Gross Mass
Gross Mass
The total weight of a container plus its contents, specified in the UN marking (e.g., Y27 = 27 kg max gross mass).
Gross mass is the total combined weight of a container and its contents, measured in kilograms. In UN packaging markings, the gross mass limit appears as a number after the packing group indicator (e.g., Y27 means maximum 27 kg gross mass for Packing Group II/III). For a standard 5-gallon HDPE pail rated UN 1H2/Y27/S, the maximum gross mass is 27 kilograms (59.5 lbs), which includes both the pail weight (~1 kg) and contents (~26 kg). Exceeding the rated gross mass voids the UN certification.