Determine calibration/registration requirements for a mobile volumetric concrete mixer under state weights-and-measures rules

Steps

1. Start from NIST Handbook 44 (current edition, nist.gov/pml/owm/nist-handbook-44-current-edition), the model specifications/tolerances document most state weights-and-measures authorities adopt for commercial measuring devices.
2. Confirm your state has adopted the current HB44 edition by checking your state Department of Agriculture/Weights & Measures program page directly, since state adoption dates lag the NIST publication and vary by state.
3. For the concrete-technical basis of volumetric/continuous-mixing equipment design (distinct from the legal-metrology side), note ACI 304.6R (Guide for Use of Volumetric-Measuring and Continuous-Mixing Concrete Equipment) — this ACI guide is a paywalled purchase (concrete.org store), not freely downloadable.
4. Contact your state's weights-and-measures office directly to confirm the specific registration, calibration frequency, and inspection process for volumetric mixer trucks operating in that state.
5. Don't assume a single, universally-numbered 'volumetric mixer' section exists in HB44 without checking the current table of contents, since device-code organization can shift between editions.