Getting Specific in Your Specification

In terms of HVAC systems, building codes address requirements pertaining to heating, ventilating, and air conditioning. They can specify specific insulation requirements for given applications, establish air-filtration requirements, and even set the standards for energy efficiency. Please keep in mind that this is not an exhaustive list by any means. There are a large number of building codes and requirements, and you can find that information updated regularly on websites like the International Code Council (ICC) website, or on the Construction Market Data (CMD) website.

The ICC publishes the International Codes® (or I-Codes®). The I-Codes express the minimum safeguards for homes, schools, and office buildings. As described on their website, “The I-Codes are a complete set of comprehensive, coordinated building-safety and fire-prevention codes.”

Similar to the ICC, the CMD’s website also includes a national list of state and local building codes. This includes detailed information regarding building codes for all 50 states, major cities, and even some counties. In addition to information on codes and amendments, both the ICC and CMD provide contact information for up to 17 authorities having jurisdiction (AHJs) in each market as well as the contact information for local utilities.

Even though building codes are the most effective, least expensive way to protect public health and safety, reduce building energy consumption, and improve workplace comfort, codes can accidentally be missed by both contractors and engineers. This can simply be from ignorance about how the insulation was tested or the proper way to install the insulation, or it can be more intentional in an effort to save time, or money, or both. While saving time and money can often be tempting, intentionally neglecting codes for any reason is highly risky and potentially illegal. Additionally, when an insulation is not installed to code, it voids the manufacturer’s warranty – thus not only is correct installation critical in terms of safety and performance, but also in terms of product performance accountability.

Since manufacturer’s installation guidelines are based largely on replicating how the material was tested, it is critical for engineers to help contractors install the material properly, by including key installation details in the specification. For example, if we look at bubble wrap insulation, the installation method is critical to achieving the manufacturer’s published R-values and maintaining code compliance.

Independently, bubble wrap insulations tend to have relatively low thermal resistance properties (R-value) when measured  by thermal test methods such as ASTM C518 or C177 that are commonly accepted by code bodies(1). The reason for this is that these insulations largely depend on a perfectly sealed dead air space and spacings on one or both sides of the reflective surface to boost the thermal performance to achieve the published R-values (1). In this example, there are two critical things engineers should be aware of prior to specifying bubble wrap insulation.

First, many codes, including the 2015 International Mechanical Code (IMC)(4) and the 2013 ASHRAE 90.1 Energy Standard (3), and test methods, like the ones mentioned above, specifically prohibit using dead air space and the thermal resistance of the film when quantifying or measuring the thermal performance of an insulation.  As such, it is crucial that specifiers not only know how the material was tested, but also understand whether or not those test methods for the insulation meet the requirements of the code.  When bubble wrap suppliers count the insulating value of the air gap and the film when measuring their R-values, they are able to promote the same insulation product regardless of whether R-4.2, R-6, or R-8 insulation values are required. This is because achieving a higher R-value with bubble wrap simply requires increasing the dead air space between the duct and the insulation(2).

Which brings us to our second critical detail: if the insulation is installed without the dead air space or spacers, then it will fail to meet code and the specified thermal performance(1). Thus, even if the material itself complies with the code during testing, incorrect installation could negatively impact both compliance and performance(1).

In this example, if spacers aren’t specifically listed as a requirement for the application and thus are accidentally skipped during the installation, then the R-value of the material can drop substantially, potentially falling below an R-3(1). Given the dramatic difference in R-values simply from using the incorrect installation technique, it is important for engineers to clearly state how the material should be installed for the application to ensure that the insulation system performs as anticipated.

To find out more information about material specifications and test methods, you can visit the ASTM website [LINK:], or, if you would like more information about how to properly install a specific insulation, the North American Insulation Manufacturers Association (NAIMA) hosts installation guidelines on their website, Additionally, Johns Manville offers dedicated technical specialists who can walk you through various code standards and help you ensure that your specification complies with the building codes for the application.

1)      Insulation Facts #61, “Facts About the Performance of Reflective Bubble Pack Insulations in Duct System Applications.” NAIMA

2)      Martin Holladay, GBA Advisor. “Stay Away from Foil Faced Bubble Wrap.”

3)      ANSI/ASHRAE/IES Standard 90.-2013 (I-P) Edition, Page 80, Footnote(a) 

4)      2015 International Mechanical Code, Page 74, Section 604.7 (Identification)  See attachment