What does COP 21 mean for building professionals?

Primer on polyiso
A paper from the global consulting group McKinsey & Company entitled “Pathways to a Low Carbon Economy” highlights insulation as the product that can provide the greatest return and offer the most carbon abatement. As designers, architects, construction professionals, and building owners look for ways to support the COP 21 agreement, the use of high-quality and effective insulation is one powerful solution.

Insulation is one of the most critical components of a roof, providing much needed thermal performance in today’s energy-conscious world. Polyisocyanurate (polyiso) is a rigid foam board insulation used in roof and wall assemblies within commercial and residential buildings of all types. Its unique benefits, strength, and versatility allow it to adapt to a variety of roofing applications. Polyiso is the only high-thermal foam to meet both the FM 4450, Approval Standard for Class 1 Insulated Steel Deck Roofs and UL 1256, Standard for Fire Test of Roof Deck Constructions, and to have third-party-certified R-values.

Based on consensus standards in both Canada and the United States, long-term thermal resistance (LTTR) is a scientifically supported way to calculate the 15-year, time-weighted average R-value of roof insulation. Most polyiso manufacturers have adopted the LTTR method as the exclusive means to measure thermal performance of permeable-faced polyiso roof insulation.

ASTM C1289, Standard Specification for Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board, is used to predict foam’s R-value equivalent to the average performance of permeably faced foam insulation products over 15 years. The LTTR method provides users, specifiers, and designers several advantages, including:

• a technically supported, more descriptive measure of the LTTR of polyiso insulation—a 15-year, time-weighted average;
• an advanced test method, based on consensus standards in Canada and the United States;
• a method that applies to all foam insulation with blowing agents other than air, such as polyiso, extruded polystyrene (XPS), and polyurethane (spray polyurethane foam [SPF]); and
• a better understanding of the thermal performance of foam.

Polyiso roof insulation LTTR values are further supported by Polyisocyanurate Insulation Manufacturers Association’s (PIMA’s) QualityMark program, which allows participating companies to certify LTTR values through an independent third party.

For wall applications, polyiso foil-faced insulation has the highest R-value per inch—meaning the U-value of the cavity wall system can be achieved with minimum thickness, which decreases the overall footprint of the building and lowers construction costs. In cavity walls, polyiso’s foil face and R-value allows increased air space between inner and outer wythes to more efficiently divert water to the outside and improve long-term thermal performance.

Polyiso sheathing insulation
As many design professionals are aware, choosing energy-efficient insulation can be one of the most effective ways to save energy and money. Typically, polyiso is used to insulate an entire wall, including the framing. Framing usually accounts for at least 20 per cent of the total wall area and is often left uninsulated. By insulating the entire wall, one can effectively reduce heat loss through both convection and conduction. Additionally, by properly insulating a structure with polyiso, condensation in walls can be decreased, which could, in turn, potentially reduce moisture-related problems.

When properly specified and installed, polyiso sheathing insulation offers:

• a wall assembly with a high R-value, which increases the energy efficiency and significantly reduces heat loss;
• a reduction in air infiltration and exfiltration, which increases the overall performance of the wall and reduces heat loss;
• a reduction in the risk of water condensation/intrusion, which increases thermal and structural performance and reduces builder call backs;
• insulation over the entire framing members, which reduces the overall energy loss;
• increased confidence the builder is providing a quality product; and
• more confidence with state-of-the-art, energy-efficient techniques.

Conclusion
COP 21 has resulted in an unprecedented operating commitment to reduce CO₂ emissions for the 196 countries that attended. One should expect to see building designers and scientists re-evaluating how existing buildings perform. The shift in attitude of the business community towards this effort is one of the reasons the conference was a success and will result in real change moving forward.

Jared O. Blum is the president of the Polyisocyanurate Insulation Manufacturers Association (PIMA), the North American trade association representing manufacturers of polyiso foam insulation. He was a civil society delegate at the (COP)21 meetings in Paris. He can be reached at joblum@pima.org.