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DAC on NRC web



In looking at the NRC web page accessed through
http://www.nrc.gov
I came across this address 

http://www.nrc.gov/NRC/CFR/PART020/part020-appb.html

which contains Appendix B of Part 20 and the  
explaination for DAC (the following is copied exactly as it appears)
 
The derived air concentration (DAC) values are derived limits intended
to control chronic occupational exposures. The relationship between
the DAC and the ALI is given by: DAC=ALI(in Ci)/(2000 hours per
working year0A60 minutes/hour0A20A104 ml per minute)=[ALI/2.40A109]
Ci/ml, where 20A104 ml is the volume of air breathed per minute at
work by "Reference Man" under working conditions of "light work."

In the same document is this note explaining  the A notation

Notation

The values in Tables 1, 2, and 3 are presented in the computer "E"
notation. In this notation a value of 6E02 represents a value of
60A102 or 0.06, 6E+2 represents 60A102 or 600, and 6E+0 represents
60A100 or 6.

So 60A102 equals 0.06 and 60A102 equals 600. Nice.

Glad I have a printed copy of Part 20 which said DAC = ALI(in 
microCi)/(2000 hours per working year X 60 minutes/hour x 2 x 10 4 ml 
per minute). 

Where micro was printed as the symbol for micro and the 4 after the ten was a 
superscript to designate the 4th power. Unfortunately the limits of my e-mail
prevent me from importing these nice features of the printed page. 

After reading that little gem, I say thanks for the upcoming holiday break. 
I wish everyone a nice holiday and a Happy New Year.
   
BOB Milwicz