01 October 2002
Frugal plant planning could backfire
By Ellen Fussell
FEDERAL DATA SOURCES
Equipment failure could include pumps or pipes breaking. A prime example is the August 2002 incident in Festus, Mo., in which a hose pipe broke between the chlorine tank and the storage tank.
"It was a random failure with no misuse involved," said Cris Whetton, technical director of ility Engineering. (Whetton is also InTech's European correspondent.)
There were about 60 people in the hospital and major evacuations but no deaths. About 50 people complained of breathing problems, and 28 were hospitalized. "That's major to us," Whetton said. (A major accident includes Category 1-multiple deaths, Category 2-a single death or major injuries, and Category 3-a single serious injury.)
ECONOMICS PRECLUDE FIXES
Insistence on saving money could keep plant owners from replacing aging equipment, Whetton said. "So equipment tends to be repaired [over and over] until it fails disastrously."
Whetton referred to one instance in which a pump housing twice developed a crack, "and each time the crack was repaired by welding a plate over it. The pump housing eventually failed catastrophically, releasing oil at 300°C and starting a major fire, which put the plant out of action for several months," he said. The cost of a new pump was about $4,000. The cost of repairs was $1.3 million.
Plants also tend to extend preventive maintenance intervals without knowing what they ought to be, Whetton said. "It was OK with a 12-month interval, so let's try a 15-month interval. That was OK; let's try 18 months next time. That was OK; let's try . . . BANG! More or less what happened on the space shuttle Challenger," he said (see story below).
The remedy for such disasters, Whetton said, is better knowledge about equipment failure rates and characteristics. "Unfortunately, it's too expensive to run life tests on process components, and companies are reluctant to share data," he said. "Consequently, knowledge needed to make informed decisions on replacement and preventive maintenance remains hidden or unused."
While studies from organizations such as the Occupational Safety and Health Administration, the Environmental Protection Agency, and the Food and Drug Administration cover mostly America, ility studies cover "as much of the world as we possibly can. Some of the European countries have databases, but they're not open to the public. And the European Union keeps its own," Whetton said.
REPORTING U.S. INCIDENTS
A number of U.S. federal agencies collect data on hazardous chemical incidents, yet according to the U.S. Chemical Safety and Hazard Investigations Board (CSB, www.chemsafety.gov), "no uniform definition of a chemical incident exists across the federal government . . . and certain categories of events may not be reportable or may be reportable only to state agencies."
That's where the CSB comes in. The board of five members, appointed by the president and confirmed by the Senate, has established a three-year goal to prevent major chemical accidents at fixed facilities by producing an average of five accident investigation reports and one hazard investigation report each year. The CSB also conducts research, advises industry and labor on actions to improve safety, and makes recommendations to local, federal, and state agencies. IT
|SPACE SHUTTLE CHALLENGER
The 1986 space shuttle Challenger, launched amid political, economical, and technical controversy in 1986 and killing all seven on board, was NASA's first attempt to produce a truly reusable spacecraft.
The solid rocket boosters were not designed to launch at temperatures below 53ºF, yet political issues pressed to launch in much lower temperatures. Engineers of the synthetic rubber O-rings advised against the launch, citing cold temperatures could decrease the elasticity of the O-rings, which might cause them to seal slowly and allow hot combustion gas to surge through the joint.
An earlier launch had occurred at a lower temperature, and the O-rings had suffered only a slight discoloration but no damage, Whetton said. So minimum launch temperature was reduced.
Then a launch took place at even lower temperatures, and more of the O-rings burned away. This continued until finally about 40% of the O-ring was gone, but it was still considered OK.
"The rest is history," Whetton said.
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