Re: SI and all that

[Bob Flood <bflood@SLAC.Stanford.EDU>]

With deference to Melissa's admonishment to conclude this thread, I feel
that a final statement is warranted.

At 12:58 PM 9/9/1999 -0500, you wrote:

>With some interest, I read Mr. Hofmeyr's contribution to the debate on SI
>units.  Regrettably and hopefully unintentionally, he has made a sweeping
>erroneous characterization about  American CHPs.  He is certainly entitled
>to his opinion but I find the statement "American CHPs want to make a last
>stand at the wrong trench .  .  . " to be odious and insulting and, simply
>stated, wrong.

I wholeheartedly agree - Mr. Hofmeyr's assessment of the basis for the
American use of traditional units is quite incorrect and has nothing to do
with CHP preferences.

In the American regulatory process, a regulatory agency that is making
changes to its coded rules is required to perform a cost-benefit analysis
for the changes. The agency must estimate the cost of implementing the
changes in the regulated industries as well as within the agency itself,
and then itemize the benefits and their value to justify the expense of the
change.

During the process of incorporating the ICRP 26/30 methodologies into its
radiation protection regulation, the NRC saw much debate on the subject of
SI units. No serious arguments were made that the units are too difficult
to understand or that they are flawed in concept in any way - the only real
consideration was cost. When the cost of changes in training, hardware,
software, procedures, etc were totaled, the amount was enormous. And there
was no demonstratable improvement to be seen in occupational radiation
protection. Remember that someone besides the HPs are ones that should
benefit from such changes. Thus, the proposal to change to SI units failed
the required regulatory cost-benefit analysis, and the traditional units
were retained.

===================================
Bob Flood
Dosimetry Group Leader
Stanford Linear Accelerator Center
(650) 926-3793
bflood@slac.stanford.edu
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