Welcome back to our ongoing discussion of EPA Tier 3. For today's discussion we look at:
- What are the accuracy statistical quality control (SQC) requirements under 40 CFR 80.47?
- Do I have to enroll each instrument in an ILCP?
- What do I have to do with the ILCP data once I get it back?
Let's dig in!
Accuracy SQC requirements involve a rigorous regime of periodic testing, calculations, control charting, investigation, and record keeping. The requirements are stated in 40 CFR Part 80.47(n)(1) for absolute fuel parameters, (o)(1) for Voluntary Consensus Standard Based (VCSB) Method-Defined fuel parameters, and (p)(1) for non-VCSB method-defined test methods with minimal matrix effects, and (p)(2) for non-VCSB method-defined test methods with high sensitivity to matrix effects. There are three requirements that are applicable to all categories of fuel parameters/methods:
- After at least 15 tests, pretreat and assess results (per D6299 Section 8.2) and construct MR and I charts with control lines (per D6299 Section 8.4).
- Calculate the absolute difference of the result obtained and the ARV of the reference material tested, and maintain the mean value of these absolute differences. If the mean of these absolute differences is greater than 75% of the published ASTM method reproducibility, facilities must investigate the cause.
- Maintain records of the SRM testing and any investigation documentation for 5 years.
For absolute fuel parameters (n)(1):
- Test every instrument at least three times per year using good laboratory practices.
- Use commercially available check standard (as defined in D6299) or gravimetric reference material.
- Calculate the accuracy qualification criterion (AQC), where the AQC = (0.75*R)2 + (0.75 * R)2 / L. L is defined as the number of results from different labs used to calculate the ARV.
For VCSB method defined fuel parameters (o)(1):
- Test every instrument at least three times per year using good laboratory practices. Participation in a VCSB ILCP (e.g., ASTM RFG) satisfies this requirement.
- Use commercially available check standard (as defined in D6299). Must be an ordinary fuel with levels close to the applicable regulatory standard or average level for the facility.
- Calculate the accuracy qualification criterion (AQC), as above
For non-VCSB methods with minimal matrix effects (p)(1):
- Test every instrument at least three times per year using good laboratory practices.
- Use commercially available check standard (as defined in D6299). Must be an ordinary fuel with levels close to the applicable regulatory standard or average level for the facility.
- Calculate the accuracy qualification criterion (AQC), as above
For non-VCSB methods with high sensitivity to matrix effects (p)(2):
- Test every instrument at least quarterly using good laboratory practices.
- The fuel must be representative of production fuels that are routinely analyzed, ARV must be determined by the reference installation of the designated test method.
- Send every 20th production batch of gasoline or diesel to EPAs laboratory, along with the facility’s measurement result used to certify the batch.
- Maintain documentation of the identity of the reference installation and its control status.
Hoefully we cleared up some of the fog surrounding the accuracy SQC requirements for EPA Tier 3. If not, feel free to email us at info@asistandards.com for any additional questions you may have. For up-to-date clarifications and to stay abreast of other Tier 3 news, subscribe to our blog.
Happy Charting!
Chris