This standard establishes minimum construction and performance requirements for small tabletop steam sterilizers that use saturated steam as the sterilizing agent and that have a volume less than or equal to 56.63 liters (2 cubic feet). This standard is the fourth edition of Table-top steam sterilizers, which was first published as an American National Standard in 1997 as ANSI/AAMI ST55:1997. In comparison to the second edition, which was approved in 2003, this new edition covers cassette sterilizers (which were excluded from the scope of previous editions), incorporates revisions of the methodology for testing the biological performance of table-top steam sterilizers with dental handpieces, and includes a requirement that certain sterilizers be tested for noncondensable gases.