This document (EN ISO 139:2005 + A1:2011) has been prepared by Technical Committee ISO/TC 38, "Textiles" in collaboration with Technical Committee CEN/TC 248 "Textiles and textile products", the secretariat of which is held by BSI. It already contains Amendment ISO 139:2005/Amd.1:2011 which is separately available at ISO. The amendments in this document are marked and indicated with "A1" between two tags. The responsible German committee is Working Committee NA 062-05-21 AA "Physikalisch-technologische Prüfverfahren für Textilien" ("Physical and technological test methods for textiles") of the Materials Testing Standards Committee (NMP) at DIN. This International Standard defines the characteristics and use of a standard atmosphere for conditioning, for determining the physical and mechanical properties of textiles and a standard alternative atmosphere that may be used if agreed between parties. This standard differs from DIN EN ISO 139:2005-04 as follows: a) the definition of "rapid conditioning" has been added; b) an additional alternative atmosphere has been added in 3.2; c) further information on conditioning has been included in 5.4; d) an error in the key of Figure B.1 has been corrected.