FOREWORD Addendum 135ak to ANSI/ASHRAE Standard 135-2010 contains a number of changes to the current standard. These modifications are the result of change proposals made pursuant to the ASHRAE continuous maintenance procedures and of deliberations within Standing Standard Project Committee 135. The changes are summarized below. 135-2010ak-1 Specify Address Range Requirements@ p. 2 135-2010ak-2 Specify 'abort-reason' Values@ p. 4 135-2010ak-3 Add Serial_Number Property@ p. 5 In the following document@ language to be added to existing clauses of ANSI/ASHRAE 135-2010 and Addenda is indicated through the use of italics@ while deletions are indicated by Where entirely new subclauses are proposed to be added@ plain type is used throughout.