Moisture Management in Buildings
ASHRAE Technical Committee 1.12

The ASHRAE Handbook is published in a series of four volumes, one of which is revised each year, ensuring that no volume is older than four years.

The Handbook can be purchased at the ASHRAE Bookstore by clicking on this link.

TC 1.12 is responsible for Chapter 62 (2015 numbering) in the ASHRAE HVAC Applications volume of the handbook:

Moisture Management in Buildings
Indoors, buildings should always be dry. When building interiors get damp and stay damp, problems often emerge for their occupants and for the building’s structure, material, and furnishings. Persistent indoor dampness has been associated with human health problems, increased risk to buildings’ structural fasteners and exterior enclosure, shortened useful life of furnishings, and reduced acceptability to occupants because of odors and stains. These and related problems can be costly and disruptive, as well as annoying to all concerned.  

Chapter 62, Applications (2015)
Chapter Title: Moisture and Management in Buildings
Current Status: Under revision for 2019 Handbook - Applications
Current Reviser: Lew Harriman

New Chapter in development
The TC 1.12 handbook subcommittee is currently drafting a Handbook chapter for future Handbook –  Fundamentals. The TC is seeking interested participants for the development of a handbook chapter. Membership on TC 1.12 is not required to participate. Contact the Handbook Subcommittee Chair (TC0112.HBK@ashrae.net) if you are interested in helping with the Fundamentals Chapter and/or the Applications chapter.       

Chapter # TBD, Fundamentals (2017)
Tentative Chapter Title: Moisture and Management in Buildings
Current Status New chapter currently in draft status. To be published in March 2017
Current Reviser: Hugo Hens

A current draft of the Fundamentals chapter can be found here. 

Comment on the Handbook: ASHRAE welcomes your comments on the Handbook or a specific Handbook chapter.  To submit a comment about any aspect or part of the Handbook series, you can use the Handbook Comment Form.

Review a Handbook Chapter: To provide your feedback about a specific Handbook chapter, you can answer the brief survey questions on the Handbook Chapter Review Form.

Technical committees develop and sponsor technical sessions at the winter and annual conferences. Information about their future technical program is discussed at each TC meeting and at the TC’s Program Subcommittee meeting.

ASHRAE publishes papers and transactions from presentations at its conference events. In addition, ASHRAE records most of the seminar sessions from its conferences on DVD. These DVDs are ideal for use at chapter meetings, in university courses, or company lunch and learns. Products available from the most recent conference may be found here.

The following was presented at the 2015 Annual Meeting in Atlanta:

SEMINAR 13 (INTERMEDIATE): How Dry Am I?: Locating, Quantifying and Reducing Microbial Growth Risk in Buildings

Persistent dampness from rainwater intrusion, plumbing leaks and condensation reduces indoor air quality and increases health risks. In recent years new instruments and novel techniques have been deployed to help quantify the risks of mold and bacterial growth, and to locate potential problem areas with more speed and certainty. This seminar describes several such tools and techniques, including case histories of research to understand microbial ecology in buildings and to reduce microbial growth risk and energy consumption.

The following was presented at the 2014 Annual Meeting in Seattle:

WORKSHOP 1 (INTERMEDIATE): Development of an ASHRAE Energy Guideline for Historical Buildings Recovery

ASHRAE is preparing a guideline for use by architects, engineers and building owners for the energy efficient preservation or rehabilitation of historic buildings. The proposed guideline will focus on design, operation and maintenance of energy-using systems that do not compromise historical preservation. The guidance will include advice, recommendations and sources of further information for: envelope rehabilitation and restoration; energy efficient HVAC systems that provide acceptable indoor environmental quality, and energy efficient lighting. The workshop has two brief presentations on successful energy efficient rehabilitations of historic buildings and a 45 minute question and answer session with a panel of four experts.

Seminar 18 (INTERMEDIATE): New U.S. Environmental Protection Agency Guidance for Moisture and Humidity Control in Buildings

Persistent and excessive dampness from rainwater and plumbing leaks and from shortcomings in HVAC design can create severe indoor air quality problems and sometimes health risks for building owners and occupants. To reduce such risks, the U.S. EPA has published guidance for architects, engineers and building operators with respect to managing moisture and humidity. These presentations provide practical, actionable suggestions for each of the professional disciplines. The information also is useful to building occupants or homeowners who have had the unfortunate experience of living or working in a building that has a dampness or high humidity problem.

The following was presented at the 2014 Winter Meeting in New York:

SEMINAR 57 (INTERMEDIATE):  Lessons Learned from Storm Recovery

The persistent and excessive dampness from floods and hurricanes creates severe indoor air quality problems and sometimes health risks for building owners and occupants. To reduce such risks, architects and engineers in New York City share valuable and hard-learned lessons from the difficult recovery from Hurricane Sandy. Experts in other climate zones share equally useful lessons from recovering from tropical storms. These presentations provide practical, actionable suggestions specific to New York City, as well as suggestions learned that are applicable to other coastal storm regions.

 The following were presented at the 2013 Annual Meeting in Denver:

SPECIAL SESSION 8 (BASIC)Workshop: Tools and Techniques for Avoiding Construction Moisture Problems

Tens of millions of dollars are lost each year because of insufficient attention to moisture control during building construction. When building materials and components get wet or are inherently wet (e.g. fresh concrete) and are not allowed to dry out before building enclosure, the result often is mold in the building as well as in the HVAC system. This seminar explores how we can ensure that buildings are dry after the building is finished and before the HVAC system is turned on.

The following was presented at the 2013 Winter Meeting in Dallas:

SEMINAR 2 (INTERMEDIATE): Diagnosing and Fixing Building Moisture Problems – Case Histories From Hot & Humid Climates

Moisture and humidity problems are often a complex mixture of decisions made by different professionals at different times about HVAC systems, architecture and building operations. Untangling the causes of problems and planning solutions requires understanding of the typical interactions between the building and its HVAC systems plus an appreciation of the practical aspects of operating buildings with limited budgets. Case histories presented in this seminar can help building owners and facility managers avoid classic moisture problems and solve them when they occur.

 The following was presented at the 2012 Annual Meeting in San Antonio:

SEMINAR 58 (INTERMEDIATE) Mold, Moisture, and Damp Buildings: New Understanding and Guidelines for Reducing the Health Effects

For years, damp buildings were thought to generate negative health effects. Until recently, the magnitude of health effects has not been quantified. The mechanisms which lead to negative effects were not understood. Research advances have provided a clearer path towards understanding what levels of dampness are problematic, what the specific links are between asthma and dampness, and what strategies are effective in reducing moisture accumulation. The presentations describe results of research as well as new guidance for architects, mechanical system designers and owners. The information is also be of interest to occupants of buildings which are perceived to be damp.

The following were presented at the 2011 Annual Meeting in Montreal:

Forum 1: What Should Be in a Moisture Management Chapter in the ASHRAE Handbook?
Moderator: Alex McGowan P.Eng., Member, Levelton Consultants, Victoria, BC

Many aspects of equipment performance and the interaction between the weather, the building envelope, its systems and its occupants will either lead to moisture accumulation or prevent it. Moisture accumulation can lead to decay, corrosion, and mold growth, among other things. At present, the guidance for these issues are spread among various handbook chapters, and some issues are not addressed at all in the Handbooks. This forum solicits input from ASHRAE members on the value of a separate chapter specifically written to address moisture management in buildings, including design, construction, operation and maintenance and commissioning.

Forum 10: Should ASHRAE Have a Standard on Building Envelopes?

HVAC designers rely on the building envelope to control thermal and hygro-thermal loads from the outdoor environment. Yet, there are very little requirements regarding these issues and no organization has taken ownership of the parameters. If ASHRAE and its members are to achieve net zero energy design for buildings, the building envelope must control and reduce to a minimum, thermal transport, vapor diffusion, air exfiltration and infiltration.

The following were presented at the 2011 Winter Meeting in Las Vegas:

Seminar 48 (Intermediate) – Cool New Tools for Finding and Fixing Problems in Buildings and HVAC Systems

Sooner or later every contractor, engineer, architect and building owner has problems that he or she must investigate and solve. The problems of air leakage and moisture accumulation have been more important lately, and the traditional problems of poor temperature and humidity control always seem to be with us. In recent years, building investigators have found (or invented) innovative, practical and economical tools and techniques for locating and diagnosing problems. This seminar focuses on new hardware and innovative techniques for building investigations.

The following were presented at the 2010 Summer Meeting in Albuquerque:

Seminar 21 – Odd Moisture Management Issues in Dry Climates

Dry climates pose unusual moisture management problems for building systems and occupants, including health issues requiring proper humidification to address, and building durability and health issues requiring proper dehumidification to address. Moisture issues can be created by HVAC systems, insulation location, and interactions between the systems and building materials. By adding moisture to the air, HVAC systems can also create some unique condensation concerns. Case studies of problems and solutions identified for dry climates are provided, with special focus on roof systems, evaporative cooling challenges and options, and occupant health effects associated with dry air.

Seminar 48 – Solving Moisture Problems Created By Energy Efficient Design

A building envelope that deteriorates over time and must be replaced is neither green nor sustainable. Excess moisture that causes dehumidifiers to work overtime is not energy-efficient. In some cases, however, energy-efficient design (high insulation levels, setback thermostats, airtight building envelopes, etc.) creates problems with moisture control. This seminar shows the link between energy-efficient design and moisture concerns, and presents guidance for preventing problems that reduce the durability of the envelope or overwork the mechanical equipment. A group of dynamic speakers from a variety of backgrounds show current research, theory, design, and real-life approaches to solving this problem.
Moisture and the Energy Efficient Building Envelope: Fundamentals

The following were presented at the 2010 Winter Meeting in Orlando:

Seminar 28 - Operating Cost Implications in Humid Environments

Hot and humid climates definitely have an impact on the operating and maintenance costs of mechanical systems and buildings. Chapter 36 of the 2007 Applications Handbook suggests that the service life of equipment is negatively impacted by being near salt water or by being operated in humid environments. What types of equipment failures and maintenance challenges are seen in the Southeast and what is their impact on owning and operating costs? This seminar identifies unique aspects of maintaining and operating HVAC systems in hot humid environments and their cost impacts. System challenges include maintaining vapor barriers on ducts and pipes, preventing biological growth inside HVAC equipment and ducts, maintaining good indoor environmental quality during periods of wind driven rain, effect of hot and humid on worker productivity while servicing equipment on a hot roof and moisture management in buildings.
Practical Designs to Reduce Operating Costs in Humid Climates

Forum 6 - Solving Moisture Problems Created by Energy Retrofits

Increasing insulation levels, setting back thermostats, reducing air leakage, modifying ventilation strategies and controls - all common activities in energy retrofits, and all lead to various problems in moisture control. This forum discusses ways to solve the energy-retrofit challenge without creating problems that reduce the durability of the building envelope or overwork the mechanical equipment.

Seminar 72 - Lessons From the School of Hard Knocks: The Revised ASHRAE Guide for Buildings in Hot and Humid Climates

The revised and expanded ASHRAE Guide for Buildings in Hot & Humid Climates was created in response to energy and mold problems with modern buildings in the humid regions of North America and the Caribbean, South Asia and the Middle East. This seminar summarizes key aspects of the new ASHRAE guidance. The co-authors of the new book provide examples of best practices for energy reduction, comfort and mold avoidance in the design of building enclosures and HVAC systems.

The following were presented at the 2009 Summer Meeting in Louisville:

Seminar 3 - Avoiding Moisture and Humidity Problems During Part-Load Hours

At part load, when outdoor temperatures are moderate but the dew point remains high, unitary and packaged rooftop cooling equipment often has difficulty keeping the dew point low enough to provide comfort and avoid mold problems. The problems multiply if ventilation air adds more humidity to the space. This seminar discusses the systems which are most prone to such difficulties, and suggests how designers can anticipate and avoid high-humidity problems at part load.
Research which Explains and Quantifies Humidity Problems at Part Load

Seminar 8 - Case Studies of Moisture Management Issues in Litigation

The three speakers have seen hundreds of buildings where moisture management has failed, resulting in significant litigation expense. Come learn from some of their experiences.

The following was presented at the 2009 Winter Meeting in Chicago:

Seminar 47 - Benchmarking Hygrothermal Tools

The hygrothermal performance of building envelope system is dictated by the response of the system to combined heat, air and moisture fluctuations produced by exterior and interior conditions that exist on either side of the envelope. Recent research in the field of assessment of hygrothermal response has focused on either laboratory experimentation or modeling, but less work has been reported in which both aspects are combined. Indeed, it is generally acknowledged that assessing the hygrothermal performance of building envelope systems is both expensive and time consuming. Such type of studies can potentially offer useful information regarding the benchmarking of models and related methods to assess hygrothermal performance of wall assemblies. This seminar is focused on the different ways to benchmark the hygrothermal models i.e. inter-model comparison, analytical and empirical verification.

The following were presented at the 2008 Summer Meeting in Salt Lake City:

Seminar 23 - Lessons to Be Learned from Failed Moisture Management That Resulted in Litigation

The three speakers have seen hundreds of buildings where moisture management has failed. Come learn from a some of their experiences.

Forum 6 - Should ASHRAE Establish Part-Load Outdoor Design Conditions? 

Designers often assume cooling systems will accomplish dehumidification in addition to sensible cooling. Problems in hot and humid climates have established that many cooling systems fail to adequately dehumidify during off-peak load outdoor conditions. Should ASHRAE help designers and equipment manufacturers by establishing part-load design conditions to use in assessing dehumidification effectiveness? If so, how could the Society go about selecting such conditions? If not, what other means are available to designers and manufacturers to ensure improvement of the current shortcomings of systems with respect to dehumidification?

Seminar 23 - Lessons to Be Learned from Failed Moisture Management That Resulted in Litigation

The three speakers have seen hundreds of buildings where moisture management has failed. Come learn from a some of their experiences.

The following were presented at the 2008 Winter Meeting in New York:

Seminar 29 - Moisture Management Concerns in Commercial and Residential Buildings

This seminar provides field applications of design and construction strategies that address moisture management concerns in commercial and residential buildings. Recommendations encompass measurement methods, performance measurements, and energy efficient moisture and mold mitigation and prevention strategies for existing and new buildings.

Seminar 62 - Mold: Where Do We Stand Now?

Mold litigation and insurance claims continue. Mold has been growing in buildings for more than 4000 years, but recently it has changed the way we do business. We now understand much more about the interaction between the HVAC systems and the building enclosure, and how these interactions sometimes grow mold. The HVAC industry may be facing new responsibilities in the current business climate. This seminar examines current engineering, architectural and legal issues for designing, constructing and operating mold-free buildings. ASHRAE's mold policy document and forthcoming publications also are discussed.

Transactions Session 7 - Building Envelope Moisture Performance Experiments and Design Analysis Criteria

This session provides information on building construction practices, assemblies, and design criteria for improved building envelope moisture performance. Results of a detailed laboratory evaluation of residential building assemblies and construction practices intended to reduce the risk of moisture penetration and mold growth in walls with stucco cladding are described. The rationale behind ASHRAE Standard 160P, Criteria for Moisture Control Design Analysis in Buildings, its current outline, and its potential uses are summarized. Standard 160P sets criteria for moisture design loads, moisture analysis methods, and building performance, and applies to the above-grade portions of all types of buildings.

The following was presented at the 2007 Summer Meeting in Long Beach:

Seminar 28 - Moisture Management Issues in Residential and Commercial Buildings

Modern construction practices have improved energy efficiency but also resulted in conditions that may be more susceptible to moisture intrusion and rapid microbial growth. This seminar provides results of laboratory evaluations and field applications of design and construction strategies that address moisture management issues in residential and commercial buildings. Recommendations encompass both mechanical and natural ventilation strategies in new and existing buildings.

The following were presented at the 2007 Winter Meeting in Dallas:

Transactions 12 - Moisture Management in Energy Efficient Homes

Modern residential construction practices have improved energy efficiency, but also resulted in conditions that may be conducive to rapid microbial growth. By improving the understanding of the susceptibility of various construction practices and building assemblies to mold growth, and communicating this understanding to affected stakeholders, improved mold loss prevention decisions can be made. This session provides information and recommendations on mold risk reduction strategies for energy efficient residential buildings. The discussion includes laboratory data and analytical modeling of energy efficient wall assembly options, and a three-part mold risk reduction strategy for builders.
Laboratory Evaluation of Residential Window Installation Methods in Stucco Wall Assemblies

Seminar 2 - Case Studies in Humidity Control, Part 1

The session offers case studies in humidity control based on the personal experiences of the presenters. The speakers will share how they solved moisture control issues in select projects
Seminar 39 - Case Studies in Humidity Control, Part 2

The session offers case studies in humidity control based on the personal experiences of the presenters. The speakers will share the issues that confronted them and how they solved the problems.

The following were presented at the 2006 Summer Meeting in Quebec City:

Seminar 40 - Mold Risk Reduction Strategies in New Energy Efficient Homes

Avoiding mold in buildings is simple in principle: keep everything dry and mold cannot grow. But we build our homes outdoors. And all buildings leak both air and water. So given time, the odds favor some things getting wet indoors, which means most buildings have some risk of having a mold problem. This seminar provides recommendations on energy efficient residential building assemblies and practices that reduce mold risk. The discussions include a three-part strategy for builders to reduce mold risk, application in production homes, and analytical modeling of energy efficient wall assembly options.

Seminar 47 - Mold in Canada

With mold an ongoing problem in Canada and the United States, this seminar addresses ways to identify and clean up the situation in both residential and commercial structures.

The following were presented at the 2006 Winter Meeting in Chicago:

Seminar 10 - Infection Control by Using Proper Solutions

With the possibility of infection being transferred to patients, staff and visitors, it is important that the causes and results of these possibilities be discussed.

Seminar 61 - Lessons Learned from Hurricane Recovery

With mold and mildew as byproducts of hurricanes and the cost relating to hurricanes, this seminar brings to the forefront ideas on how to assist in the recovery of these dollars and show ways of protection to assist in reducing or eliminating these costs and devastating damages in the future.

The following were presented at the 2005 Summer Meeting in Denver:

Seminar 18 - Indoor Humidity in Buildings

One of the least known design and performance parameters of buildings is indoor humidity. Indoor humidity is a function of various complex building design factors such as: mechanical systems, number of occupants, indoor moisture sources and sink, building enclosure types, air tightness and size of building. This seminar examines the various contributors that affect indoor humidity for residential and commercial buildings.

Seminar 53 - Moisture Measurement Techniques

Excessive moisture in building assemblies and high indoor dew points can lead to mold growth and other costly problems of public concern. During 2003, mold claims against property and casualty insurance reached $12 billion – the same level as fire claims. This seminar discusses specific cases that describe tools and techniques to locate excessive moisture and high humidity, along with management practices for avoiding such problems.

The following was presented at the 2005 Winter Meeting in Orlando:

Seminar 10 - Mold and Mildew Case Studies of Florida

With mold and mildew on the rise especially in Florida, this seminar demonstrates tactics to assist in their elimination and shares four case studies of high-profile mold and mildew case studies in Florida.

The following was presented at the 2004 Summer Meeting in Nashville:

Seminar 36 - Mold: Where Do We Stand Now?

By some estimates, mold litigation and insurance claims may exceed asbestos and Superfund claims combined. This microbial contamination has been around for more than 4,000 years yet it has taken on a new life that will change the way we do business. It is time to reexamine this issue to understand the responsibility our industry faces in the current business climate. Environmental consultants are suggesting that HVAC systems in buildings may cause mold growth. This seminar examines current engineering and legal issues that must be considered in designing, constructing and operating buildings.

Forum 25 - Dehumidification, How To Do It Properly: It's Not Just Another Air Conditioner

Moisture control in buildings has become an absolute necessity for new systems as well as retrofits. What guidelines do we need in our Handbooks for proper design? What codes and standards do we need?

The following was presented at the 2003 Summer Meeting in Kansas City:

Seminar 37 - Mold and Mildew Control and Observations on Residential Construction

With the concern of mold and mildew in residential construction becoming more of a viable concern among homeowners, insurance companies an realtors, we feel it is at a point where possibilities of cures and mitigation should be identified. This seminar looks at some of the observations and ways to contain and mitigate mold and mildew in residential construction.

The following was presented at the 2003 Winter Meeting in Chicago:

Seminar 30 - Mold and Mildew Mitigation in Construction

Mold and mildew in construction is becoming a large problem that seems to touch every portion of the building and is getting more difficult to eliminate. This seminar discusses systems relating to dry construction, building envelope, learning from mistakes, and unusual growth in air handling systems.

The following were presented at the 2002 Summer Meeting in Honolulu:

Forum 12 - Moisture Management in Hawaii and Other Tropical Climates

This forum explores solutions to moisture and mold problems in the Hawaiian Islands and other similar climates and islands. What are moisture and mold design and operation solutions? What are unique requirements for Hawaii? What is different between the wet and dry side of islands? Which moisture requirements are not related to potential mold in building assemblies and systems? What research, programs, standards or guidelines should ASHRAE pursue?

Seminar 17 - Case Studies for Moisture Control

With the ongoing issue of moisture in facilities and the problems it has created, TG 9.MMB (now TC01.12)  is sponsoring this seminar on four different types of facilities that had moisture problems and how those problems were handled. The necessity of proper insulation and correct design and construction practices in areas prone to this problem are demonstrated.

Seminar 26 - The Impact of Standards 62 and 90 on the Moisture-Related Problems
The issue of moisture-related problems in facilities is no longer concentrated just along the coastal areas of North America. Problem facilities are now being found from the Northeast, through the Midwest to the West Coast and even into Texas. Claims that more efficient buildings in conjunction with higher ventilation rates are the "root causes" for these situations are evaluated and addressed in this seminar. The participants represent manufacturers, consultants and researchers who are actively involved in moisture-related engineering activities.

Technical Committees are responsible for identifying research topics, proposing research projects, selecting bidders, and monitoring research projects funded by ASHRAE. Information about their specific research program is discussed at each TC meeting and at the TC’s Research Subcommittee meeting.

Research Plan
Current Research Projects
1712-RP, "Development of the ASHRAE Design Guide for Dedicated Outdoor-Air Systems"

TC 8.10, Mechanical Dehumidification Equipment and Heat Pipes; Co-sponsoring TCs: 1.12, Moisture Management in Buildings,   TC 5.5, Air-To-Air Energy Recovery & TC 8.12, Desiccant Dehumidification Equipment and Components

This design guide will help practicing HVAC engineers design dedicated outdoor-air systems that minimize energy use, maximize indoor environmental quality, and balance life-cycle cost with environmental impact.

Current Work Statements
TC 8.10 WS-1566 “Pool evaporation work statement” (co-sponsoring with TC 8.10) - on going

Current RTARS
1718-RTAR “Development of a method to determine the moisture transport properties of a roof shingle system under real conditions” (co-sponsoring with TC 4.4)  - on going

A brainstorming session held in Chicago 2012 generated 51 possible research ideas.

ASHRAE writes standards for the purpose of establishing consensus for: 1) methods of test for use in commerce and 2) performance criteria for use as facilitators with which to guide the industry. ASHRAE publishes the following three types of voluntary consensus standards: Method of Measurement or Test (MOT), Standard Design and Standard Practice. ASHRAE does not write rating standards unless a suitable rating standard will not otherwise be available. ASHRAE is accredited by the American National Standards Institute (ANSI) and follows ANSI's requirements for due process and standards development. Standards may be purchased at the ASHRAE Bookstore.

TC 1.12 has no standards responsibilities at this time.

TC 1.12 participates in the following multi-disciplinary task group:

Building Dampness
MTG.BD will develop a definition of a damp building and an assessment protocol to assess building dampness in accordance with recommendation 3 of the ASHRAE Board of Directors’ 2013 position document titled Limiting Indoor Mold and Dampness in Buildings. The group will also propose research to test the practicality, utility and cost-effectiveness of the protocol, and oversee that research if such is approved.

ASHRAE Technical FAQs are provided as a service to ASHRAE members, users of ASHRAE publications, and the general public. While every effort has been made to ensure their accuracy and reliability, they are advisory and provided for informational purposes only, and in many cases represent only one person’s view. They are not intended and should not be relied on as an official statement of ASHRAE. Technical questions not addressed may be submitted to the ASHRAE Technical Services department at tse@ashrae.net.