CALIBRATION SET POINTS
November 2008 Update

DATE: November 24, 2008

TO: All Persons Performing Site Assessments Pursuant To "Regulations for Registration, Installation, Operation & Closure of Underground Oil Storage Facilities (Appendix P of CMR, Chapter 691)"

FROM: George Seel, Director Division of Technical Services, Bureau of Remediation & Waste Management

SUBJ: Calibration Set Points For Photoionization- (PID) and Flame Ionization- (FID) Detectors Used in Field Headspace Determinations at Maine Petroleum Remediation Sites

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The following table gives the set points for various PIDs and FIDs when calibrated with manufacturer-recommended span gas. The listed set points were determined for each make and model of PID using the lamp normally supplied by the manufacturer for petroleum investigations, usually in the 10.2 – 10.6 eV range. The set points are not valid for lamps of other energies.

Please note that the set points previously established for several instruments have changed (new or changed values are shown in red). This was necessary due to a recent change in the test gas formulation. Set points are intended only to normalize response of various PID and FID models to complex petroleum mixtures, not to evaluate the cleanup level achieved at most sites. DEP’s guidance for determining cleanup standards, DEP Procedural Guidance For Establishing Standards For The Remediation Of Oil-Contaminated Soil And Groundwater In Maine ("Decision Tree") requires laboratory analysis of soil or groundwater for the closure of any Stringent (ST) or Intermediate (IN) site. These changes, therefore, should seldom affect the extent of a remediation or produce outcomes inconsistent with past practices.

Only the makes and models of instrument listed below may be used in Maine site assessments pursuant to Chapter 691 closure requirements. The notification level using instruments adjusted to these set points is 100 ppm for motor vehicle fuels, aviation fuel, marine diesel fuel, and middle distillate heating products. The headspace method is not appropriate and should not be used for evaluating heavy oil or waste oil sites.

Instruments calibrated to the listed set points may be used to determine compliance with the cleanup standards at Baseline (BL) sites, where a petroleum discharge poses minimal risk to human and ecological health or environmental resources.

Instruments may be made to read directly by entering the appropriate set point when the calibration routine requests the span gas concentration. Alternatively, the instrument may be calibrated to the actual span gas concentration and its readings later multiplied by the set point divided by 100. Concentrations obtained by either method should not be corrected to "benzene equivalents," as suggested by some instrument manufacturers.

This list is periodically updated as set points are established for additional instruments. For the most current listing, please contact the Division of Technical Services, Bureau of Remediation & Waste Management (BRWM) at (207) 287-2651.

Photoionization Instruments (PIDs)

 

Flame Ionization Instruments (FIDs)

 

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