AW: ANNUAL DOSE, DOSERATE and the MAXIMUM INDIVIDUAL

["Franz Schoenhofer" <franz.schoenhofer@CHELLO.AT>]

-----Ursprüngliche Nachricht-----

Von: owner-radsafe@list.vanderbilt.edu

[mailto:owner-radsafe@list.vanderbilt.edu]Im Auftrag von Quintino De

Notariis

Gesendet: Mittwoch, 11. September 2002 15:34

An: radsafe@list.vanderbilt.edu

Betreff: ANNUAL DOSE, DOSERATE and the MAXIMUM INDIVIDUAL





If the ANNUAL dose limit for the public is an EFFECTIVE DOSE (ED) of 1

mSv/year, why some radsafers seem to take for granted that this IMPLIES a

DOSERATE limit of 0,114 microSv/h (1000 microSv/year x 8760 hours/year) ?



So if, for example, in an X-ray facility we MEASURE 0,200 microSv/h above

the background in correspondence of a door on an alley with a very limited

or no time occupancy by members of the public (say, ONLY 1 hour/year),

should we conclude that that facility is out of low, no matter that the

total ED in a year would be ONLY 0,200 x 1 = 0,200 microSv ?



Regulations give an ANNUAL dose limit NOT a DOSERATE limit.

Please, radsafers, help me to clarify and correct me if there is something

that I miss.

---------------------------------------



Yes, I agree with your reasoning. At least in the EU there is only an annual

dose (rate) (1 mSv/y is a dose rate!). We have rejected recently an Austrian

standard, which derived for radiation workers maximum permissible monthly

and even weekly doses.



To give you another example: Italy has set (which is its right) a maximum

permissible concentration for Rn-222 in working places of 500 Bq/m3. On the

contrary other countries like Germany, Sweden and Finland have chosen to use

values in terms of Bq/m3h - so clearly the occupancy factor has been taken

into account. Both approaches are legitime, but in the case of the 1 mSv/y

the value is strictly defined as a dose per year and in order to calculate

this the occupancy factor has to be taken into account.



Best regards,



Franz









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