An Introduction to Fiberglass Metal Building Insulation

In order to meet the stricter insulation requirements of the last few code cycles, double-layer filled cavity systems have become standard for metal buildings. The two most common include liner systems and long tab banded systems. Liner systems are private labeled and must meet ASHRAE requirements in order to be defined as a liner system (Ls). Long tab banded systems are usually non-proprietary and meet the specifications of a filled cavity (Fc) system. The photo above shows a long tab banded system while the photo further down in the article shows a liner system. One key difference in these two types of systems is that certain banded liner systems also qualify as OSHA-compliant fall protection systems. Most long tab banded systems typically do not offer fall protection. Both options fulfill the metal building insulation U-value code requirements, so the system selected boils down to budget and preference.

by the National Insulation Association (NIA) Metal Building Laminator Committee

Metal building systems (also known as pre-engineered metal buildings) have long been favored for their strength, durability, and cost-effectiveness. However, one crucial aspect that often goes unnoticed is the insulation system. Proper insulation is essential for reducing energy consumption, maintaining comfortable indoor temperature, and ensuring the longevity of these metal structures. Among various insulation materials, fiberglass insulation stands out as a reliable and cost-effective choice. In this comprehensive article, we will explore why fiberglass insulation remains relevant and efficient for metal building systems.

Evolution – Where It Began

The evolution of fiberglass insulation use has progressed significantly since its inception, transitioning from basic single-layer applications with low R-values to sophisticated, multilayered systems that offer enhanced thermal performance and energy efficiency. Initially, fiberglass insulation was available in the form of batts or rolls, designed to be sandwiched between framing members and the roof or wall panels. While this is still a primary method of insulating a metal building, today's energy codes have required the development of different solutions.

Over time, advancements in manufacturing and material science have led to the development of higher density fiberglass insulation products and more efficient installation techniques. Innovations include the introduction of multilayered systems, in which the installer utilizes two layers of fiberglass to further enhance performance. Modern fiberglass insulation systems often incorporate vapor barriers, reflective coatings, and other materials to address issues such as moisture control and radiant heat transfer. These systems are designed to maintain their R-value over a wider range of temperatures and conditions, ensuring consistent performance throughout the year. Unlike the single-layer fiberglass mentioned in the previous paragraph, these systems utilize the framing cavity, filling it with fiberglass to improve thermal performance.

In a banded liner system, large panels of fabric or other vapor retarder material is supported by banding and installed underneath the purlins. Multiple layers of unfaced and/or faced (air barrier) metal building insulation is installed on top of the supporting fabric and banding filling the cavity. The purlins are covered by the fabric vapor retarder in a banded liner system.

Code Requirements

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and the International Code Council (ICC) play crucial roles in developing energy codes in the United States. ASHRAE develops standards like ASHRAE Standard 90.1, which sets minimum energy efficiency requirements for commercial buildings and large multifamily housing. This standard is continuously updated through a consensus process involving industry experts, government representatives, and other stakeholders. The ICC publishes the International Energy Conservation Code (IECC), which includes energy efficiency requirements for both residential and commercial buildings. The IECC is updated every 3 years through a public consensus process, allowing for broad participation from various stakeholders. These organizations ensure that energy codes evolve to improve energy efficiency, reduce environmental impact, and promote sustainable construction practices.

Code agencies continue to value and require the properties of fiberglass insulation as a viable solution for achieving energy efficiency goals. The great news is that fiberglass insulation systems are able to meet all current energy codes.

As states adopt new codes, you will begin to see more requirements around air infiltration. This topic is becoming more relevant with each new code cycle. You should know that fiberglass insulation systems have been put to the test and perform to the current code requirements.

Benefits

Here are some of the benefits of fiberglass insulation and why it is a practical choice for metal buildings.

•  Fiberglass insulation is budget friendly, making it an attractive option for metal building projects. Although it is budget friendly, you are not sacrificing performance.
•  Fiberglass stands out for its low installed cost per R-value. R-value measures the material's thermal resistance.
•  With the shortage of skilled labor and escalating labor costs, fiberglass insulation could be considered “user-friendly,” with its specific product markings and the general ease of handling.
•  Its flexibility allows it to fit into irregular spaces (allowing for a filled cavity). The flexibility and ease of handling helps minimize installation costs.
•  Its durability is almost unprecedented. Unlike some materials that are prone to absorbing moisture, fiberglass insulation remains unaffected. It does not promote mold or mildew growth, ensuring a healthier indoor environment. Properly installed fiberglass insulation can last for decades without significant degradation, underscoring its cost-effectiveness over time.

Fiberglass insulation can contribute significantly to achieving, or exceeding, energy efficiency goals. The thermal performance of fiberglass insulation effectively reduces heat transfer, keeping indoor spaces warmer in winter and cooler in summer. A metal building system’s insulating properties help maintain a consistent temperature, enhancing occupant comfort, and can lead to reduced heating and cooling costs.

Tested

Metal building insulation must be tested for a myriad of safety and performance characteristics. The American Society for Testing and Materials (ASTM) is a primary agency for the development of standards that help enhance the performance of products and foster the confidence in those products that you, as both a consumer and/or architect/engineer/specifier, buy and use.

A couple of examples are:

•  ASTM E84 is the “Standard Test Method for Surface Burning Characteristics of Building Materials.” This standard should be used to measure and describe the properties of materials, products, or assemblies in response to heat and flame under controlled laboratory conditions. Fiberglass by nature is noncombustible; however, when you add a facing and some sort of adhesive material, it is important to test the final produced product.
•  ASTM C991 is the “Standard Specification for Flexible Fibrous Glass Insulation for Metal Buildings.” This specification covers the classification, composition, and physical properties of flexible fibrous glass insulation for use in metal building roofs and walls.

NIA 404 Standard

NIA and its Metal Building Laminator Committee* understand the importance of safety and performance characteristics related to the products we provide the market. The committee meets regularly and recently published a revised standard, “NIA Certified Faced Insulation Standard (Version 404.2–2024).” The specifics of the standard can be found at 404.2–2024

Metal building systems continue to be a popular choice for the one- and two-story commercial and industrial construction markets, since these projects require materials that are engineered to keep pace with constantly evolving design concepts and aggressive energy codes. As a committee, we are committed to providing a fiberglass insulation solution that meets the industry safety and quality requirements, as well as the most stringent energy efficiency codes.

This series of articles highlights the various aspects of metal building insulation systems and their
benefits. If you need more information, or have questions on utilizing certified faced fiberglass insulation solutions on your next project, reach out to NIA and our Metal Building Laminator Committee members at membership@insulation.org.

* A committee that meets within NIA, which is a not-for-profit service organization dedicated to meeting the needs of mechanical and specialty insulation contractors, distributors, fabricators, manufacturers, and metal building insulation laminators.

This article was written by a task force from the National Insulation Association’s (NIA’s) Metal Building Laminator Committee. The member companies that make up this committee are:

•  Bay Insulation Systems, Inc. (www.bayinsulation.com)
•  DAW Construction Group, LLC (www.dawcg.com)
•  The E.J. Davis Company ( www.ejdavis.com)
•  International Insulation Products, LLC ( www.iiproducts.com)
•  L&L Insulations ( www.llinsulation.com)
•  Silvercote, A Service Partners Company ( www.silvercote.com)
•  Therm-All, Inc. ( www.therm-all.com)

You can learn more about metal building insulation at www.insulatemetalbuildings.org. Read the newly revised NIA Certified Faced Insulation® Standard (Version 404.2–2024) at www.insulation.org/mblstandard. To learn more about NIA’s Metal Building Laminator Committee, or to join, email membership@insulation.org. For questions or comments about any of the articles, please email publications@insulation.org.

This article was reprinted with permission and was originally published in the September 2024 issue of Insulation Outlook magazine, copyright © 2024 National Insulation Association (NIA), all rights reserved. Since 1953, NIA has been the voice of the insulation industry and is dedicated to keeping the commercial and industrial insulation industry up to date on the latest industry trends and technologies. For more information, visit www.insulation.org or email niainfo@insulation.org. Learn more about metal building insulation at www.insulatemetalbuildings.org.

About The National Insulation Association

NIA is a not-for-profit trade association representing both the merit (open shop) and union contractors, distributors, laminators, fabricators, and manufacturers that provide thermal insulation, insulation accessories, and components to the commercial, mechanical, and industrial markets throughout the U.S. Since 1953, the northern Virginia–based association has been the voice of the insulation industry and is dedicated to keeping the commercial and industrial insulation industry up to date on the latest industry trends and technologies. For more information, visit www.insulation.org.