Selecting the ideal insulation for greater energy efficiency, aesthetics and resiliency of metal buildings can be challenging for specifiers. Following is a guide with some key considerations that can help to ensure that many of the important aspects are covered with your client, that expectations are set and the right decisions are made to meet goals for the project, including the timeline for construction. Insulation is integral to the building envelope and a happy client will likely result in future business.
Selecting the Right Insulation for Metal Structures
Steps to determine the factors to meet code and other certifications:
• Which path will you use to meet the code: prescriptive or performance method?
Building codes determine the minimum R-value or U-value required for your project; the path gives you flexibility to choose how you meet the required R-value and other requirements for your zone.
• What type of structure(s) are you working with?
Insulation and products ideal for application on block walls are generally much different than insulation systems that work well for pre-engineered and structural steel; some structures may have insulation built into the exterior sheathing, such as metal panels.
• Who will be involved in the product selection?
A BIM process early in the planning is a good way to collaborate with contractors, engineers and other consultants to determine the best overall building materials for a resilient building including the insulation.
• Is product availability a key issue for the on-time completion of this project?
Supply chains and product availability are still an issue as we slowly recover from the pandemic; there are viable alternatives on the market that have stock available.
• What green building attributes are required?
Recycled content, indoor air quality, net zero energy efficiency, life cycle analysis, zero carbon emissions.
Steps to Ensure Quality, Reliability and Resiliency:
• How long has the manufacturer been in business and do they provide a sufficient warranty?
A limited one-year warranty is common; a 10-year warranty will often be offered by higher quality, more resilient systems.
• Does the product Flame Spread Rating meet code and insurance requirements?
Any exposed insulation that serves as a wall or ceiling is generally required to have a Class A fire rating with F.S.< 25 and S.D.< 50.
• How do you plan to seal the building?
The exterior of the building should be air sealed properly and all joints and penetrations of the insulation system should also be taped or sealed securely to create an effective vapor barrier.
• Will the product withstand any extreme environments within your building?
Some adhesives cannot withstand extreme temperatures so these products cannot be in close proximity to high heat or extreme cold environments. Knowing what the space will be used for will help determine the right insulation.
• Is the product available in a width that fits purlins, bar joists or wall girts of the building?
Especially in retrofit applications, determining the width between metal purlins, joists and girts is helpful for cost projections. Considering a material that can fit easily around existing wiring, utility boxes, ducts and skylights will help you decide on the right insulation. When there are several penetrations across the building, an ideal system will be flexible, easy to cut, easy to fit and seal.
• Does the product have an attachment system that provides a strong connection and ease of installation?
Stick-pin or banding systems require a two-step installation and these systems are prone to loosen over time. Mechanical fastener systems can be installed in one-pass and offer a much stronger connection with some fasteners holding up to 60 pounds of backloaded insulation. Using mechanical fastener systems has proven to provide better performance for a longer life and therefore improved resiliency of these buildings.
• If higher R-value is desired to save monthly utility costs, does the product provide continuous insulation (CI) with an advanced low-E reflective surface(s)?
A reflective insulation system installed with mechanical fasteners will significantly reduce radiant heat transfer. This can lower monthly utility costs by up to 30% to 40% during summer and improve comfort for those living and working in the building.
Common options for pre-engineered metal buildings:
- Vinyl-faced fiberglass insulation
- Open- or closed-cell spray foam
- Reflective bubble insulation
- Loose cellulose insulation
- Rigid foam board insulation—exterior roofing assembly
- Fabric liner insulation
Jan Bradford is director of architectural sales at Fi-Foil Co., Auburndale, Fla. For more information, visit www.fifoil.com.