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RTB  
#1 Posted : 13 November 2016 14:35:14(UTC)
Rank: New forum user
RTB

I'm looking for some help in figuring out the proper formula for benzene exposures over a 10 hour work day with 2 hours of break time. Max concentration without a respirator.

E=(cxt)/10  C= Ex10/T  E is O.5PPM, T is 8 hours  C = 0.5 x 10/8 =5/8 = .625

Can anyone tell me if the math is correct?

Thank you

James Robinson  
#2 Posted : 14 November 2016 11:05:30(UTC)
Rank: Forum user
James Robinson

Benzene in EH40 is classified as a Carcinogen. If you read Para 7 of EH40, the standard to be achieved is now "as low as resonably practical" - ALARP -  because of its carcinogicity, also reiterated within CoSHH. The WEL in effect becomes redundant. It is not a target to comply or reach or achieve. You must in effect do whatver is reasonable to reduce the level to as low as you possibly can, not just below the WEL.

So forget the formula. Do all that you can to lower the exposures.  

thanks 1 user thanked James Robinson for this useful post.
RTB on 14/11/2016(UTC)
PIKEMAN  
#3 Posted : 14 November 2016 12:01:02(UTC)
Rank: Super forum user
PIKEMAN

James is correct and about Benzene being a Carcinogen, so you need to go "ALARP". As regards the calc it is a time weighted average. If, as you say on a ten hour shift there is a 2 hour break (I assume no exposure for this?) the calc would be 0.5 * 8  divided by 8 so you would have the answer as 0.5 ppm.  If they still had exposure on break your calc  would be correct.  If you cannot get "ALARP" I would rigorously review and document your controls, and your logic for this.

thanks 1 user thanked PIKEMAN for this useful post.
RTB on 14/11/2016(UTC)
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