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Method 624 and 625 Tune Frequency
Diane Lawver
Posted: Saturday, May 15, 2010 12:16 PM
Joined: 4/27/2010
Posts: 1

I am interested in knowing what frequency is used for tuning when performingEPA 624 and 625.  Guidance from a Draft generated by EPA in 1996 regarding Method Flexibility (Attachment C) states that EPA intended the instruction for 'daily' to mean "every workshift" (8 hours or 12 hours).  I can't find any language in any recent regulations or communications clarifying EPA's intent.  Bottom line, is it ok to only tune every 24 hours for wastewater?  Drinking water and SW-846 procedures are either every 8 hours or 12 hours which are clearly stated.  Thank you for your insights on this question. 

Posted: Tuesday, May 18, 2010 8:36 AM



I am unaware of the verbiage in the 1996 guidance. I suggest you contact your appropriate state agency or your USEPA regional office. If they have no definitive answer I think it is up to your lab to define. As long as you clearly define and it meets the (perhaps vague) "daily" requirement of Methods 624/625 you should be OK.


For the record, we perform a Tune check every 12-hour window because we run Methods 8260/8270 more than only 624/625.