Open Cell Spray Foam Insulation in Commercial Buildings
The significance of the air barrier qualities of spray foam insulation has been observed and studied by independent research organizations. The National Research Council of Canada (NRCC) in particular has produced a Wall Energy Rating factor that compared the performance delivered during controlled testing versus the expected performance based on nominal R-values. In these tests, spray foam consistently performed at more than 90 percent of nominal R-value whereas air-permeable, fibrous insulation performed in the range of 35 percent to 65 percent of nominal R-value even with a plastic vapor barrier in place. The study concludes that, without a proper air barrier, insulation alone cannot deliver optimal energy efficiency and comfort. This is why air barriers are now a mandatory provision of energy codes and industry standards such as ASHRAE 90.1. Further, the NRCC study found that low-density open cell foam was the most effective air barrier material out of the insulation and air barrier alternatives studied.
It should be noted that while open cell insulation is an effective air sealant, it does allow water vapor to diffuse through it. Hence, in cold climates (climate zones Marine 4 and higher), a warm side vapor retarder (e.g. vapor retardant paint) will be needed to control vapor diffusion in an exterior wall or unvented attic assembly.
Overall, the use of spray foam insulation, then, goes beyond just R-values and truly addresses a comprehensive way to optimize energy efficiency, making the thermal performance arguments for using open cell spray foam insulation very compelling. It has the highest expansion (100 to 1) of any spray foam insulation product, giving it the ability to flow into and seal cracks and gaps. It has the widest application envelope (temperature and humidity), giving it maximum flexibility to mesh with tight construction schedules and deadlines. It doesn't trap moisture, allowing it instead to escape and thereby dry adjacent materials.
Cost Effectiveness of Open Cell Insulation
Achieving the multiple properties of thermal insulation and air sealing in a single step obviously saves labor and material costs compared to other multi-component assemblies. This is usually seen as the first and most obvious contributor to the cost effectiveness of open cell spray insulation. Some architects and designers working in cold climates (all of Canada and Zones 5 to 8 in the U.S.) may still select medium-density foam thinking that they can also get an integral vapor barrier in the one product. However, the cost difference between the higher-density foam is much greater than the cost of using a simple vapor retarder. There may be other reasons to consider medium-density foam, but the cost effectiveness changes when the density of the foam changes.
Image courtesy of ICYNENE, Inc.
Part of the cost-effectiveness of open cell low-density spray foam insulation is directly tied to its greater yield in comparison to medium-density foam.
From an installation standpoint, open cell low-density foam can be applied in a single continuous application without regard for depth. This is in contrast to most closed cell medium-density insulation that is limited to 2-inch lifts to allow setting and curing. Hence, the open cell installation is quicker and therefore reduces labor cost.
Perhaps one of the biggest contributors to the cost effectiveness of open cell, low-density insulation is its inherently high yield. In this context, yield is a measure of the coverage capability of foam. Low-density foam has a yield that is three to four times higher (100:1 versus 30:1) than medium-density foam. In practical terms, that means that one drum each of the two ingredients needed to create low-density foam covers the same portions of a building that would require three drums each of ingredients for medium-density spray foam. This simple math directly contributes to making open cell low-density foam more cost effective than other alternatives.
Union Wharf, Baltimore, Maryland
The 280-unit Union Wharf apartment development overlooks the Inner Harbor of the Patapsco River in the trendy and historic area of Fell's Point in Baltimore. The $72-million project by The Bozzuto Group incorporates a range of green and modern features, including a 150-foot infinity edge pool, a fitness and yoga center, as well as a cyber cafe. Completed in 2013, Union Wharf complements its historical surroundings and is walking distance to restaurants, bars, parks, museums, theaters, and art galleries.
Photo by Patrick Ross Photography 2013
The Challenge
Situated on a wharf in the heart of Baltimore, the four-story community presented a number of challenges that encouraged architectural firm, Hord Coplan Macht, and Bozzuto Construction contractors and subcontractors, including local spray foam contractor AC&R Insulation, to think outside the box to ensure the building was constructed as envisioned and on schedule.
Given that it was located in a historic area, the site offered contractors very limited options and space for delivery and parking, which also meant that storage space for building materials was at a premium. This prompted Bozzuto Construction to think of new ways to bring their materials onto the site and maintain open access routes for other contractors.
In addition to the site's space restrictions, Bozzuto Construction Company needed to ensure that all teams were able to work efficiently enough to meet their well-thought-out construction schedule. And of course, jobsite safety for all contractors and site visitors was a priority at all times.
Photo courtesy of ICYNENE, Inc.
In order to create an energy-efficient and environmentally sensitive building, Union Wharf was designed to achieve LEED® Silver certification. This required the use of sustainable materials, including durable and energy-efficient insulation, to ensure it met sustainability requirements while also providing the desired thermal performance and occupant comfort.
The Solution
By addressing the multiple challenges that contractors faced, innovation flourished. Contractors were allowed to locate their trailers on floating barges docked in Baltimore's Inner Harbor, which freed up the limited available on-site space. Additionally, the use of portable equipment devices allowing for the movement of construction materials from one floor to the next made sure that subcontractors had the ability to move needed materials without obstructions or impediments. A 150-foot tower crane was also employed to bring materials and equipment into the building which helped ensure there were minimal delays during construction. For any materials that required protection from the cold Baltimore winter nights, temporary heater boxes were fabricated on-site to keep the materials warm.
Union Wharf also included a number of energy-efficient and green building features which Bozzuto Construction also addressed, including the use of low-density spray foam insulation. Local spray foam contractor AC&R Insulation was recruited to install both low-density open cell spray foam insulation and some medium-density spray foam into the 280-unit apartment community. More than 50 sets of foam containers were used throughout the project and the insulation subcontractors ensured that job-site safety was maintained both during the spray application and 24 hours after application. While both of these insulation materials provide thermal comfort and air sealing, they individually offer additional benefits for both the designers and the residents. The low-density open cell spray foam provides excellent thermal performance and sound absorption properties, ensuring a more comfortable, quieter living space without disturbance from neighbors or outside traffic.
The Result
Union Wharf has been one of the most successful and fastest leasing apartment communities that Bozzuto has undertaken in its 25-year history. The community has become a shining example of modern, sustainable living in Baltimore and is on track to achieve LEED Silver accreditation from the U.S. Green Building Council.
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