Lightning need not hit a petrochemical storage tank to set it ablaze, said Dwight Williams, president of Williams Fire & Hazard Control. A fire in a 140-foot diameter gasoline storage tank in Glenpool, OK, that was extinguished by Williams F&HC, the Glenpool Fire Department, Sunoco and Explorer Pipeline on June 12 may well be a case in point.
"As we know there have been cases of lightning hitting columns of hydrocarbon vapor rising off tanks and blowouts," Williams said. "I've seen it before."
The Explorer Pipeline terminal at Glenpool, located about 60 miles south of Tulsa, is an important link in a 1,400-mile pipeline system that transports gasoline, diesel fuel and jet fuel from the Gulf Coast to the Midwest. That means a great deal of product is moved through the Glenpool tank farm, Williams said.
Operators had just filled the internal floating roof storage tank to 43 feet, two feet short of its full sidewall height. Within an hour a thunderstorm moved through the area, bringing with it the lightning strike that ignited the tank.
"Lightning loves hydrocarbon," Williams said.
As a result of the 11-hour fire, Explorer was forced to shut its 28-inch oil pipeline into Tulsa, OK, and its 24-inch pipeline to Explorer's Wood River, IL, terminal. With record prices being paid at the gas pump, the fire received national attention in the media. On the positive side, action taken by Williams F&HC and Explorer saved nearly 38 feet of the product in the affected tank.
Explorer Pipeline's Glenpool tank farm consists of 31 tanks with a combined capacity of about 3.4 million barrels. At 9:10 a.m. the first report of a lightning strike at the tank farm reached the Glenpool Fire Department, said Captain Clay Ward. He responded with everything he had available -- three firefighters and one engine.
"One engine is all we've got," Ward said.
Company officials met the firefighters at the front gate. The tank, alone inside a large dike, held 120,000 barrels of blended gasoline. Firefighters initially identified the emergency as a seal fire because the tank was burning around the outside of the roof. This proved to be incorrect since the tank was topped by a fixed roof, not a floating roof.
"What Explorer wanted us to do was set up some kind of command center for when we got the resources needed and could go ahead," Ward said. "So for the first hour all we did was call in our mutual aid resources and set up staging areas for when resources started to arrive."
At about 11:30 a.m., the external cone roof collapsed and fell into the tank, sinking the floating roof beneath it. Fire spread across the full surface of the exposed flammable liquid.
"All we could do was protect the other exposures," Ward said.
At about this time Explorer contacted Williams F&HC.
"They asked us if we could respond," Williams said. "We told them we could. They called us back about 45 minutes later and said 'Please respond.' That was shortly after noon."
Explorer also notified Williams that it was drawing product out of the burning tank. Although Williams often advises against drawing out product, this situation was different.
"The only reason not to draw product out is that the roof is intact and you don't want to lose it," Williams said. "If you draw product out you are likely to lose it. But they had already experienced a loss of the roof. I could not give them a good reason not to draw it out. I told them 'Either draw it out until it gets too hot or gets below the pan. If it gets under that, vapor could collect and blow the pan right out of the tank. Then we'd have running fire all over this country."
The pan of the internal floating roof sits on six-foot legs. Explorer stopped drawing product at the 10 foot level when the product itself became too hot to move.
"They could move this tank with a 30-inch line," Williams said. "They were jerking that product out."
Glenpool called in mutual response from Jenks, Bixby and Tulsa. Another volunteer department in nearby Kiefer staffed the Glenpool fire house, covering the city until the Glenpool firefighters could return, Ward said.
"We decided that we needed to establish two different water sources independent of the municipal supply," Ward said. "We laid 5-inch hose into the facility and hooked to Explorer's hydrant loop. The other line came from the municipal water supply which we set up to go straight into the big pump that Williams was bringing in from Tulsa. We had 1,100 to 1,500 feet of 5-inch hose. We borrowed all the 5-inch hose that Jenks and Bixby had, then some more from Tulsa, Sun Oil and the Sapulpa Fire Department."
Other tanks were located about 60 yards to the north and east. The tanks to the north also contained gasoline. Fortunately, the wind was initially blowing out of the northeast at a relatively gentle 5-to-10 mph, Ward said.
"Normally it blows out of the south at about 7,000 mph all the time," he said. Still, Explorer took the precaution of rapidly draining the neighboring gasoline tanks. Later, a passing thunderstorm passing to the west shifted the wind again. As the day wore on, the wind again changed to out of the north-northeast at about 15-20 mph. By the time the first foam attack could be mounted, the wind was blowing out of the south.
By 4 p.m., Williams was in flight to Oklahoma aboard a chartered twin-engine King Air with five Williams F&HC personnel, two through-the-pump proportioners, several four-by-five Storz cross over fittings and a gated Y with a 5-inch connection. Also on board was a throw down model Daspit Tool, a 500-to-2,000 gpm automatic nozzle complete with stabilizing stakes.
Williams said the secret to traveling light when it comes to flammable liquid fire fighting is the TKO Hired Gun Gang, a worldwide resource network operated by Williams F&HC and Ansul, Inc, maker of fire fighting foam products. Foam inventory and cashes of equipment are left on standby at various refineries, warehouses and other locations, waiting until needed.
"I did not have to respond with barrels and barrels of foam, just some key equipment," Williams said. "I had foam almost across the street. It got there faster than I could fly up there."
In this case, a 4,000 gpm pump and 18 265-gallon totes of Williams F&HC's Thunderstorm 1X3 foam was obtained from the Sunoco refinery in Tulsa for extinguishment and post suppression.
"This was our third call into that area in 2? years," Williams said. "We have increased our inventory level in the region as a result of that, just for a faster response."
Traveling by air also gave Williams a chance to scope out the tank fire from above as he was arriving. As reported, the roof was in the product. How it ended up there is a matter of conjecture.
"Any time you get a lightning strikewith flammable vapor it has a tendency to suck air as it moves," Williams said. "That flame front moving into the tank put a hammer on the pan and cocked it into the product. I think that is very probable. Now, having done this, the flame has to follow into the tank itself to some degree and that compromised the roof. Basically there was an explosion inside a small vapor space of some two or three feet."
The top of the side wall of the tank is not the top of the roof, he said. The roof actually rises much higher.
"So you've all this room," Williams said. "As you're filling the tank you're pushing this vapor up. Then when it flashes it goes back into the tank. I think it compromised the roof to the point that it just weakened. After it burned for a length of time it just gave up and fell in."
After meeting with all the principles, Williams made his customary walk around the burning tank. His first major decision was to move the command post to a location almost 180 degrees from where it was to be closer to the fire.
"Then we started assigning tasks," Williams said. "Within two hours we were hitting the fire."
Explorer Pipeline provided important equipment such as trucks and forklifts. Meanwhile, Glenpool and the other firefighters were busy laying hose.
"I don't know that I've been helped any better anywhere else in the world," Williams said.
As usual with tank farm fires, water was precious, he said. Williams' plan called for using a Hired Gun monitor to flow 2,000 gpm, backed up by the Daspit Tool operating at between 800 and 1,000 gpm. To handle fires after the major extinguishment, a react line using 300 gpm was also put into action.
Williams started out using his standard "Footprint" methodology, a patented combination of application rate, massed stream/application density, foam run and technique of application.
"Fourteen minutes into the attack we changed to teasing or wiping the flame," Williams said. "That is another patented methodology that we have incorporated into the Footprint. We do it a lot on crude oil. We had never done it on gasoline until this one."
What made the change in tactics necessary was a large pipe in the center of the tank that was blowing fire above the flammable liquid and the foam blanket.
"Historically, you're supposed to use dry chemical to put that kind of fire out," Williams said. "The tease is a technique where if you don't have dry chemical or can't get people close enough to use it you can use your expertise and talent to do the job -- that and divine intervention."
The technique is to raise the nozzle (increase the angle) slightly higher and use the height to give the monitor more surface area, transversing the flame back and forth. It also came in handy in four or five areas where the sunken roof protruded above the blanket, fire burning at each point. Little fires that threaten to reignite the big fire can be the biggest problems with extinguishment.
"We had a little problem with some coke buildup on the underside of the roof that was sparkling a little bit," Williams said. "We had to kind of wash around on top, through and under that and it took some time. It took about 30 percent of our foam to cool and protect from that hot coke."
By 8 p.m. there was no flame visible in the tank.
Williams said he believes the following are the key lessons that the Glenpool fire teaches about storage tank fire fighting:
- PUMP OUT PROCEDURES -- "If the roof goes down into the product you should quit pumping out so that you can have some assurance that the roof will remain covered by product. If the roof is not covered, you don't have an open surface that allows your foam to communicate all the way across. You're fighting a multitude of smaller fires."
- WATER IS VITAL -- "People have got to realize that you need water to put these fires out."
- EXPERIENCE -- "Even if you have water, the best support you can have is experience. How many times do people get to fight these fires and see them done right? How many time do firefighters have a successful experience that can teach them this technique?"
At Williams F&HC, a host of young firefighters such as Chauncey Naylor, Eric LaVerne, Herman Ladner, Doug Daspit and others have gained that experience.
"I have boys who wade in hot water chest deep to put in my react line," Williams said. "These are my boys. I've got a crew that is very well disciplined and very sure of their leadership. And as for me, the good Lord smiled on us one more time."