State and local weights and measures jurisdictions or other testing laboratories that use transfer standards developed using the air-oven reference methods (referred to as air-oven reference standards) to test commercial grain moisture meters, collect grains that are typically grown and traded in their State, and transport them to their laboratory for testing. In the laboratory, these grains are cleaned, mixed, and tested for moisture content and weight per bushel. The grains are then divided into smaller grain samples and assigned moisture and weight per bushel reference values. These samples with known reference moisture and weight per bushel values are issued to weights and measures officials to test commercial grain moisture meters in accordance with NIST Handbook 44, Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices, Section 5.56.(a) Grain Moisture Meters. Commercial grain moisture meters are meters that provide rapid grain moisture content to a buyer. The moisture content of grain is used to determine the amount of money a seller will receive for the grain. For example, if grain moisture content is too high, the buyer must dry the grain before storage, so cost adjustments are made by the buyer to offset the cost for drying. Conversely, if the moisture is too low the grain quality may be affected and cost adjustments may be made for low moisture. This reference manual provides technical guidelines for: (1) laboratory grain sample preparation and testing; and (2) the field evaluation of grain moisture meters, in accordance with NIST Handbook 44, Section 5.56.(a) for field testing using air-oven reference method transfer standards.
Handbook (NIST HB) - 159
GMM, grain moisture meters, standards, air-oven reference standards, grains, grain moisture content