40 CFR § 1090.1390 - Requirement for automated detergent blending equipment calibration.

---
identifier: "/us/cfr/t40/s1090.1390"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 1090.1390 - Requirement for automated detergent blending equipment calibration."
title_number: 40
title_name: "Protection of Environment"
section_number: "1090.1390"
section_name: "Requirement for automated detergent blending equipment calibration."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "U"
subchapter_name: "AIR POLLUTION CONTROLS"
part_number: "1090"
part_name: "REGULATION OF FUELS, FUEL ADDITIVES, AND REGULATED BLENDSTOCKS"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 7414, 7521, 7522-7525, 7541, 7542, 7543, 7545, 7547, 7550, and 7601."
regulatory_source: "85 FR 78469, Dec. 4, 2020, unless otherwise noted."
cfr_part: "1090"
---


# 1090.1390 Requirement for automated detergent blending equipment calibration.

(a) An automated detergent blending facility must calibrate their automated detergent blending equipment once in each calendar half-year, with the acceptable calibrations being no less than 120 days apart.

(b) Equipment recalibration is also required each time the detergent package is changed, unless written documentation indicates that the new detergent package has the same viscosity as the previous detergent package. Calibrating after changing the detergent package may be used to satisfy the semiannual recalibration requirement in paragraph (a) of this section, provided that the calibrations occur in the appropriate calendar half-year and are no less than 120 days apart.