TNT

the

NDT Technician

The American Society for Nondestructive Testing

www.asnt.org

Near vision acuity is a subject that

has been addressed in NDT

certification standards for years, yet

the process and purpose of

measuring near vision acuity is still

widely misunderstood. The most

common means to measure near

vision acuity for NDT personnel in

the U.S. is to have them read text

from a standardized reading card

using either the Jaeger or the

Snellen numbering system. Another

system, the Point system, uses text

in the Times Roman font on a near

point chart where each point is

0.35 mm (1/72 in.).

Standardized Reading Cards

Jaeger Chart. The Jaeger eye chart

is named for Edward Jaeger, who

in the nineteenth century

introduced a near point chart with

text divided into sections. The

letter sizes from one section to the

next are incremented from 0.5 mm

to 19.5 mm; sections are designated

J1 to J20. The smallest Jaeger text,

J1, subtends the visual angle of five

minutes, or 1/12 of a degree, at a

distance of 0.45 m (17.7 in.).

Snellen Chart. The Snellen chart,

developed by Herman Snellen, also

in the nineteenth century, uses

lower case letters which also

subtend the visual angle of

5 minutes of arc at 0.45 m

(17.7 in.). With the Snellen

technique, vision acuity is described

using a fraction d/D, where d is the

test distance and D is the distance

at which the letter subtends

5 minutes of arc. For example, if at

6 m (20 ft) a person can only read

a letter that subtends 5 minutes of

arc at 9 m (30 ft), then the Snellen

fraction would be 6/9 (20/30). A

simplistic way to explain this level

of vision is that the person can

only see letters that are at least

1.5 times larger [9/6 (30/20)] than

the smallest letter read by someone

with 6/6 (20/20) vision.

FOCUS

Understanding Near Vision Eye Tests

James W. Houf

FOCUS continued on page 2.

TNT · October 2009 ·

Vol. 8, No. 4

James W. Houf, Senior Manager, Technical Services

Department, American Society for Nondestructive

Testing, Columbus, OH 43228. (800) 222-2768,

jhouf@asnt.org.

Table 1. Equivalent letter sizes for common near vision acuity tests. The Snellen

fractions here are exact. Most Snellen charts using feet are in increments of 5

(20/20, 20/25, 20/30, etc.), so the Snellen number is usually rounded to the

nearest 5 (20/20, 20/25, etc.).

Eye chart Letter size

Jaeger J1 J2 J3

Jaeger viewing distance, cm (in.) 38 (15) 50 (20) 63 (25)

Snellen equivalent, m (ft) 6/7 (20/22 ) 6/8 (20/27)* 6/12 (20/40)*

Times Roman (points) 3.5 (N3.5) 4.5 (N4.5) 6.0 (N6.0)

* Snellen numbers here are equivalent only when viewed at 38 cm (15 in.).

Point Chart. The Point chart uses Times Roman

text as noted above. In the United Kingdom, the

point sizes are preceded by an "N", N5, N6, and so

forth. Table 1 shows the relationship between the

Jaeger, Snellen and Point charts for the smallest

three Jaeger numbers.

Visual Angle

The visual angle is the angle formed by two lines

drawn from the center of the eye lens to the

top and the bottom of one of the vision acuity

letters as shown in Fig. 1. As can be seen, both

letters “f ” subtend the same visual angle, but

because one letter is twice as far away from the

eye, its height is actually taller. This

demonstrates the fact that if the distance from

the eye to the object is greater, the letter must

be taller in order to maintain the same visual

angle.

As a result, one reading card may use a small

letter at a closer distance while another may

have a larger letter that must be read at a greater

distance yet each will be a valid test for the

same vision acuity. Viewing the larger letter at

the closer distance will increase the visual angle,

and conversely, viewing the smaller letter at a

greater distance will decrease the visual angle,

and neither would be a valid acuity test since

both charts would have been read at an

incorrect distance.

The Jaeger Reading Card

Character size (height) on a Jaeger reading card

(Fig. 2) will vary with the reading distance

specified on each individual card for a given

acuity.

Most cards will have a statement at the bottom

that says something like “the above letters subtend

the visual angle of 5 minutes at the designated

distance in inches.” This statement is printed on

the bottom of the Western Optical

reading cards

now published by Western Ophthalmics and sold

by ASNT. The height of letters on reading cards

will vary depending on the reading distance

specified on the individual card. There is usually a

set of numbers down the center of a card, one for

each Jaeger size, and that is the distance at which

ASNT’s Technical Services Department receives many calls throughout

he year concerning the proper use of eye charts as a means of

measuring near vision acuity. “Near Vision Eye Tests” provides an

in-depth explanation of some basic concepts of vision testing and

discusses three standardized reading cards as well.

The relationship between an NDT inspector and

welders is sometimes laden with more than average

potential for misunderstandings. In our “Practitioner

Profile,” structural steel inspector Timothy Crick

explains that both a working knowledge of welding

processes and finding and fairly evaluating

discontinuities can go a long way in building and

maintaining a good reputation among welders.

In 2005, researchers for the Antikythera

Mechanism Research Project used enhanced visual testing techniques and

microfocus computed tomography to unravel an ancient puzzle. The

nondestructive tests were used to examine the remnants of an ancient

device recovered from a Roman ship that sank more than two thousand

years ago near the tiny Aegean island of Antikythera

Hollis Humphries,

TTNNTT

Editor

PO Box 28518, Columbus, Ohio 43228; (800) 222-2768 X206;

fax (614) 274-6899; e-mail <[email protected]>

· Vol. 8, No. 4

OCUS continued from page 1.

FROM THE EDITOR

TTeecchh TToooonn

that size text is to be read to meet the

requirement for that Jaeger number. At

that distance, the letters will subtend the

visual angle of five minutes. Five minutes

is the standard visual angle used for

most reading cards.

Distance for Reading Test

As noted above, using a Jaeger reading

card at other than the distance

specified for the given text size will

cause the results to be inaccurate.

Similarly, Snellen 20/22 and 20/25 are

just that; one cannot be said to be

equivalent to another because they are

not. Again, a specific distance should

be used for the chart that is used, and

that distance should be specified on

the card or chart.

If you check two different reading

cards, you may find that the specified

distances vary. The taller letters should

specify a greater reading distance; the

distance at which the card is to be

ead changes with the font size. Using

the card at other distances will lead to

a false eye test.

Because many specifications state

that near distance vision acuity shall

be J1 (or J2) "at a distance of not less

than 12 inches," many people believe

that they can move the reading card in

to 300 mm (12 in.) and they will get a

J1 or J2 eye examination. This is not

so; the text selection must be read at

the appropriate distance as specified

on the card.

Most NDT certification documents

don't specify a near vision acuity test

at 300 mm (12 in.); they usually state

that the test is “not to be given at less

than 12 inches.” This statement was

intended to prevent the use of smaller

reading cards that might specify a

reading distance less than 300 mm

(12 in.) This prohibits the use of

miniature reading cards (some the size

of business cards) that have specified

reading distances less than 300 mm

(12 in.). To clarify this in the 2006

edition of Recommended Practice

No. SNT-TC-1A, the text in

paragraph 8.2.1 was changed to read,

“... the applicant is capable of reading

a minimum of Jaeger Number 2 or

equivalent type and size letter at the

distance designated on the chart but

not less than 12 inches (30.5 cm) on a

standard Jaeger test chart.” The bold

text is added for emphasis here to

ensure that the intended use of the

card is understood.

Jaeger Equivalents

In 2004, when ASNT first began to

draft ANSI/ASNT CP-106,

Non-destructive Testing — Qualification

and Certification of Personnel

(the U.S.

adoption of ISO 9712

), the phrase

TNT · October 2009 ·

FOCUS continued on page 5.

Figure 1. The concept of visual angle. From different distances, letters of different

sizes may subtend the same visual angle. In terms of vision acuity, they are

effectively the same size if read at the appropriate distances.

isual angle

Eye lens

J1 designation for

smallest text size

Corresponding reading

distance for J1 text

Chart must be held at

distance that corresponds

with text group

being read

Figure 2. The Jaeger eye card is widely used for performance examinations of

near vision acuity. Text groups gradually increase in size and are designated as J1,

J2 and so on. The vision acuity equivalent of each Jaeger designation depends on

the distance at which the chart is held. This image has been scaled and

processed for publication and must not be used for vision examination.

“or equivalent” was used in the near

ision acuity section. Because

"equivalent" values were not given, the

ASNT Technical Services Department

received numerous calls asking for

clarification of what was considered

equivalent to the various Jaeger

numbers, so the Standards

Development Committee (SDC),

ASNT’s consensus committee for

developing American National

Standards, was asked to include a note

regarding equivalents to clarify what

would be accepted. The committee

agreed. To determine “equivalency,”

the following organizations were

contacted:

1. for Snellen values and Times

Roman points, the American

Optometric Association, the

National Optometric Association,

The Ohio State University College

of Optometry and several local

optometrists;

2. for OrthoRater

values, the

Ophthalmic Division that passed

from Reichert, Inc., to Bausch &

Lomb and Leica-Microsystems;

3. for Titmus

values, the

Bacou-Dalloz Company (now

Sperian).

On Items 2 and 3, both companies

gave the values listed in CP-106. On

item 1, many of the responses to our

inquiries referred us the handbook for

optometry, Clinical Refraction, by Irvin

M. Borish.

Dr. Timothy Wingert,

then Acting Director of the Clinical

Care Group of the American

Optometric Association, provided

specific page and chapter references

from the 1975 edition of Clinical

Refraction, pointing out that while this

edition is out of print,

the data are

till valid, and he provided the

comparative information shown in

Table 1. Because most optometrists

record values in even numbers, 6/6

(20/20) is usually accepted for J1 and

/7.5 (20/25) for J2, but a company

should consider describing whatever

convention they choose to use in their

written practice, remembering that

acceptance of a certification program

is a matter of agreement between the

NDT supplier and purchaser.

Disclaimer

The information in this article is

provided for instructional purposes

and is not a statement of ASNT

policy or practice.

References

1. Recommended Practice

No. SNT-TC-1A, Personnel

Qualification and Certification in

Nondestructive Testing. Columbus,

OH: American Society for

Nondestructive Testing (2006).

2.ASNT CP-106 (national adoption

with modifications of ISO 9712),

Nondestructive Testing —

Qualification and Certification of

Personnel, third edition. Columbus,

OH: American Society for

Nondestructive Testing (2008).

3. ISO 9712, Non-Destructive Testing

— Qualification and Certification of

Personnel. Geneva, Switzerland:

International Organization for

Standardization (2006).

4. Borish, Irvin M. Clinical Refraction,

third edition. Volume 1. Chicago,

IL: Professional Press (1970, 1975):

pages 391 and 418.

5. Borish’s Clinical Refraction, second

edition. St Louis, MO: Butterworth

Heinemann (2006).

TNT · October 2009 ·

FOCUS continued from page 3.

Near Vision Acuity

equivalent 20/20 near vision

acuity: Vision acuity with

remote viewing or other indirect

viewing that approximates

20/20 direct viewing closely

enough to be considered the

same for visual testing purposes.

far vision: Vision of objects at a

distance, generally beyond arm’s

length.

jaeger eye chart: Eye chart used

for near vision acuity

examinations.

near vision: Vision of objects

nearby, generally within arm’s

length.

vision acuity: Ability to distinguish

fine details visually.

Quantitatively, it is the

reciprocal of the minimum

angular separation in minutes of

two lines of width subtending

one minute of arc when the

lines are just resolvable as

separate.

1,2

vision: Perception by eyesight.

visual angle: Angle subtended by

an object or detail at the point

of observation. It usually is

measured in minutes of arc.

1,2

References

1.Nondestructive Testing Handbook,

second edition: Vol. 8, Visual

and Optical Testing. Columbus,

OH: American Society for

Nondestructive Testing (1993).

2.IES Lighting Handbook:

Reference Volume. New York,

NY: Illuminating Engineering

Society of North America

(1984).

NDT GLOSSARY

In 1901, Greek sponge divers, blown

off course in a storm, sought refuge

by anchoring their ship in the lee of

the tiny Aegean island called

Antikythera. When the storm abated,

one of the crew donned a diving suit

and went over the side. It is unclear

whether the diver was looking for

sponges or foraging for food but he

was amazed when he found the

remains of a shipwreck directly below.

Strewn before him was a priceless

tangle of booty. It would eventually be

determined that the wrecked

ship was a Roman trader,

probably on its way to Rome. It

had been filled with treasures

from Greece. Dates on coins

from Pergamum found among

its wreckage showed the ship

sank around 80 BC.

The find was reported to

authorities and a major

underwater recovery expedition

was mounted by the National

Archeological Museum in

Athens. The recovered artifacts

were taken to the museum

where they reside today. The

items recovered included

classical Greek bronze and

marble statuary and even fine

glassware. In addition, a lump

of calcified bronze, shoebox-size, was

lifted from the seabed. Eventually, it

would come to be known as the

Antikythera Mechanism and would

attract international attention but, at

the time, it seemed relatively

insignificant and when it reached the

museum in Athens, it was set aside on

a shelf. After some time however, the

structure split apart to reveal intricate

gearing inside (Fig. 1). Modern

research was unaware that mechanical

sophistication of this degree existed in

ancient Greece. More than a thousand

years would have to pass before

structures approaching this complexity

would begin to appear again.

What was the Antikythera

Mechanism?

Much research has determined that

the Antikythera Mechanism was a

device to model astronomical

phenomena; its purpose was to link

the cycles of Greek culture with the

celestial cycles incorporated into its

gearworks. Its highly complex dials

and spirals, gears, and pointing devices

had the ability to track progressions of

the sun and moon (and possibly the

five planets known then). It was a

calendar and could predict eclipses. It

was a calculator with the ability to

multiply, divide and subtract. Recent

interpretations of its inscriptions lead

researchers to believe that its origin

was in the Corinthian colonies of

northwestern Greece, or possibly

Syracuse in Sicily. Although the device

had puzzled academics and scientists

for more than a hundred years, study

of the apparatus did not gain impetus

until the 1950s and 60s. In the early

1970s various kinds of imaging,

including X-ray, were done.

The mechanism housing had a

front door plate with

inscriptions. The front of the

mechanism itself also included

many inscriptions and a device

for showing the positions of the

sun and moon. Internal gearing

for the apparatus was formed

from bronze sheet

(approximately 2 mm thick).

The back of the structure had

an upper and lower dial as well

as additional inscriptions.

Significantly, the Antikythera

Mechanism is dated by its

inscriptions. Greek script varied

considerably during the period

when the mechanism was

manufactured. The structure of

the letters in the inscriptions

and the way they are put

together in sentences make it possible

to date it quite accurately. It is

relatively certain that it was made at

end of the second century BC —

140 to 100 BC.

Formation of the AMRP

Lead by astronomer Mike Edmunds,

Professor in the School of Physics

and Astronomy at Cardiff University

Visual Testing and X-Ray Used to Examine Antikythera

Mechanism

Insight

· Vol. 8, No. 4

Figure 1. Largest fragment of Antikythera Mechanism

shown in natural light. © Antikythera Research

Mechanism Project.

in Wales and mathematician Tony

reeth, a freelance producer and

director working in television and

independent production of scientific

documentaries, the Antikythera

Mechanism Research Project (AMRP)

as formed to collect new primary

data on the device. In late 2005,

permission to carry out proposed

investigations was granted and

state-of-the-art technology was

recruited to probe the interiors of the

Antikythera Mechanism using

enhanced digital imaging techniques

developed by Hewlett Packard Labs in

Palo Alto, California and microfocus

computed tomography (CT)

developed by X-Tek Industries (now

Metris) in Hertfordshire in the U.K.

Reflectance Imaging Techniques

The Antikythera Research Project

invited Hewlett Packard Labs research

scientists to Athens to apply

reflectance imaging to the front and

rear surfaces of the more than

70 fragments that comprise the

mechanism. The noninvasive

technique involves taking photos of

an artifact from a fixed point while

using 50 different light sources arrayed

n a hemisphere or dome placed over

the object (Fig. 2). The light sources

fire in succession and the camera

registers them individually. Software

can then be used to tie the images

ogether. In effect, this enables the

archaeologist to change the angle of

light or texture of the surface of the

object to make faint markings appear

more vivid. It’s as though the object

being investigated can be held and

moved around. Originally developed

for looking at indentations on

papyrus, the technique is a very good

way of discerning very subtle surface

detail. In addition, reflectance imaging

can be used to digitally manipulate the

surface quality of an object to

enhance its detail. Dull surfaces can be

made to look shiny, for example

(Fig. 3).

Microfocus Computed

Tomography

A major expedition brought the

400 kV microfocus computed

tomography machine – weighing more

than 7.5 metric tons – to examine the

artifact in Greece. Originally designed

by X-Tek Industries to search for

imperfections in turbine blades,

printed circuits and other industrial

devices, the machine creates detailed

hree-dimensional X-ray images. It was

originally thought that

three-dimensional CT results would

prove most useful by producing good

images of the gear train. This would

llow researchers to obtain accurate

teeth counts for the mechanism’s

gears, thereby resolving arguments

regarding relationships between the

gears. However, it came as surprise

when investigators realized how well

the machine was able to image

inscriptions inside the fragments of

the apparatus (Figs. 4, 5). It was

expected that some faint inscriptions

would be revealed but

three-dimensional CT not only

TNT · October 2009 ·

Figure 2. Researchers demonstrate

domed structure used to photograph

objects under varying light conditions.

Figure 3. Photos of Antikythera

Mechanism fragment show how the

device appears under conventional

lighting and how surface features are

enhanced by use of reflectance

imaging. © Antikythera Mechanism

Research Project.

Figure 4. Three-dimensional

computed tomography scans resulted

in high-resolution digital radiographs

that revealed textual and other details.

Project.

INSIGHT continued on page 8.

Figure 5. Digital radiographs obtained

with three-dimensional computed

tomography allowed researchers to

follow impression of inscriptions down

into fragment surface. © Antikythera

Mechanism Research Project.

allowed researchers to see the

inscriptions, it made them much

clearer by allowing researchers to

follow the impressions of the

haracters down into surfaces and

thus beneath corrosion. The CT

images, from various angles, enabled

the research project to read 932

characters, far more than any previous

attempt.

Conclusion

The mechanical complexity of the

Antikythera Mechanism implies a

technological tradition; one in which

its builders were accustomed to

working with gears and figuring out

how mechanisms were made. When it

was built, bronze was both extremely

valuable and difficult to produce. It’s

possible that devices such as these

would have been melted down when

they stopped working, lost their

novelty or people forgot how to use

them. Still, we are left to wonder what

happened to the rest of the

technology and how it all was lost.

Bibliography

1. Antikythera Mechanism Research

Project. <http://www.antikythera-

mechanism.gr/>.

2. X-Tek Group (now Metris).

Hertfordshire, United Kingdom.

<http://www.xtekxray.com/

applications/antikythera.html>.

3. Hewlett-Packard Laboratories.

<http://www.hpl.hp.com/research

/ptm/antikythera_mechanism/

index.html>.

4. Freeth, T., Y. Bitsakis, X. Moussas,

J. Seiradakis, A. Tselikas, E.

Maglou, M. Zafeiropoulou, R.

Hadland, D. Bate, A. Ramsey, M.

Allen, A. Crawley, P. Hockley, T.

Malzbender, D. Gelb, W. Ambrisco

and M. Edmunds. “Decoding the

Ancient Greek Astronomical

Calculator Known as the

Antikythera Mechanism.” Nature.

Vol. 444, No. 30. London, United

Kingdom: Nature Publishing

Group (November 2006):

587-591.

5. Seabrook, J. “Fragmentary

Knowledge.” The New Yorker.

New York, New York: Conde Nast

Publications (May 2007) p 94-102.

. Freeth, T., A. Jones, J. Steele and Y.

Bitsakis.. “Calendars with

Olympiad Display and Eclipse

Prediction on the Antikythera

Mechanism.” Nature. Vol. 454,

No. 30. London, United Kingdom:

Nature Publishing Group (July

2008) p 614-617.

· Vol. 8, No. 4

NSIGHT continued from p 7

Got a topic for “Working Smarter”? If

published, you can earn $50 in cash or

a $75 credit for ASNT merchandise.

Contributors to TNT also earn recert

points in the following programs:

• ACCP Level II,

• ACCP Professional Level III and

• ASNT NDT Level III.

A full article of 1000+ words earns

three points; short articles or items for

“Working Smarter” earn one point.

Contact the TNT Editor:

PO Box 28518, Columbus, OH 43228

(800) 222-2768 X206;

(614) 274-6899 fax

<hhumphries@asnt.org>

TNT · October 2009 ·

4. Liquid that enters cracks.

6. Instrument measuring UV light intensity.

8. Light used at fluorescent penetrant wash station.

10. Specification compliance document.

11. Aerospace known defect test piece.

12. Passive penetrant process activity.

16. Instrument measuring aqueous developer concentration.

17.Method D processing

step that precedes

emulsifier.

18.Approved penetrant

materials are listed on

the ___.

19.Penetrant flow rate.

21.Developer in spray can.

22.Tool for measuring

viscosity.

23.Sound wave cleaning.

27.Processing step following

penetrant dwell.

28.Method B and D

penetrant and emulsifier

are approved as a ______.

31.Black light output.

Across

3. Emulsifier diluted with water.

5. Early user of oil and whiting.

7. Highest sensitivity level for fluorescent penetrants.

9. Materials lot identification number.

12. Parts for penetrant inspection must be clean and ___.

13. Unit for measuring ultraviolet intensity per square centimeter.

14. Instrument measuring

Method D emulsifier

concentration.

15. Abbreviation for

solvent suspended

developer.

17. Instrument measuring

white light intensity.

20. Method B emulsifier.

24. A penetrant test kit is

used for _____

testing.

25. The Karl Fischer

analysis tests for

_____ content.

26. Document describing

any hazards.

28. Device used to

measure fluorescent

brightness.

29. Method C remover.

30. Penetrant requiring darkened area for inspection.

32. Static charge spray application method.

33. First thing you must do with an aerosol can of developer.

34. Forms A, B and C developers are supplied as ______.

35. Step preceding application of penetrant.

Down

1. Form B and C developers are applied before ______.

2. Method A remover.

Across

3. hydrophilic

5. railroad

7. four

9. batch

12. dry

13. microwatt

14. refractometer

15. NAD

17. photometer

20. lipophilic

24. field

25. water

26. MSDS

28. fluorometer

29. solvent

30. fluorescent

32. electrostatic

33.shake

34. powder

35. preclean

Down

1. drying

2. water

4. penetrant

6. radiometer

8. ultraviolet

10. certification

11. TAM

12. dwell

16. hydrometer

17. prerinse

18. QPL

19. viscosity

21. nonaqueous

22. viscometer

23. ultrasonic

27. removal

28. family

31. UVA

Crossword Challenge

LLiiqquuiidd PPeenneettrraanntt TTeessttiinngg

TThhee PPeenneettrraanntt PPrrooffeessssoorr**

Crossword Challenge

Michael White and William Mooz, Met-L-Chek Company, 1639 Euclid Street, Santa Monica,

California 90404; phone (310) 452-4046; fax (310) 452-4046; e-mail info@me-l-chek.com.

Answers

PRACTITIONER PROFILE

1100

· Vol. 8, No. 4

While the working relationship between an NDT inspector and a

welder can sometimes be problematic, Timothy Crick demonstrates

that a good inspector with a proven record of finding and fairly

evaluating discontinuities can build and maintain a good

reputation among the welders whose work he inspects.

Q: How did you get started in NDT?

A: In the early 90s, I worked as a welder for a pipeline

manufacturer up in northern California doing flux core

arc welding and dual wire submerged arc welding. I’ve

always wanted to learn everything I could and when they

asked if I wanted to become an inspector I said yes.

Inspectors, if laid off, will get a job somewhere else, so

employers are reluctant to lay them off. So, number one,

there was definitely better job security and, number two, I

wanted to lean more than welding. The firm I was

working for did UT and RT inspections and I became a

level II in both. Our company Level III, Mr. Charles

Hanson, performed all of our training and certification.

Q: Tell us about your NDT experience to date.

A: I left northern California and moved to San Diego where

I worked for a one-man company. We did everything from

NDT in Navy and commercial shipyards to welder and

procedure qualifications. From there, I actually took two

jobs. One was eight hours a day and the other was as

many hours as I could fit into the rest of the day. I was

inspecting aircraft parts in the aerospace industry but that

only needed my X-ray Level II working experience. I really

enjoy doing UT and I couldn’t pass it up when somebody

needed me to do what I’m doing now —ultrasonic testing

on commercial buildings. So I kept both of my

certifications going by doing both. Each form of

inspection is totally different. I get dirty and climb all over

buildings in one and I sit in a clean room interpreting film

in the other. My next job was with an independent lab in

Texas where I did NDT in aerospace, oilfields, power

plants, and even in the amusement park industry. I got to

do different types of ultrasound there that I had only read

or heard about, such as through-transmission inspecting

747 parts that were as big as a car. In

through-transmission, there are two transducers facing

each other at a set distance apart. One transducer sends

and the other receives. A stream of water aimed at each of

them is used as the couplant. If there are any indications

within the part, you have a loss of sound. I also leaned to

do mag particle and became certified in that method.

Q: What are your current certifications?

A: I am currently certified as a Level II in UT, RT, MT, and

PT. I’ve also done ET, but not for many years.

Q: What was your educational background before you began

training in NDT?

A: My education was high school. I did learn mechanics in

the air force. I’ve always had a technical background and

hands-on is where I excel. I love the hands-on experience

and that’s definitely what NDT has been. I’ve inspected

parts that went five miles underground and parts that are

floating right now on the international space station. That

gives me a rewarding feeling.

Q: What kind of structures do you inspect now?

A: I’m inspecting welds in structural steel on the biggest

hospital project ever in the state of California — moment

connections — mainly beam splices and column splices

using UT and MT.

Timothy Crick

“It’s not my job to

advise the welders

but at the same time,

our common goal is

to complete an

acceptable product.”

TNT · October 2009 ·

1111

Q: Is phased array any part of that?

A: I’ve only had limited observation of phased array but not

its actual use. I understand its benefits and it’s something I

will be getting in the future.

: How does your experience as a welder help you when

conducting inspections?

: It helps me understand the indications or the

discontinuities that I find. It also makes it easier for me to

help the welder understand problem areas so that we can

reduce the number of discontinuities and rejects. It’s not

my job to advise the welders but at the same time, our

common goal is to complete an acceptable product. My

experience has taught me that it’s much better to have a

weld done right the first time than to have to go back and

have it fixed.

Q: As an NDT inspector, how do you maintain a productive

relationship with the people that do the work you inspect?

A: Some inspectors out there have a bit of a power issue and

some couldn’t care less if the welder continues to get

rejects. My approach is to let them know that I’m there to

help. I also let them know that I have previous welding

experience so that they might be able to relate to me

better.

: Do you see that your efforts reduce the number of rejects?

A: Definitely.

: What’s the best part of your job?

A: The best part of my work is the people — people that

I’ve had the opportunity to learn from and work with.

Q: What’s the worst part?

A: I think the hardest part has been when I had to work

away from home, away from my family.

Q: How would you advise someone considering an NDT career?

A: Try to work for good people. I’ve found that the best

people to work for are those that raise the bar. Earlier I

threw out Charlie Hanson’s name. Charlie worked in the

pipeline industry with codes and specs that didn’t require

high quality but he took his prior work experience and

used it to raise the standards in the pipeline industry.

You can contact Timothy “TC” Crick by e-mail,

<tcrick41[email protected]>.

the

NDT Technician

Volume 8, Number 4 October 2009

Publisher: Wayne Holliday

Publications Manager : Tim Jones

Editor: Hollis Humphries

Technical Editor: Ricky L. Morgan

Review Board: W illiam W. Briody, Bruce G. Crouse,

Anthony J. Gatti Sr., Edward E. Hall, James W. Houf, Jocelyn

Langlois, Raymond G. Morasse, Ronald T. Nisbet, Angela

Swedlund

he NDT Technician: A Quarterly Publication for the NDT Practitioner

(ISSN 1537-5919) is published quarterly by the American Society for

ondestructive Testing, Inc. The TNT mission is to provide information

valuable to NDT practitioners and a platform for discussion of issues

elevant to their profession.

SNT exists to create a safer world by promoting the profession and

technologies of nondestructive testing

2009 by the American Society for Nondestructive Testing, Inc. ASNT is

ot responsible for the authenticity or accuracy of information herein. Published

opinions and statements do not necessarily reflect the opinion of ASNT. Products or

services that are advertised or mentioned do not carry the endorsement or

ecommendation of ASNT.

RRSP, Materials Evaluation, NDT Handbook, Nondestructive Testing Handbook,

The NDT Technician and www.asnt.org are trademarks of The American Society for

Nondestructive Testing, Inc. ACCP, ASNT, Level III Study Guide, Research in

ondestructive Evaluation and RNDE are registered trademarks of the American

Society for Nondestructive Testing, Inc.

the

NDT Technician

PO Box 28518

olumbus, Ohio 43228-0518

NONPROFIT

US POSTAGE

PAID

ST JOSEPH, MI

PERMIT NO. 84

The American Society for Nondestructive Testing

www.asnt.org

Q:Where can I get an ASNT certification application?

A: All ASNT certification applications can be found on ASNT’s Web site at

http://www.asnt.org/certification/certification.htm.

Q:Where can I find ASNT’s exam schedules?

A: ASNT exam schedules can be found at

http://www.asnt.org/certification/schedules/index.htm.

Q:How long does it take to get exam results?

A: Examination results are mailed within four to six weeks for those residing in the

US or Canada. Results for candidates living outside the US may take one to two

weeks longer. Exam results cannot be given over the phone or via e-mail.

Q:How long does ASNT certification remain valid?

A: ASNT certification remains valid for five years.

E-mail, fax or phone your questions for “Inbox” to the Editor:

hhumphries@asnt.org, fax (614) 274-6899, phone (800) 222-2768 X206.

INBOX