Environmental and Green Building Contributions of Open Cell Insulation

For architects, building owners, contractors, and occupants, low-density open cell spray foam insulation has been shown to be a valuable component of green and sustainable building design. This is true due to several properties that help low-density open cell spray foam contribute to achieving very favorable green building designs. The US Green Building Council (USGBC) has developed the LEED® rating system for green buildings which has been recognized as the leading green building standard in this country. The LEED 2009 system is in place until the year 2015 which overlaps with LEED version 4 introduced late in 2013. Since buildings are currently being designed under both systems, credits available will vary based on the version used for a particular building.

Both LEED 2009 and LEED v. 4 place a strong emphasis on reducing the use of fossil fuels and increasing the use of non-polluting renewable energy. Open cell low-density spray foam insulation has been shown to contribute to excellent thermal performance both by contributing to higher, more complete R-values and by reducing air infiltration. In order to receive points in the Energy Optimization category the building must demonstrate a percentage increase in energy savings in accordance with ASHRAE standards. The number of points available depends on the degree of energy savings.

The Materials and Resources category under LEED v. 4 takes a rather different approach to defining the green nature of building products. There are still credits for things like Building Re-use and Construction Waste Management, but the rest of the approach focuses on the full life cycle of those products. The key documentation needed to demonstrate performance under this approach is referred to as an Environmental Product Declaration (EPD). Individual manufacturers or a trade association can prepare specific or generic EPDs for products. In the case of spray foam insulation, architects should request this document from manufacturers, if available, early in the design process to see the specific environmental impacts of the products being considered. The overall intent is to address an emphasis on transparency in the sourcing, ingredient, and manufacturing processes as called for in LEED v. 4. EPDs are intended to provide Life Cycle Analysis based information and details about the products' environmental aspects thus assisting purchasers and designers in making informed comparisons between products. They contain valuable facts about product definition, building physics, the basic material and its origin, product manufacture and processing, in-use conditions, life cycle assessment results, and testing results and verifications. Environmental impacts are assessed throughout the product's lifecycle, including raw material extraction, transportation, manufacturing packaging, use, and disposal at the end of a building's useful life.

From a life cycle analysis standpoint, the high yield of low-density foam makes it more resource-efficient than medium-density foams, requiring fewer raw materials to achieve equivalent thermal performance. Spray foam gets shipped to the jobsite in its unreacted state, so it is more compact and minimizes transportation energy use. Overall, because of the impact on energy use reduction, the average building life cycle savings can be 10 times the initial investment in construction costs. Further, the cost of construction using spray foam can be comparable to buildings not seeking LEED certification, meaning there is little or no “green premium.”

Indoor Environmental Quality continues to be a focus of LEED. The ability to help keep moisture out of construction assemblies allows open cell low-density insulation to safeguard indoor environmental quality. Not only does it help prevent mold and other problems from forming, it doesn't contribute to problems either. The blowing agent for open cell insulation is water so there are no chemicals that can out-gas or create environmental health concerns. Further, some open cell insulation products are compliant with Collaborative for High Performance Schools (CHPS) EQ 2.2 Section 01350 meeting nationally recognized requirements as a low-emitting material in accordance with the California Department of Health Services Standard Practice.

An environmental issue specifically related to spray foam insulations is the required use of a blowing agent to allow the spray foam to be mixed and installed. Materials used as blowing agents are rated based on their Global Warming Potential (GWP) by comparing it to other materials. The reference point for GWPs is the most basic greenhouse gas of carbon dioxide with a GWP rating of 1, the lowest on the index. By comparison, compounds such as nitrous oxide have a 20 year rating in the high 200s while hydro fluorocarbons can have 20-year GWP ratings anywhere between 3,400 and 12,000 depending on its makeup. Obviously, using a blowing agent that has a low GWP rating is a much more environmentally sensitive choice. Hence, since many open cell spray foam insulation uses only water and carbon dioxide as the blowing agents it is rated with the lowest possible GWP rating of 1. Currently, there are several low-density spray foams with this very low environmental impact rating and at least one medium-density spray foam product has it as well. By contrast, all rigid foam board insulation and most medium-density closed cell spray foam insulation need to rely on other blowing agents beside water and CO₂ to produce the desired results. Some can be very high due to their hydro-fluorocarbon (HFC) make up. Of course there is only an environmental impact if it actually gets released from the insulation and into the air, which may or may not happen during installation. Nonetheless, by using open cell low-density spray foam insulation, the lowest possible GWP is assured.

Conclusion

Open cell spray foam insulation is a logical and proven choice for commercial buildings as well as residential buildings. It can reduce upfront insulation costs by taking advantage of its higher yield and ability to provide an air barrier without complex air sealing and finishing procedures and materials. It also makes it easy to address hard-to-insulate areas like floor areas over unconditioned space, complicated framing, etc. It allows architects to explore high performance design options not feasible with other forms of insulation in buildings with complex angles, curves, domes, etc. From an energy standpoint, it has been shown to reduce ongoing energy costs by up to 50 percent by creating an integral air-barrier to minimize air infiltration, while maintaining long-term thermal (R-value) performance. These lower energy requirements can translate to lower HVAC loads and associated equipment costs. From a user perspective, the open cell insulation can improve the indoor environment with more consistent building envelope performance to enhance workplace productivity, performance and occupant comfort. For the architect and design team, open cell low-density spray foam insulation provides a high performance solution that enhances, not limits, design possibilities in commercial buildings. For the building owner, it contributes to a durable, efficient building that can attract higher occupancy rates and building values well into the life of the finished building.

Peter J. Arsenault, FAIA, NCARB, LEED AP, practices architecture, consults on green and sustainable design, writes on technical topics, and presents nationwide on all of the above. www.linkedin.com/in/pjaarch

 

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