Mechanical Insulation Design Guide: A User’s Guide to the Power of Insulation

March 1, 2021

Whether you are looking for a better understanding of insulation or need to design or specify a complex insulation system, NIA’s Mechanical Insulation Design Guide (Design Guide) is a comprehensive, well-organized, and easy-to-use resource. Created to assist the novice and seasoned user alike in the design, selection, specification, installation, and maintenance of mechanical insulation, the Design Guide is continually updated with the most current and complete information. In the coming months, the Design Guide will move to NIA’s website from its current location on the National Institute of Building Sciences’ Whole Building Design Guide site.

The Design Guide leads users naturally through the engineering design process, including the following steps:

  1. Identify the need or define the problem,
  2. Gather pertinent information,
  3. Identify possible solutions,
  4. Analyze and select a solution, and
  5. Communicate the solution.

To assist insulation designers, the Design Guide is divided into sections that answer five basic questions:

  1. Why am I insulating this?
  2. What am I insulating?
  3. Where am I insulating, and what are the ambient design conditions?
  4. What materials and systems are best for this job?
  5. How much will this cost, and what is the best way to implement this solution?

This article provides an overview of the Design Guide’s contents.

Design Objectives

This section helps answer the questions why, what, and where. It discusses the potential design objectives and considerations for mechanical insulation systems. An insulation system can be designed for specific objectives, such as energy conservation or condensation control, or for multiple objectives. To select the right insulation system, you need a clear understanding of the objectives for the finished system.

The most familiar uses of insulation are to reduce heating and cooling loads, and to control noise in building envelopes. However, mechanical insulation is primarily used to limit either heat gain or heat loss from surfaces operating at temperatures above or below ambient temperature. It also may be used for the following design objectives.

Condensation Control

The design problem is best addressed as two separate issues: 1) avoiding surface condensation on the outer surface of the insulation system, and 2) minimizing or managing water vapor intrusion. This section of the Design Guide includes helpful tables on insulation thickness required to prevent condensation, design weather data for condensation control, as well as a design example using an outdoor chilled water supply piping serving a commercial building expansion in Tampa, Florida.

Energy Conservation—Financial Considerations

Mechanical insulation is commonly used to reduce the rate of unwanted heat loss or gain from/to mechanical systems and equipment. There are three primary reasons:

  • To minimize the use of scarce natural resources and their financial expense,
  • To minimize the greenhouse gas emissions associated with energy usage, and
  • To maximize return on investment (ROI) and minimize the life-cycle costs of projects.

Examples in this section include calculating ROI and a simple payback period. The section also focuses on sustainability and green buildings, providing a table on carbon equivalents for various greenhouse gases.

Fire Safety

Mechanical insulation materials are often used as a component in systems or assemblies designed to protect buildings and equipment from the effects or spread of fire (i.e., fire-resistance assemblies). They can include walls, roofs, floors, columns, beams, partitions, ducts, joints, and through-penetration fire stops. This section of the Design Guide highlights relevant codes and standards, and it defines terms such as noncombustible.

Freeze Prevention

Insulation can prolong the time required for freezing or prevent freezing if flow is maintained at a sufficient rate. This section includes information on calculating time required for water to cool in a pipe with no flow and also provides an informative table with time to cool water to freezing based on nominal pipe size and insulation thickness.

Personnel Protection—Safety

In many applications, insulation is provided to protect personnel from hot or cold piping and equipment. In addition, there are safety and comfort concerns related to personnel working in high-temperature, high radiant exposure locations. This section provides relevant standards as well as information related to indoor and outdoor applications, retail considerations, jacketing materials, and more.

Process Control

Insulation systems are often designed to minimize variation of temperatures in processes. This section highlights several common examples, including insulation on tanks or vessels and the use of insulation to minimize temperature change of a fluid from one location to another.

Noise Control

Insulation is often specified on mechanical systems and equipment to control noise within buildings and other facilities. Topics in this section include noise radiating from pipes, noise from ducts, and breakout noise.

Other factors to consider when designing a mechanical insulation system include:

  • Abuse resistance,
  • Corrosion under insulation,
  • Indoor air quality,
  • Maintainability,
  • Regulatory considerations,
  • Service and location, and
  • Service life.

Materials and Systems

In most cases, one can choose from multiple types of mechanical insulation materials for any given application. The Materials and Systems section discusses material categories and provides links to additional information and to the material manufacturers. The list changes continually as existing products are modified, some products are phased out, and new products are developed.

In addition to commonly used materials, this section also describes important performance or physical properties for insulation materials and associated weather barriers, vapor retarders, and finishes.

The Design Guide categorizes mechanical insulation materials into the following major types (listed alphabetically):

  • Cellular,
  • Fibrous,
  • Flake,
  • Granular, and
  • Reflective.

Selecting an insulation material for a particular application requires understanding the physical properties associated with insulation materials. This section provides an overview of 13 properties, from alkalinity to wicking. It also provides links to specific material data, including submittal sheets. (Note: Additional links are provided in the Resources section, described on page 34.)


Installation of mechanical insulation is typically managed by experienced contractors who specialize in the mechanical insulation sector of the commercial, industrial, and HVAC sectors of the construction industry. Within this section, the Design Guide covers pre-work considerations, securing methods, finishes, special considerations, and inspection and maintenance.

NIA has launched an on-demand training portal for easy access to our educational offerings. Available are 33 videos, including NIA’s webinars, the Mechanical Insulation Installation Video Series (in English and Spanish), and others covering topics like manufacturer’s recommendations, leadership, installation, health and safety, and more. The complete list is available at

Design Data

This section of the Design Guide contains information on estimating heat loss and gain, controlling surface temperature, determining dimensions of standard pipe and tubing insulation, and estimating heat loss from bare pipe and tubing. Users also will find seven useful tables covering a range of design-related concerns and calculations.


The mechanical insulation specification is an important but often overlooked part of the overall design process. Good specifications should communicate the design objectives, materials, thicknesses, finishes, securements, and other systems requirements. Specific topics covered in this section include formats, methods of specifying, scope of work, specification language, coordination with drawings and other specification parts, as well as ensuring adequate clearance for proper insulation installation and application.

Education on Demand

If you are looking for basic insulation education, the online Mechanical Insulation Basics (formerly known as “Mechanical Insulation Education and Awareness Campaign E-Learning Modules”)series is an excellent place to start. Available anytime, it contains 5 different e-learning modules, ranging from 15 to 35 minutes in length. The content of each module is fully outlined, so your team can choose how to pair them with your company’s existing training program. In 2 hours, new hires and office support staff will have a great foundation to better understand the industry so you can explain your company’s role within it. Subjects include:

  • The principles of understanding energy,
  • What the various types of insulation are,
  • How insulation works,
  • How to design an insulation system and specify materials,
  • How the insulation calculators work and are designed for the unique needs of insulation contractors and engineers, and
  • How to oversee maintenance to keep a facility running smoothly.

The self-paced series will be available at They are being transferred from the National Institute of Building Sciences’ website and will be housed on NIA’s website in the coming months. The series also provides data on the science behind insulation, helps specifiers and system designers construct insulation systems, explains design considerations, and reveals practical data and case studies outlining potential energy savings. The course is a prerequisite for the Understanding Mechanical Insulation learning program, and NIA offers professional development hours (PDHs) for its completion.

Insulation Calculators

The Design Guide offers access to eight easy-to-use insulation calculators related to various design objectives.

  • Condensation Control Calculator—Horizontal Pipe estimates the thickness of insulation required to avoid condensation on the outer surface of an insulated horizontal steel pipe.
  • Energy Calculator for Equipment (Vertical Flat Surfaces) estimates the heat flow through a vertical flat steel surface (typical of the sides of a large steel tank containing a heated or cooled fluid).
  • Energy Calculator for Horizonal Piping estimates the heat flow through horizontal steel piping.
  • Mechanical Insulation Financial Calculator provides a convenient way to estimate the financial returns related to investments in mechanical insulation. Options include Simple Payback in Years, Internal Rate of Return (IRR or ROI), Net Present Value (NPV), and Annual and Cumulative Cash Flow.
  • Time to Freezing for Water in an Insulated Pipe Calculator estimates the time for a long, fluid-filled pipe (no flow) to reach a freezing temperature.
  • Personnel Protection Calculator for Horizontal Piping estimates maximum contact exposure time with the outer surface of a horizontal pipe insulation system based on the potential for contact burn injuries.
  • Temperature Drop Calculator for Air Ducts estimates the temperature drop (or rise) of air flowing in a duct.
  • Temperature Drop Calculator for Hydronic Piping estimates the temperature drop (or rise) of air flowing in a pipe.

Resources, Case Studies, Glossary, and Update Summary

The Design Guide links to resources from NIA; American Society of Heating, Refrigerating and Air-Conditioning Engineers; American Society for Testing and Materials; National Fire Protection Association; Underwriters Laboratories; manufacturers by product type; and many more sources for information. Case studies, a glossary, and a summary of update notes also are included.

Hosted by NIA, the Voice of the Insulation Industry

The Design Guide was developed by the National Institute of Building Sciences and NIA with contributions from 15 organizations, 60 manufacturers and fabricators, and 12 contractors, as well as the involvement of more than 100 individuals. The Design Guide is an unbiased, comprehensive, living document to assist engineers, specifiers, facility owners, insulation contractors, and other users of mechanical insulation systems with a wide range of industrial and commercial applications.

NIA is committed to being the insulation industry’s leader in education. Through access to this comprehensive guide, NIA continues to pave the way to improve the quality of insulation systems nationwide. Results show the value and ROI of having properly engineered, installed, and maintained mechanical insulation systems that conserve energy, reduce emissions, improve processes and productivity, reduce life-cycle costs, and protect personnel.

The Design Guide can be accessed at in the coming months.