BETHESDA, Md. — Final hearings last month for the 2012 International Green Code yielded a number of advances, including what some call a straightforward approach to minimum thermal requirements for roof and wall systems. The new code will also extend the minimum thermal requirements to all low-slope roof replacements involving above-deck insulation.
The council will publish the first edition of the code in the spring of 2012, and expects it to become the primary benchmark for green construction standards and practices.
Jared Blum, president of the Polyisocyanurate Insulation Manufacturers Association (PIMA), said the group was impressed that, for the first time, a national energy code included specific and clear requirements on the thermal performance of a retrofit roof.
“Increasing insulation levels to the [International Energy Conservation Code] minimum when replacing the roof offers a tremendous opportunity to significantly accelerate efficiency and save money,” Blum said. “Insulation, through its consistent and enduring performance, remains one of the most important components in a re-roofing project when it comes to reducing energy costs and carbon footprint.”
While the minimum thermal requirements will be the same as originally planned in the 2012 code, the language was clarified to avoid potential confusion regarding whether replacement roofs require compliance.
Roof R-values — an indicator of an insulation’s resistance to heat flow — will be calculated by reducing the current IECC roof U-values — the rate of heat loss — by 10 percent, which will yield a minimum above-deck roof R-value ranging from R-22.2 in U.S. Climate Zone 1 to R-33.3 in U.S. Climate Zone 6.
This provides a single mathematical approach to establishing R-value, and it allows organizations like PIMA to publish R-value tables and design guides that help building designers comply with the new code.
The hearings also resulted in a language addition to the Existing Buildings chapter of the code to require low-slope roof replacements involving above-deck insulation to meet the minimum thermal requirements of the current IECC.
“Although the R-values will be slightly lower than the new construction minimums discussed previously, they will provide a reasonable and uniform thermal standard for the most common form of commercial re-roofing,” a statement from the association said. “And for situations involving low roof clearances that make it difficult to add more roof insulation, the new language includes an exception for roofs with limited flashing heights or other restrictions.”
Additionally, restrictions on the use of prescriptive R-value standards were eliminated, which will allow roofing and siding projects of all size to use the measure instead of more complicated energy complications, according to the group.
Further changes included proposed additional materials to the code that will likely stimulate new material recycling opportunities in the roofing industry.