 2001 FBC for 120 mph (3-second peak gust) winds and associated windborne 
debris impact protection over openings applicable in most of Charlotte County, 
the observed damage may have been avoided. Furthermore, many critical facilities 
were housed in lightly engineered buildings such as pre-engineered metal 
buildings. When this was the case, few if any of these lightly engineered 
structures were mitigated or retrofitted to design levels other than minimum 
code requirements for general use buildings in place at the time of 
construction. 

The performance of buildings used as hurricane shelters also varied widely 
during Hurricane Charley. In Charlotte County, the MAT visited the two shelters 
(schools) on the state approved list that tracks and identifies shelters (the 
yearly Statewide Emergency Shelter Plan [SESP]); these shelters are on the list 
despite being located within the storm surge inundation zone for a Category 3 
hurricane. At these two schools, the county was operating shelters in the areas 
of the school designated by the SESP. These areas only experienced minor roof 
covering (with some water leakage problems) damage during the storm; the 
structural systems, roof deck, and shutter systems performed without failure.

However, in De Soto County, the new multi-purpose Turner Agri-Civic Center 
designed for use as a shelter experienced a partial end wall/roof collapse. In 
Lee County, the county opened shelters for residents of the barrier islands with 
the belief that these shelters were recovery shelters that would not be 
impacted by hurricane force winds; most of these shelters were also located in 
Category 3 storm surge inundation zones, but these buildings experienced 
tropical force winds (with gusts near hurricane strength) and roof covering 
damage with associated rain water intrusion damage. Fortunately, due to the 
compact size of Hurricane Charley, only limited significant storm surge was 
generated by the hurricane and none of shelters in Charlotte and Lee Counties 
were flooded.

The building damage to critical and essential facilities experienced during 
Hurricane Charley led to a significant, and avoidable, loss of function. 
Specific conclusions for critical and essential facilities based on these 
observations are:

--When older buildings are used as critical and essential facilities, damage 
will likely occur to the roof covering, wall coverings, window and door systems, 
and rooftop equipment. This damage will often lead to significant loss of 
function at the facilities.

--Some buildings designed to critical and essential facility requirements 
experienced damage and partial failures during the hurricane due to lack of 
protection from windborne debris. Lack of protection of windows was common at 
hospital and medical buildings, and led to window failures and severe damage to 
building interiors and contents.

--Large rolling and sectional doors at fire stations can be purchased and 
installed to provide protection from high-wind and debris impact, but 
catastrophic failure of the doors can occur when these systems are not installed 
correctly and when track systems are not reinforced for the larger wind loads. 
These door failures led to pressurization of the buildings and, in some cases, 
roof collapse that should have been prevented by proper installation of the 
high-wind rated doors. 

--Rooftop equipment loss such as loss of HVAC units and vents, antennas, 
communication dishes, and lightning protection systems was prevalent. All of 
these failures caused damage to roof coverings (and sometimes supporting 
structural systems) that often resulted in rain water intrusion into the 
facilities.

--Critical facilities housed in lightly engineered buildings such as pre-
engineered metal buildings will continue to experience damage and loss of 
function unless the designs are substantially improved and close attention is 
given to all connections of the structure and the building envelope.

--Windborne debris could injure or kill first responders at fire and police 
stations, as well as EOCs, late arrivers at shelters, or those seeking medical 
attention at hospitals. Although people are not usually outdoors during 
hurricanes, buildings used as critical and essential facilities can be the 
exception. It is common for people to arrive at these facilities during a 
hurricane and additional efforts should be made to reduce the potential for 
windborne debris at these sites. 

--In some communities, shelters sited in a storm surge inundation zone and 
located in the projected landfall area were used during the hurricane. Only the 
unique nature of this storm with a small radius of maximum winds and landfall 
near low tide kept the shelters from being flooded. Shelters located in the 
projected landfall area and sited in storm surge zones place large numbers of 
individuals at risk of injury or death due to flooding from the storm surge. 

--Designing to minimum Enhanced Hurricane Protection Area (EHPA) requirements 
does not guarantee that a building being used as a shelter will be properly 
designed and constructed to resist extreme wind events.

--ARC 4496 provides a baseline for a shelters integrity and performance, but 
meeting this criterion does not guarantee that the building will resist wind and 
windborne debris associated with all hurricanes. 

--Peer review of the design of critical and essential facilities would greatly 
improve the likelihood that a building has been adequately designed to resist 
extreme winds.

--Special inspections for key structural items and connections, and for 
installation of envelope components would help ensure the performance of 
critical and essential facilities.


7.7   Observed Mitigation Successes

In addition to the successful performance of structures built to the 2001 FBC, 
successes in older structures and structures mitigated to resist wind and flood 
loads were observed. Examples of successful residential, commercial, and 
critical/essential facility mitigation are provided in this section. In addition 
to these observed mitigation successes, additional examples of mitigation 
successes can be found on the DHS/FEMA Mitigation web site at 
http://www.fema.gov/fima/bp.shtm. 

7.7.1	Mitigation Success in Residential Construction
Two examples of well-executed mitigation against flood and wind were observed. 
First, on North Captiva Island, where Hurricane Charley battered buildings with 
estimated winds in excess of the 130 mph (3-second peak gust) winds required by 
the 2001 FBC, many homes withstood the winds with minimal damage. Figure 7-1 
shows a residence constructed to the design requirements of the 2001 FBC. This 
building had a well-secured standing seam metal roof that performed well and 
only experienced some light trim damage (shown in the center of the photo). The 
windows and doors were protected with a combination of impact resistant, 
laminated glazing products and shutters. In addition, the residence was elevated 
above the predicted 100-year flood level on an open pile foundation. 

Second, many residences and businesses on the north end of Fort Myers Beach have 
been elevated on pile foundations to allow water to pass beneath these V-zone 
structures. In one of the few areas investigated by the MAT that experienced 
flooding and overwash, Fort Myers Beach experienced storm surge from Charley. 
The house in Figure 7-2 is one of eight residential units located along the 
beach in this small development. During Charleys storm surge, water 
approximately 2 to 3 feet deep washed through the development (see water mark on 
door of enclosure below house). These older residences, however, were atop pile 
foundations that allowed the floodwaters to pass safely beneath the houses. As a 
result, only minor damage to enclosures and access stairways was experienced. 
This success illustrates the use of best practices on older homes that has been 
recommended by FEMA in publications such as FEMA 55, Coastal Construction 
Manual.

Figure 7-1. Photograph. Residence constructed to the design requirements of the 
2001 FBC performed well and only experienced some light trim damage (shown in 
the center of the photo) (North Captiva Island).

Figure 7-2. Photograph. Older residence atop pile foundation that allowed 
floodwaters to pass safely underneath, resulting in only minor damage to 
enclosures and access stairways (Fort Myers Beach)

7.7.2	Mitigation Success in Commercial Construction
When Hurricane Charley hit Fort Myers Beach, the Lighthouse Resort Inn and 
Suites shown in Figure 7-3 remained dry, undamaged, and full of customers, while 
other hotels and motels on the island were damaged or flooded, and closed. In 
the past, the Lighthouse Resort would also have been closed. Over the last two 
decades, seven hurricanes have caused flood and wind-related damage to the 
resort, resulting in nearly $l00,000 in repair costs per event. The resort, 
which sits 200 feet from the beach, had been elevated as part of a joint State 
of Florida, Federal, and local mitigation project. In approximately 1 year, the 
owners have saved nearly $200,000 in repair costs alone, almost 50 percent of 
their mitigation investment. 

Figure 7-3. Photograph. Exterior view of the elevated Lighthouse Resort Inn and 
Suites, which remained dry and undamaged after Hurricane Charley (Fort Myers 
Beach)

At the Charlotte County South Annex building, significant damage and loss of 
function was prevented when new shutters were installed to protect the building 
during Hurricane Charley. The galvanized metal shutters were funded in part by a 
grant to the State of Florida under FEMAs Hazard Mitigation Grant Program 
(HMGP). With the shutters in place, the Annex suffered only minimal damage. An 
investment of less than $10,000 saved the taxpayers over half a million dollars 
in losses avoided in just one hurricane event. 

The countys grant application was approved in 2003. Shutters were purchased for 
$9,546, using a combination of local funds and the HMGP grant and installed for 
the first time on August 11, 2004, in anticipation of Hurricane Charley. Two 
days later, they were severely tested when 125 mph winds slammed the coastal 
city. 

If it wasnt for the shutters, said George Dahlke, Charlotte County Facilities 
Construction and Maintenance Project Manager, all the glass in the building 
would have been gone. Without the windows, we feel that the uplift [of the wind] 
would have taken the roof off. (Figure 7-4)

Figure 7-4. Photograph. Exterior view of the galvanized shutters that protected 
the Charlotte County South Annex (Punta Gorda)

Only one shutter was damaged. Hit hard by flying debris, the shutter panel was 
dented, breaking the glass behind it, but remained in place and prevented the 
wind from penetrating the building and causing major wind and water damage. 
Although windborne debris damaged the roof, creating some leaks and damaging 
some of the buildings contents, this damage was minimal in contrast to other 
buildings according to Charlotte County Facilities Manager, Michael Sheridan. 

The Health Department Building, without shutters, located about a mile away, is 
badly damagedbroken glass panels, roof and ceiling upliftedtheyre still not 
in service [nearly 5 weeks later]. It may cost $500,000 to repair, he related. 
Mr. Sheridan credited the shutters on the 20,000-square foot South Annex 
building with saving the county approximately $600,000 in repairs. That is the 
amount that would have been needed had the glass panels been broken, allowing 
wind and rain water to penetrate the building. The total repair estimate for the 
South Annex is $80,000. Eighty percent is earmarked for roof repairs due to 
damage from windborne debris. The remainder is for damage to the contents from 
the roof leaks. The monetary loss avoided by installing the shutters is 
$520,000. 

Employees and the community also avoided losses in time off from work and 
interruption of services due to lengthy repairs. Just 2 days after Hurricane 
Charley, with minimal repairs still in progress, the South Annex was up and 
running. Employees were back at work, providing much-needed services to 
Charlotte County residents. 

7.7.3	Mitigation Success in Critical and Essential Facility 		
	Construction
A success in school design and construction that resulted in no loss of function 
was observed at the Sanibel School on Sanibel Island (Figure 7-5). Dedicated on 
August 10, 2004, less than a week prior to the landfall of the storm, this 
school was designed and constructed to the 2001 FBC. Although the school 
building likely experienced wind speeds that were below the 130 mph (3-second 
peak gust) design wind speed for the site, the building did experience hurricane 
force winds around the level of Category 2 winds and sustained little damage. 

Figure 7-5. Photograph. Courtyard of the newly constructed Sanibel School that 
was operational immediately after Hurricane Charley passed

Damage at the school was limited to loss of gutters on the east side of the 
building and some wind-driven rain issues. At the time of the MAT visit, the 
school was preparing for an on-time school opening and did not experience a loss 
of function as a result of the hurricane. In addition to avoiding significant 
damage to the school building itself, the successful performance of the design 
allowed residents of Sanibel Island to move forward with their rebuilding 
process because the school was functioning.