UL 181A Closure Systems for Use With Rigid Air Ducts tr1 FEBRUARY13,2008-UL181A Underwriters Laboratories Inc. (UL) 333 Pfingsten Road Northbrook, IL 60062-2096 UL Standard for Safety for Closure Systems for Use With Rigid Air Ducts, UL 181A Third Edition, Dated May 20, 2005 Revisions: This Standard contains revisions through and including February 13, 2008. Summary of Topics These revisions to ANSl/UL 181A include the following changes in requirements: Clarify construction material requirements for mastic closure systems for use with rigid fiberglass air ducts, Part IlI Section 26 Correct UL 181 test reference to specify the burning test, Section 35 Add the requirement for the minimum application width to be included as part of the installation instructions, Section 37 Revise the mesh requirement in the Adhesion Test on the mastic system to comply with the Standard Test Method for Adhesion-in-Peel of Elastomeric Joint Sealants, ASTM C794, Section 29 Revise ASTM D3654 reference Text that has been changed in any manner is marked with a vertical line in the margin. Changes in indicating the date of publication or the date on which the changed requirement becomes effective. The new requirements are substantially in accordance with UL's Proposal(s) on this subject dated August 10, 2007. Attention is directed to the note on the title page of this Standard outlining the procedures to be followed to retain the approved text of this ANSI/UL Standard. The UL Foreword is no longer located within the UL Standard. For information concerning the use and application of the requirements contained in this Standard, the current version of the UL Foreword is The master for this Standard at UL's Northbrook Office is the official document insofar as it relates to a UL service and the compliance of a product with respect to the requirements for that product and service, diskette for a Standard-on-Diskette and the file for the Standard on the distribution diskette should be altered in any way. All of UL's Standards and all copyrights, ownerships, and rights regarding those Standards shall remain the sole and exclusive property of UL.