Current textIn force on Dec. 9, 2021Source: eCFR

§ 325.9 Measurement tolerances.

Current wording, first on file in the 1996 annual edition.

eCFR as of December 9, 2021 ↗

49 CFR § 325.9 — Measurement tolerances.. Text in force on December 9, 2021. This wording effective October 1, 1996 to present. Source: eCFR as of December 9, 2021, https://www.ecfr.gov/on/2021-12-09/title-49/section-325.9. Retrieved from FMCSR.com, https://fmcsr.com/reg/325.9?asof=2021-12-09, on October 26, 2026. Unofficial compilation; verify against the official source.

(a) Measurement tolerances will be allowed to take into account the effects of the following factors:

(1) The consensus standard practice of reporting filed sound level measurements to the nearest whole decibel.

(2) Variations resulting from commercial instrument tolerances.

(3) Variations resulting from the topography of the noise measurement site.

(4) Variations resulting from atmospheric conditions such as wind, ambient temperature, and atmospheric pressure.

(5) Variations resulting from reflected sound from small objects allowed within the test site.

(6) The interpretation of the effects of the above cited factors by enforcement personnel.

(b) Measurement tolerances shall not exceed 2 decibels for a given measurement.

Amendment history

1 distinct wording on file since Oct. 1, 1996

Oct. 1, 1996 → presentannual editions 1996–2016viewing

A new entry appears whenever the regulatory words change between government snapshots. Day-precise from the eCFR (2017 onward); before that, one snapshot per annual CFR edition (revised as of October 1). Bracketed citations are the Federal Register history printed with the section.