Mechanical Systems Insulation
ASHRAE Technical Committee 1.8

Scope of TC 1.8

TC 1.8 is concerned with the application and performance of thermal and acoustical insulation systems used on pipes, tanks, equipment and ducts.


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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This TC is responsible for the following chapter in the Fundamentals Volume:

Insulation for Mechanical Systems
This chapter deals with applications of thermal and acoustical insulation for mechanical systems in residential, commercial, and industrial facilities. Applications include pipes, tanks, vessels and equipment, and ducts.

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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.

 The Research Subcommittee writes and proposes research projects to ASHRAE’s Research Acceptance Committee (RAC).  One of these has recently been accepted by RAC whereas two others are still being discussed by the TC 1.8 Research Committee.  Summaries of these activities follow.

This committee has the following active research project: Feb 2020 meeting, updated April 23, 2020

 1703-TRP, “Performance of Vapor Retarder Systems Used on Mechanical Insulation” – This research project has been approved by ASHRAE’s Research Acceptance Committee (RAC) and has been sent out for bid.    This research project is being co-sponsored by TC 10.3: Refrigerant Piping, Controls, and Accessories.  It is scheduled to be awarded to the successful bidder later in the year.

The Work Statement includes lots of detail and can be accessed separately.  However, its Executive Summary is as follows:

Preventing the passage of moisture in ambient air into the insulation of mechanical piping and equipment operating at below ambient temperature is critical in assuring the long-term function of the insulation and service life of the piping and equipment.   The performance of vapor-retarder (VR) materials such as flexible vapor retarders, tapes and mastics, as well as low permeability insulation materials requiring no separate vapor retarder, is verified and published as technical data by manufacturers.  However, the performance of these component materials as installed systems has not been tested and therefore system performance data is not available to the designer. For purposes of this project, low permeance insulation with sealed joints is considered a vapor retarder system.


It is the aim of this project to develop this vapor retarder system performance data to make it available to designers of insulation for mechanical systems operating at below ambient temperatures.  The system performance data obtained will make it possible to predict the water gain over time, and therefore the life expectancy, of the insulation system based on the rate of moisture vapor passage through an installed vapor retarder system.  Water vapor migration and condensation in mechanical insulation on below ambient surfaces can particularly be a problem when located in unconditioned spaces for long durations, i.e., up to twenty-five years.  


The theme of the ASHRAE Research Strategic Plan (RSP) is “Navigation for a Sustainable Future”.  Thermal Insulation, including mechanical insulation for pipes, ducts and equipment, is a distinct and critical part of the equation for sustainability and energy efficiency.  In the context of the RSP, this research project aligns well with two of the 2014 goals-  Goal 1: Maximize the actual operational energy performance of buildings and facilities, and Goal 9: Support the development of improved HVAC&R components ranging from residential through commercial to provide improved system efficiency, affordability, reliability and safety. 


This research is directly related to sustainability in the context of maintaining the efficiency, and assuring the longevity, of thermal insulation systems.  Insulation of new mechanical systems provides an immediate, significant energy efficiency boost and very quick payback.  Minimizing moisture ingress into the system to offset or negate the energy efficiency gains is critical in efforts to achieve ever-higher levels of sustainability.      

The results of this research will be included in Fundamentals Chapter 23, Mechanical Systems Insulation.   and in Refrigeration Chapter 10, Insulation Systems for Refrigerant Piping. A research report will be generated and presented at a future ASHRAE conference. 


The ultimate application of the results will be in the design and installation of the vapor retarder system to help assure optimum performance and longevity of the mechanical insulation system of which it is a part. The results will establish system performance.  Applying this knowledge, designers can make informed decisions on the insulation vapor retarder system design. 

The committee is working on the following RTARs:

RTAR 1871: Hygrothermal Modeling of Below Ambient Pipe Insulation Systems in Both Buildings and Refrigeration Systems

At the direction of RAC, this proposed research project is on hold until significant data has been generated by WS-1703.  The Executive Summary for RTAR 1871 is below:

This analytical project would mathematically model, using hygrothermal algorithms, a below ambient pipe with several different pipe insulation systems, at a fixed pipe diameter, inputting hourly weather data from each of several different cities, for a long duration.  Output would be the predicted water vapor ingress, with condensation, into the pipe insulation system and the pipe insulation’s thermal performance with that moisture.  The generation of this new information, linking water vapor permeance to pipe insulation performance over time, would be a unique and valuable asset to those designing and specifying below ambient pipe insulation systems.

RTAR 1862: Determining the Impact of Sealing Hot Insulation System Metal Jacketing Joints on Water Intrusion and Retention in the System

TC 1.08 is actively working on developing a Work Statement for this RTAR.  Chair Jim Young took input from the February 2020 meeting and will use that to write a Work Statement.  What we have to date for an Executive Summary is as follows (and this is subject to change in the future):

Lab research is proposed to determine if using sealant on the joints of hot insulation system metal jacketing will help or harm the accumulation of water in the insulation system.  This topic has never been studied and has immediate and significant value to the members of ASHRAE who are specifiers, engineers, manufacturers, or owners of these insulation systems.


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.

This TC is not cognizant for any standards at this time.

Other Activities

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


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