Fire Following Earthquake

Fire Following Earthquake

FEATURES

DISASTER MANAGEMENT

Two recent earthquakes that occurred in the United States demonstrate the variety of demands that are placed upon the fire service during a major disaster.

A problem that has been given relatively little attention, and yet is potentially of disastrous proportions, has been the subject of fire spread in urban regions following a major earthquake. This phenomenon is important in cities with a large building stock composed primarily of wood (e.g., Los Angeles and San Francisco, CA) and with industrial installations, such as oil refineries, large factories, chemical plants, etc.

The problem is an especially complex and challenging one since an earthquake has the potential to initiate a chain of events that can damage structures and urban lifelines, such as water supply, gas, electricity, transportation and communications systems. A moderately damaging seismic event could result in a conflagration* of disastrous proportions.

The single most damaging fire of the twentieth century in the United States was actually a post-earthquake fire—San Francisco, 1906.

*In this article, the term conflagration is used in the layman’s sense, referring to any large, disastrous fire. In the fire sense, conflagration means any fire that jumps either 300 feet or crosses a natural barrier.

In 1906,80% of the damage in San Francisco was due to fire, amounting to a burned area of 4.7 square miles, 28,000 structures in all. In today’s dollars, this would be a loss of about $3 billion. Often overlooked today is that the central business district of the city of Santa Rosa also suffered a significant fire on that April day in 1906, albeit much smaller than the San Francisco fire, and that fires occurred elsewhere in the state’s damaged areas.

The post-earthquake fire problem is complex and involves many diverse elements. A simplified flowchart describing post-earthquake fire potential is shown in Figure 1. The fire spread begins with the occurrence of the earthquake, which causes structural and non-structural damage to buildings, lifelines, and fire stations themselves. Structural damage also causes many of the fire safeguards we rely upon to lose their integrity. Firewalls/stops/doors, non-combustible wall and roof coverings, sprinkler systems, fire alarms, etc., all become less effective because of earthquake stress.

The earth movement causes fires to break out by overturning open flames (candles, fireplaces, water heaters), shorting electrical circuits, arcing power lines, rupturing flammable material containers and pipelines (gas, liquid, vapor). This list is limited only by your imagination.

Many of these fires can quickly and easily be controlled and/or extinguished by civilians if they are uninjured, aware of the fire, able to get to it, and if they have the knowledge and means with which to fight the fire. However, if the fires spread to the stage where they require professional firefighting services and firefighting teams can quickly respond, the fire can usually be contained. However, an earthquake can result in simultaneous outbreaks of dozens of fires.

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It’s rare to be able to respond to all multiple outbreaks of fire in a timely manner. Also, fire departments are called upon to mitigate hazardous material incidents, building collapses, etc. Two recent California earthquakes (the 1983 Coalinga and the 1984 Morgan Hill earthquakes) have illustrated many of these aspects.

THE MAY 2, 1983,

COALINGA EARTHQUAKE

On Monday, May 2, 1983, at 4:42 p.m., an earthquake struck the town of Coalinga in California’s San Joaquin Valley. Coalinga, with a population of 7,000, consists primarily of one-story wooden residences. The buildings in the older downtown area are two-story brick and joist construction. Coaiinga’s economy is based on nearby oil fields and farming.

A large aftershock followed slightly more than three minutes after the earthquake. Although the main earthquake was of moderate magnitude (6.7 on the Richter scale), ground motion was clearly perceptible 200 miles to the north and south, in San Francisco and Los Angeles. First reports, although greatly exaggerated, indicated that there existed fires of conflagration proportions. The fire-related events of May 2 contain valuable lessons with respect to the postearthquake fire problem.

The Coalinga Fire Department consists of 30 personnel (11 paid, 19 volunteers). Equipment consists of one 1,250-gpm and two 1,000-gpm pumpers, one hose wagon, and two ambulances. Also located in Coalinga is a California Division of Forestry fire battalion. Following the earthquake, there were about 15 grass fires in the surrounding countryside caused by downed or arcing power lines. Immediately after the main shock, forestry personnel decided to respond to Coalinga rather than to the grass fires because of a greater likelihood of injuries at the earthquake site.

At the time the earthquake occurred, fire department personnel left the station and saw collapses of nearby buildings in the downtown area. After the shaking stopped, they moved the fire equipment out of the station and issued a radio “all call” (all fire department personnel report to the fire station).

Captain John Donelan went to the central business district to perform a reconnaissance. Donelan radioed the station, declaring a disaster and requesting notification of the Office of Emergency Services and mutual-aid fire companies. An aftershock struck 3 minutes 46 seconds after the main shock. Donelan moved to a safer location several blocks away and continued setting up a command structure and radioing outside authorities. By this time, more buildings had collapsed, spreading bricks in a collapse zone 20 feet into the street on all sides.

About eight minutes after the main shock, as dust was clearing, smoke was emanating from the central business district. The fire department responded with two engines, but with only one man on each. Hydrants and hose layouts were assigned, downed power lines were identified, and firefighting began. The fire was in a two-story brick building that had partially collapsed. Because of the shortage of firefighters, civilians manned hose lines, with a professional firefighter at the nozzle. The fire proved extremely difficult to extinguish.

Based on interviews with the owner and an inspection of the debris, it is believed that the fire was fueled by high-proof liquor from broken bottles in a storeroom on the first floor. Other factors estimated to have contributed to the difficulty of the firefighting operation were: the storage of flammable liquids; debris deflecting hose streams; the large open area of the partially collapsed structure; and aftershocks and collapses of adjoining buildings.

Only exterior firefighting operations were employed because of the danger of additional structural collapses.

After four hours, the fire had spread to an adjacent building and was threatening other exposures. Twice, the fire had spread to a twostory brick building 20 feet away. Finally, it was decided to create a firebreak by demolishing the adjoining building using earth moving equipment.

Other incidents that occurred and actions taken within 5 1/2 hours after the main shock were:

• • Chemical spills at the West Hills Community College, the

• Coalinga High School, and a dry cleaning establishment,
• Fire alarms (but no fire) at the Coalinga Convalescent Center and the Coalinga Hospital.
• Verification that the town’s gas had been shut off (Coalinga has a municipal gas system). Many residents on their own initiative had turned off their own and their neighbors’ gas.
• An electrical outage caused by the main shock. Unlike the gas, residents did not turn off their electricity.
• Flat tires on vehicles, including fire department apparatus.
• Shortages of fuel for fire department vehicles and shortages of drinking water at the fireground.
• Several residential fires resulting from overturned open flames and electrical appliances.

Earthquake Preparations

Fire following earthquake did not cease to exist as a problem in San Francisco, CA, when the last embers of the 1906 earthquake were quenched and the last shaking had stopped on the San Andreas Fault.

Given San Francisco’s close proximity to the San Andreas Fault, its relative isolation (surrounded on three sides by water) and its dense building pattern of row housing (much of it of wood construction), it was apparent that earthquakes and associated fire would always be a problem. Therefore, during the rebuilding of the city after 1906, a special auxiliary water supply system (AWSS) was installed to serve the downtown and densely built area that is independent of the domestic water supply system. The AWSS, specially constructed to avoid pipe breakage and be able to valve around large breaks, is regularly employed by the San Francisco Fire Department in all large fires.

Supplementing the AWSS, there are also 150 underground cisterns at major street intersections as well as at 1,000-foot intervals on Van Ness Avenue, which is considered to be the city’s main north/south firebreak.

Recently, the fire department has taken steps to improve its emergency water supply capability by acquiring flexible agricultural piping and large diameter hose that can be quickly laid in the streets. The fire department also improved its communications and damage reconnaissance capabilities by having standing agreements with several organizations for rapid aerial reconnaissance and special navigational assistance in case of poor visibility.

Several years ago, the San Francisco Fire Department undertook a structural audit of all fire stations to ensure personnel and equipment survival. The results of the audit were the basis for several bond issues that provided funding for the construction of many fire stations to meet current seismic safety standards.

Emmet Condon

Chief, San Francisco Fire Department Member, California Seismic Safety Commission

THE APRIL 24, 1984 MORGAN HILL EARTHQUAKE

On April 24, 1984, at 1:15 p.m., a widely felt tremor, subsequently named the Morgan Hill earthquake, jolted the San Francisco Bay Area and central California. Preliminary data indicates that the earthquake occurred on the southern part of the Calaveras Fault, south of San Jose, and measured 6.2 on the Richter scale. Reported losses and less publicized damage to sensitive industrial facilities may reach $20 million.

Although the damage from the Morgan Hill earthquake was of moderate magnitude, the fire operations related to the earthquake contain significant lessons. In the six hours that followed the earthquake, a total of 79 confirmed earthquake-related incidents were reported: 32 for the Morgan Hill Fire Department, 29 for the San Jose Fire Department, 4 for the California Division of Forestry, and 14 for Gilroy and the area south of Morgan Hill. Of these incidents, three fires resulted in major structural damage. Other incidents included gas leaks without fire, chemical spills, and structural damage.

Events in Morgan Hill

The City of Morgan Hill (population 18,000) has 14 paid-on-call and 30 volunteer firefighters. Equipment includes a 1,500-gpm and a 1,250-gpm engine, each carrying 500-gallon tanks. There is also a 750-gpm reserve engine (300-gallon tank) and a quick-attack vehicle capable of pumping 250 gpm and carrying a 500-gallon tank. Located at the south end of Morgan Hill is a California Division of Forestry station with three engines equipped for brush fires.

While there were numerous small fires, medical aid calls, etc., in the first few minutes after the quake, the major damage in Morgan Hill, structural collapse in the Jackson Oaks area, was not reported until 32 minutes after the earthquake. This report was given by an engine company responding to a medical aid call. Firefighters first observed water running downhill from broken water mains, and then noticed single family dwellings with damage varying from minor to partial collapse.

Civilians, some with minor injuries, were in the street, and victims were reported trapped in some structures. Residents had turned off about 30% of their gas service, and firefighters completed the cut-off of all gas and electricity. A primary search was conducted in all homes in the affected area.

A first aid station was established; the affected area cordoned off; an incident command post established; and operations involving the California Division of Forestry, Morgan Hill Fire Department, California Highway Patrol, and Santa Clara Sheriff’s Office were coordinated.

Due to the water main breakage, about 500 homes were without water, so the outbreak of fire was a serious concern. It was recommended that victims in the affected area not remain in their homes until the buildings had been declared structurally safe by the Building Department. Additional problems involved:

• School buses returned school children to their homes, making enforcement of the cordon more difficult.
• Ten to fifteen helicopters and fixed-wing aircraft arrived in the vicinity, sometimes flying less than 500 feet above the ground. One helicopter landed in the cordoned-off area and attempted to discharge what appeared to be journalists, but left after a warning

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• from the Morgan Hill Fire Department.
• By about 4 p.m., approximately 40 media personnel were in the area.
• At about 4:10 p.m., there was a near collision involving a helicopter and a fixed-wing aircraft.
• At 4:15 p.m., following a request by the Morgan Hill Fire Department, the Federal Aviation Administration established a fivemile radius restricted airspace.
• General Telephone set up three emergency telephones in the area within several hours, two for use by residents and one for use by the fire department. This was a grateful consideration, as it permitted firefighters to confirm the well-being of their own families.
• A structural fire involving a double-wide mobile home. Probable cause was a broken natural gas pipe in the water heater enclosure. Total loss was estimated at $40,000.

There were a total of 35 incidents in approximately nine hours following the earthquake as compared with about 1.9 incidents per day on an average day.

Events in San Jose

San Jose Fire Department, serving a 206 square mile fire district with a population of about 730,000 people, consists of 680 personnel (174 per shift) in 28 fire stations and four district headquarters. Equipment includes 28 engines (1,200 and 1,500 gpm), 10 ladder trucks, 10 light units, 6 hose wagons, 6 patrol tankers (usually used in wildlands), 3 tankers, a hazardous materials unit, and several rescue units.

On an average day, the department responds to approximately 3.5 to 4.5 incidents per hour. Following the earthquake, the San Jose Fire Department handled 62 incidents within five hours.

In the first four hours, 29 calls, confirmed to be earthquake-related, were broken down as follows:

gas investigations 8

wires down 5

structural fires 4

alarm sounding 3

transformer leak 2

service calls 4

hazardous materials spill 1

grass fire 1

evacuation 1

The largest fire occurred at 1:31 p.m. in a shopping complex in the southern portion of San Jose. There appears to have been a delay in reporting this fire due to slow telephone dial tones, and, in fact, the report was made by a civilian who drove to the nearest fire station. The fire was in a one-story wood framed, wood shake (shingle) roofed building approximately 45 X 125 feet. The structure housed an auto parts store, an aquarium business, and a video shop.

The fire appeared to have been caused by a broken connection to a gas heating element in the auto parts store. The auto parts store filled with smoke and the first-arriving engine attacked the fire with two 1 1/2-inch lines and laid a 3-inch supply line to a nearby hydrant. Flashover occurred at about this point, and the fire spread rapidly through the attic area to the other two businesses in the building. Second and third alarms were turned in.

Four engines and two trucks, using approximately 50,000 gpm of water over a 60-minute period, kept the fire from reaching nearby exposures, one six feet away and having a wood shingle roof. The wind velocity was about 12 to 16 mph. Total loss was estimated at $500,000 for the structure and $415,000 for the contents. Dwellings directly to the rear of the fire building sustained some smoke damage, and a wood shingle roof on a dwelling one block downwind was ignited by flying brands.

CRITIQUE

Some observations and issues that have emerged from experiences in these two earthquakes are:

• The fire departments functioned extremely well in both earthquakes, coordinating their efforts and establishing emergency command centers and procedures.
• Communications were an essential but vulnerable link in the firefighting effort. Reports of fires are too dependent on the telephone system, which is the sole means of reporting fires in San Jose. The fire involving the shopping complex and another one involving a mobile home were reported by civilians driving to fire stations. Fortu-
• nately, the stations were manned at the time. Had the units been out of the station, reporting of the incidents would have been delayed even more.
• In an earthquake, some damage to telephone equipment should be planned for. Immediately following the earthquake, Pacific Telephone experienced an increase of 84% over usual telephone use. The system is designed to handle this overload by causing a slowdown in response (delays in receiving a dial tone of about 30 seconds were experienced in this earthquake), which can be perceived as “the phones are out.” Therefore, emergency services should expect less than ordinary telephone response in a major earthquake, and should be prepared with alternative communication methods to optimally allocate resources. The public should know the location of the nearest fire station. Emergency officials should have pre-planned aerial reconnaissance, block-by-block “windshield surveys”, or other methods of quick size-up.

• Due to confusion and a false alarm in the San Jose City Hall, the city hall and the emergency operations center were temporarily evacuated. Back-up emergency operations centers should be provided for, with automatic referral if the prime emergency operations center is designated as not functional.
• A significant portion of the incident load in these earthquakes was not specifically fire-related (e.g., gas investigations, hazardous material incidents, structural damage checks, medical aid calls). Although these incidents are part of a firefighter’s normal job, in an earthquake these tasks overburden limited fire department resources, which should be first reserved for firefighting. Therefore, in a major emergency, some of these tasks should be coordinated with and assumed by utility companies, building departments, structural engineers, medical services, etc. Dispatching of this supplemental aid via the emergency operations center might be considered with considerable planning.
• Media relations and coordination need improving. Their legitimate requirements for information are sometimes burdensome. The media can actually prove of benefit to emergency operations if cooperation is planned for and agreed upon. For example, rapid damage reconnaissance procedures could be performed in part by media aircraft, which are video equipped and experienced in aerial reconnaissance.
• Restoration of utilities (gas and electric) can result in fires hours or days after the initial disaster. Careful thought must be given as to how and when to restore power to an area. Consideration might be given to restoring service only after individuals are present in every structure (with public officials authorized to enter structures where owners are absent) in order to check for fire or gas leaks. Also, fire units should stand by in the area at the time of utility restoration.
• Although no fire occurred in the Jackson Oaks area of Morgan Hill, about 500 homes were isolated for 45 minutes after the earthquake. The area was deprived of water for several days due to broken water mains. The Morgan Hill Fire Department stationed a water tank truck at the scene, sufficient to control a small fire.
• The San Jose Fire Department dispatching center’s computer temporarily “crashed,” due to a power outage. Emergency service operations should not rely on computers without dependable back-up power. Operations should be regularly exercised with computers “down.”