Be careful what you wish, particularly if you are, 1), a leading authority in extinguishing large-volume flammable liquid fires and, 2), driving almost border toborder across Texas. One afternoon in July 2000, Dwight Williams took a professional interest in some local scenery while driving through the southeast Texas town of Sealy, population 5,248.
For a single brief moment, five storage tanks in the 120-foot diameter rangesitting in a tank farm beside Interstate 10 caught his attention.
"I remember when I drove by saying to myself 'That would be a great place for a tank fire,'" Williams said. "'It would sure be an interesting operation.'"
Almost an hour later and nearly home, the only Sealy on Williams' mind might have been a soft mattress. Then he heard his pager. Thanks to a passing thunderstorm, a blazing crude oil storage tank beside I-10 required his immediate attention — one of the same tanks he had been daydreaming about earlier."When they told me where it was, I said to myself, 'Hell, I know exactly where that tank is,'" Williams said. "I was astonished."
Coincidence is one thing, similarity another. No two fires have ever been identical, most of all storage tank fires, Williams said. Each has its own unique set of circumstances to contend with. What type of product is involved? Is the fire full-surface or a more limited seal fire? What resources such as personnel and equipment are available? How close is the nearest source of water? What is the danger to surrounding exposures, such as other storage tanks?
All that Dwight Williams knew about the tank farm in Sealy was what he had seen from the road. To prepare for a successful response he would need a lot more information. At the Sealy fire, much of that information came from the firefighters already on the scene — the Sealy Volunteer Fire Department. Their initial assessment would determine how well equipped the Williams crew would be when it arrived to tackle the storage tank fire.
Around 5 p.m. on July 24, 2000, the Sealy firefighters responded to what was initially reported to as a gasoline fire "somewhere behind the Whataburger."
Firefighters quickly tracked the fiery glow to the tank farm near the busy intersection of State Highway 36 and Interstate 10. Assistant Chief Cliff Langton, arrived aboard one of Sealy VFD's three engines, found flames leaping from a 120-foot-diameter open-floater storage tank containing at least 224,800 gallons (70,000 barrels) of light sweet crude, the type of crude most sought after for gasoline and other products.
Firefighters caught two important breaks early on. First, the weather after the thunderstorm was calm. Smoke from the burning tank rose straight up. Second, the tank farm dated from the early part of the 1900s. Riveted storage tanks such as the one a blaze were common in the 1920s. In the era when land was cheap and industrial firefighting much less effective, the best fire protection for a tank farm was distance. A good 300 feet stood between the burning tank and any neighboring exposures.
Sealy, located about 50 miles west of Houston, supports a well-trained and well-equipped volunteer fire department. Operating out of a single station, the 32-member Sealy VFD covers 120 square miles. Beside its three engines, apparatusincludes a 3,000-gallon tanker, three brush trucks and one rescue truck. In 1999, the department made 245 runs, including 41 emergency medical runs, 26 hazmat callsand 10 structure fires. No tank fires, however. The last major fire at the Sealy tank farm happened at least 30 years earlier.
On the advice of tank farm employees, the engine and crew soon moved to aparking lot a full block away. This location served as an operations command post throughout the emergency. Meanwhile, police began evacuating two motels andnearly 40 homes within a half-mile radius of the fire. Authorities closed both State Highway 36 and rail traffic through the area.
Alerted about the emergency, Sealy Fire Chief Joe Schmidt cut short a training visit to the Emergency Services Training Institute at Texas A&M University in College Station, almost 90 miles away.
"The owners made the decision to call in Williams within the first hour," Schmidtsaid. "When I got there, we were waiting for his phone call."
Tragedy enough had already tested the Sealy VFD in 2000. In January, the department lost a fire captain who suffered a cardiac arrest during an interior attack on a burning house. No one was anxious to put firefighters at risk in asituation as alien as a storage tank fire, particularly Chief Schmidt.
When Williams contacted Schmidt, the chief's first question was how far fromthe tank should he keep his firefighters, Williams said.
"Under the impression that we were dealing with a full surface fire, I told him that 500 feet was the absolute minimum I would recommend unless he had a specific task that was required."
Tiny Mauriceville near Beaumont makes Sealy look like a major metropolis. At Williams F&HC headquarters in Mauriceville, a well-practicedprocedure was in motion. Even before Dwight Williams responded to his page, his sister Randy Williams, in charge of logistics, busied herself with contacting other key personnel.
"All I had to do was call the office and I had people already there ready for instructions," Dwight said.
Williams F&HC keeps two trucking companies on call. A tractor-trailer rig is always parked near its headquarters. That rig and others can be loaded and o nthe road in less than half an hour. To shave even more valuable time off their E.T.A., care is taken not to duplicate resources already available at the fire scene. Just finding those resources is not enough, though. Quantities sufficient for bulkflammable liquid firefighting must be available.
Sealy VFD's foam supplies, purchased mainly as an emergency reserve, amounted to less than 100 gallons.
"When I told Dwight, he said 'Well, that ain't enough,'" Schmidt said. At leastone rig destined for Sealy would be hauling a full load of ATC-AFFF (Alcohol-Type Concentrate - Aqueous Film Forming Foam).
To do its job, that foam concentrate would need lots of water. No water system existed at the Sealy tank farm for Williams F&HC to draw on. Lack of water would determine much of what the firefighters brought from Mauriceville.
"You need to realize that not everyone is going to have water," Williams said."It's typical of facilities this size that there isn't any water for firefighting."
To reach the nearest municipal water, railroad employees used special equipmentto dig under the nearby tracks. This allowed Chief Schmidt to stretch a 4-inch linefrom the closest city fire hydrant. However, with Williams F&HC bringing nozzles throwing thousands of gallons per minute, a large-volume source would be needed. The closest candidate was a 12-inch water line nearly 2,000 feet away.
To relay water that far, the Williams F&HC crew loaded four big pumps, two primaries and two backups, and enough large-diameter hose to stretch the distance. Chief Schmidt's firefighters would provide the last necessary local resource — manpower — to accomplish the major hose laying operation ahead.
Until that equipment arrived, expertise became Williams F&HC's major contribution. Accepted practice with many companies is to pump out burning tanks to reduce volume and save product. Told that this was being done in Sealy, Williams strongly urged against it.
"Normally on a crude oil fire, we will stop any movement of product in or out if it is an open floater and already at a high mark in the tank," Williams said. "If you reduce the product, you take a chance of causing more damage. As the product goes out, the (floating roof) goes down with the product and you actually expose more of the tank shell to damage."
Draining the tank also creates more space for flammable vapors to accumulate,increasing the risk of explosion, Williams said. This only increases the danger thatalready exists if vapor has penetrated the hollow pontoons supporting the floating roof. The owners at the Sealy tank farm took Williams's advice and discontinuedthe draining.
At least six miles before reaching Sealy, Williams realized that the emergency was not a worst-case scenario. If it were, the roiling, billowing fireballs climbing into the sky that denote a full-surface fire would be visible. Williams was not disappointed.
"I still remember every full-surface crude fire I've ever been to," Williams said. "They are not easy. They are a very deliberate foe. Those are the kind of fires that can and will kill firefighters. When I saw there was no flare in the sky, I was about half glad."
Williams and firefighter Chauncey Naylor reached Sealy at about 11 p.m., at least 35 minutes ahead of four fully loaded tractor-trailer rigs. Also on hand from Williams F&HC were Eric Lavergne, Jason Williams and Doug Daspit. Because Williams F&HC is a commercial concern, the first order of business was to establish who is financially responsible for the cost of extinguishment. Work commences only after a contract has been signed, period. In this case, a representative of the Sealy tank farm immediately stepped forward to execute the legal preliminaries.
Instead of assuming some lofty authority, Williams said he prefers to win the confidence of the emergency personnel working the scene. His approach is tolearn what has been attempted so far, eliminate what has not worked and, applying his own hard-won expertise, guide the responders in a new direction.
"So often when we get there, people are worn out," Williams said. "We have to be a cheerleader to get people back on their feet."
If you believed the Houston-area television reports, there was plenty to begloomy about. Throughout the evening, the Sealy fire dominated every news break. From beyond the half-mile evacuation radius, newscasters could only offer their audiences a distant flicker against the night sky. None of that compares to the video Naylor shot as he and Williams climbed the staircase curving around the 45-foot-tall tank to take their first close look at the enemy.
"You could see coke and burning paint along the top edge," Naylor said. "When the camera backs off, you can see that the tank shell is glowing in that one spot (right under the platform at the top of the ladder). We checked that ladder carefully to make sure there was no give."
Williams and Naylor, wearing protective bunker gear, quickly confirmed what they suspected. Inside the tank, the floating roof sat about 12 feet below the rim. Around the circumference, flames rose from the rubber seal between the roof and the tank shell. The firefighters had a classic seal fire on their hands.
As opposed to a full-surface fire involving a sunken roof and exposed product, a seal fire is relatively stable if treated with respect, Williams said.
"I have no trouble with an open floater burning 15 or 20 hours, although I have seen some strange things happen to open floaters that burned longer than that," Williams said. "But usually it is a real abnormal situation to have trouble with anopen floater burning in the seal area. I had one in Louisiana that burned 25 hours. Some in Kuwait burned for 30 days."
The mistake that firefighters unfamiliar with either full-surface fires or seal firesmake is to start pouring large volumes of water into the blaze. In a full-surface fire involving crude oil, this simply adds to the risk of a boilover. Crude oil contains water that settles to the bottom of a storage tank over time. A full-surface fire slowly heats the crude beneath it. When the descending heat wave reaches the bottom, the waiting water turns to steam. What follows is an almost volcanic eruption of burning oil and searing heat that instantly overwhelms firefighters working at close quarters.
What you've got with an open floater like this one is a giant stove," Williamssaid. "Those things will cook and act just like a Coleman stove."
With a seal fire, throwing large amounts of foam and water onto the floating roof risks sinking it and igniting a full-surface fire.
"Water does not go on top of a roof and distribute itself evenly," Williams said."In other words, you'll find three inches on one part and 18 inches on another." Besides the burning seal, at least six inspection ports in the floating roof hadblown open with flames visible. That presented its own set of special problems, Williams said. Product, or at least vapor, had seeped into the pontoons supporting the roof. On the positive side, the roof did not have any standing water on it. With the heat involved, that water would have turned into steam.
Williams offered to take any local firefighters up to see the fire themselves. Atleast one of Schmidt's firefighters was eager to go.
"Then we got busy and I forgot to tell Dwight about it until the foam was flowing," Schmidt said. "By then it was too late."
The equipment from Mauriceville soon arrived. The truck drivers pushed their rigs at the legal speed limit and, in one case, beyond.
"One of them got a speeding ticket," Williams said. "The highway patrol said that 18-wheelers do not qualify as emergency vehicles. So, I paid the kid's ticket."
Efforts now turned to tapping the nearest large-volume water source, a 12-inch main capable of 3,600 gallons per minute. To relay that water the 2,000 foot distanceto the fire, Williams set up a 4,000-gpm pump near the main and a 2,000-gpm pump midway between the main and the fire. Two thousand feet of five-inch hose, also supplied by Williams F&HC, tied the main, the pumps and the fire together. Foam concentrate was injected into the system at the 4,000-gpm pump using a through the-pump proportioner.
"It's also important to identify secondary sources such as canals or stock ponds, so if the primary source gives out you don't have to drive around in the middle of the night looking for more water," Williams said.
At the fire scene, the five-inch supply line fed into a portable hydrant with athree-inch line coming off it to evacuate water, leaving the foam. The five-inch line then continued up the stairway to the top of the tank. A portable monitor was placed at the base of the stairway to protect firefighters working above.
"The biggest effort in the whole operation was finding a piece of line to tie the five-inch hose off on the ladder," Naylor said. "Unless the hose is laid right you could break the coupling off once it is charged. The hose has to be arranged so the weight is not on that joint." Fully charged, the hose holds about a gallon per foot, roughly equal to eight pounds per foot.
With the hose laid, the remaining operation broke into two steps. Step 1 was to clear the flames immediately surrounding the platform to give firefighters room to work. A device known as a Foam Wand permitted this. Shaped like a crooked U, the Foam Wand easily slips into position over the rim of a storage tank. Once the firefighter retreats to a safe distance, the wand delivers foam at a 4:1 expansion rate to put out the fire in a specific area.
Williams used two wands charged at 90 pounds per square inch that together produced about 200 gallons of foam per minute. One wand had to be custom-fitted to the tank rim. A petroleum storage tanks has a wide stiffener ring or wind girder around the top of the tank shell. An unusual feature of this tank was that it had a handrail along the wind girder. Firefighters attached the second wand to the handrail. The wands took a sizeable bite out of the ring of fire within six minutes of application. The glowing tank shell below the platform cooled.
With the Foam Wand still flowing, the Williams team moved in for Step 2 — installing the Daspit Tool, a portable 4-inch waterway monitor capable of a 250-foot reach at 2,000 gpm. Named for Williams F&HC associate Doug Daspit, the Daspit Tool is designed specifically for storage tank fire application.
"We came up with it after one particular incident," Williams said. "We were upon a roof that was glowing hot with boiling crude on top of it from a long burn (greater than 25 hours). We were having to walk on hot steel, extinguishing theseal fire as we went along the inner wall of the tank. We thought 'Boy, if we had apiece of equipment we could hang on the inner wall, we could minimize our risk."
Using a rim claim, the Daspit Tool was fixed to the tank shell at the top of thestairway. The firefighters set it to overshoot the tank and moved halfway down the stairway to be a safe distance from any fittings when the hose was charged. The monitor was then directed down onto the fire once the foam content richened. The foam-water solution pouring through the roof drain was at least 150 degrees Fahrenheit, Williams said.
"You could not keep your hand in it without burning yourself," he said. "Not only are you extinguishing the fire, but you are removing the hot water and replacing it with cooler water, which helps cool all the material in the tank."
Once the Daspit Tool was hung, the fire was extinguished within 10 minutes,Williams said. In total, Williams used less than 360 gallons of foam and less than 12,000 gallons of water. The tank lost far less than a one-inch layer of product which amounts to 7,200 gallons. Damage to the tank was limited to replacing the seal and some paint.
Throughout the foam operation, Sealy firefighters moved up to positions behind the Williams crew to protect the manifold as insurance against the unexpected.Having the Sealy VFD completely occupied with a tank fire did not eliminate all other emergencies in the community. Firefighters from San Felipe, 25 miles away, helped by handling at least two routine runs in Sealy during the fire.
Only two big chores remained — picking up the hose and finding a placeopen at 3:30 a.m. to eat breakfast. Tank farm employees assisted with the hose handling. Feeding the Williams F&HC crew at that hour meant driving almost 30 miles to another town. The tank farm owners treated the Sealy firefighters to a free meal, but they had to wait until 7 a.m., the earliest that any local restaurant opened. Williams had nothing but praise for the cooperation he received from Chief Schmidt and the Sealy volunteers.
"It was a good team effort between the community, the fire chief, my people, andthe oil company," Williams said.
Schmidt, a junior captain with the Houston Fire Department, served 20 years simultaneously in two departments — Houston and Sealy. Yet, for all his two decades of experience, he admits that fighting the storage tank fire was unfamiliar territory.
"In this kind of situation, you should bring in the experts right away," Schmidt said. "Unless you have the equipment, the knowledge and the experience, these things can turn bad. You should fall back and set up your command structure instead."
Editor's note: This after-action review appeared in "Disasters Man-Made" by David White and Anton Riecher that was published in 2011.
See all comments