02:00 Feb-16-1998 Rolf Diederichs Director, Editor, Publisher, Internet, PHP MySQL NDT.net, Germany, Joined Nov 1998 598
More on the the Impact Echo Discussion
I am pleased to see such an in-depth forum discussion regarding the Impact-Echo method.
As we follow the thread, we can see a very important aspect:
******** 'A new method can be successfully established only if more than just the equipment is developed and promoted'. ****
Operator qualification is an important issue. Also ultrasonic testing can't be successful unless the complete package is established at a very early stage.
When the equipment buyer becomes aware of this aspect when reading the legal stuff in the operator's manual like 'successful usage is dependent on operator skill', it is too late. Are they supposed to stop everything and recruit new personnel? Or enroll their current employees in incredibly expensive training courses?
I read a lot of NDT literature but I haven't been able to find any references that answer the following questions:
Are training courses for the Impact-Echo method offered? Do associations like NDT societies define certain certification levels?
Re: More on the the Impact Echo Discussion rses for the Impact-Echo method offered? : Do associations like NDT societies define certain certification levels?
: Any advice is appreciated.
: Rolf Diederichs
Mr. Diederichs has asked questions about operator qualifications and training for the use of NDT methods in general, and the Impact-Echo method in particular.
I am not aware of any regular training courses offered on the Impact-Echo method at this time. Two-day courses were offered at Cornell University from 1992-1995, but the interest did not justify their continuation.
Impact-Echo is a powerful but complex method for nondestructive evaluation of concrete and masonry structures. Some users have concluded that it does not work as advertised, and the blame for failure has always been placed on the method. In our view the blame sometimes rests with the user. Other users who have invested the time and effort to learn the capabilities and limitations of the method have found it highly useful. It is not a 'magic box' that can always be used to tell what is inside a concrete structure. It is best used in situations where the dimensions and make-up of the structure are known, and when the engineer is searching for particular kinds of internal flaws and defects that are known or suspected to be present. Even in these cases it will fail if the user does not understand the limitations as well as the capabilities of the method.
At this time all of the information necessary for learning to use impact-echo effectively is available in the instruction manuals and books that accompany our instruments. We are working to develop computer-based demonstrations and tutorials that will speed up the learning process.
In the long run the acceptance of impact-echo will increase when the fundamentals are taught in NDT courses at the university level. Special discounts are offered on impact-echo test systems sold to universities (see http://www.impact-echo.com).
Some progress has been made. A standard method for measuring P-wave speed and for measuring the thickness of concrete plates has recently been approved by the American Society for Testing Materials (ASTM) and will be published in the 1998 ASTM Book of Standards. At this time, the ASTM has not assigned a number to this standard method. This means that in the U.S. impact-echo is now an approved method for measuring the thickness of concrete plates, such as new highway pavements, which until now were measured only by coring. In the time required to drill, measure, and repair a single core, as many as 30 thickness measurements can be made, nondestructively and with equal accuracy, using impact-echo.
William B. Streett Cornell University Ithaca, NY 14850 e-mail: email@example.com