Humidifying Equipment
ASHRAE Technical Committee 5.11

Scope of TC 5.11

Technical Committee 5.11 is concerned with equipment for raising the humidity of air in residential, and commercial, and industrial spaces; its application and control; effect of humidity on structures, content, processes, materials, and occupants; and testing and standards defining environmental and physiological requirements.


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.

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TC 5.11 is responsible for this chapter in the ASHRAE HVAC Systems and Equipment Handbook Volume:

In the selection and application of humidifiers, the designer considers (1) the environmental conditions of the occupancy or process and (2) the characteristics of the building enclosure. Because these may not always be compatible, compromise is sometimes necessary, particularly in the case of existing buildings.

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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.


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.

TC 5.11 has an on-going research project co-sponsored by TC 9.6 - Health Care Facilities:

To determine and quantify the effect of low level of relative humidity (10-40%) on the comfort, health, and IEQ for humans in residences and non-industrial workplaces, including adolescents and the population over 65 years old. The project will entail comprehensive literature review, detailed data analysis, developing conclusions and recommendations, and preparation of the final report


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 5.11 is cognizant for the following standards:

Standard 164.1: Method of Test for Residential Central System Humidifiers
Standard 164.2: Methods of Test for Self-Contained Residential Humidifiers
Proposed Standard 164.3: Method of Test for Commercial and Industrial Isothermal Humidifiers

Other Activities

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Include other activities, such as MTG involvement, into this section.


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