eCFR Reference Browser

---

title: "40 CFR §1065.325"

source: "https://www.ecfr.gov/current/title-40/section-1065.325"

title_number: "40"

volume_number: "37"

chapter_number: "Unknown"

subchapter_code: "U"

subchapter_subject: "AIR POLLUTION CONTROLS"

part_code: "1065"

part_subject: "ENGINE-TESTING PROCEDURES"

subpart_code: "D"

subpart_subject: "Calibrations and Verifications"

section_number: "1065.325"

section_subject: "Intake-flow calibration."

cfr_reference: "40 CFR 1065.325"

title_name: "Title 40"

title_subject: "Protection of Environment"

parts_covered: "Part 1060 to End"

revised_date: "Revised as of July 1, 2019"

publication_date: "As of July 1, 2019"

contains_description: "Containing a codification of documents of general applicability and future effect"

publication_info: "Published by the Office of the Federal Register National Archives and Records Administration as a Special Edition of the Federal Register"

---

(a)Calibrate intake-air flow meters upon initial installation. Follow the instrument manufacturer's instructions and use good engineering judgment to repeat the calibration. We recommend using a calibration subsonic venturi, ultrasonic flow meter or laminar flow element. We recommend using calibration reference quantities that are NIST-traceable within 0.5% uncertainty.

(b)You may remove system components for off-site calibration. When installing a flow meter with an off-site calibration, we recommend that you consider the effects of the tubing configuration upstream and downstream of the flow meter. We recommend specifying calibration reference quantities that are NIST-traceable within 0.5% uncertainty.

(c)If you use a subsonic venturi or ultrasonic flow meter for intake flow measurement, we recommend that you calibrate it as described in § 1065.340.

§1065.325 - Intake-flow calibration.