Doctors who take the Hippocratic Oath pledge the following - "First, do no harm." Something very much like that applies to firefighters as well. Firefighters responding to an Oct. 31, 2007, oil refinery explosion near London found themselves in a position where they could do very little firefighting.
Essex County Fire and Rescue Services Assistant Divisional Officer Mark Samuels serves as the brigade's specialist petrochemical officer. He was among the first responders to arrive at the fire atop a tall naphtha column at the refinery.
"Basically, the only firefighting that took place was cooling everything around the fire," Samuels said. "We made sure no flames hit grade. Beyond that it was cooling the vessel that showed spikes in pressure."
The refinery, located in Coryton 25 miles east of central London, produces 220,000 barrels-per-day. At 11:26 a.m., ECFRS received multiple reports of an undisclosed emergency at the refinery.
"We dispatched a pre-determined attendance which included three pumping appliances, one aerial ladder platform and a bulk foam unit," Samuels said.
The refinery is located on a peninsula at least three miles from the nearest residential area. Samuels arrived to find a large fire at the top of a 100-foot tall naphtha column designated C5C6.
"What I did first was go straight to the incident to ascertain the safety of our crews," Samuels said. "I wanted to quickly look to see what were the first actions our crews were taking."
Almost immediately, Samuels called for a stage one major foam attack, which employs 10 pumping appliances, each rated at 4,500 liters per minute, and three bulk foam units. Then he moved to a bunker specifically designed to serve as the on scene incident command center for refinery emergencies.
In the U.K., incident command is a three-tiered affair. Gold command, located off site, is in overall control. Silver command, located on site, is the senior incident commander at the scene. Bronze command is on the front lines with the firefighters. Samuels took charge as the silver commander.
"The bunker is designed to withstand the worst explosion," Samuels said. "You've got these massive doors that are hydraulically power to shut behind you."
One unexpected problem that arose involved communications. The bunker, fortified against overpressure, was located almost 900 yards from the actual fire. Unfortunately, while the radios used by the refinery personnel could penetrate the bunker, it was discovered that the radios used by ECFRS could not.
"We had to use fixed land lines going out to our patrol units to take the messages," Samuels said. "The refinery firefighters were with us and their radios could talk to silver command. We're working on that communications link now so that in future our radios will at least have a feeder into that bunker."
On hand in the bunker was a host of refinery engineers to advise Samuels.
"The decisions were reasonably simple to make on most of the issue because there was a consensus on the way forward," he said.
As for direct firefighting, options were limited, Samuels said. None of the ground based equipment on hand could reach fire that high on the column. The only way to get water on it might be to use an aerial ladder. But the apparatus needed was still en route to the scene.
"There was a single road in and out of the refinery and it was full of tankers," Samuels said. "Those had to be parked somewhere else and the road was starting to get snarled up. We decided to keep a lot of appliances staged about a kilometer away from the incident so they wouldn't get caught in the congestion."
Engineers had an alternative to direct fire fighting in the works. They were busy dumping product to flares to try and bring the pressure down inside the column.
"We decided to move back until we got the okay because the fire was pretty intense during those first few minutes," Samuels said. "We were cooling all the vessels and pipework around the column using fixed monitors."
Also on hold was a search for possible casualties.
"The owners were 99 percent sure there wouldn't be anybody on the unit," Samuels said. "Everyone who was supposed to be there was accounted for. But there was still the possibility that someone had wandered into the area and gotten caught."
Within 45 minutes of the initial call, the large flames dwindled to almost a trickle. Samuels was not necessarily anxious to extinguish that last visible flame.
"It was just the head of the naphtha in the column," Samuels said. "Having it burn off was better than having naphtha coming out unignited, hitting grade and then leaving the firefighters to fight a vapor cloud."
For the next two or three hours, firefighters established water sprays to cool the impacted area. Eventually, the remaining fire went out. Since naphtha vapors were still a problem, firefighters switched to larger water sprays that mixed the vapors with air to bring it down below its lower explosive limit (LEL).
Explosive meters determined that only low amounts of vapor were reaching grade. The next concern was fluctuations in pressure in a hydrogen unit next to the naphtha column.
"A lot of that concern was because the fire had burned out all the motors, instrumentation lines and electrical equipment," Samuels said. "None of the pumps were working. We put some extra monitors on that to cool it down while we tried to dump some of its contents to flare as well."
A subsequent search of the site revealed no unknown casualties from the incident.
As petrochemical officer for ECFRS, Samuels said he visits the refinery site at least once every week. A contingent of ECFRS firefighters visit the refinery once a month to remain familiar with the facility. Also, ECFRS and the refinery brigade perform at least one major training exercise each year.
"We try to mirror the kind of mutual aid relationship that you find on the Houston ship channel," Samuels said. "We have a really good relationship with lots of communication, particularly about compatible equipment. That's why it went so well that day."