Short answer
Steam table pans, also called hotel pans, are sized as fractions of a full-size pan, which is nominally 12 by 20 inches: two-thirds, half, third, quarter, sixth and ninth. Common depths are about 2.5, 4 and 6 inches. Fractions combine to fill one full-size opening in a steam table or prep table.
European Gastronorm pans follow the same fraction system, with a GN 1/1 pan measuring 530 by 325 mm. The sizes are close to North American pans but not always identical, so check the fit before mixing the two in one unit.
Some fraction layouts need adapter bars to support the pans in a well. Deeper pans hold more but take longer to heat through and to chill, which matters for food held hot or cooled in the pan.
Stainless pans suit hot holding and the oven; polycarbonate and other plastic pans suit cold storage and prep, within the temperature range the manufacturer lists.
Updated · By Norpex