40 CFR § 1065.790 - Mass standards.

---
identifier: "/us/cfr/t40/s1065.790"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 1065.790 - Mass standards."
title_number: 40
title_name: "Protection of Environment"
section_number: "1065.790"
section_name: "Mass standards."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "U"
subchapter_name: "AIR POLLUTION CONTROLS"
part_number: "1065"
part_name: "ENGINE-TESTING PROCEDURES"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 7401-7671q."
regulatory_source: "70 FR 40516, July 13, 2005, unless otherwise noted."
cfr_part: "1065"
---


# 1065.790 Mass standards.

(a) *PM balance calibration weights.* Use PM balance calibration weights that are certified as NIST-traceable within ±0.1% uncertainty. Make sure your highest calibration weight has no more than ten times the mass of an unused PM-sample medium.

(b) *Dynamometer, fuel mass scale, and DEF mass scale calibration weights.* Use dynamometer and mass scale calibration weights that are certified as NIST-traceable within ±0.1% uncertainty.

[88 FR 4687, Jan. 24, 2023]