TR-147 Fire at Watts Bar Hydroelectric Plant - US Fire Administration ...

U.S. Fire Administration/Technical Report Series
Fire at Watts Bar
Hydroelectric Plant
Rhea County, Tennessee
USFA-TR-147/September 2002
Homeland
Security

U.S. Fire Administration Fire Investigations Program
The U.S. Fire Administration develops reports on selected major fires throughout the country.
The fires usually involve multiple deaths or a large loss of property. But the primary criterion
for deciding to do a report is whether it will result in significant “lessons learned.” In some
cases these lessons bring to light new knowledge about fire--the effect of building construction or
contents, human behavior in fire, etc. In other cases, the lessons are not new but are serious enough
to highlight once again, with yet another fire tragedy report. In some cases, special reports are developed
to discuss events, drills, or new technologies which are of interest to the fire service.
The reports are sent to fire magazines and are distributed at National and Regional fire meetings. The
International Association of Fire Chiefs assists the USFA in disseminating the findings throughout the
fire service. On a continuing basis the reports are available on request from the USFA; announcements
of their availability are published widely in fire journals and newsletters.
This body of work provides detailed information on the nature of the fire problem for policymakers
who must decide on allocations of resources between fire and other pressing problems, and within
the fire service to improve codes and code enforcement, training, public fire education, building
technology, and other related areas.
The Fire Administration, which has no regulatory authority, sends an experienced fire investigator
into a community after a major incident only after having conferred with the local fire authorities
to insure that the assistance and presence of the USFA would be supportive and would in no way
interfere with any review of the incident they are themselves conducting. The intent is not to arrive
during the event or even immediately after, but rather after the dust settles, so that a complete and
objective review of all the important aspects of the incident can be made. Local authorities review
the USFA’s report while it is in draft. The USFA investigator or team is available to local authorities
should they wish to request technical assistance for their own investigation.
For additional copies of this report write to the U.S. Fire Administration, 16825 South Seton Avenue,
Emmitsburg, Maryland 21727. The report is available on the Administration’s Web site at http://
www.usfa.dhs.gov/

Fire at Watts Bar
Hydroelectric Plant
Authored by: Jennifer L. Roberson
Hollis Stambaugh
This is Report 147 of the Major Fires Investigation Project conducted
by Varley-Campbell and Associates, Inc./TriData Corporation under
contract EMW-97-C0-0506 to the United States Fire Administration,
Federal Emergency Management Agency.
Homeland
Security
Department of Homeland Security
United States Fire Administration
National Fire Data Center

U.S. Fire Administration
Mission Statement
As an entity of the Department of Homeland
Security, the mission of the USFA is to reduce
life and economic losses due to fire
and related emergencies, through leadership,
advocacy, coordination, and support.
We serve the Nation independently, in coordination
with other Federal agencies,
and in partnership with fire protection and
emergency service communities. With a
commitment to excellence, we provide public
education, training, technology, and data
initiatives.
Homeland
Security

ACKNOWLEDGMENTS
The U.S. Fire Administration greatly appreciates the cooperation received from the following people
and organizations during the preparation of this report:
U.S. Tennessee
Valley Authority (TVA)
David J. Icove, P.E., TVA Police
Thomas K. Heffernan, Safety, Transmission Power Supply, TVA
H. Lee Hustead, Training Supervisor, TVA
Rhea County
Emergency
Management
Billy Cranfield, Rhea County Emergency Manager
Wolf Creek Fire Department
Spring City Fire Department
Evensville Fire Department

Table of Contents
Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Summary of Key Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Building Structure and Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Incident Narrative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Injuries and Fatalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
The Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Damage Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Key Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Building Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Fire Protection Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Risk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Pre-planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Power Generation and Terminal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Compliance with Life Safety Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Fire Origin and Spread . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Lessons Learned . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Fire at Watts Bar
Hydroelectric Plant
September 27, 2002
Executive Summary
On September 27, 2002, at approximately 8:30 a.m., the Rhea County, Tennessee 9-1-1 Center began
receiving calls about a fire at the Watts Bar Hydroelectric Plant. The plant, built between 1939-42
and operated by the U.S. Tennessee Valley Authority (TVA), is constructed of steel and concrete, and
sits on the Tennessee River midway between Knoxville and Chattanooga. The dam supplying water
to the hydroelectric plant is 112 feet high, and approximately one-half mile long. The plant has a
generating capacity of 175,000 kilowatts. It supplies power for TVA, and provides back-up power
for the Watts Bar Nuclear Power Station located directly south of dam.
At the time of ignition—estimated to be 8:15 a.m.—there were five employees working in the
hydroelectric plant control room. The fire spread rapidly, giving these personnel only four minutes
to realize that there was a fire and to escape. All five were able to evacuate the control building,
although each employee suffered smoke inhalation. There were no injuries.
The first call concerning the fire was made by a water delivery man who was at the control building.
A second call was made from the Watts Bar Lake Resort located down the street from the plant.
The fire began in the vertical cable shaft and spread so rapidly to the control building and burned so
intensely that fire suppression personnel were unable to make entry into the building until 9:10 a.m.
The fire self-extinguished due to lack of fuel at some point, although investigators could not determine
precisely when this occurred. The intensity of the heat generated during the fire prevented
firefighters from accessing the seat of the fire until 12:17 p.m. In all, over forty personnel from both
volunteer and industrial fire departments responded to the fire.
A multi-agency investigation team lead by the TVA Police began the origin and cause investigation on
the following day, September 28 th . Based upon physical evidence, the area of origin was determined
to be within a 120-foot vertical cable shaft running from the hydroelectric plant to the control building.
Fire modeling was then used to determine fire development and spread, and to estimate the
temperature of the fire. The hydroelectric plant has remained closed since the fire, at a business loss
of approximately $100,000 per day.
Although many people perceive a steel and concrete structure as not being a fire risk, this fire illustrated,
once again, that a fire in an electrical system can quickly be life-threatening regardless of the
structure type.

U.S. Fire Administration/Technical Report Series
Building Structure
Issue
Fire Protection Systems
Communications
Risk
Pre-planning
Training for Response Personnel
Power Generation and Transmission
Compliance with Life Safety Code
Building Structure and Site
Summary of Key Issues
Comments
The concrete and steel construction of the building trapped heat, elevating temperatures.
In addition, the plant had a constant breezes flowing through it, from the dam
up through the control building. Five people nearly became trapped due to their
location in the building, rapidity of fire development, and difficulty of egress.
There were no fire suppression systems within the control building. The annunciator
alarm wires were severed as a result of the fire.
Due to topography, there was very little radio reception. Moreover, radios for the
Watts Bar Nuclear Power Station fire brigade must maintain a weak signal due to
the power station. Most decisions and communications were face-to-face. Once the
cables in the shaft were cut, communication with personnel in the powerhouse was
lost. Employees there were unaware of fire in the control building.
The potential for a fatality was great, both within the control building and the powerhouse.
Injuries to personnel in the powerhouse were prevented because a senior
supervisor had a flashlight and led the employees to safety.
Local responders had no pre-plans, and had never been through the building except
as tourists. Emergency plans for the building were kept in the building, and as a
result were inaccessible to responders.
Local responders and WBN fire brigade personnel were unfamiliar with tactics for
fighting a fire in this type of structure. Additionally, firefighters were unfamiliar with
TVA tactics for fighting electrical fires.
There was uncertainty about whether some areas of the building were still electrically
charged. In fact, while power to the structure had been cut, the batteries retained
their charge for another full day.
WBH had been grandfathered in under the Life Safety Code, and so was non-compliant.
This is now being addressed by TVA.
The Watts Bar Hydroelectric Plant is located at mile marker 529.9 of the Tennessee River, sitting halfway
between Knoxville and Chattanooga, in Rhea County. It is one of nine TVA dams located on the
river, and has been in continuous service since it opened in 1942. Originally constructed to provide
power to Oak Ridge Laboratories and the public, and flood control for the Tennessee Valley, the plant
still provides those services along with backup power to the Watts Bar Nuclear Power Station and
cooling water for the reactor. The plant is bordered to the north by State Road 68, to the West and
South by the Watts Bar Nuclear Power Station complex, and to the East by the Tennessee River and
Miegs County. The hydroelectric plant consists of a powerhouse, a control building, and a switchyard.
The hydroelectric plant sits adjacent to the Watts Bar Nuclear Power Station, the two facilities
are operated by different TVA department.
The hydroelectric powerhouse sits directly on the Tennessee River, and consists of five 30,000-kilowatt
unites. Water is fed directly into turbines to generate power, while excess water flows through
sluice gates connected to the powerhouse. Power created by these units is fed from the powerhouse
to the control building and the switchyard via copper cables covered in butyl rubber insulation. The
cables run directly from the generators to the switchyard by way of an L-shaped cable shaft. The shaft

TVA departments.
The hydroelectric powerhouse sits directly on the Tennessee River, and consists of five
USFA-TR-147/September 2002 3
30,000-kilowatt units. Water is fed directly into turbines
runs
to generate
horizontally
power,
west
while
from
excess
the generators
water flows
for
through
approximately
200’, sluice then gates runs connected vertically to from the powerhouse. the powerhouse Power to created the control
building by these and units cable is fed switchyard from the through powerhouse a 120’ to shaft. the control The tunnels
are constructed of concrete, with cable trays lining the walls on
building and the switchyard via copper cables covered in
both sides of the horizontal shaft. The five generator leads are
carried butyl rubber through insulation. a concrete The conduit cables located run directly on the from floor the in the
middle generators of the to horizontal the switchyard shaft. by The way diagram of an to L-shaped the right cable shows a
cross-section shaft. The shaft of the runs horizontal horizontally shaft. west from the
Ten generators platforms for are approximately located in the 200’, vertical then cable runs vertically shaft. The platforms
from
are
the
made
powerhouse
of steel
to
grating,
the control
and are
building
spaced
and
vertically
cable
at tenfoot
intervals. The platforms can be used to visually inspect the
cables,
switchyard
and to
through
perform
a
maintenance.
120’shaft. The
Platforms
tunnels are
are accessed and
connected constructed by of steel concrete, ladders—one with cable ladder trays connects lining two the walls platforms,
with on both ladders sides on of alternating the horizontal sides shaft. of the shaft The five as they generator ascend.
More leads specifically, are carried the through cable shaft a concrete contained conduit several located types on of the electrical
cable, floor including:
the middle of the horizontal shaft. The diagram to
the • right Generator shows a leads cross-section for five hydroelectric of the horizontal units consisting shaft. of two 1750 MCM (Thousand Circular
Mils) diameter cable per phase running in conduit and a concrete duct bank at the west end
of the shaft.
Ten platforms are located in the vertical cable shaft. The platforms are made of steel
grating,
• One
and
set
are
of
spaced
480V cable
vertically
running
at ten-foot
from two
intervals.
separate
The
480V
platforms
Main Auxiliary
can be used
buses
to visually
with 1000
MCM cable per phase running up both the north and south sides of the shaft;
inspect the cables, and to perform maintenance. Platforms are accessed and connected by steel
• Two sets 250V DC “00” cable running up both the north and south sides of the shaft;
ladders—one ladder connects two platforms, with ladders on alternating sides of the shaft as they
ascend. • Over 150 multi-conductor instrument and control cable at the east end of the shaft;
• Telephone cable; and
• Annunciator fiber optic cables.
Prior to the fire, the cables running through the shaft were coated in a variety of substances, including
the previously mentioned butyl rubber and polyvinyl chloride (PVC). The 480V cables were
mounted in the shaft using wood blocks to prevent their contact with the metal platforms. Running
parallel to the cable shaft is a visitor’s elevator. Before the fire, the elevator was used to show visitors
the powerhouse as a part of their tour of the plant. At the time of the fire, there were no visitors at
the plant.
The control building is located on the south side of State Road 68 on a cliff above the powerhouse,
and consists of a visitor’s center, control room, terminal room, cable spreading room, and other
smaller areas. The building consists of two main levels: the control room level and the terminal room
level. Prior to the fire, the control room level was accessible via a pedestrian overpass from the north
parking lot, and consisted of several large windows overlooking the Tennessee River and the powerhouse.
The terminal level was accessible via stairs from the control room level, or through a door
from the south western side of the building. Entrance from that point was offset –people entering
through the southwest doors would find themselves on a landing between the two floors, with a half
flight of stairs leading up or down. The terminal room level also had several small windows, located
along the top of the east side of the building and directly next to the southwestern door.
2
Cross-section of the
horizontal cable shaft

U.S. Fire Administration/Technical Report Series
View of the Control Building from the Dam
View of the Control Building from the Dam
View of the Control Building from
the Dam
View of the Control Building from across Route 68
View of the Control Building from across Route 68
View of the Control Building from across Route 68
View of the Control Building from the Dam
View of the Control Building from across Route 68
The tops of the elevator and cable shafts were also located within the control building.
The tops of the elevator and cable shafts were also located within the control building.
The tops of both shafts contained machinery not only for the operation of the elevator, but also to
The tops of both shafts contained machinery not only for the operation of the elevator, but also to
hoist or lower cables and steel platforms. Below the terminal level was the cable spreading
hoist or lower cables and steel Watts platforms. Bar Hydroelectric Below the Plant terminal Control level Building was the cable spreading
room. It was here that the cables terminated their vertical ascension and once again began to run
room. It was here that the cables terminated their vertical ascension and once again began to run
The tops of the elevator and cable shafts were also located within the control building.
4
The tops of both shafts contained machinery not only 4 for the operation of the elevator, but also to
hoist or lower cables and steel platforms. Below the terminal level was the cable spreading
room. It was here that the cables terminated their vertical ascension and once again began to run

5
USFA-TR-147/September 2002 5
The tops of the elevator and cable shafts were also located within the control building. The tops of
both shafts contained machinery not only for the operation of the elevator, but also to hoist or lower
cables and steel platforms. Below the terminal level was the cable spreading room. It was here that
the
horizontally.
cables terminated
Contained
their
in
vertical
this room
ascension
was a small
and once
flight
again,
of stairs,
began
which
to run
could
horizontally.
be used by
Contained
an
in engineer this room or was other a employee small flight to of inspect stairs, the which cables could before used they ran by an underground engineer or into other employee cable to
inspect switchyard. the cables before they ran underground into the cable switchyard.
Due to the hydraulic properties of the site, a constant breeze flows from the powerhouse floor,
through the Due cable to the and hydraulic elevator properties shafts, to the of control the site, building. a constant At breeze a minimum, flows from this breeze the powerhouse is 1/8 miles
per hour—any fluctuation in wind speed outside the structure increases the velocity of the breeze.
floor, through the cable and elevator shafts, to the control building. At a minimum, this breeze is
The chimney effect resulting from this natural phenomenon contributed significantly to the fire
development 1.8 miles per and hour--any spread. fluctuation On the day in of wind the fire, speed the outside wind speed the structure outside increases the plant was the velocity 16 mph. of
the breeze. The chimney effect resulting from this natural phenomenon contributed significantly
to the fire development and spread. On the day of the fire, the wind speed outside the plant was
16 mph.
Side view of the Watts Bar Hydroelectric Plant

(located at water level), traveled up to a cable separating room and the switchyard by means of a
120-foot vertical shaft. The electrical fire started in the vertical shaft and rapidly became a
ventilation-based U.S. fire, Fire Administration/Technical which was fed by the large Report number Series of cables and the constant breeze
running through the shaft. According to the National Weather Service, weather conditions on the
day of the Incident fire were temperature Narrative of 72 °F, humidity 83%, and a wind speed of 16 mph.
At approximately 8:15 a.m. September 27, 2002, a phase-ground-phase fault occurred from two
At 4808:24 Volt a.m., AC power the Watts cables Bar and Hydroelectric a steel grating Plant located Line in “A” a vertical tripped, concrete indicating cable that shaft. The control
something cables was carried wrong power within from the plant. the powerhouse At approximately to the control the same building time, for five normal workers operation who were of the plant
located directly
and the plant
above
equipment.
the cable shaft
As previously
noticed smoke.
described,
In the
the
four
control
minutes
cables
it took
(located
workers
at water
to
level), traveled
up to a cable separating room and the switchyard by means of a 120-foot vertical shaft. The
evacuate,
electrical
fire conditions
fire started
worsened,
in the vertical
and smoke
shaft
spread
and rapidly
throughout
became
the
a ventilation-based
building. The workers
fire, which was fed
successfully by the exited large the number building of cables despite and suffering the constant from breeze the effects running of smoke through inhalation. the shaft. According to the
National Weather Service, weather conditions on the day of the fire were; temperature of 72 degrees
F, humidity 83%, and a wind speed of 16 mph.
Since the fire intensified so quickly, and it was
imperative At 8:24 to evacuate a.m., the immediately, Watts Bar Hydroelectric workers were Plant not Line
“A” tripped, indicating that something was wrong
able to call 911 or the plant prior to fleeing. The first
within the plant. At approximately the same time,
911 call five was workers made bywho a water were deliveryman located directly who notified above the
his dispatcher cable shaft of the noticed fire, and smoke. requested In the that four they minutes call it
911. A
took
second
workers
call was
to evacuate,
made to the
fire
Rhea
conditions
County
worsened,
911
and smoke spread throughout the building. The
center by workers a Watts successfully Bar employee. exited Rhea the County building began despite
receiving suffering these calls from at the 8:30 effects a.m. of The smoke Rhea inhalation. County
Emergency Since Manager the fire was intensified notified of so the quickly, fire at and 8:31 it was
a.m. Watts imperative Bar Nuclear to evacuate Power immediately, Station, located workers directly were
south of not the able Hydroelectric to all 9-1-1 Plant, or the dispatched plant prior members to fleeing. of
Control building building and switchyard, and switchyard, looking southeast looking on
The first 9-1-1 call was made by a water deliveryman
their Fire Protection
who notified
Unit to
his
assist
dispatcher
with fire
of
suppression
southeast Highway on Highway 68 68
the fire, and
activities requested at approximately that they the call same 9-1-1. time. A second call was made to the Rhea County 9-1-1 center by a Watts
Bar employee. Rhea County began receiving these calls at 8:30 a.m. The Rhea County Emergency
Manager was notified of the fire at 8:31 a.m. Watts Bar Nuclear Power Station, located directly south
of the Hydroelectric Plant, dispatched members of their Fire Protection Unit to assist with fire suppression
activities at approximately the same time.
At 8:35 a.m., units from Wolf Creek Fire Department and Spring City Fire Department arrived on the
scene at the southwestern side of the control building. Simultaneously, the fire brigade from TVA’s
Watts Bar Nuclear Power Station arrived at the north parking lot with their Tele-squirt. The fire brigade
immediately requested additional off-site assistance, with the result that units from Pine Grove
Fire and Evensville Fire Department responded to the scene.
6
The units on-scene were informed that the hydrants located in the plant switchyard were inoperable,
and that water supply would be drawn from hydrants located directly off State Road 68.
500’ of 5” supply line was laid from the Tele-squire in the north parking lot to a hydrant on the
State road. The Tele-squirt then supplied a 3” line laid from the apparatus to the north end of the
pedestrian footbridge. Running off the 3” line were two 1 ¾” attack lines. In addition, units from
Pine Grove Fire Department had laid 900’ of 5” supply line from a hydrant on the northwest side
of the switchyard to one of their engines on the south side of the building. This engine supplied
a 2 ½” line to a wye, which then fed two uncharged l-1/2” attack lines. Water supply was successfully
established at 9:10 a.m.

USFA-TR-147/September 2002 7
Site Diagram and Apparatus Location
1. Control Building
2. Powerhouse
3. Location of Watts Bar Nuclear Power Station Tele-Squirt
4. Location of volunteer units
5. Location of Hydrant 1
6. Location of Hydrant 2

northwest side of the switchyard to one of their engines on the south side of the building. This
engine supplied a 2-1/2” line to a wye, which then fed two uncharged 1-1/2” attack lines. Water
supply was successfully established at 9:10 a.m.
U.S. Fire Administration/Technical Report Series
Initial entry Initial into entry the into control the control building building was made was
at made 9:11 at a.m. 9:11 Attack a.m. Attack crews crews crossed crossed the pedestrian the
footbridge pedestrian footbridge on the north on side the north of the side building, of the and
made entry into the control building via the control
building,
room.
and
Fire
made
personnel
entry into
used
the
a thermal
control
imaging
camera building to via locate the control the seat room. of the Fire fire, personnel and attacked
the used fire a thermal using a imaging 1-3/4” camera attack to line. locate Due the to seat the
severity of the heat, however, firefighters backed
of the fire, and attacked the fire using a 1-3/4”
out of the building at 9:20 a.m. and an alternative
attack strategy line. Due was to developed. the severity A of second the heat, attack was
attempted however, firefighters upon the order backed of the out Watts of the Bar building Nuclear
Power at 9:20 Station a.m., and unit an commander, alternative who attack the strategy time was
Ventilation attempt on the southwest side of the
functioning as the Incident Commander. At 9:35
attempt on the southwest side
building
was developed. A second attack was attempted
a.m., the two 1-1/2” attack lines running from the
of the building
Pine upon Grove the order engine of the were Watts charged Bar Nuclear and advanced Poweron
Station unit commander, who at the time was
the functioning southwest as door. the Incident Firefighters Commander. forced entry At 9:35 through a.m., the the door two at 1-1/2” 10 a.m. attack and lines proceeded running to from knock
down
the Pine
a small
Grove
amount
engine
of
were
fire
charged
before backing
and advanced
out due
on
to
the
the
southwest
heat. After
door.
this attack,
Firefighters
firefighters
forced
from
Watts Bar Nuclear Power Station hydraulically ventilated the visitor’s center/control room using a
1-3/4” entry through hand line, the door and then at 10:00 a smoke a.m. ejector. and proceeded During ventilation, to knock down three a firefighting small amount teams of fire of two before personnel
backing each out rotated due to the heat. fire attack After through this attack, the southwest firefightersdoor, from with Watts each Bar team Nuclear making Power three Station attacks
and hydraulically further knocking ventilated down the the visitor’s fire. center/control room using a 1-3/4” hand line, and then a
Nuclear smoke ejector. During ventilation, three firefighting Personnel teams from of two the TVA personnel Sequoyah each rotated Nuclear the Power fire
attack through the southwest door, with each Station team making (SQN), three located attacks outside and of further Chattanooga, knocking arrived
m.,
on-scene at 10:47 a.m. reported to the unified command
post in the north parking lot, and immediately
down the fire.
e north
began assisting with fire suppression. Since Federal
ng with
regulations governing fire protection of nuclear power
plants 8 limit the amount of time that scheduled fire
personnel can be off-site, firefighters from the Watts
r plants
Nuclear Power Station Fire Protection Unit were
e
required to return to their posts within two hours.
the
Command
personnel
personnel
meeting
meeting
to discuss
to Likewise, at 11:45 a.m., personnel from the Watts Bar
strategy
tection
discuss strategy
Nuclear Power Station Fire Brigade returned to the
Nuclear Power Station. At this time, incident command
within two hours. Likewise,
was transferred
at 11:45
from
a.m.,
the
personnel
Watts Bar Nuclear Power Station Fire Brigade to the Rhea County
Fire Brigade returned Emergency to the Manager. Nuclear Power Station.
ferred from the At Watts 11:50 Bar a.m., Nuclear personnel Power made Station entry Fire to the Terminal Room, believed at that point to be the seat of the
anager. fire. Attack crews extinguished three fires in the cables and terminal boards, and exited at 12:05 p.m.
Even with continuing ventilation, heat in the room remained overwhelming. In order to improve
ry to the Terminal ventilation, Room, believed the west at exterior that point windows to be of the building were removed. Crews then re-entered the
control room, extinguished a small fire in the relay board, and vented into the visitor gallery by
hed three fires
breaking
in the cables
a large
and
window
terminal
separating
boards, and
the two rooms. Crews exited the building at 12:30 p.m.
ventilation, heat in the room remained overwhelming.
To release the heat from below the control building, crews re-entered the building at 12:50 p.m.
xterior windows to of open the the building hatch were to the removed. cable shaft. Crews The crew exited the building after successfully completing
shed a small fire their in a mission relay board, at 1:09 and p.m. vented Further into the reconnaissance of the building was required to determine fire
separating the two rooms. Crews exited the building
control

then re-entered the control room, extinguished a small fire in a relay board, and vented into the
visitor gallery by breaking a large window separating the two rooms. Crews exited the building
at 12:30 p.m.
USFA-TR-147/September 2002 9
spread. To At release 1:20 p.m., the heat an attack fromcrew below was the directed control to enter the
building, crews advance re-entered to the cable the spreading building at room, 12:50 and p.m. if to possible,
open
check
the
the
hatch
battery
to the
room.
cable
The
shaft.
crew
The
was
crew
able
exited
to advance
the
to the
cable spreading room where they found a small fire on a cable
building reel, smoldering after successfully fires in filing completing cabinets, their and mission almost at complete
1:09 burnout. p.m. Further The attack reconnaissance line was not of long the building enough to was reach the
required room, so to firefighters determine used fire spread. hose from At the 1:20 damaged p.m., an hose attack rack to
extinguish the cable reel fire. Once the fire was extinguished,
crew was directed to enter the building, advance to the
firefighters checked the lower battery room, but were unable
cable to determine spreading the room, extent and of if damage. possible, check They then battery checked the
Briefing prior to first entry to
room. cable tunnel and found severe fire damage in the first fifteen
fifteen feet. The Firefighters crew was able wereto forced advance to leave to the thecable
building at 1:40 p.m. when their SCBA cable alarms gallery
spreading
feet. Firefighters were forced to leave the building at 1:40 p.m.
activated. room where they found a small fire on a cable reel, smoldering fires in filing cabinets,
when their SCBA alarms activated.
and almost complete burnout. The attack line was not long enough to reach the room, so the
the Officer was informed that
firefighters used hose from the damaged At 1:42, hose the rack TVA to extinguish Public Information the cable Officer reel was fire. Once the fire
the informed fire was that extinguished the fire was extinguished and overhaul and was overhaul in progress. Unit
was extinguished, firefighters checked commanders the lower battery met to room, discuss but their were course unable of to action, determine while the personnel
forced the cable to checked leave tunnel the the building and Control found at 1:40 severe Room p.m. fire level when damage for their further SCBA in the fire first alarms and
was in progress. Unit commanders met to discuss their
extent of damage. fifteen feet. They Firefighters then checked were
course of action, while personnel checked the Control
activated.
performed additional ventilation. A crew checked the terminal
room Room level for further fire at 2:15 fire and p.m., performed and found additional only small spot fires
burning. ventilation. At 9A 2:25 crew p.m., checked crews the began terminal systematic room level
At 1:42, the TVA Public Information Officer
entries
was
into the
building for fire at to perform overhaul and cool the structure as much
informed that the fire was extinguished and overhaul
as 2:15 possible. p.m., At 3:15 p.m., crews again checked all floors of the
building and was the in cable progress. tunnel Unit to commanders see that there met were to discuss no further their
Burned cables, cables, running running from the cable from tunnel the and found
cable tunnel to the to switchyard the switchyard fires and that course the of areas action, were while cooling. personnel An additional checked the check Control for
only small
spot fires in Room the cable level for spreading further fire room and was performed conducted additional at 3:45
spot fires burning. At 2:25 p.m., crews began
p.m. No fires were found, and crews reported that ventilation. areas of A the crew building checked were the cooling terminal off. room level
systematic entries into the building to perform
Interior operations were concluded at 4:00 p.m. for At fire 4:20 at
overhaul and cool the structure as much as possible. p.m.,
fire personnel, Watts Bar Nuclear Power Station 2:15 Fire p.m., Brigade,
At 3:15 p.m., crews again checked all floors of the
Sequoyah Nuclear Power Station fire brigade, fire Personnel investigation
personnel from to the TVA switchyard met to determine scene security
preparing to enter the Control
Burned cables, running from the cable tunnel
building and the cable tunnel to see that there were no
and found
Building
further issues. fires One and fire that engine the areas from were Rhea cooling. County An
only small
remained on-scene
additional spot
throughout check fires
the for night spot burning.
in fires At
the in event the 2:25 cable p.m.,
that spreading crews began
additional room fires was might conducted at 3:45 p.m. No fires
were flare found, up. systematic and crewsentries reported into that the areas building of the to building performwere cooling off.
overhaul and cool the structure as much as possible.
Injuries Interior At and 3:15 operations Fatalities p.m., crews wereagain concluded checked at 4:00 all floors p.m. At of 4:20 the p.m., fire Personnel personnel, preparing Watts Bar to enter the Control
Nuclear Five personnel Power building Station working and Fire the in cable Brigade, the control tunnel Sequoyah building to see Nuclear that at there Power time were of Station no the fire Personnel brigade, and preparing Building fire to enter the
investigation fire suffered further personnel from fires smoke and from inhalation that TVA the met areas and to were determine two cooling. were scene transported An security to issues. One fire Control engine Building from
Rhea local County hospitals. additional remained Upon check on-scene the for arrival spot throughout of fires fire in personnel, the cable night spreading the the building event room that additional was conducted fires might at 3:45 p.m. No fires
flare
had been
up. were completely found, and evacuated. crews reported No fire that personnel areas of were the building injured were during cooling fire suppression, off. overhaul, or
investigation activities. Fire and investigation personnel were quick to point out that there could have
Injuries
been more
and
injuries
Fatalities
had the fire occurred later in the day. Had visitors been using the elevator at the
time of the fire,
Interior
they would
operations
have had
were
no
concluded
means of
at
escape.
4:00 p.m.
Fire
At
personnel
4:20 p.m.,
also
fire personnel,
stated that
Watts
the length
Bar
of time Five it Nuclear took personnel to Power gain working entry Station to in Fire the control Brigade, building Sequoyah at most the Nuclear time likely of Power the helped fire Station suffered prevent fire from injuries. brigade, smoke According and fire to
inhalation several firefighters, investigation and two were if they personnel transported had been from to local able TVA to hospitals. met reach to the determine Upon terminal the scene arrival room security of on fire their personnel, issues. first One try, the they fire engine would from have
building been in had very Rhea been serious County completely trouble remained evacuated. from on-scene the heat No throughout fire and personnel the amount the were night of injured fire the present. event during that fire additional suppression, fires might
overhaul, or flare investigation up. activities. Fire and investigation personnel were quick to point out that
Briefing prior to first entry to cable gallery
there could have been more injuries had the fire occurred later in the day. Had visitors been
Injuries and Fatalities
using the elevator at the time of the fire, they would have had no means of escape. Fire
personnel also stated Five that personnel the length working of time in it the took control to gain building entry to at the the control time of building the fire most suffered from smoke

10 U.S. Fire Administration/Technical Report Series
By the time fire suppression operations were concluded, over forty fire and medical personnel had
responded to the scene. Unites from the Watts Bar Nuclear Power Station Fire Brigade, Wolf Creek
Fire Department, Sequoyah Nuclear Power Station Fire Brigade, Evensville Fire Department, Pine
Grove Fire Department Stations 1 and 2, Spring City Fire Department, Miegs County, and Rhea
County Emergency THE INVESTIGATION
Medical Services had worked together to ensure the successful extinguishment
of the blaze.
As soon as the control building was determined to be safe, a multi-agency
Investigation into the origin and cause of the fire began the next morning, September 28.
investigation team lead by the TVA Police began their origin and cause determination. The
The Investigation
team consisted of investigators from the Bureau of Alcohol, Tobacco and Firearms, Knox
As soon as
County
the control
Sheriff’s
building
Department,
was determined
TVA Office
to be safe,
of the
a multi-agency
Inspector General,
investigation
and TVA
team
Police.
lead by
Of top
the TVA Police priority began was their ensuring origin that and the cause fire determination. was not the result The of team a deliberate consisted act. of investigators Investigators from prepared
the Bureau a of preliminary Alcohol, Tobacco report, which and Firearms, was released Knox County in November Sheriff’s 2002. Department, The report TVA concluded Office of that the the
Inspector General,
fire was initially
and TVA
caused
Police.
by
Of
a
top
phase-ground-phase
priority was ensuring
fault
that
between
the fire
one
was
of
not
the
the
480V
result
cables
of a
deliberate act. Investigators prepared preliminary report, which was released in November 2002.
The report running concluded from that the the 480V fire main was initially buses, and caused presented by a phase-ground-phase the results of a fire fault model between run by the one TVA
of the 480V Police. cables running from the 480V main buses, and presented the results of a fire model run
by the TVA Police.
Based on damage Based to the cables on damage and the to steel the cables decking, and investigators the
concluded steel that prolonged decking, investigators rubbing of the concluded steel decking that against the
butyl rubber insulation on the cable had resulted in a breaching
of the cable
prolonged
insulation
rubbing
at the
of
number
the steel
five
decking
level (roughly
against
60 feet
above ground) the butyl in the rubber cable insulation shaft. This on resulted the cable in an had arc from the
cables to the resulted decking, a and breaching back to the of the cable. cable The insulation extreme temperature
generated by this arc was enough to cause a small amount of
at
the number five level (roughly 60 feet above
the insulation to deteriorate into a flammable substance, thereby
resulting in ground) ignition. in the The cable large shaft. quantity This of flammable resulted in materials an in
the shaft, coupled arc from with the cables a continuous to the decking, chimney and effect, back provided to the
small fire with the cable. enough The fuel extreme to self-sustain temperature and generated free burn. Within
a matter of seconds, the fire started to spread rapidly. The high
Point of of fire origin
flammability
by this
of the
arc
insulation
was enough
surrounding
to cause a
the
small
cabling
amount
magnified
the speed of propagation. the insulation Those to deteriorate cables which into were a flammable covered substance, with PVC released thereby polyvinylchloride resulting ignition. gas The
as they burned. large quantity of flammable materials in the shaft, coupled with a continuous chimney effect,
The construction provided of the small cable shaft fire with and enough the Control fuel Building to self-sustain also helped and free the burn. fire. The Within solid a construction
of the seconds, building the trapped fire started heat inside to spread the rapidly. structure, The resulting high flammability in severe spalling of the within insulation the cable
matter of
spreading room, and causing temperatures on the terminal room and control room levels to skyrocket,
even without visible flame. Based on the results of a fire model run by TVA Police, and using
surrounding the cabling magnified the speed of propagation. Those cables which were
data from covered the United with States PVC Fire released Administration, polyvinilchloride the National gas as Institute they burned. of Standards and Technology,
and the Nuclear Regulatory Commission, it was determined that temperatures within the control
building reached The or exceeded construction 1,200 of degrees the cable F during shaft and the the fire. Control The heat Building generated also in helped the shaft the fire. was The
so intense that steel decking 60 feet below the area of origin was severely warped, while water used
during the
solid
first
construction
hours of attack
of
instantly
the building
boiled
trapped
on the
heat
floor
inside
of the
the
structure
structure,
or
resulting
turned to
in
steam.
severe spalling
within the cable spreading room, and causing temperatures on the terminal room and control
Heat, smoke and flame generated by the initial fire traveled up the cable shaft, hitting their first
obstacle in room the cable levels spreading to skyrocket, room. even The without sudden visible change flame. in direction, Based upon lack the of results flammables, of a fire and model
compression run of by space TVA could Police, have and smothered using data the from fire. the United However, States due Fire to the Administration, advanced stage the of National the
Institute of Standards and Technology, and the Nuclear Regulatory Commission, it was
determined that temperatures within the control building reached or exceeded 1,200º F during

and
the fire. The heat generated in the shaft was so intense that steel decking 60 feet below the
red the fire. area of origin was severely warped, while water used during the first hours of attack instantly
he fire, it boiled on the floor of the structure or turned to steam. USFA-TR-147/September 2002 11
annels into
r as one fire, it continued Heat, smoke, several and feet flame down generated the cable by channels the initial into
In addition, the switchyard
fire traveled
and
up
damaged
the cable
cables
shaft,
as
hitting
far as
their
one hundred
first
feet
from the control building. In addition, the fire spread into
niting the fire
the terminal obstacle level, in the igniting cable spreading the fire load room. in the The terminal sudden room,
t that with change the result in direction, that firefighters lack of flammables, initially considered and it to be
e room of the room compression of origin of and space therefore could have the primary smothered target the fire. of their
f their attack.
attack. The smoke and the heat further penetrated the control
However, due to the advanced stage of the fire, it
room level, damaging everything on that level and causing
d the control further continued fires. Effects several below feet down the fire the consisted cable channels of severe into heat
t level and and the smoke switchyard damage. and damaged cables as far as one
fire consisted hundred Warped decking feet from below the control area of origin building. In addition,
Damage Assessment
the fire spread into the terminal level, igniting the fire
Although the fire occurred in a vertical shaft, there was a significant
amount of damage to all parts of the hydroelectric
load in the terminal room, with the result that
plant. firefighters All cables initially running considered through the it to shaft be the were room destroyed of
ertical shaft, there and was origin severed a significant and as a therefore result amount of the primary fire, of resulting target of in their a loss attack. of communications,
fire annunciation systems, and most importantly,
lant. All cables running The smoke through and the shaft heat were further penetrated the control
power transmission. Additionally, the ladders and steel decking
a loss in
ire, resulting in room
the oflevel, vertical communications, damaging
shaft were
everything fire warped.
on that level and
ntly, power transmission. causingAdditionally, further fires. the Effects ladders below the fire consisted
Warped decking decking below below the area the of area origin
The cable spreading room above the shaft sustained significant
spalling
of severe
and smoke
heat and
damage.
smoke
The
damage.
of origin
re warped.
control building sustained
significant damage, both from the effects of the fire and the effort associated with its extinguishment.
Damage Assessment
the shaft
Items within the building, including records, files, desks,
breathing apparatus, and power control stations, were irrevocably
in a vertical damaged shaft, by the there fire. was In an a significant effort to ventilate amount the of build-
damage.
Although the fire occurred
t damage, damage to all parts of the hydroelectric ing and plant. reach All the cables fire, running firefighters through forced the doors shaft and werebroke
effort
destroyed and severed as a result of
windows.
the fire, resulting
Overhaul
in
of
a
the
loss
site
of
resulted
communications,
in further damage,
fire
as
firefighters pulled ceilings and breached walls to ensure the
s within annunciation systems, and most importantly,
fire was completely
power transmission.
out. Water damage
Additionally,
was also
the
extensive,
ladders
ks,
and steel decking in the vertical shaft due were to the warped. significant volume of water necessary to cool the
structure and extinguish the fire.
Control Building, The cable approximately
Control Building, approximately
spreading
two hours
room
into
above Due to the shaft destruction of the power transmission cables, the
two hours
sustained significant the
into
fire
the fire
13
spalling and smoke generators damage. had to be shut down. In order to prevent flooding
upriver from the dam and to ensure that there was enough
The control building sustained significant damage,
water flowing downstream to provide cooling for the Watts Bar Nuclear Power Station, the floodgates
had both to be from opened. the The effects closure of the of fire the generators and the effort and the opening of the floodgates have resulted in a
significant associated loss of with revenue its extinguishment. for TVA. Estimates Items place within the daily loss of revenue at up to $100,000.
the building, including records, files, desks,
13
Control Building, approximately two hours into
the fire

KEY ISSUES
12 U.S. Fire Administration/Technical Report Series
Building Structure
The Watts Bar Hydroelectric plant
Key Issues
was constructed of concrete and steel, and
Building located directly Structure on the Tennessee River.
The The Watts plant Bar was Hydroelectric essentially plant a bunker, was constructed with
of concrete very few and windows steel, and on the located powerhouse directly floor, on the
Tennessee River. The plant was essentially a bunker,
with very few windows on the powerhouse
and small, sealed, windows in the lower
floor, levels and of small, the control sealed, building. windows Even in the the lower
levels large of the plate-glass control building. windows Even located the large on the plateglass
control windows room located level of on the the control control building room level
of the control building were unable to be opened;
their
were
purpose
unable
was
to
simply
be opened;
to provide
their purpose
a view of the
View of the control building building from the from South. the Note South. the
dam was for simply visitors. to The provide building a view was of comprised the dam for of solid Note concrete the solid construction concrete and construction
lack of windows.
various visitors. levels, The connected building by was one comprised staircase of on the
and lack of windows.
western side of the building. The layout of the
various levels, connected by one staircase on the western side of the building. The layout of
building, combined with the limited number of windows, made it a difficult structure to ventilate.
the building, combined with the limited number of windows, made it a difficult structure to
The construction of the hydroelectric plant contributed to heat build-up and distribution. The concrete
walls, floors, and ceilings acted as an oven, intensifying the heat and trapping it in the building.
ventilate.
These conditions made firefighter entry and fire suppression extremely difficult. During fire suppression
activities, The construction firefighters of reported the hydroelectric that the water plant they contributed were using to heat to fight build-up the fire andwas turning
to steam
distribution.
or boiling
The
upon
concrete
contact
walls,
with
floors,
the floor.
and
The
ceilings
level
acted
of heat
as
in
an
the
oven,
building
intensifying
was further
the heat
evident
during the post-incident investigation. Investigators found heavy spalling in the cable spreading
room.
and trapping it in the building. These conditions made firefighter entry and fire suppression
extremely difficult. During fire suppression activities, firefighters reported that the water they
The location of the building on a major body of water is significant for more reasons than power
generation. were using Moving to fight water the fire generates was turning a pressure to steam differential or boiling within upon the contact local atmosphere. with the floor. As a The result,
a slight level breeze of heat is in produced. the building This was principle further evident is commonly during known the post-incident as the Venturi investigation. Effect. Firefighters
are Investigators familiar with found this principle heavy spalling through in the the practice cable spreading of hydraulic room. ventilation – using a hose line to
ventilate a building by spraying a fog pattern out a window, thereby creating a pressure differential
and drawing air out of the room. The constant flow of water through the turbines in the powerhouse
resulted in The the Venturi location effect of the in building the Watts on Bar a major Hydroelectric body of plant, water with is significant more damaging for more results. reasons The
control than building power generation. was connected Moving to the water powerhouse generatesby a pressure a vertical differential shaft, half of within which the carried local cables,
and
atmosphere.
half of which
As
served
a result,
as an
a slight
elevator
breeze
for visitors
is produced.
touring
This
the
principle
plant. The
is commonly
breeze generated
known
by
as
the
constant flow of water through the turbines took the path of least resistance, moving from the powerhouse,
the Venturi through Effect. the cable Firefighters shaft, and areout familiar the cable with trays. this This principle constant, through ever-present the practice breeze of fed the
fire hydraulic in the cable ventilation—using shaft, resulting in a rapid hose fire line spread. to ventilate a building by spraying a fog pattern out a
Within window, the hydroelectric thereby creating plant a complex, pressure differential there are a limited and drawing number air of out egress of the routes room. from The the control
constant building. flow On of a water normal through day, in the order turbines to exit in the building powerhouse workers resulted on the in the terminal Venturi room effect level in
are the required Watts to Bar walk Hydroelectric the length of plant, the building with more through damaging a variety results. of rooms The control and passages building in was order to
reach the stairwell. They then have to climb a half-flight of stairs in order to reach the door. Visitors
and workers on the control room level have easier access to an exit, although there is still only one
on that level. An alternative exit for personnel on 15 this level is to go downstairs to the exit used by
personnel on the terminal level.
The day of the fire, firefighters would have had limited access to any personnel who might have
become trapped on the terminal room level. While there were windows on the east side of the

USFA-TR-147/September 2002 13
building there, they were small and very thick, making them a poor choice for entry. The only practical
way for firefighters to enter this level was through the sole means of egress- -the southwest door.
In the case of this fire, had any Watts Bar personnel become trapped on the terminal room level—a
situation that nearly happened—they would have likely become casualties almost immediately.
Fire Protection Systems
The Watts Bar Hydroelectric Plant was constructed before the use of sprinklers were a standard part
of building construction and was not originally designed to comply with what is the current NFPA
101 code. Even after the advent of sprinklering, there was little interest in installing sprinklers at
this point. Conventional wisdom throughout the hydroelectric and the broader power generation
community held that the fire risk to hydroelectric plants was minimal, based on their type of
construction and proximity to water. As a result, retrofitting the building with fire sprinklers or
suppression systems was not considered necessary. While the powerhouse floor was outfitted with
a carbon dioxide (CO 2) dump system to suppress any fires that might occur in the generators, there
were no fire suppression systems in the control building. Additionally, there were no detection or
alarm systems in the control building. There was a detection system in the powerhouse, specifically
in the hall storage room, generator cabinet, and governor cabinet. This system was connected to an
annunciator panel in the control room, but the fire had effectively severed the connection rendering
it inoperable.
Fire suppression services at Watts Bar Hydroelectric Plant are provided through long-standing mutual
aid agreements with local volunteer fire companies in Rhea and Miegs Counties. While all personnel
are familiar with these agreements, they are not set forth as formal, written policies. Rather, they are
simply understood to be the way fire protection assistance is handled. In addition, the fire brigade
from the Watts Bar Nuclear Station provides assistance when necessary.
Presumptions that hydroelectric power plants were essentially “fireproof” led to a decision in 1993
to reduce fire suppression personnel and training at the Watts Bar Hydroelectric Plant. For budgetary
reasons, TVA decided to remove the on-site fire brigade from the plant and instead train plant
personnel on incipient firefighting only.
TVA defined incipient fires as those that could be easily extinguished by one person, or a fire roughly
the sizes of a small trash can fire. While this decision was reasonable based upon previous experience
with hydroelectric plants, it left a gap in fire protection for the facility. Also missing was a formal
plan for incorporating volunteer personnel into a fire response team that included or designated a
command structure in the event of a fire. This lack of planning was evident on the day of the fire
when personnel were initially unsure of who was responsible for incident command. While that
uncertainty did not materially affect fire operations in this case, it is a point of concern. TVA, in
their post-incident analysis, recognized this problem and is taking steps to develop and implement
an incident management plan. They also have begun comprehensive program to bring all of their
hydroelectric plants into compliance with the Life Safety Code and to set up fire suppression systems
with the facilities.
Communications
The location of the Watts Bar Hydroelectric plant had a direct impact on fireground communications.
The plant is located in a rural section of Rhea County in a very hilly and heavily wooded area.
Although there are repeaters throughout Rhea and Miegs Counties, the radio signal in the immedi-

14 U.S. Fire Administration/Technical Report Series
ate vicinity of the plant is still weak. The radios used by local response personnel were useful in
communicating with other local personnel on the scene, but they did face some difficulty in clearly
communicating with central dispatch.
Adding to the communications challenge, the fire brigade personnel from the Watts Bar Nuclear Power
Station
communicating
have radios with
directly
weak
with
signals
each
because
other at
material
the nuclear
located
power
within
station
the nuclear
site, but
power
they
station
have a
is very
sensitive severely to radio limited signals. range. Their As a radios result, are fire useful brigade for personnel communicating were unable directly to with communicate each other with at the
nuclear the nuclear power station power site, station but from they the have hydroelectric a severely limited plant range. site. As a result, fire brigade personnel
were unable to communicate with the nuclear power station from the hydroelectric plant site.
Some TVA Some fire brigade TVA fire personnel brigade have personnel been conducting
tests using cell phones with digital walkietalkie
capabilities as an alternative to using the
have been conducting tests using cell
radios. phones Several with of digital these walkie- personnel talkie were on-scene
during capabilities the fire. as However, an alternative the radio to using signal the difficulties
radios.
related
Several
to topography
of these
applied
personnel
to the
were
enhanced
onscene
capabilities of cell phone as well. One member of
the Watts
during
Bar Fire
the
Brigade
fire. However,
stated that
the
during
radio
the
fire signal he found difficulties an approximately related to 10-square topography foot area
in the applied north to parking the enhanced lot where capabilities he could of use cellhis
phone. Whenever he needed to communicate with
phone as well. One member of the Watts
his phone, he had to go to this spot to get a signal.
Bar Fire Brigade stated that during the fire
Another difficulty faced by personnel was the lack
Response personnel meeting meeting face-to-face face-to-face discussto
he found an approximately 10-square foot
of interoperability of the portable radios. Local
discuss strategy strategy
volunteer area in departments the north parking used lot one where kind he of could radio,
while use responders his phone. from Whenever the Watts he Bar needed Nuclear to communicate Power Station with used his another phone, kind he had of radio to go that to this operated spot
on a
to
different
get a signal.
frequency. Due to these differences, personnel were unable to communicate with each
other by radio, so on-scene communications among response agencies were made face-to-face..
Personnel are aware that using radios is preferable, and local response agencies and the TVA are now
planning to Another carry portable difficulty radios facedfrom by personnel the other was response the lack agency of interoperability on their apparatus. of the In portable this way,
Watts radios. Bar Nuclear Local volunteer Power Station departments fire brigade used personnel one kind will of radio, have while a Rhea responders County radio from for Watts use in Bar an
emergency, and Rhea County fire apparatus will have a Watts Bar Nuclear Power Station fire brigade
Nuclear Power Station used another kind of radio that operated on a different frequency. Due
radio.
to these differences, personnel were unable to communicate with each other by radio, so onscene
There were also communications difficulties within the actual hydroelectric plant. The powerhouse
and control
communications
building are linked
among
via
response
landline.
agencies
When the
were
fires
made
started
face-to-face.
in the vertical
Personnel
cable shaft,
are
communication
aware that lines using between radios the is control preferable, building and local and powerhouse response agencies were cut. and The the result TVA was are that now personnel
planning the powerhouse to carry portable were completely radios from unaware the other of the response fire in agency the cable on shaft, their and apparatus. that people In this in the
control building were being evacuated. Due to the constant breeze flowing through the powerhouse,
way, Watts Bar Nuclear Power Station fire brigade personnel will have a Rhea County radio
all smoke from the fire was directed upwards and away from the powerhouse. The first indication
that for any use powerhouse in an emergency, personnel and had Rhea of a County problem firewas apparatus when their will power have a went Watts out Bar as Nuclear a result of the
fire. Power There Station was no fire effective brigade backup radio. means of communication to warn workers of the fire and the
pending need to leave the building. TVA recognized this problem in the after-action analysis of the
fire, and is working to address it.
There were also communications difficulties within the actual hydroelectric plant. The
powerhouse and control building are linked via landline. When the fire started in the vertical
cable shaft, communication lines between the control building and powerhouse were cut. The
result was that personnel in the powerhouse were completely unaware of the fire in the cable
shaft, and that people in the control building were being evacuated. Due to the constant
breeze flowing through the powerhouse, all smoke from the fire was directed upwards and

Risk
USFA-TR-147/September 2002 15
Personnel working within both the control building and the powerhouse faced
challenges in exiting during the fire. As described earlier in this report, the layout and design
Risk
of the control building resulted in a limited means of egress for personnel in the control
Personnel building. working In the within case of both this fire, the control personnel building had to and pass the above powerhouse the fire to faced reach challenges the exit. in Had exiting
during the fire. As described earlier in this report, the layout and design of the control building
there been any significant delay, personnel in the building could have been seriously harmed
resulted in a limited means of egress for personnel in the control building. In the case of this fire,
personnel trying to had escape. to pass above the fire to reach the exit. Had there been any significant delay, personnel
in the building could have been seriously harmed trying to escape.
The design The of the design powerhouse of the powerhouse also contributed also
to contributed existing problems. to existing The problems. building is The a large
windowless
building is
structure,
a large windowless
with heavy
structure,
machinery
and other dangers located throughout. It, too,
has with very heavy limited machinery means of and egress, other with dangers exits to
ground located level throughout. on the west It, end too, and has an very exit to the
top limited of the dam means on the of egress, east end. with The exits powerhouse to
has several levels, both above and below the
ground level on the west end and an exit to
waterline, with exits located on only one level.
When the top power of the to the dam building on the east was end. lost, workers The
were powerhouse plunged into has complete several darkness. levels, both Personnel above
would
and
have
below
had
the
to
waterline,
rely on their
with
knowledge
exits located
of
the building and their sense of touch and hear-
Powerhouse floor floor
ing on to only exit the one building. level. When Luckily, power a supervisor to the on
the building floor had was a flashlight, lost, workers and was were able plunged to find into people complete and lead darkness. them safely Personnel from the would building. have had TVA’s
review to rely of life on their safety knowledge issues will likely of the include building increased and their exit sense lighting of touch per NFPA and hearing 101 7.8.1. to exit the
While building. personnel Luckily, in both a supervisor buildings on had the received floor hadtraining a flashlight, on evacuation, and was able evacuation to find people drills are and not
routinely lead them held. safely Following from the the building. fire, TVA TVA’s accident review investigators of life safety determined issues that will this likely was include a problem
that needed to be addressed, and they have recommended frequent training on and demonstrations
increased exit lighting per NFPA 101 7.8.1.
of emergency and evacuation procedures.
Pre-planning While personnel in both buildings had received training on evacuation, evacuation
Local
drills
response
are not
personnel
routinely
were
held.
aware
Following
that they
the
would
fire, TVA
be the
accident
first responders
investigators
to an
determined
event at the
that
Watts
Barr this Hydroelectric was a problem Plant. that Nevertheless, needed to be responders addressed, were and not they provided have recommended with plant diagrams, frequent nor training were
there on any and plant demonstrations pre-plans. Several of emergency of the local and evacuation responders procedures. stated that they had only been in the plant
on the visitor’s tour, and had no idea what else was inside the building.
Control building diagrams were available at the site, stored in filing cabinets on the terminal room
level. Due to the rapidity of fire spread and the need for quick evacuation, there was no time for
personnel to grab the plans—they were lost in the 19 fire. As a result, personnel working on-scene
initially had to rely on employee’s knowledge of the building to plan fire suppression activities and
ventilation. Watts Bar Nuclear Power Station personnel requested that TVA fax copies of the plans to
the site; these plans arrived several hours into the incident and were immediately utilized by onscene
personnel.
As a result of this fire, TVA and local response agencies are working together to develop comprehensive
pre-plans for use in the event of another emergency at the hydroelectric plant. In addition, TVA
is planning to provide local responders with a tour of the plant: the goal is to make this part of the
annual training for responders.

16 U.S. Fire Administration/Technical Report Series
Training
Prior to the fire at the hydroelectric plant, local responders, plant personnel, and the Watts Bar
Nuclear Power Station fire brigade had not trained together. One of the firefighters from the fire brigade
is a volunteer firefighter in Rhea County, but that was the extent of regular interaction among
the response organizations.
In addition, Inpersonnel addition, personnel from the nuclear from the power station
and nuclear local response power station agencies and were local unfamiliar response with the
various tactics necessary to fight a fire in the control
agencies were unfamiliar with the various
building of the hydroelectric plant. Local responders
have tactics been necessary trained to to fightthe a fire types in the of control fires they are
most building likely to of encounter: the hydroelectric fires in plant. homes, Local brush or businesses.
responders
Personnel
have
from
been
the
trained
nuclear
to fight
power
the
station have
been trained to fight fires inside a nuclear power plant.
While types some of fires of the they tactics are from most each likely type to of training can
be used encounter: in fighting fires in a fire homes, in a brush, hydroelectric or plant control
businesses. building, there Personnel are still from special the nuclear considerations power and
suppression tactics. Specifically, none of the responders Fire in the breaker panels; looking
station have been trained to fight fires inside a
were familiar with the special tactics needed to fight a Fire in from the breaker outside panels; the looking Control from Building, outside the
fire nuclear involving power an electrically plant. While charged some object. of the
Control three Building, hours three into hours the into fire. the fire.
tactics from each type of training can be used in fighting a fire in a hydroelectric plant control
TVA has developed tactics and methods for successfully fighting electrical fires using water. Some
field building, personnel there are are trained still on special these considerations tactics, and frequently and suppression use them tactics. to suppress Specifically, fires. As none a result of of
their the post responders incident were investigation, familiar with TVA recognized the special tactics the necessity needed of to training fight a fire local involving response an personnel
who
electrically
provide or
charged
support
object.
on-scene fire suppression in these specialized tactics. The challenge lies
in finding the time and the funding to provide volunteer responders with this training. Volunteer
firefighters stated that the best time for them to attend training would be during the weekend,
when they TVA are not has at developed work. However, tactics TVA and methods stated that for providing successfully training fighting on weekends electrical would fires using be a
financially water. Some difficult field option, personnel due to are the trained need to on provide these tactics, instructors and frequently with overtime use them pay. TVA to suppress and local
responders are working together on these issues, to ensure that responders receive the appropriate
fires. As a result of their post incident investigation, TVA recognized the necessity of training
specialized training.
local response personnel who provide or support on-scene fire suppression in these
Local responders and TVA personnel also recognize the need to train together, in order to become
familiar
specialized
with the
tactics.
operating
The
procedures
challenge lies
and
in
tactics
finding
used
the
by
time
each
and
agency.
the funding
Responders
to provide
plan on
volunteer
drilling
together responders more with frequently this training. and holding Volunteer training firefighters exercises on stated TVA that property. the best time for them to
attend training would be during the weekend, when they are not at work. However, TVA
Power Generation and Terminal
stated that providing training on weekends would be a financially difficult option, due to the
Upon need arrival to provide at the control instructors building, with overtime TVA and local pay. response TVA and personnel local responders were uncertain are working as to whether
the hydroelectric plant was still generating power. Due to the fact that the control building is the
together on these issues, to ensure that responders receive the appropriate specialized training.
point where power from the hydroelectric plant is distributed to power lines, it was critical to determine
if electricity was still flowing through the cables. Additionally, the building housed several
backup batteries Local of responders varying voltage, and TVA which personnel were supposed also recognize to provide the need power to to train the together, plant in the in event
of a
order
sudden
to become
power loss.
familiar
There
with
was
the
uncertainty
operating procedures
during fire
and
suppression
tactics used
operations
by each
as
agency.
to whether
these batteries had discharged their electricity, or if they were still charged.
Responders plan on drilling together more frequently and holding training exercises on TVA
Due
property.
to the uncertainty concerning the electrical situation, the decision was made by command
personnel to treat all electrical apparatus within the control building as charged. This proved to be a
prudent decision as it was discovered during the initial post-incident investigation that the batteries
indeed Power were Generation still charged. and Terminal
Upon arrival at the control building, TVA and local response personnel were uncertain
as to whether the hydroelectric plant was still generating power. Due to the fact that the

USFA-TR-147/September 2002 17
Compliance with Life Safety Code
As the hydroelectric plant was finished in the early 1940’s, the building was not originally designed to
comply with the Life Safety Code (NFPA 101). In addition, there was no requirement that the building
be retrofitted to meet the code. As a result, egress was severely limited, emergency lighting was not
provided throughout the facility, and there was no mechanism for remotely activating a fire alarm.
Since the fire, TVA has recognized the importance of bringing all hydroelectric facilities into compliance
with ORIGIN the Life Safety ANDCode. SPREAD While out of service, Watts Bar Hydroelectric Plant is undergoing
FIRE
renovations that will bring it into compliance. Additionally, the plant is undergoing comprehensive
maintenance During on their all equipment. initial investigation, TVA Police investigators worked with input from the
United States Fire Administration, the National Institute of Standards and Technology, and
Fire Origin and Spread
the Nuclear Regulatory Commission to perform a fire engineering hazard analysis. According
During their initial investigation, TVA Police investigators worked with input from the United States
to the TVA Police record of investigation, this analysis “assesses the investigation of the fire’s
Fire Administration, the National Institute of Standards and Technology, and the Nuclear Regulatory
origin Commission and cause, to perform evaluates a fire the engineering performance hazard of fixed analysis. fire According protection to systems, the TVA and Police identifies record of
significant investigation, aspects this analysis of fire “assesses dynamics.” the investigation Data generated of the by fire’s this origin analysis and would cause, evaluates then be used the performance
of fixed fire protection systems, and identifies significant aspects of fire dynamics.” Data
to
help identify not only the fire origin and cause, but to determine specific hazards that might
generated by this analysis would then be used to help identify not only the fire origin and cause, but
exist to determine similar specific plants. hazards that might exist in similar plants.
Three-dimensional Three-dimentional computer computer model model of WBH of WBH fire fire
TVA investigators TVA investigators utilized NIST’s utilized Fire NIST’s Dynamics Fire Simulator Dynamics Version Simulator 2.9, inputting Version not 2.9, only inputting their own not
data but also information provided by USFA, NIST and NRC. The simulator modeled smoke and fire
only development their own and data distribution but also information over a period provided of time using by USFA, a three-dimensional NIST and NRC. computer The simulator image modeled provide a smoke second-by-second and fire development breakdown of and the distribution fire. The results over were a period telling. of According time using to a the threedimensional
record
of investigation,
computer
“The model
image
of
to
the
provide
WBH
a
(Watts
second-by-second
Bar Hydroelectric)
breakdown
Plant after
of the
527
fire.
second
T he
(8.78
minutes)…shows a fire plume extending up the cable shaft to the entrance to the ante room, which
results leads up were a staircase telling. to According the cable spreading to the record room.” of investigation, “The model of the WBH [Watts
Bar Hydroelectric] Plant after 527 seconds (8.78 minutes)...shows a fire plume extending up
the cable shaft to the entrance to the ante room, which leads up a staircase to the cable
spreading room.”

18 U.S. Fire Administration/Technical Report Series
Using information provided in the model, investigators were able to understand not only how the
fire developed, but also why personnel working in the building had such short notice of the fire’s
existence. According to the report, smoke and heat from the fire hit the lower levels of the control
building, “with a good portion of the heat and smoke being transferred out through the upper level
cable shaft leading to the switchyard.” Instead of smoke and heat spreading into the building, it was
channeled down the path of least resistance, thereby, diverting any early warning that employees may
have had. Smoke and heat penetrated the location of the employees only after the fire had built to
such a fury that the path of greater resistance (the control building itself) could be penetrated.
The information this simulator generated was critical to developing a comprehensive understanding
of fire development in a hydroelectric plant. It also served to illustrate the dangers associated with
a fire in such a structure—namely, the rapidity of fire development, and the need for fire detection
and protection systems.
Lessons Learned
While the firefighting and suppression efforts at Watts Bar were successful, there were several lessons
learned. These include the necessity of pre-planning, the importance of local firefighters and
industrial firefighters conducting training exercises together, the need for adequate training of local
response personnel in industrial firefighting, the need for effective primary and secondary communications
methods, and the importance of compliance with fire codes.
Although plans for the Watts Bar Hydroelectric Plant existed, they were kept in the control building.
There was no time for employees inside the building to collect the plans prior to exiting the building,
so the plans were unreachable and unusable. Local fire departments were not provided with a
copy of the plans, and so not only were they unfamiliar with the structure, but also did not have a
visual guide to the design and layout of the building. Fortunately, several firefighters associated with
the Watts Bar and Sequoyah Nuclear Power Stations and personnel from the hydroelectric plant were
on-site during fire suppression operations, and were able to provide site and structural information
verbally. It is critical that facilities relying upon local first responders ensure that these responders
are provided with all necessary information to respond to and fight a fire at the facility. In addition to
providing pre-plans to local response agencies, local responders should be given a tour of the facility,
ideally on an annual or semi-annual basis.
Local first responders should become familiar with their counterparts at the facility, including any
safety or fire suppression personnel who may work at the site. Not only should responders meet
during site or facility tours, but they should also periodically drill on response procedures together.
While the Rhea County emergency manager knew some of the personnel from Watts Bar, local
responders were not familiar with their colleagues from the Watts Bar Nuclear Power Station fire
brigade. Training together not only allows for personnel to meet each other, but it enables them to
become familiar with any differences or similarities in response protocols and equipment that may
exist between agencies.
In the case of the Watts Bar, an important difference exists between the firefighting training of local
responders and that of personnel from the Watts Bar Nuclear Power Station. Local responders are
trained in standard structural firefighting techniques, while personnel from Watts Bar are trained in
industrial firefighting techniques. While these techniques all focus on fire suppression, they use different
methods to achieve the goal. Moreover, fire personnel from TVA have received special training
in techniques used to extinguish electrical fires, and are familiar with the hazards and limitations

USFA-TR-147/September 2002 19
associated with fighting such fires. Traditionally, structural firefighters are trained to avoid fighting
an electrical fire until the power source or the actual fire has been de-energized, or using a suppressant
other than water. TVA employees, however, are trained to extinguish a wide variety of electrical
fires using traditional hose lines. It would be beneficial for local responders to receive training,
even alongside their industrial counterparts, in the special challenges and techniques of industrial
firefighting. In this way, all response personnel would be familiar with the same techniques and
objectives.
Another critical aspect of successful fire suppression is effective communications. Due to the geographical
location of the hydroelectric plant, there were several “dead spots”—areas where radios
cannot receive or send messages. Further complicating matters, the radios of local responders and
TVA personnel were not compatible. Finally, the signal strength of the radios for the TVA Watts Bar
Nuclear Power Station Fire Brigade was very weak. Although members of the nuclear power station
fire brigade were within eyesight of the nuclear power station, personnel could not use their radios
to reach it in order to keep supervisors there aware of their fireground operations.
On-scene TVA personnel were able to communicate using Nextel phones because of their digital
walkie-talkie capabilities; however, these phones were only able to receive a signal in an area that
was roughly ten square feet. Unit officers met face-to-face throughout the incident to communicate
and make decisions. While effective in this instance, this means of communication is not always
practical or reliable. If financially feasible, local response units should be provided with a radio from
the industrial site, thereby ensuring that a means for radio communication exists. Additionally, the
industrial site should be provided with a radio from the local response agency. These radios could be
carried in response units, and used exclusively for communication during an incident or drill.
One of the most important lessons learned from this fire is the importance of compliance with the
Life Safety Code. Although the Watts Bar Hydroelectric plant was grandfathered in due to its age,
non-compliance with the code could have had fatal results in this fire. As mentioned before, personnel
on the powerhouse floor did not know there was a fire burning in the cable shaft. There was also
no means for warning them, as communication between the control building and powerhouse had
been cut by to the fire. There are very few means of egress from the powerhouse, and several places
where an employee could be trapped and seriously injured or killed. Worse, there was no emergency
lighting, and employees were plunged into total darkness when the power failed. Only the quick
thinking of a floor supervisor ensured the safe exit of employees. As a result of this fire, TVA has
realized the importance of the life safety code, and plans to bring all of its hydroelectric plants into
compliance.