A Review of ASHRAE Standard 160—Criteria for Moisture Control Design Analysis in Buildings

Abstract

Abstract Many of our current recommendations for moisture and condensation control are not based on quantitative analysis under a consistent set of design assumptions, even though a growing number of computer tools are beginning to make such analysis practical. To address this issue, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) published ASHRAE Standard 160, “Criteria for Moisture-Control Design Analysis in Buildings,” in January 2009. The standard provides performance-based procedures and criteria for moisture design analysis for buildings. It sets criteria for moisture design loads, moisture analysis methods, and satisfactory building performance. The standard can be used for the design analysis of the building envelope or to help guide specifications for HVAC equipment and controls. Eventually, it should form the basis for prescriptive moisture design rules based on a uniform set of design assumptions and loads. It is intended to help reduce building failures in service, provide consistency in design approach and recommendations, offer more flexibility in design for moisture control and better ability to incorporate new materials, and provide greater transparency by requiring reporting of design assumptions. This paper describes the rationale behind this standard, what is in it, its potential uses, and areas of uncertainties. A standing ASHRAE Standard Project Committee has now been formed to update the standard. The paper discusses some of the main changes that are likely to occur in the next update.