Month: August 2013

Facts about Polyurethane Foam

Heating and cooling costs amount to 50% to 70% of the energy used in the average American home, according to the U.S. Department of Energy. To stem these costs, maintain uniform temperature, and lower noise levels in homes, as well as commercial properties, builders turn to rigid polyurethane and polyisocyanurate (polyiso) foam — one of today’s most effective insulation materials available for roof and wall insulation, insulated windows and doors and air barrier sealants. Polyurethane use in building and construction accounts for more than 25% of the total polyurethane market in North America.

Rigid polyurethane and polyiso products deliver a unique combination of properties, as described below.

Energy Efficiency

• Polyurethane and polyiso foams have one of the highest insulating R-values per inch of all commercially available products today. With typical values in the range of R 5.6 to R 8 per inch, it is possible to have thinner walls and lower profile roofs while maximizing efficiency, increasing space utilization and reducing operating costs.
• Increasing the thickness of polyiso roof insulation by 1 degree or more above the ASHRAE required thickness significantly reduces your energy costs while providing a positive rate of return on the cost of installation.
• Entry doors having a rigid polyurethane foam core help inhibit sound and add insulation value that further reduces heating and cooling energy needs.
• Polyurethane foam sealants, applied on-site, expand to fill energy-wasting, air-infiltrating gaps around window frames, plumbing pipes, and electrical outlets.
• Energy studies performed by Texas A&M on their own roofs show the energy cost reductions obtained by applying spray polyurethane foam (SPF) to more than 8 million square feet of roofing paid for the cost of the retrofit in a little over three years.
• “Reflective” plastic coverings over polyurethane foam-insulated roofs bounce sunlight and radiant heat away from a building, helping the structure stay cool and reducing energy use for air conditioning.

High Performance

• Rigid polyurethane and polyiso foams are made with a remarkably strong, yet lightweight, low-density structure that is both dimensionally stable and moisture-resistant with low vapor transmission.
  

  This special combination of properties allows manufacturers to design thermal insulating products that are self-supporting, can be combined with a wide range of substrates while requiring no additional adhesive, and — when combined with the proper materials — perform as external weather and moisture barriers.

• High-performance polyurethane insulation can be spray applied to various substrates, or molded to special shapes in relatively large sizes. It can also be protected against UV degradation and re-coated to extend performance life.
• Polyurethane and polyiso products, when properly installed, are not affected by oil-based waterproofing or dampproofing compounds, insecticides or fertilizers.
• Both polyurethane and polyiso foams are widely used in the fabrication of steel faced building panels for various categories of commercial building construction. Applications range from cold storage warehouses used in the food and beverage industry to high-tech looking offices, medical buildings, airports and even manufacturing facilities. When bonded to metal skins, a composite building unit is formed with long spanning capabilities. The light in weight and high insulation value make these products ideal for renovating exteriors of older buildings because typically the existing building cladding can be left in place and the existing structure does not need to be reinforced.

Versatility

• Polyiso laminate boardstock is one of the most popular insulations used in conventional roofs. In fact, polyiso laminate boardstock, used primarily in roofing and wall insulation, accounts for 85 percent of the total usage of rigid polyurethane foam in construction applications.
  

  For special exterior designs, foam core panels offer a wide variety of colors and profiles for walls and roofs, and reduced weight for easier handling and a lighter supporting structure.

• Some rigid polyurethane foams can be applied on-site to seal gaps and cover irregular shapes. Such foams include spray, pour-in-place, and one-component foams.
• SPF forms a seamless layer of insulation, fills gaps and seams during application, and covers irregular shapes that are hard to insulate with rigid boards. This reduces drafts considerably while creating stiffer, quieter buildings.
• For durability and stability, rigid polyurethane foam-cored entry doors and garage doors are available in finishes and styles to suit even the most particular client.
• Structural insulated panels (SIPS) have a foam core insulation with both an exterior and interior facing, and can be made part of the structure of a building. Facing materials include gypsum, engineered wood or natural wood products. These insulated panels, manufactured in a controlled environment, improve product quality, speed erection of buildings, and reduce the amount of wood necessary for the structural framing. The finished product saves not only time and energy, but natural resources and the environment as well.

Thermal/Mechanical Performance

• The qualities of rigid polyurethane and polyiso foam reduce energy transfer, resist moisture, maintain dimensional stability, remain airtight and often support a structural role.
  

  Polyurethane and polyiso foams also function in temperature extremes, do not deform or distort, and are not subject to damage by the moisture that may result from condensation. Polyiso is stable over a wide temperature range (-100°F to +250°F) and can be used as a component in hot- asphalt roofing systems.

• The mechanical strength of these foams is remarkable. High compressive and shear strengths allow low-density insulating cores to be faced with relatively thin steel or aluminum, yet span long distances unsupported. For example, the foam can hold together many of the components in a refrigerator or hot-water heater while it continues to perform as thermal insulation. This unique combination of properties allows rigid polyurethane foams to be used in many diverse applications.
• Polyiso roof insulation is a Factory Mutual Class 1 material approved for use in all types of roofing systems without a thermal barrier, saving both labor and material while providing the best energy efficient roof available.

Environmental

• The environmental benefits of rigid polyurethane foam are significant, and include increased energy efficiency and reductions in energy-efficient construction costs, reduced project weight and savings of all the construction components that the material replaces. Given the widespread adoption of rigid polyurethane foam in today’s construction, these savings are multiplying at an increasing rate around the world.
  
• Better insulation typically results in lower energy use. In some cases, mechanical heating and cooling equipment can be downsized, further increasing space utilization.
• Buildings can be constructed with thinner walls, while roofs require shorter fasteners.
• Less complicated and lighter-weight products are usually produced using fewer manufacturing steps, less energy in manufacturing, and less energy in transportation.
• By increasing the thickness of polyiso roof insulation by 1” or more above the ASHRAE required thickness in commercial buildings, it reduces CO2 emissions by thousands of pounds, SO2 emissions by thousands of grams, and NOx emissions by thousands of grams per year and the energy conservation achieved by insulating and sealing the building effectively helps reduce CO2 emissions associated with the burning of fossil fuels.

Rigid polyurethane and polyiso foams contribute to society and culture by conserving resources. Their ideal properties exceed those of any comparable material in strength-to-weight ratio, R-value and durability, while their versatility enables builders to use them for dozens of different applications, each yielding high performance and exceptional energy efficiency.

Click Here to read article written by Green Builder Magazine