WEF Discussion Forums
Laboratory Management and Technical Issues
Method 624 and 625 Tune Frequency
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.
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.