Building owners today are much more environmentally conscious than they were just a few years ago. There are very clear building owner trends toward using "green" construction products, such as glazing products that reflect the sun, automatic lighting products, lighter colored (i.e. "cooler") construction products including roofing and cladding materials, and products that improve energy efficiency of the structure. And while polyisocyanurate insulation has long been on the list of products that can help improve a structure's energy efficiency, it can now be placed squarely on the list of "green" construction products, due to recent manufacturing developments. Polyisocyanurate foam insulation (polyiso) has long been the choice for commercial roofing applications. In fact, polyiso roof insulation represents over 60% of all insulation used in new roof construction and at least 40% of all insulation used in re-roofing applications, according to the Polyisocyanurate Insulation Manufacturers Association (PIMA). Furthermore, PIMA reported that in 1999, 4.5 billion board feet of polyiso were used as both wall and roof insulation, clearly establishing the confidence of the construction industry for its energy efficient productivity. To make polyiso even more appealing many manufacturers have qualified in participation of various Energy Starr programs. Polyiso foam insulation is a mix of polyisocyanurate and polyurethane polymers that form a closed cell structure. During manufacture, the liquid foam forming mix is deposited onto a continuously moving facing, where it expands, then the upper facing is applied. The combined form and facer "sandwich" then goes through a heated conveyer press where the expansion of the foam and the integral bond to the top and bottom facer sheets is completed. The preference for polyiso insulation among commercial building owners has not been without its challenges, the most notable being the Montreal Protocol which in March of 1985 adopted requirements to protect the ozone layer. Among other things, the Montreal Protocol required that polyisocyanurate foam insulation manufacturers eliminate harmful ozone depleting chemistry which first affected the use of CFCs. By 1994, the polyiso industry had reformulated its products around a new blowing agent, HCFC141b, a compound with only about 10% of the ozone depleting potential of CFC-11, which had been used as a blowing agent since the introduction of polyiso in the 1970s.
In keeping with Montreal Protocol requirements, however, all HCFC141b must be eliminated by January 2003, so that polyiso is manufactured with zero ozone depleting blowing agents. One of the concerns stated by the National Roofing Contractors Association (NRCA) at this year's convention is that there doesn't seem to be a clearly defined chemistry transition for elimination of HCFCs as there was for the elimination of CFCs to HCFC141b. Very few polyiso manufacturers are on the fast track for compliance, and only a few to date have fully met the rigid new standards. Atlas Roofing Corp. led the industry and was the first polyiso manufacturer to introduce a plant conversion dedicated to HCFC-free technology, shifting its blowing agent from HCFC141b to a hydrocarbon type chemistry. To date, Atlas has converted two additional plants, constructed another, and is finishing conversion on five additional facilities, which is expected to be completed within 18 months. Rick Gelatka, marketing services manager for Atlas Roofing Corp., says that his company is phasing-out the use of HCFC141b earlier than required and is seeing benefits for doing so. "We're now seeing HCFC-free requirements in many commercial specifications and we've seen a real trend for building owners becoming much more environmentally conscious about the products that they use on their buildings." New technologies are not immediately embraced by an industry that relies on testing approvals and proven track records. However, the good news is that there are currently two years of field-tested applications from the earliest manufacturer, Atlas Roofing, as well as additional field performance data from their first prototype roof applied in 1995 and subsequent installations. Material characteristics and performance ratings of HCFC-free polyiso products are equal to or better than polyiso with HCFCs. Adhesion, compression strength, fire ratings, moisture vapor transmission, water absorption and R-values have proven test results. The data in Table 1 represents typical physical properties of this new HCFC-free polyiso insulation.
While conversion of polyiso from HCFC141b to new blowing agent technology has been going on, the U.S. Green Building Council has developed the "Green Spec" and polyiso insulation is now listed as a "green" building product. And in fact, polyiso can be considered "green" for several reasons:
The U.S. Green Building Council announced the first standard for green buildings. Its LEED - Leadership in Energy and Environmental Design - Building Rating System is a voluntary, consensus-based, building rating system based on the environmental performance from a "whole building" perspective over a building's life cycle, providing a definitive standard for what constitutes a "green" building. The LEED program has identified five specific environmental goals:
In conclusion, the new generations of HCFC-free polyiso rigid board insulation meet the requirements for the LEED program and for the first time are considered a "green building" product. The Montreal Protocol was the motivation to the industry for making polyiso more environmentally friendly. However, programs like LEED also have incentives for working with green products. Companies like Atlas Roofing and others continue to lead the industry in research and development of new technologies. With the 2003 Montreal Protocol polyiso conversion deadline a short time away, building owners and specifiers are well advised to keep aware of trends. About the Author |
