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Were the annual limits expressed in SI units? Were
they round numbers, or was it just 4 (or 4.7) WLM converted to the SI unit with
3 or 4 significant figures?
There is no incentive in Canada for anyone to
change procedures to calculate J/m3, when the annual limit is in WLM. Of course
you are correct and it would not be difficult to change the calculation once
J/m3 has some meaning wrt limits.
----- Original Message -----
Sent: Tuesday, April 08, 2003 5:58
PM
Subject: RE: SI unit of WL (was: Bq
soon)
When
I worked in a uranium mine we always calculated J/m3 (or should i say micro
J/m3). It is a simple matter to include the conversion factor for WL to J/m3
into the calculation. Basically the calculation involves counts, detector
efficiency and a "factor". This "factor" is a single number that takes into
account sample, decay and counting times, volume collected among other times
like the number that converts WL to J/m3. I guess the calculation used by the
technicians should have been updated.
I believe the HPS once endorsed J/m3 for
WL and Jh/m3 for WLM. Of course, h is not an SI unit (even though its
use is still permitted) and the correct unit should be Js/m3. People
get paid by the hour, not by the second, so Js/m3 is not very
convenient.
A while ago, it looked like Canada was going to
adopt SI units and we once wrote an entire EIS in J/m3 and Jh/m3. It is easy
to do theoretical calculations in those units. The problem is that the
technicians on the ground don't have any means of measuring J/m3.
They collect radon progeny on a filter and then count the activity
in a portable counter. The formulas that they use for converting the counts
to airborne activity either have never been converted to produce J/m3, or
the converted formulas have not been widely distributed and the regulatory
agencies have not given their stamp of approval on the
formulas.
The technicians would therefore have to
calculate the airborne radiation in WL and then convert it to SI units. This
defeats the purpose of adopting SI units, which is to make things simpler.
The SI units for radon progeny never caught on
and we ended up converting the predictions back to WLM. [And yes, there
were some conversion mistakes, but of course these happened after I quit the
company :).]
My guess is that WL will be one of the last
things to get converted to SI, but they will get converted.
Kai
----- Original Message -----
Sent: Tuesday, April 08, 2003 8:17
AM
Subject: Re: Bq soon
This is the best posting I've seen on this subject. I
remember the top down, "Do it my way or else..." campaign in the
1970's. My facility had a full time, "metrification
coordinator." I was reprimanded for not supporting
metrification with sufficient enthusiasm. That, more than anything,
is what turned me against SI units.
Regarding "Working Levels." - If there was ever a unit that needed to
be SI'd, this is it. On the other hand, I think that most persons,
other than those who earn a living from Rn testing and remediation, agree
that this is a solution looking for a problem, EPA scare ads
notwithstanding.
The opinions expressed are strictly mine.
It's not about dose, it's
about trust.
Curies forever.
Bill Lipton
liptonw@dteenergy.com
mark.hogue@SRS.GOV wrote:
I think
Bjorn gave us the best flavor of what it takes to get used to a
system.
The reason it's taking so long
for the US to go metric is because the big push in the '70's (when I was
in grade school) was such a flop. Instead of trying to give everyone a
feel for the 'new' units, we were told, hey, look, an inch is 2.54
centimeters and a gallon is 3.7854 liters! No problem! Here's a table
for you to memorize. Naturally, that made no sense to anyone. Plus,
manufacturers objected to the real cost: retooling factories for metric
sizes on nuts and bolts, etc.
Now, I have to think we've come a
long way. Most people who use wrenches have already bought a metric set
and maybe wish they wouldn't have to keep the english set
too.
By the way, for radon
measurements, is there anything metric that captures the real meaning of
a working level?
Mark G. Hogue, CHP
mark.hogue@srs.gov
"But we surely overrate the
usefulness of what we like to call "stimulation" and underrate the need
for time, peace of mind, mature reflection." - Susan
Haack
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