# Anhydrous ammonia · 1.0 · 3.37. Mass Flow Meters — How far off a US fuel pump, LPG meter or EV charger is allowed to be (NIST Handbook 44)

For Anhydrous ammonia · 1.0 · 3.37. Mass Flow Meters, device or commodity is Anhydrous ammonia; accuracy class is 1.0; acceptance tolerance (new or newly repaired device) is 0.6 %; maintenance tolerance (device already in service) is 1.0 %; special test tolerance is 1.0 %, verified against its source on 2026-08-20.

- **Device or commodity:** Anhydrous ammonia _(verified: appears in the quote below)_
- **Accuracy class:** 1.0 _(verified: appears in the quote below)_
- **Acceptance tolerance (new or newly repaired device):** 0.6 % _(verified: appears in the quote below)_
- **Maintenance tolerance (device already in service):** 1.0 % _(verified: appears in the quote below)_
- **Special test tolerance:** 1.0 % _(verified: appears in the quote below)_
- **Handbook 44 section:** 3.37. Mass Flow Meters _(verified: appears in the quote below)_
- **Edition:** 2026 _(verified: appears in the quote below)_

## What the source says

> 1.0 - Anhydrous ammonia 0.6 % 1.0 % 1.0 % - LP Gas (including vehicle-tank meters)

## Source

- https://www.nist.gov/document/2026-nist-handbook-44-section-337

Last verified: 2026-08-20. Review by: 2027-08-20.
Part of [How far off a US fuel pump, LPG meter or EV charger is allowed to be (NIST Handbook 44)](https://referencesource.org/motor-fuel-dispenser-measurement-tolerances-nist/).