Piecing Together the Insulation Puzzle

February 1, 2010

Need to get familiar with the basics of mechanical insulation? Lost in the wilds of the Web? Here’s a guide to some of the pieces you can find online to get you started putting the puzzle together.


Need to demystify a spec? R-value? K-value? Mean Temperature versus Ambient Temperature? For those new to mechanical insulation, it can seem confusing. Check out the Glossary at www.insulation.org/techs/glossary.cfm, where you can learn facts such as:

  • Ambient Temperature is the average temperature of the medium, usually air, surrounding the object under consideration.
  • Compressive Strength is the property of an insulation material that resists any change in dimensions when acted upon by a compaction force.
  • Cupped Head Pin is a capacitor discharge welded insulation fastener pin with a fixed washer.
  • C-Value (Thermal Conductance) is a measure of the rate of heat flow for the actual thickness of a material (either more or less than 1 inch), 1 square foot in area, at a temperature difference of 1°F. If the K-value of a material is known, the C-value can be determined by dividing the K-value by the thickness. The lower the C-value, the higher the insulating value.
  • K-Value (Conductivity) is the measure of heat in Btus that pass through one square foot of a homogeneous substance, 1 inch thick, in an hour, for each degree F temperature difference. The lower the K-value, the higher the insulating value. Textbook definition: The time rate of steady heat flow through a unit area of a homogeneous material induced by a unit temperature gradient in a direction perpendicular to that unit area.
  • R-Value (Resistance) is a measure of the ability to retard heat flow rather than the ability to transmit heat. R-value is the numerical reciprocal of “U” or “C,” thus R = 1/U or 1/C. Thermal resistance R-value is used in combination with numerals to designate thermal resistance values: R-11 equals 11 resistance units. The higher the “R,” the higher the insulating value.
  • T-Rating is a rating usually expressed in hours indicating the length of time that the temperature on the non-fire side of a fire-rated assembly exceeds 325°F above its ambient temperature as determined by ASTM E-814 (UL-1479).
  • Wicking is the action of absorbing by capillary action.

Frequently Asked Questions

Another good place to start is the Frequently Asked Questions, or FAQs. At www.insulation.org/techs/faq.cfm, you’ll find the answers to questions like:

How Do You Choose the Right Insulation for the Job?

Answer: Finding the “right” insulation begins with asking some basic questions such as:

1. What is the operating or line temperature of the system your customer needs to insulate?

In general, systems needing insulation can be divided into three temperature ranges:

  • Low Temperature Range (-100°F to 60°F): Refrigeration, cold/chilled water, and commercial heating and cooling systems.
  • Medium Temperature Range (61°F to 600°F): Hot water and steam, power/process piping, ovens, and stacks.
  • High Temperature Range (601°F to 1,500°F): Power generation, turbines, kilns, smelters, exhaust systems, and power piping.

2. Is the system outdoors or indoors or a combination of both?

This will help you determine whether or not the system and the insulation need protection from weather, corrosive atmospheres, water or chemical washdowns, abuse, or other conditions.

3. Is the ambient temperature constant or will it fluctuate?

The answer to this question will guide you in the selection of the appropriate thickness to protect against condensation, heat loss or gain, or other temperature control problems.

Now that you’re clear on the basic facts, you can start putting together an action plan. The following resources can help you get started on your mechanical insulation project.

Mechanical Insulation Design Guide

This comprehensive, living guide at www.wbdg.org/midg was developed by the National Institute of Building Sciences and the National Insulation Association to help users walk through the process of learning about, specifying, purchasing, and installing mechanical insulation. Don’t even know what mechanical insulation is? The Mechanical Insulation Design Guide (MIDG) explains it: “Insulations used for pipes, ducts, tanks, and equipment—primarily used to limit heat gain or loss from surfaces operating at temperatures above or below ambient temperature.”

Trying to figure out what kind of insulation to use and how it needs to perform? MIDG has handy calculators to do some of the work for you, and its Materials and Systems section explains the different kinds of insulation materials: cellular, fibrous, granular, and reflective. It also explains insulation’s physical properties, including thermal conductivity, compressive resistance, and wicking, as well as various covering and finish materials.

The installation section explains everything from project planning to final inspection and maintenance. Resources, a glossary, and case studies round out this invaluable guide to mechanical insulation.

MTL Product Catalog

When you’ve figured out what type of insulation product you need for your job, you can turn to the MTL Product Catalog at www.insulation.org/MTL to compare products from different manufacturers. The MTL Product Catalog offers a one-stop shop for mechanical insulation, with product literature from manufacturers of all types of insulation. Rather than searching various manufacturers’ sites for their literature, you can search this one site by type of insulation product and find what you need. Links to company websites and the Mechanical Insulation Design Guide are also included.

Insulation Specification Information

Need to learn about the differences in insulation materials? The Insulation Materials Specification Guide at www.
, created originally for NIA’s National Insulation Training Program, explains physical and material properties of various insulation materials as specified in ASTM Materials Specifications. NIA’s Technical Information Committee created this unbiased, easy-to-use selection guide to help students look up the physical and material properties of different types of insulations.

The Guide to Insulation Product Specifications at www.insulation.org/techs/gtips.cfm is updated regularly by NIA’s Technical Information Committee. This guide lists ASTM, federal, and military specifications pertaining to the thermal insulation industry. It encompasses both industrial and commercial mechanical insulations, as well as building envelope and fire resistance insulations. Related application and finishing accessory materials also are included.

At www.insulation.org/techs/doe_thickness.cfm, you’ll find the Department of Energy’s Insulation Thicknesses for Economics and Burn Protection, which gives you tables to help you choose economically justified insulation thicknesses based on calculations listed for specific physical and economic parameters.

Need some information on a specific topic? Check out the following resources.

Technical Articles

Over the years, NIA’s flagship publication Insulation Outlook has covered just about every topic you could think up for mechanical insulation. At www.insulation.org/articles/, you can search the article database by technical topic, keyword, author, issue, and date. The search page also offers a handy list of Quick Links to popular topic searches, including Acoustics, Basic Understanding, Condensation Control, Contractor/Distributor Services, Corrosion, Energy Savings, Environmental Control, Fabrication, Fire Stopping/Fire Protection, Health and Safety, Material Selection, Metal Building Insulation, Personnel Protection, Refractory, and Steam.

Offline Resources

NIA’s Bookstore at www.insulation.org/products contains many resources for all levels of knowledge about mechanical insulation, including the National Commercial and Industrial Insulation Standards Manual.

You can also find out everything you need to know about the insulation in your facility and how much money you could save by maintaining or upgrading it by calling a Certified Insulation Energy Appraiser in your area. You can find a list at www.insulation.org/training/ieap/appraisers.cfm. Those in the insulation industry can find out how to become a Certified Insulation Energy Appraiser at www.insulation.org/training/ieap/.

These resources should help you answer your mechanical insulation questions and give you enough information for whatever project you have in mind. For more about the general value and benefits of mechanical insulation, check out the Mechanical Insulation Marketing Initiative website at www.insulation.org/mimi. Several documents there outline mechanical insulation’s uses and role in energy efficiency.