White Paper Identifies Appropriate Mean Reference Temperature Ranges and R-values of Polyiso Roof Insulation within this Range

A number of recent articles have explored the relationship between temperature and R-value with an emphasis on the apparent reduction in R-value demonstrated by polyisocyanurate (or polyiso) roof insulation at cold temperatures. The science behind this apparent R-value decrease is relatively simple: All polyiso foam contains a blowing agent, which is a major component of the insulation performance provided by the polyiso foam. As temperatures decrease, all blowing agents will start to condense, and at some point this will result in a marginally reduced R-value. The point at which this occurs will vary to some extent for different polyiso foam products.

a mean reference temperature of 40 F is based on the average between a hot-side temperature of 60 F and a cold-side temperature of 20 F.

A mean reference temperature of 40 F is based on the average between a hot-side temperature of 60 F and a cold-side temperature of 20 F.

Because of this phenomenon, building researchers have attempted to determine whether the nominal R-value of polyiso insulation should be reduced in colder climates. Because of the obvious relationship between temperature and blowing-agent condensation, this certainly is a reasonable area of inquiry. However, before determining nominal R-value for polyiso in colder climates, it is critical to establish the appropriate temperature at which R-value testing should be conducted.

TO DETERMINE the appropriate temperature for R-value testing of polyiso, it is important to review how R-value is tested and measured. Figure 1 provides a simplified illustration of a “hot box” apparatus used to test and measure the R-value of almost all thermal-insulating materials. The insulation sample is placed within the box, and a temperature differential is maintained on opposing sides of the box. To generate accurate R-value information, the temperature differential between the opposing sides of the box must be relatively large—typically no less than 40 F according to current ASTM standards. The results of this type of test are then reported based on the average between these two temperature extremes, which is referred to as mean reference temperature. As shown in Figure 1, a mean reference temperature of 40 F is based on the average between a hot-side temperature of 60 F and a cold-side temperature of 20 F. In a similar manner, a mean reference temperature of 20 F is based on a hot-side temperature of 40 F and a cold-side temperature of 0 F.

NOW THAT we’ve had an opportunity to discuss the details of R-value testing, let’s apply the principles of the laboratory to the real-world situation of an actual building. Just like our laboratory hot box, buildings also have warm and cold sides. In cold climates, the warm side is located on the interior and the cold side is located on the exterior. If we assume that the interior is being heated to 68 F during the winter, what outdoor temperature will be required to obtain a mean reference temperature of 40 F or 20 F? Figure 2 provides a schematic analysis of the appropriate mean reference temperature.

As illustrated in Figure 2, the necessary outdoor temperature needed to attain a 40 F mean reference temperature would be 12 F while an outdoor temperature as low as -28 F would be needed to obtain a 20 F mean reference temperature. And herein lies a glaring problem with many of the articles published so far about the relationship between temperature and R-value. Although a 20 F or 40 F “reference temperature” may sound reasonable for measuring R-value, average real-world conditions required to obtain this reference temperature are only available in the most extreme cold climates in the world. With the exception of the northernmost parts of Canada and the Arctic, few locations experience an average winter temperature lower than 20 F.

schematic analysis of the appropriate mean reference temperature.

A Schematic analysis of the appropriate mean reference temperature.

To help illustrate the reality of average winter temperature in North America, a recent white paper published by the Bethesda, Md.-based Polyisocyanurate Insulation Manufacturers Association (PIMA), “Thermal Resistance and Temperature: A Report for Building Design Professionals”, which is available at Polyiso.org, identifies these average winter temperatures by climate zone using information from NOAA Historical Climatology studies. As shown in Table 1, page 2, the PIMA white paper identifies that actual average winter temperature varies from a low of 22 F in the coldest North American climate zone (ASHRAE Zone 7) to a high of 71 F in the warmest climate zone (ASHRAE Zone 1).

In addition to identifying a realistic winter outdoor average temperature for all major North American climate zones, Table 1 also identifies the appropriate mean reference temperature for each zone when a 68 F indoor design temperature is assumed. Rather than being as low as 40 F or even 20 F as sometimes inferred in previous articles, this mean winter reference temperature varies from a low of no less than 45 F in the coldest climate zone to above 50 F in the middle climate zones in North America.

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GAF Completes Extensive Roof Replacement Project at Corporate Headquarters

GAF has completed an extensive roof replacement project at its new corporate headquarters at 1 Campus Drive in Parsippany, N.J. GAF has been relocating to the new property, which has been completely renovated with quality products in all areas—including, of course, the roof.

GAF worked closely with its Master Select Contractors to ensure the installation of an energy-efficient roofing system at 1 Campus Drive. The system included GAF’s RUBEROID HW 25 Smooth Membrane, EnergyGuard Polyiso Insulation (for high insulation value), and EnergyGuard HD Cover Board (which offers a high R-value and impact resistance). It also included GAF’s single-ply membrane, EverGuard Extreme Fleece-back TPO Membrane. GAF is proud of how EverGuard Extreme Fleece-back TPO Membrane outperforms competitive TPO membranes (based on heat-aging tests), and backs it with a commercial roofing guarantee.

As GAF prepared to move into its corporate headquarters, it was imperative to make sure they had a durable, energy-efficient and easy-to-install roofing system. The combination of GAF EverGuard Extreme Fleece-back TPO Membrane in 2-Part Roofing Adhesive over EnergyGuard HD Cover Board and EnergyGuard Polyiso Insulation set in Olybond, along with RUBEROID HW 25 Smooth Membrane was the perfect system to keep its building dry and comfortable for years to come.

When using EverGuard Extreme Fleece-Back TPO Membrane with Low-Rise Foam Adhesive (compared to EverGuard Extreme Smooth TPO Membrane), the fleece on the back of the membrane provides an added cushioning layer, especially for hail-prone areas. Also, when combining EverGuard Extreme TPO Accessories with EverGuard Extreme Fleece-Back TPO Membrane, it helps save labor (versus field fabrication)—and provides an overall cleaner-looking roof.

PIMA Announces Environmental Product Declarations for Polyiso Roof and Wall Insulations

Consistent with its delivery of energy-efficient and sustainable building insulation solutions, the Polyisocyanurate Insulation Manufacturers Association (PIMA) announced the receipt of third party-verified ISO-compliant Environmental Product Declarations (EPDs) for polyisocyanurate (polyiso) roof and wall insulations as manufactured by PIMA members across North America. An EPD is an internationally recognized and standardized tool that reports the environmental impacts of products.

These EPDs document that the energy-savings potential of polyiso roof and wall insulation during a typical 60-year building life span is equal to up to 47 times the initial energy required to produce, transport, install, maintain, and eventually remove and dispose of the insulation. In addition to a high return on embodied energy, the EPDs document that polyiso roof and wall insulation offer high unit R-value per inch, zero ozone depletion potential, recycled content, opportunity for reuse and outstanding fire performance.

Beyond providing consistent and comparable environmental impact data, the PIMA polyiso EPDs also present information about additional environmental and energy characteristics, including the high net return on energy provided by polyiso roof and wall insulation.

Specifically, the polyiso EPDs describe the environmental impacts of the combined weighted average production for PIMA member manufacturing locations located across the United States and Canada, based on an established set of product category rules applicable to all types of building thermal insulation. The environmental impacts reported in the PIMA polyiso EPDs are derived from independently verified cradle-to-grave life cycle assessment (LCA) process, including all critical elements related to the resourcing, production, transport, installation, maintenance, and eventual removal and replacement of polyiso roof and wall insulation.

Using the LCA process, the PIMA polyiso roof and wall insulation products are evaluated on a number of impact categories including global warming potential, ozone depletion potential, eutrophication potential, acidification potential, and smog creation potential, as well as other environmental indicators including primary energy demand, resource depletion, waste to disposal, waste to energy, and water use.

PIMA polyiso roof and wall insulation EPDs also meet the requirements of the U.S. Green Building Council (USGBC) LEED v4 Green Building Rating System under Credit MRC-2 Building Product Disclosure and Optimization: Environmental Product Declarations as industry-wide or generic declarations that may be valued as one-half of an eligible product for the purposes of credit calculation.

“These third party-verified EPDs for polyiso roof and wall insulation products produced by PIMA manufacturers reflect our industry’s commitment to sustainability and transparency in reporting environmental performance,” says Jared Blum, president of PIMA. “These EPDs will be a valuable tool to provide environmental information to all building and design professionals, and they should be especially helpful in meeting emerging criteria for green building design.”

PIMA Approves Four Testing Labs for QualityMark Certification Program

PIMA announced that four accredited testing labs have been approved for use by participating polyiso insulation manufacturers in its QualityMark program, the only third-party program for the certification of the thermal value of polyiso roof insulation.

“The integrity of this third-party certification program, which has been overseen since its inception by Factory Mutual, is maintained by the quality assurance obtained through the use of these well respected labs, which all have International Accreditation Service accreditation,” says Jared O. Blum, president of PIMA. “Exova, R&D Services, QAI Laboratories and Architectural Testing are all members of national and international accreditation bodies.”

The PIMA QualityMark certification program is a voluntary program that allows polyiso manufacturers to obtain independent, third-party certification for the Long Term Thermal Resistance (LTTR) values of their polyiso insulation products. Polyiso is the only insulation to be certified by this unique program for its LTTR value. The program was developed by PIMA and is administered by FM Global.

To participate in PIMA’s QualityMark certification program, a Class 1 roof is suggested to have a design R-value of 5.7 per inch. PIMA member manufacturers will publish updated R-values for their polyiso products later this year. Polyiso is unique in that the R-value increases with the thickness of the foam, so three inches of polyiso has a higher R-value per inch than 2 inches.

Heaton to Oversee Atlas Roofing’s Polyiso Division

Atlas Roofing Corp. has announced Steve Heaton will oversee product sales and marketing for the polyiso division, including Atlas Roof Insulation and the Wall CI Board. He will succeed Tom Rowe, vice president—Polyiso Division—who will retire from Atlas Roofing in early 2015 after spending more than 21 years with the company.

“We are pleased to welcome Steve back to the Atlas organization as his expertise in branding and sales management will help further our momentum leading into 2015,” says Ken Farrish, president of Atlas. “We know he will be a great addition to our company with his more than twenty five years in the building products industry, his exceptional leadership and history of working with the Atlas team.”

Heaton has been in the building products and materials industry since 1986. He studied Business & Marketing at USC’s Marshall School of Business and Management at The Wharton School, University of Pennsylvania. He has served in a number of sales, marketing and management roles, including working for James Hardie Building Products for 15 years. Most recently he served as the vice president of Sales at Parex USA. Heaton spent five years at Atlas Roofing when he served as the director of Sales & Marketing for the Atlas EPS division.

Insulation Types, Application Methods and Physical Characteristics Must Be Reviewed, Understood and Selected to Ensure Roof System Performance

Designing and constructing roof systems (see my previous articles about roof decks, substrate boards and vapor barriers) continues with the thermal insulation layer. The governing building codes will dictate the minimum R-value required and, based on the R-value of the selected insulation, the thickness of required insulation can be determined. This plays into the design of the roof edge, which will be the subject of future articles. For now, let’s focus on insulation.

Photo 1: Polyisocyanurate (ISO) with organic facers

Photo 1: Polyisocyanurate
(ISO) with organic facers

Thermal insulation has multiple purposes, including to:

    ▪▪ Provide an appropriate surface on which the roof cover can be placed.
    ▪▪ Assist in providing interior user comfort.
    ▪▪ Assist in uplift performance of the roof system.
    ▪▪ Provide support for rooftop activities.
    ▪▪ Keep the cool air in during the summer and out during the winter, resulting in energy savings.

INSULATION OPTIONS

For the designer, there are numerous insulation material choices, each with its own positive and negative characteristics. Today’s insulation options are:

    ▪▪ Polyisocyanurate (ISO)

  • »» Varying densities
  • »» Organic facers (see photos 1 and 2)
  • »» Double-coated fiberglass facers (see photo 3)
  • ▪▪ Expanded polystyrene (XPS) (see photo 4)

  • »» Varying densities
  • ▪▪ Extruded polystyrene (EPS) (see photo 5)

  • »» Varying densities
  • ▪▪ Mineral wool (see photo 6)

  • »» Varying densities
  • ▪▪ Perlite
    ▪▪ High-density wood fiber

With today’s codes, the use of perlite and high-density wood fiber as primary roof insulation is very limited. The R-value per inch and overall cost is prohibitive.

Some attributes of the more commonly used insulation types are:
POLYISOCYANURATE

Photo 2: Polyisocyanurate (ISO) with organic facers

Photo 2: Polyisocyanurate
(ISO) with organic facers

    ▪▪ Predominate roof insulation in the market
    ▪▪ Organic and double-coated fiberglass facers (mold-resistant)
    ▪▪ Varying densities available: 18 to 25 psi, nominal and minimum, as well as 80 to 125 psi high-density cover boards
    ▪▪ Has an allowable dimensional change, per the ASTM standard, that needs to be understood and designed for
    ▪▪ Can be secured via mechanical fasteners or installed in hot asphalt and/or polyurethane foam adhesive: bead and full-coverage spray foam
    ▪▪ Has an R-value just under 6.0 per inch but has some downward drifting over time

EXPANDED POLYSTYRENE (EPS)

    ▪▪ Has good moisture resistance but can accumulate moisture
    ▪▪ Direct application to steel decks is often a concern with fire resistance
    ▪▪ Has varying densities: 1.0 to 3.0 pound per cubic foot
    ▪▪ Very difficult to install in hot asphalt; basically not appropriate
    ▪▪ Certain products can be secured with mechanical fasteners or lowrise foam adhesive
    ▪▪ Has stable R-values: 3.1 to 4.3 per inch based upon classification type

EXTRUDED POLYSTYRENE (XPS)

    ▪▪ Has good moisture resistance and is often used in protected roof membrane systems and plaza deck applications
    ▪▪ Direct application to steel decks is often a concern with fire resistance
    ▪▪ Has varying compressive strengths: 20 to 100 psi
    ▪▪ Not appropriate to be installed in hot asphalt
    ▪▪ Has stable R-values: 3.9 to 5 per inch based on classification type

MINERAL WOOL

    ▪▪ Outstanding fire resistance
    ▪▪ Stable thermal R-value: 4.0 per inch
    ▪▪ No dimensional change in thickness or width over time
    ▪▪ Available in differing densities
    ▪▪ May absorb and release moisture
    ▪▪ Can be installed in hot asphalt or mechanically attached

PHOTOS: HUTCHINSON DESIGN GROUP LTD.

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Polyiso Insulation to Be Used in Innovative Apartment Complex for the Homeless

Polyiso roof insulation will be used in an innovative apartment building project that combines state-of-the-art environmental features with affordable rents for homeless families. The polyiso insulation, donated by the Polyisocyanurate Insulation Manufacturers Associations (PIMA), Hunter Panels and Atlas Roofing Co., will be used in the Transitional Housing Corp.’s Harry and Jeanette Weinberg Commons (Weinberg Commons).

The Washington, D.C., Weinberg Commons will reclaim three blighted buildings in Southeast D.C., using Passive House architectural principles that reduce the carbon footprint and the utility costs for low-income tenants.

When finished in mid-2015, the apartments will provide 36 low and moderate income families including 12 homeless or formerly homeless families with below-market rents, employment services and other support for youth and families. One-third of the units will be reserved for families with more intensive needs.

“Our goal is sustainability, not just in the environmental sense, but in an economic sense to keep these families in a stable, supportive situation,: said Polly Donaldson, executive director of the Transitional Housing Corporation, a D.C.-based nonprofit that functions as the co-developer, landlord and service provider on this project.

Generally considered the most stringent energy standard in the world, Passive House building is an innovative approach to net-zero building. Instead of relying on active energy reduction systems with high installation costs, Passive House buildings concentrate on energy use reduction. Passive House buildings work with natural systems to manage heat gain and loss, saving up to 90% of utility costs. In fact, the U.S. DOE recognizes the Passive House approach as the most efficient means of achieving net-zero building operations

“It is a privilege for our members to be part of a project that addresses both homelessness and sustainable housing,” said Jared Blum, President, PIMA. “Polyiso insulation is known for it high thermal performance and will be a key contributor for this net-zero building that is extremely insulated, heated by passive solar gains and requires ultra-low energy for space heating or cooling.”

The groundbreaking ceremony for Weinberg Commons was held in October and attended by Washington Mayor Vincent Gray.

Fire Resistance Is Built into Polyiso’s Polymer

ENRGY 3.E from Johns Manville

ENRGY 3.E from Johns Manville

ENRGY 3.E from Johns Manville is the next generation of polyisocyanurate roof-board insulation whereby the fire resistance has been engineered into the polymer backbone without the need for added halogenated flame retardants. Unlike conventional halogenated flame retardants that are free un-bonded plasticizers mixed with the foam, the reactive polymer modifier used to produce ENRGY 3.E is a non-halogenated organo-phosphorus monomer that chemically reacts and bonds directly to the polymer network. This results in the polyiso performance attributes of the existing ENRGY 3 while being inherently fire-resistant and meeting all current fire codes.

TPO Has Begun Shipping from GAF’s New Cedar City, Utah, Plant

GAF has started shipments from its new thermoplastic polyolefin (TPO) and polyisocyanurate (ISO) plant in Cedar City, Utah. Construction of the state-of-the-art site was announced in spring of 2013; it houses GAF’s third TPO and third ISO production lines (and it’s the company’s second combined TPO/ISO facility). TPO began shipping from Cedar City on Aug. 1 and ISO products are expected to begin shipping in early 2015.

The 541,000-square-foot plant produces the full line of GAF TPO products, including EverGuard TPO and EverGuard Extreme TPO, and it will manufacture both ISO roof insulation and residential sheathing. In addition, the plant will include a new training center for CARE (the Center for the Advancement of Roofing Excellence), to support the continued and growing demand for their training classes.

“Our venture in Cedar City is an example of GAF’s continued strategic investment in the commercial roofing industry,” stated Gerry Messina, GAF’s executive director of commercial marketing. “The facility will give us the ability to better service our customers throughout the country.”

An American-owned company with American-made products, GAF is proud to create additional jobs in the U.S. There are currently 40 employees at the plant, with an additional 10-15 expected. The company also produces TPO at its Mount Vernon, Ind., and Gainesville, Texas, facilities.

Washington, D.C., Habitat for Humanity Uses 8 Inches of Polyiso on Roof

Six passive townhomes that are part of Habitat for Humanity’s Ivy City community of Northeast Washington are including 8 inches of polyiso insulation on the roof. These passive townhouses are designed to reduce overall energy consumption by 70 percent and heating and cooling demand by 80 to 90 percent.

The six townhouses are being built to meet the Passive House Institute US (PHIUS) Passive House specifications. Founded in 2007, PHIUS is the leading certifier of passive buildings.

“The Ivy City townhouses show the role high-performance insulation plays in the built environment, particularly when it comes to designing homes that are more affordable to operate,” said Jared Blum, president of the Polyisocyanurate Insulation Manufacturers Association (PIMA). “We are proud to be involved with this Habitat for Humanity project that will provide much needed affordable housing in the nation?s capital.”

PIMA member companies—Atlas Roofing, Firestone Building Products, GAF, Hunter Panels, JM, and R-max—donated the polyiso for this project in celebration of the association’s 25th anniversary.

“The passive house model embodies Habitat for Humanity’s vision that all people deserve safe, comfortable, affordable and sustainable housing, and the polyiso insulation contributes to that vision,” said Andrew Modley, production manager, Habitat for Humanity of Washington, D.C. “Passive housing will provide our homeowner families with an ability to consume significantly less energy overall by using passive integrated design, climate appropriate insulation, and airtight construction. These benefits will not only save the homeowners money, but will empower them to create a more sustainable lifestyle.”