Nondestructive testers check objects for flaws in a way that doesn't affect
their future usefulness. The types of objects they examine include everything
from boats to boilers to bridges.
Testers use some cool stuff to examine objects. One method is ultrasonic
testing, where internal imperfections in the material cause changes to high-frequency
sound waves.
"If I'm examining a one-inch material and there is a crack at three-quarters
of an inch, the sound comes back sooner than expected," says Joseph Rajhard,
a boiler field inspector. "The crack sends the sound back at the three-quarter-inch
mark."
Another technique involves coating a material with a dye. Changes in the
color of the dye pinpoint cracks.
Nondestructive testers also do electromagnetic tests. Imperfections in
the material of some objects will interrupt the flow of electrical current.
Finally, nondestructive testers use X-rays to discover changes in the internal
soundness of a part, in much the same way they show broken bones.
Technicians often discover defects that are invisible to the naked eye.
That can be a challenge, says William Klene, an assistant professor in the
nondestructive evaluation department at Illinois' Moraine Community College.
"You may never see the defect that will potentially cost your client a
huge sum of money. It can be hard for young people. You must have the knowledge
and personality to convince the client you know what you're doing. Your integrity
must be pristine."
Some testers work in aerospace, spending their days in an aircraft hangar
checking aircraft parts. A few lucky ones even work for NASA. Others work
at nuclear power plants, in the petroleum industry or at commercial testing
laboratories.
Nondestructive testers must be persistent. "You need to be a go-getter,"
says Allen Russell, a nondestructive evaluation operations manager.
The ability to make quick decisions is a must. "People who can't think
quickly don't last in this business," says atomic research engineer Laura
Obrutsky.
Computer skills are also helpful. "In the past, technicians had to do lots
of mundane tests over and over," says Klene. "Now computers perform routine
tasks. There'll always be some hand testing. But it's hard to predict how
far technology will go in 10 to 15 years."
Applicants must meet certain medical requirements to be a nondestructive
tester. You should have perfect vision and no allergies. Physical demands
range from moderate to severe.
"The worst extreme is when you're following a pipeline constructed in the
middle of nowhere," says Klene. "You're in mud up to your knees, X-raying
pipe. You could be crawling around inside a nuclear power plant, outdoors
looking at locomotive engines or working in an airplane hangar repairing aircraft."
Nondestructive testers can put in some irregular hours. Due to concerns
over radiation poisoning, 99 percent of radiography testing is performed at
night.