GUIDANCE
Quality assurance (QA) quarterly audit requirements for a continuous emission monitoring system (CEMS) serving an air emission source that does not operate for more than 168 hours during one or more calendar quarters.
Applicability
This guidance applies to all facilities in the State of Maine who use CEMS to monitor emissions and addresses conducting Relative Accuracy Test Audits, a Relative Accuracy Audit, Cylinder Gas Audit or Opacity Audit ( RATA/RAA/CGA/Audit) after a facility shuts down or does not operate for more than 168 unit operating hours during a quarter. Continuous Emissions Monitoring System or (“CEMS”) is defined as the total equipment required for the determination of a gas concentration or pollutant emission rate or opacity reading and the associated data recording equipment (i.e., strip chart, computer disk, magnetic tape, etc.). This guidance is to be used at the discretion of the Department, please contact the Department prior to implementing this document.
RATA
When a previously shut down facility returns to operation it must conduct RATA and/or Performance Audits in accordance with Chapter 117 of the Department's regulations unless the unit has not had 168 unit operating hours (as defined in 40 CFR Part 72) in a quarter in which case that quarter shall be excluded in determining the deadline for the next RATA. If the RATA has not been completed by the end of the eighth calendar quarter since the quarter of the last RATA, then the RATA must be completed within a 720 unit operating hour grace period following the end of the eighth successive elapsed calendar quarter, or the data from the CEMS will become invalid.
The source owner or operator shall conduct RATAs at least every fourth successive calendar quarter. If the emission unit has not had 168 unit operating hours in a quarter then that quarter shall be excluded in determining the deadline for the next RATA. If the RATA has not been completed by the end of the eighth calendar quarter since the quarter of the last RATA, then the RATA must be completed within a 720 unit operating hour grace period following the end of the eighth successive elapsed calendar quarter, or the data from the CEMS will be invalid from that point until a successful RATA can be conducted. If an emission unit is shutdown during a quarter in which a RATA is due before the RATA can be completed then there is a grace period of 30 operating days before the data from the CEMS will be considered invalid. Where the Department determines it is technically infeasible to conduct a RATA, a CGA may be substituted for any RATA required under this paragraph or subsection 4(B)(3) of 06-096 CMR 117, unless the compliance monitor is subject to NSPS, NESHAPS or the Acid Rain Program standards. Unless waived by the Department, the source owner or operator shall notify the Department thirty (30) days in advance of the planned RATA and shall allow the Department to observe the procedure.
CGA
The source owner or operator shall conduct a CGA every calendar quarter that a RAA or RATA is not conducted. If during a calendar quarter the emission unit has not operated for 168 unit operating hours, then the CGA may be postponed until a quarter that exceeds the 168 unit operating hour trigger. After four successive calendar quarters have elapsed without a CGA then the operator has a grace period of 168 unit operating hours in which to perform a successful audit or the data from the CEMS will be invalid from that point until a successful RATA, RAA or CGA can be conducted. CGAs may be conducted at any load. The Department may require written notification of the CGA scheduled date at any time. Unless waived by the Department, the source owner or operator shall provide verbal notification to the Department of the date of the CGA or linearity test ten (10) calendar days prior to the testing and shall allow the Department to observe the testing;
Opacity Audits
Quarterly audits shall be performed with the monitor in place in accordance with the procedures contained in "Performance Audit Procedures for Opacity Monitors EPA-450/4-92-010, April 1992, or equivalent procedures previously approved in writing by the Department. Audits must be conducted every operating calendar quarter. If during a quarter the unit has not had 168 unit operating hours then the audit may be postponed until a quarter that exceeds the 168 unit operating hour trigger. After four successive calendar quarters have elapsed without an audit then the operator has a grace period of 168 unit operating hours in which to perform a successful audit or the data becomes invalid from that point until a successful audit can be conducted.
EFFECTIVE DATE: June 3, 2009
