Tornado Protection: Selecting Refuge Areas in Buildings 

Chapter 3: Case Studies




A large number of schools have been destroyed or heavily damaged by tornadoes, and 
there have been many injuries and deaths. The three school buildings presented as case 
studies in this booklet were selected for the following reasons:  

 All were hit by different, but intense storms. 

 The three structures varied in size, age, and type of construction. 

 All were designed by different architects and engineers to national building codes. 

 All had to be partially or totally destroyed later because of the extent of the 
tornado damage. 

The building damage was examined by teams of structural engineers, building 
scientists, specially trained members of engineering and architectural faculties and 
firms, building administrators, and representatives of the archi-
Guidance for Refuge Area Selection 
Detailed evaluation checklists for selecting the best available refuge areas in existing 
buildings and guidance for designing and constructing shelters are presented in FEMA 
publication 361, Design and Construction Guidance for Community Shelters(for more 
information, see the section of this booklet titled Information Sources). 
tectural firms that designed the buildings. 
The determination of the best available refuge areas in the three buildings (shown on 
floor plans presented later in this chapter) was based on three sources of information, in 
the following order of importance: 

 persons who were in each building during the tornado 

 building examinations by engineers and architects 

 aerial photographs taken shortly after the storms 

The identified refuge areas in these buildings are the best that were available in each of 
the three buildings when the storms occurred. 
These case studies are presented here with two goals: 

 to help building designers and administrators locate accurately the parts of a 
building that would likely be left standing after a tornado-before the tornado strikes 

 to help architects and engineers design buildings that offer occupants excellent 
tornado protection 




Xenia Senior High School

Xenia, Ohio 
Building population: 1,450, including staff 
12 students, 3 staff in building during tornado 
Tornado 
direction: 
From southwest 
Damage 
intensity: 
F5 
Time: 
4:45 p.m. 
Date: 
April 3, 1974 

Xenia Senior High School (Figure 3-1) was a two-story, slab-on-grade building without 
a basement located on the north side of Xenia, Ohio. It faced Shawnee Park to the 
west. 
The massive tornado hit 1 hour and 45 minutes after school dismissal. It was spotted by 
a student who was leaving the school. She alerted drama students who were rehearsing 
in the auditorium. The students ran and dove for shelter in a nearby corridor. 
The tornado passed directly over the school. Two school buses came to rest on the 
stage where the students had been rehearsing. Some of the students were treated for 
injuries at a nearby hospital. 
The building was found to be unsafe to enter and was demolished.



Construction 

The construction types varied among the main parts of the school-original building, 
three additions (A, B, and C): 
Original building and addition B: Lightweight steel frame, open-web steel joists, 2-inch 
gypsum roof deck. 
Addition A: Loadbearing masonry walls, hollow-core precast concrete roof planks. 
Addition C: Precast concrete frame, concrete double-tee floor/roof beams. 
Girls' gym: Loadbearing masonry wall, precast concrete tee beams. 
Auditorium and boys' gym: Loadbearing masonry walls, steel trusses.



Tornado Damage 

The tornado passed directly over the school, engulfing the entire building and the 
adjacent fieldhouse to the south (Figure 3-2). 
The enclosure walls failed on the west and south sides, allowing the winds to enter the 
building. The roofs collapsed over the three large spans-the auditorium, the boys' 
gym, and the girls' gym. The lightweight roof over the original two-story building was 
torn off by the extreme winds.



Hazardous Elements 

All windows on the west and south sides were blown into the interior. The high single-
story, loadbearing masonry walls of the long-span rooms failed, allowing the roofs to 
fall in. The unbaffled west entrances allowed the east-west corridors to become wind 
tunnels. 
Debris from nearby houses, vehicles, and Shawnee Park became missiles, many of 
which hit and entered the school. The 46-foot-high masonry chimney collapsed. A non-
loadbearing second-floor wall on the north side collapsed onto a lower roof.




Protective Elements 
The only portion of the original building that offered refuge was the lowest floor (first 
floor). The completely interior spaces remained intact, especially the smaller spaces. 
Most of the corridors that were perpendicular to the storm path offered considerable 
protection (Figures 3-3 and 3-4). 
The concrete structural frame of addition C remained intact. As a result, interior 
portions of the second floor provided refuge for some custodians. 
The heavy concrete roof remained in place, wherever the supports were rigid frames. 
It also remained intact in addition A, with its loadbearing walls. 
The concrete block interior partitions stopped incoming missiles from reaching 
adjacent interior spaces. 
As a result of combinations of the above protective elements, extensive refuge space 
existed in scattered locations throughout the building (Figure 3-4).



Selecting Refuge Areas 

An understanding of the effects of hazardous and protective elements allows the best 
available refuge areas in an existing building to be identified. The checklists in FEMA 
publication 361 should be used to confirm that the selected refuge areas are the best 
available.



Comments 

"The cast had just done the big dance number from the show. They had done a sloppy 
job and I was just getting ready to tell them to do it again when a girl yelled, 'Hey, you 
want to see a tornado? There's a funnel cloud outside.' I came very close to telling 
everyone to forget it and do the dance again. That would have been a fatal mistake. 
"Instead, I jumped off the stage and told everyone to follow me so that we could get a 
view of it. We ran out the front doors of the school nearest the auditorium. It looked like 
a lot of dirt or smoke swirling around. We couldn't see anything that looked like a 
clearly defined funnel cloud. We were looking out at the park across from the school. 
The mass of wind, dirt, and debris was everywhere. I would say between 100 and 200 
yards away. Cars parked in front of the school started to bounce around a bit from the 
force of the winds. It was really beyond belief. 
"Someone said we'd better take cover, so we turned around and ran from the hallway 
we were in into the center hall that ran north and south. Before we could reach the 
center hall, the lights went out.
 
"I only opened my eyes a couple of times. When I did, I saw large pieces of dirt and 
wood flying through the air. Lockers clanged open and shut, and several sections of 
lockers were actually pulled from the wall and thrown onto the floor. One section 
barely missed some of my students when it came out of the wall. 
"I was sitting directly across from one of the restrooms, and a metal door kept flying 
open and shut constantly during the time that the tornado was on us. That was my 
greatest fear." 
English/Drama Teacher 


"I was watching the sky, and the lightning seemed to get worse. The minutes went by, 
and it at first had been going vertically, and slowly it started to go on angles. 
"The black cloud looked like it was about 2 miles away from the school. As I watched, 
the lightning came concentrated into the middle of the cloud and began going on angles 
until it was horizontal. 

"For a few seconds, I didn't know that the shrinking cloud was forming a tornado 
funnel. The funnel was a whitish-grey color more in the shape of a column than it was 
a funnel. I realized it was a tornado when I saw air currents begin to swirl. At first I was 
not afraid. Instead, I was fascinated that you could really see air currents in it. 
"I went to the main office to get the principal, but the office was locked and everyone 
was gone. Just as I started to move, the drama cast started to rehearse a song in the 
auditorium 

"I walked down the aisle past 24 rows of seats to one of my friends in the second row 
and said, 'Hi Paul, have you ever seen a tornado?' He said 'Ya' and put his arm up on 
the back of a chair like he's getting ready for a long conversation. I said 'Neat, there's 
one across the street.' He looked up at me. Then they all stood up and started to walk 
out. They got about halfway out and started running. 

"All the kids were yelling, 'Hey, neat, look at that' and things like that. All of a sudden 
everyone was dead silent for about 4 seconds. Then everyone started screaming and 
yelling at once. Julie yelled, 'Get to A-1.' I said, 'Get to the southwest corner.' Mr. 
Heath turned around and yelled, 'Go to the main hall.' So all the cast started to rush out 
of the doors and promptly got stuck, so they had to wait and go slow and go out one or 
two at a time." 
Student (spotter) 

"When we were warned about the tornado, we all ran to the door to look at it. I was 
about the last one to arrive there, and I stood there very long until someone yelled from 
around the corner to get over there. The last thing I saw the tornado doing was picking 
up my car which was parked out on the street. 

"I then ran around the corner and found everyone already lying along each side of the 
wall and some around the corner. I then ran to the intersection of the two halls and laid 
alongside the wall. 

"When it was all over, I was buried from the waist down in little pieces of gravel, 
boards, and a lot of water from the lake across the street in the park." 
Student 
"The first place I ran to was this little cubbyhole right in front of the girls' restroom 
door. If I had stayed there, I would have been splattered across the hall, because it blew 
so hard it almost came off its hinges. For some reason, which I cannot account for, I 
dived across the hall right after the lights went out and got to the other side of the hall 
just as the front doors were breaking. 
"I kept my eyes open, which was stupid on 
my part. I was looking down at the floor 
rather than out and I could see big chunks of wood and debris flying down the hall by 
my feet. It was incredible." 
Student



St. Augustine Elementary School and Gymnasium 
Kalamazoo, Michigan 
Building population: Approximately 400, including staff 
One staff person in the building during tornado 
Tornado 
direction: 
From west 
Damage 
intensity: 
F2-F3 
Time: 
4:09 p.m. 
Date: 
May 13, 1980 



St. Augustine Elementary School Building 

The St. Augustine Elementary School was a two-story, 17-classroom building 
constructed in 1964. Classes had been dismissed when the tornado struck. Only the 
facility engineer remained in the building. He took refuge in a janitor's closet on the 
first floor and escaped injury. 


Construction 

The structural system consisted of 3-foot-wide masonry piers constructed of 8-inch 
concrete masonry units and 4-inch face bricks. The piers were 8.7 feet apart. Steel 
beam lintels spanned the window openings between the piers. Steel open-web joists at 
2 feet on center supported the 1.5-inch steel roof deck, which was welded to joists. The 
top chords of the joists were extended to provide a 2-foot overhang. 
Tornado Damage 
The tornado winds lifted part of the roof and collapsed the second-floor piers in one 
wing of the school building (Figures 3-8, 3-9, and 3-10). The wind and windborne debris 
blew in most of the windows, and windborne debris was found in the classrooms 
(Figure 3-11). The exterior solid-core wood doors stayed in place and kept the debris 
out. Wired glass windows near the exterior doors remained intact. The interior doors to 
the classrooms remained in place although the hinges were damaged. The school was 
damaged to an extent where demolition was required. 
Hazardous Elements 
The structural system of unreinforced masonry piers collapsed and almost one-third of 
the second-floor lightweight roof structure was lifted. Roof removal occurred over the 
classrooms as well as over the corridor. Most of the skylights in the corridors were 
removed by wind or broken by windborne de-
bris. Almost all the windows on both floors were broken. Windborne debris	
and broken glass were found in the classrooms.	Collapsed second floor of St. 
Augustine Elementary School building. 


Protective Elements 

The structural system of the first floor remained intact. The exterior solid-core wood 
doors stayed in place and kept the debris out. The interior walls and doors were able to 
prevent debris from entering the corridors. The corridors, offices, and toilet areas on the 
first floor, which had two or more walls to the exterior, would have protected the 
occupants from serious injury (Figure 3-12). 
Selecting Refuge Areas 
An understanding of the effects of hazardous and protective elements allows the best 
available refuge areas in an existing building to be identified. The checklists in FEMA 
publication 361 should be used to confirm that the selected refuge areas are the best 
available.



St. Augustine Elementary School Gymnasium 

An 80-foot by 100-foot, 23-foot-high gymnasium building was adjacent to the school 
building. 
Construction 
The structural system consisted of loadbearing masonry walls constructed of 12-inch 
concrete masonry units and 4-inch face brick. The walls were not reinforced in the 
vertical direction. The roof structure consisted of long-span steel joists spanning 80 feet 
between the walls and spaced 6 feet apart. The steel roof deck was connected to the 
joists with puddle welds. 


Tornado Damage 

The building was destroyed (Figures 3-13 and 3-14). The loadbearing west wall 
collapsed inward, and the east wall fell outward. The roof fell in the building when the 
walls collapsed. 
Hazardous Elements 
Slender unreinforced masonry walls and long-span roof structure. 
Protective Elements 
None




Observations: School Building and Gymnasium 

The unreinforced masonry walls combined with the lightweight roof structure in the 
building as well as the gymnasium building were vulnerable to collapse in windstorms. 
Gymnasium buildings are not considered suitable for occupant protection because they 
usually include tall walls and long-span roofs. Lightweight roof structures that are not 
adequately anchored can be lifted in windstorms. Except in violent (F4 and F5) 
tornadoes, the lower floor (in two-story or higher buildings) generally provides good 
protection for occupants when there are two or more walls between the refuge area and 
the outside. 
Kelly Elementary School




Moore, Oklahoma 
Building population: 490, including staff 
Tornado direction: 
From southwest 
Damage intensity: F4 
Time: 7:25 p.m. 
Date: May 3, 1999 


The Kelly Elementary School was a one-story slab-on-grade building, without a 
basement, located in Moore, Oklahoma. 
The tornado hit after school hours and passed just to the north of the site. Damage to the 
school building was both severe and extensive (Figure 3-15). As discussed in the 
Lessons Learned section in this case study, the remaining structure was demolished 
and the school was rebuilt. The new school includes structural elements designed to 
provide increased wind resistance. 



Construction 
Three basic wall types were used in the construction of the school: 

 reinforced masonry 

 unreinforced masonry topped by reinforced bond beams 

 lightweight steel frame with masonry infill 

The roof system consisted of open-web steel roof joists, metal decking, and a built-up 
roof. Wall and roof construction of this type is common to many schools in the United 
States. 

Hall corridors were the designated areas of refuge (see Figure 3-16). The corridor 
walls were of lightweight steel frame with masonry infill. The infill extended to a height 
of approximately 7 feet. Above this height were clerestory windows that extended to 
the tops of the walls. Had the halls been occupied during the tornado, many injuries and 
deaths would have occurred (see Figure 3-20, later in this chapter). 


Tornado Damage 

Wall and roof structures, including those of designated areas of refuge, failed under the 
combination of uplift and lateral loads caused by the tornado winds. Connections 
between bond beams, joists, and walls were adequate for gravity loads, but could not 
resist the high uplift loads caused by the wind. 

Unreinforced masonry walls failed when the roof system was lifted or removed by 
tornado winds (Figures 3-17, 3-18, and 3-19). Figures 3-17 and 3-19 show failed interior 
and exterior walls, respectively. Figure 3-18 shows the separation of the reinforced 
bond beam (indicated by circles) from the upper part of a corridor wall. The inclusion 
of clerestory windows in some corridor walls contributed to their failure under loads 
imposed by tornado winds (Figure 3-20). 

Figure 3-18 Corridor area. Separation of reinforced bond beam (indicated by circles) 
from supporting wall. 
 
Figure 3-20 Failed interior corridor walls.

These  walls consisted of unreinforced brick 
masonry infill between steel-frame members.The brick masonry extended to a height 
of approximately 7 feet. Clerestory windows extended from the top of the masonry to 
the tops of the walls. 

Inspection of the roof damage revealed that the roof decking failed at the points where 
it was welded to the tops of the steel trusses. Although the spacing of the welds 
appeared to be consistent with standard practice, the welds were not strong enough to 
resist the wind uplift forces (Figure 3-21). 

Damage was also caused by the impact of windborne missiles. Figure 2-3, in Chapter 
2, shows a steel door that appeared to have been opened by the impact of a heavy 
object. This door led into an area where the roof was missing. The opening created by 
this breached door may have allowed wind to enter the building and create internal 
pressure that increased the load on the building envelope. Figure 3-22 shows damage to 
a laminated glass window hit by a table. 

Figure 3-21 
Failed roof structure showing broken welds between metal roof deck but the glass 
remained in its frame.
and tops of joists (upper circle) and lack of vertical reinforcement
(bottom circle).



Hazardous Elements 

Walls with clerestory windows, such as the corridor walls of the designated areas of 
refuge, have limited capacity to resist lateral forces. 

Unreinforced masonry walls failed when the reinforced bond beams at the tops of the 
walls failed. 

Welds between the roof decking at the tops of the metal joists failed because they were 
not strong enough to resist the uplift. 

Unprotected doors and windows can be breached by windborne missiles. The resulting 
openings allow wind to enter the building, where it causes increased pressures on the 
building envelope. 


Protective Elements 
None 


Lessons Learned 

Because the damage to Kelly Elementary School was so great, the school was 
demolished and completely rebuilt. The new building, although constructed on the 
same footprint, incorporated several structural improvements specifically designed to 
provide improved resistance to extreme winds and create refuge areas for the school's 
occupants. As in the original building, the central corridors of the three wings are the 
designated refuge areas (Figures 3-23 and 3-24). 

The creation of refuge areas in the new school involved, among other improvements, 
the design and construction of stronger loadbearing walls, roofs, roof-to-wall 
connections, and wall-to-foundation connections. Figure 3-25 is a typical cross-section 
of the top of a safe area (corridor) wall in the new school. As shown in this figure, the 
wall is constructed of reinforced concrete masonry. Note the continuous, closely 
spaced (8 inches on center) vertical reinforcement bars, fully grouted block cells, 6-
inch-thick reinforced concrete roof slab, and strong connection between the roof slab 
and wall. The new ceilings over the corridors are constructed of poured reinforced 
concrete, which will provide nearly ultimate resistance to winds and damaging 
missiles. 
The improvements discussed here are designed to prevent the types of damage to 
interior corridor walls and roofs shown previously in Figures 3-17, 3-18, 3-20, and 3-21. 
The reconstruction of the Kelly Elementary School is a good example of how refuge 
areas can be incorporated into new construction.