【国外标准】 Standard Guide for Evaluation and Rehabilitation of Mass Masonry Walls for Changes to Thermal and Moisture Properties of the Wall

4.1 Energy conservation is being addressed more often on existing and historically significant buildings constructed with solid exterior mass masonry walls. Without proper evaluation, changes to the thermal and moisture properties of the exterior walls could have serious negative impacts on the existing masonry, new or existing wall components, and building operations.4.2 A thorough understanding of the original construction and subsequent alterations, condition of materials, properties, initial moisture content, water and air leakage potential, and building operations are necessary before undertaking the addition of interior insulation, air barrier, vapor retarder, or other changes to thermal or vapor resistance of the wall.4.3 Degradation of the existing masonry along with moisture related problematic conditions and indoor air quality issues could develop if alterations are undertaken in an improper manner to the exterior wall assembly.1.1 This guide addresses the evaluation of existing mass masonry walls for the potential addition of interior insulation and continuous air barrier or vapor retarder or other changes to the thermal and moisture management properties of the wall.1.2 This guide describes methods for evaluating moisture accumulation related problems specific to mass masonry walls. This guide does not apply to walls that include provisions to manage bulk water through internal drainage, flashings, or other measures other than the moisture storage capacity of the wall.1.3 This guide describes analysis, design, and specification of materials with the required thermal, air, and vapor resistance to improve the energy performance of an existing mass masonry wall, but that would not create problematic conditions to the masonry units or within the masonry wall or interior of the building.1.4 This guide applies to walls of masonry construction meeting the requirements of a “mass masonry wall” as defined herein. This guide does not apply to masonry walls that, by design, are intended to manage water as a barrier wall system or drainage wall system.1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.