The following changes in requirements are being proposed:
1. This proposed Second Edition of the Standard for Fire Resistive Grease Ducts, UL 2221 includes the following changes: a) A title change from "Standard for Tests of Fire Resistive Grease Duct Enclosure Assemblies" to "Standard for Fire Resistive Grease Ducts", b) Removal of Condition B which represented non-ventilated combustible enclosures, c) A requirement for measurement of pressure and temperature data at maximum 1 minute intervals to better reflect current laboratory operations, and d) Editorial revisions such as correcting references and language clarifications.