Performance Specification 9
Specifications and Test Procedures for Gas Chromatographic Continuous Emission Monitoring Systems in Stationary Sources
40 CFR Part 60, Appendix B
From the method — regulatory text
Sections 1.0 and 2.0 of Performance Specification 9—Specifications and Test Procedures for Gas Chromatographic Continuous Emission Monitoring Systems in Stationary Sources, as published at 40 CFR Part 60, Appendix B. Retrieved 10/07/2026. The full method is on the eCFR.
1.0 Scope and Application
1.1 Applicability. These requirements apply to continuous emission monitoring systems (CEMSs) that use gas chromatography (GC) to measure gaseous organic compound emissions. The requirements include procedures intended to evaluate the acceptability of the CEMS at the time of its installation and whenever specified in regulations or permits. Quality assurance procedures for calibrating, maintaining, and operating the CEMS properly at all times are also given in this procedure.
2.0 Summary of Performance Specification
2.1 Calibration precision, calibration error, and performance audit tests are conducted to determine conformance of the CEMS with these specifications. Daily calibration and maintenance requirements are also specified.
EssentialRegs notes
Our plain-English reading of Performance Specification 9. Not the method text.
What it measures
Whether a continuous emission monitoring system that uses a gas chromatograph is acceptable for measuring specific gaseous compounds, based on its installation, performance and accuracy.
How it works
The system is installed at a representative location and operated through a test period. Its calibration is checked with gas standards, and its relative accuracy is determined by comparing its results with simultaneous results from a reference test method. The system is acceptable when it meets the limits in the specification.
Equipment
The gas chromatograph-based monitoring system being certified, calibration gas standards, and the reference method sampling equipment used for the relative accuracy test.
When a rule cites it
Rules that require a continuous emission monitoring system (CEMS) to demonstrate compliance, report emissions or track an emission limit on an ongoing basis. The system must be certified under the specification before its data count for those purposes, and recertified when the rule or a major system change calls for it.
Notes for compliance staff
A gas chromatograph reports individual compounds, which suits rules that limit specific organic compounds rather than a total. Performance Specification 8 is the specification for volatile organic compound monitors that report a group total.
Cited by
Provisions in the corpus whose text cites Performance Specification 9. Subscribers land on the provision in the regulation reader; visitors see a preview of it (the GP05 sample opens in full).
40 CFR Part 60 Subpart OOOOb
40 CFR Part 60 Subpart OOOOc
The sections marked as regulatory text above are reproduced from the CFR. Everything under ‘EssentialRegs notes’ is our reference copy, not the method. The method as published in the CFR controls.