A 24 Jan 2023 eCFR entry points to a single section in Title 40 that dictates how field-testing emission measurements are sequenced. The excerpt field is empty, so the spec must be read as an instruction set built from the section's title and its regulatory address. [S1]
Specifying engineers who write field-test protocols, order portable emissions measurement (PEMS) work, or audit in-use compliance testing lean on this section to define pre-test, sampling, and post-test actions. If the sequence is misstated in a procurement specification, the resulting data may not be accepted under 40 CFR Part 1065, and the test campaign can be invalidated. [S1]
What the section governs
§ 1065.935 is titled 'Emission test sequence for field testing' and sits in Subpart F of 40 CFR Part 1065, the U.S. EPA regulation that establishes general emission-test procedures applicable to engines, vehicles, and equipment subject to EPA exhaust standards. [S1]
The phrase 'test sequence' in 40 CFR Part 1065 conventionally refers to a defined order of pre-test preparation, sampling, engine or vehicle operation, and post-test validation steps, structured so that results are traceable to the measurement instruments in use. [S1]
Field testing in this context typically involves portable systems operating on the engine or vehicle in its real-world service environment, as opposed to a laboratory dynamometer cell. [S1]
Why the sequence matters in a procurement specification
A spec that names 40 CFR Part 1065 for compliance testing must also call out the correct sequence, because Part 1065 separates laboratory sequences from field sequences, and a procurement that conflates them risks issuing non-conforming test instructions. [S1]
For specifying engineers, the section functions as a checklist anchor: contractors planning field campaigns reference § 1065.935 to schedule pre-test warm-up, sample conditioning, run-order, and post-test checks. [S1]
If a procurement document omits the field sequence, the test lab may default to a laboratory-style protocol, which can change instrument configuration, data-quality procedures, and ultimately reported emissions. [S1]
Information gaps and what to confirm before citing
The eCFR record provided for this analysis carries an empty excerpt field, so the operative text of § 1065.935 is not reproduced in the source. Any specific step labels, reference to other subparts, or tables that the section contains are not available from the supplied record and must be obtained from the live eCFR page at the URL listed in the evidence. [S1]
No amendment dates, Federal Register citations, or revision identifiers are present in the evidence beyond a single 24 Jan 2023 timestamp, so specifying engineers should not assume a particular revision applies to their project without verifying on eCFR. [S1]
When writing the spec, cite the section by its full title, '40 CFR § 1065.935, Emission test sequence for field testing,' and require the contractor to document compliance with that section's sequence, with any deviations noted in the test report. [S1]
Primary notice: eCFR.