This Fourth Edition includes the following proposals: a) Revision to Scope of Standard to Reference New Sprinkler Technology; b) Revisions to Bring Definitions in Closer Alignment With Other Standards, c) Additional Requirement for Design Parameters and Installation Instructions to Reference Whether Recessed or Concealed Sprinklers are Vented; d) Revisions To More Closely Align Text with UL 199, Clarify Requirements And Maintain Consistency With Existing Testing Practices; e) Sprinkler Assembly Load Measurement; f) Fitting Type for Horizontal Surface Water Distribution Test; g) Revision To Heptane Specifications; and h) Revision To Operation - Lodgement Test.