Itch-Free Zone Pricier alternative-fiber insulation may offer benefits for pros By Katie Gerfen DIYers always know when their neighbors are installing new fiberglass residential insulation. The ubiquitous rolls of fiberglass batting are always accompanied by a cloud of glass dust, dense and foreboding enough to keep away neighbors, friends, and even family members. Because with that dust comes another side effect: itching that’s strong enough to affect even the most allergy-resistant visitors. So when Dow Chemical started researching a new fiberglass- free insulation product several years ago, they had several goals in mind—but a major aim was to stop the itch. To do so, the materials scientists considered several alternate insulation materials and manufacturing processes. What they came up with and released to the public last September is SAFETOUCH fiberglass-free interior house insulation, a polyester-based batting that is virtually dust-free and offers a nearly toolless installation that its counterparts can’t offer. With an R-rating equivalent to that of traditional fiberglass wall insulation at roughly the same depth (polyester batts are available in R-13 and R-19), polyester fiber offers the same energy conservation and sound absorption benefits of traditional fiberglass insulation. But, says Doug Todd, business development manager at the Dow Chemical Company, “clearly there was a need in the marketplace for a new alternative, from a comfort and ease-of-use perspective. Our initiative was to go out there and address that need by changing the game.” Improvements over time Throughout the research and development phase of the fiberglass-free insulation product, the manufacturer evaluated the existing marketplace for alternative fibers and reduced-dust wall insulation. Present at the time was a variety of methods by which fiberglass products attempted to contain the dust. Todd cites Johns Manville’s formaldehyde-free ComfortTherm insulation, released in 2006, as such an example. “It’s still using fiberglass,” he notes. “It’s basically fiberglass sheltered by a protective plastic sleeve.” Other alternative fibers provided similar dead ends. Denim-based wall insulation still produces much dust, has a tendency to sag in the wall cavity, and still requires the application of chemical fire-retardants. The same is true of wool materials. Eventually, the materials scientists and chemists settled on polyester batt insulation because it addressed a variety of these concerns.
Transcript
Itch-Free ZonePricier alternative-fiber insulation may offer benefits for pros
By Katie Gerfen
DIYers always know when their neighbors are installing new fiberglass residential insulation. The ubiquitous rolls of fiberglass batting are always accompanied by a cloud of glass dust, dense and foreboding enough to keep away neighbors, friends, and even family members. Because with that dust comes another side effect: itching that’s strong enough to affect even the most allergy-resistant visitors.
So when Dow Chemical started researching a new fiberglass-free insulation product several years ago, they had several goals in mind—but a major aim was to stop the itch. To do so, the materials scientists considered several alternate insulation materials and manufacturing processes. What they came up with and released to
the public last September is SAFETOUCH fiberglass-free interior house insulation, a polyester-based batting that is virtually dust-free and offers a nearly toolless installation that its counterparts can’t offer.
With an R-rating equivalent to that of traditional fiberglass wall insulation at roughly the same depth (polyester batts are available in R-13 and R-19), polyester fiber offers the same energy conservation and sound absorption benefits of traditional fiberglass insulation. But, says Doug Todd, business development manager at the Dow Chemical Company, “clearly there was a need in the marketplace for a new alternative, from a comfort and ease-of-use perspective. Our initiative was to go out there and address that need by changing the game.”
Improvements over timeThroughout the research and development phase of the fiberglass-free insulation product, the manufacturer evaluated the existing marketplace for alternative fibers and reduced-dust wall insulation. Present at the time was a variety of methods by which fiberglass products attempted to contain the dust. Todd cites Johns Manville’s formaldehyde-free ComfortTherm insulation, released in 2006, as such an example. “It’s still using fiberglass,” he notes. “It’s basically fiberglass sheltered by a protective plastic sleeve.”
Other alternative fibers provided similar dead ends. Denim-based wall insulation still produces much dust, has a tendency to sag in the wall cavity, and still requires the application of chemical fire-retardants. The same is true of wool materials. Eventually, the materials scientists and chemists settled on polyester batt insulation because it addressed a variety of these concerns.
The right mixThrough a proprietary development process, the manufacturer created a batting made from thin polyester fibers. These fibers create almost no dust because of their spun form, woven into a thick, form-retaining structure. This approach eliminates the dust and itch problem, as well as the need to wear a mask. While still considered a combustible material, polyester batt insulation possesses an inventive characteristic: The thin fiber construction enables the polyester to resist continued smoking and burning. Instead, the fibers will tend to melt
together and pull away from contacting surfaces. The polyester wall insulation passes the 2006 International Residential Code (ASTM E84 and ASTM E970).
Polyester wall insulation did not enter the market until after three years of research and testing. “We processed different types of fibers,” says Todd, “actually making mockups of insulation batts, testing them, testing the thermal performance and the different properties that were requested by the market place.” These mockup insulation batts were installed in test areas, sometimes replicating a wall, sometimes a whole house. A series of tests were conducted in a laboratory setting to measure the dust, fumes, fire, installation hazards, and thermal and sound-dampening performance of each option, until the final formula for the wall insulation material was reached. Products were also tested on job sites, with the network of contractors and building professionals.
Business implicationsThe main drawback of the product is its price: It currently retails well above the market rate for standard fiberglass insulation products. But despite the cost differential, Todd says that “we have had a 100 percent positive response from the DIY market.” The reason for consumers’ lack of concern over price is that, for many home owners, DIY stops at insulation because the installation hassles are too great. The higher price of polyester-fiber insulation evens out because, thanks to the friction-grip system that keeps batts in place, DIYers don’t have to hire contractors or purchase installation equipment to put up the product. “There are a lot of people who are looking for things that will have benefit for them to do it themselves, versus contracting something out, and they can do that with this product,” Todd notes.
The price of polyester insulation is an issue for professional installers, however, because they are not the ones selecting the products to go in place. That is, since the benefits of polyester-fiber insulation are highest during the installation process, homeowners are not likely to pay the premium just to make their contractors’ work easier. That said, the benefits for professional installers are the same as for DIYers, and might potentially outweigh the cost differential on some projects. Despite the professional contractor’s access to specialized gear that can make standard fiberglass installation less painful, insulation jobs can still be tough on workers. The itching, inhalants, and potential health concerns are not always mitigated by protective gear. As a result, individual contractors may be motivated to prevail upon business managers to absorb the cost of the more labor-friendly polyester wall installation.
Furthermore, when the polyester batt insulation product goes to market with R-values appropriate for the rest of the home (say, the attic) and the cost comes down in the next few years, polyester batting may become the preferred alternative for large-scale contractor jobs.
Bringing down the cost of installing polyester wall insulation will require potential change on a number of fronts. “It is a combination of looking at materials that we’re using and the manufacturing process,” Todd explains. And as long as the benefits of improving a home’s heating and cooling performance continues to add savings for the homeowner, green-savvy manufacturers have good reason to keep innovating wall performance systems—even the familiar batt.
You Say You Want A Revolution Home
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You Say You Want A Revolution
The international publicity of ETFE roofing material in some of Beijing’s2008 Olympic structures is awakeningthe potential for alternatives
By Lisa Marquis Jackson
It’s transparent, it’s self-cleaning, and best of all, it’s incredibly versatile. And despite the fact that it will be lauded in November at a 25th anniversary fete in Germany, the fluorocarbon-based polymer ethylene tetrafluoroethylene (ETFE) is probably not a material that most people are familiar with. However, that’s all about to change.
Today, thanks to the innovative engineers and creative architects involved in the structures being showcased for the 2008 Olympics in Beijing, China, the unusual properties of ETFE are about to get their moment in the international spotlight. And as a result, more traditional transparent materials, like glass or fiberglass, may have some serious competition for projects where natural light considerations are a critical design component.
The resin is unique in many aspects. It can be manufactured into a thin film, stored in rolls, and designed for application in sheets or even inflated into pillow-like units of varying size, shape, and color.
A typical three-layer system consists of two layers measuring 250 microns thick and one layer roughly 200 microns thick. “If you put your fingers together, it would still slide between,” notes Foiltec North American Division Project Manager Nathan Brekker of the product his company pioneered. But things get really interesting when air is added in between both the first and second layers and the second and third layers. Barely
measurable with a ruler when deflated, the material expands to create a structural barrier several feet in depth.
Though its added benefits include energy efficiency, cost effectiveness, and surprising durability, it’s the light weight and delicate appearance of ETFE that offer never-before-seen design opportunities.
Nicknamed the Watercube, the 750,000 square foot National Aquatic Center in Beijing, China, is the largest ETFE project to date and showcases the material’s ability to bridge the gap between fantasy-like, futuristic design and reality. Scheduled to be completed by the end of the year, the project gives the appearance of a box made of bubbles by utilizing blue-tinted ETFE cushions not only in the roofing structure, but in all four walls as well.
In stark contrast, less than 500 meters away is the National Stadium, an intricate woven configuration of steel girders laced with red-tinted ETFE cushions. Much like a bird’s nest, the structure projects the appearance of a sturdy, safe haven. Underscoring the appeal is that the systematic design is tinged by random, seemingly natural inconsistencies that are possible only because of the light weight and versatility of ETFE.
Back to the futureThough it’s taking a swimming arena crafted from bubbles and a stadium resembling an enormous nest to bring attention to the material, especially in the U.S., ETFE has been used in European mainstream projects with simple architecture like medical facilities, office projects, and zoo structures since the 1980s.
It all began in the 1970s when DuPont created the chemistry behind the product, (which is a unique form of their more mainstream Teflon property) as insulation material for the aeronautics industry. It was then that German-based Stefan Lehnert, a passionate sailor and mechanical engineer to boot, came across the technology in his quest to create a new type of sail. Because the resin of the material could be spun into a durable thin film with the ability to expand and contract, Lehnert began experiments hoping to revolutionize his pastime. Though that use eventually proved to be inappropriate, he recognized that ETFE’s transparency and versatility had great potential in other applications.
In 1982, Lehnert founded Bremen, Germany-based Vector Foiltec as he sought to bring the technology into the building material arena. Eventually catching the attention of architects for an atrium application, the product was first put to use in a pavilion roof of a Holland zoo. Gaining credibility over the next decade, ETFE was also used in a variety of roofing applications throughout Germany and England. Eventually, in 2000, the use of ETFE in two enormous conservatories as a part of a British environmental complex called the Eden Project brought attention to the product’s engineering potential.
Now, the world is apparently catching on to the possibilities of ETFE. Not only did three out of the four proposals for the Beijing Aquatic Center contain ETFE, but several of the submissions for London’s 2012 Olympics also integrate the material. In fact, Foiltec, which has offices in 12 locations around the world, is working on more than 100 projects and is focusing on expanding its U.S. presence. Already, eight applications are slated for next year. To date, simply designed gable roofs in aquatic places, tennis facilities, and arenas make up
the majority of stateside interest, but indoor rain forests, indoor waterparks and facilities requiring a natural habitat with sunlight all year can also benefit from the application.
On the plus sideWeighing in at roughly one percent of the weight of glass, no one can dispute the reduction in structural costs associated with implementing ETFE. Though savings vary by job and the level of complication, using ETFE can reduce costs anywhere from 10 percent to 60 percent. “Even in a simple roof structure, the benefit over glass is in the span,” says Brekker recalling a recent project with 33 panels, all 8 ft wide. “The panels were 50 ft long, so that is 8 ft by 50 ft with no structural support in the middle. With glass you need support every 8 or 10 ft, so this cuts down on your steel costs.”
The material can be produced in a variety of shapes, sizes, colors, finishes, and even patterns to answer a variety of architectural considerations, light transmission needs, and general
The material, which is typically pre-stressed to inflate and take loads optimally, can stretch up to three times its original length. Surprisingly, it’s also puncture resistant. In hurricane testing the company shot 2x4s into the material at a high velocity. In most instances, the board didn’t blast through but was caught up somewhere in the layers.
As is the nature of the plastic, when exposed to fire, ETFE only melts and pulls away in spots where the flame is in direct contact —which reduces the risk of a fire spreading across the material. Only exposed areas would require replacement. For smaller tears, patching is often all that is needed. A sticky-sided tape that is essentially made from the same material can be applied and is virtually invisible. And in a true testament to its environmental appeal, ETFE is considered recyclable since the material and be melted and used again.
Nobody’s perfectAlthough the benefits seem to outnumber the concerns, ETFE does possess some characteristics that the builder should keep in mind. With its layered structure, a continuous stream of air pressure is necessary to maintain stability. In order to facilitate the infusion, an air-supply hose is connected to the cushions and integrated with other lines into a computerized pressure monitoring system.
It’s this system that enables the lightweight material to bear a more impressive load than glass could. “Because there is a constant regulated air supply, when it reaches a maximum air pressure, the system automatically shuts off,” says Brekker. “But if a large gust of wind presses down on the top foil, instead of bearing all the stress on the outside layer, the design disperses the pressure by spreading the force of a wind or snow load, across all three layers evenly,” acting much like a shock absorber. A bleeder valve automatically releases air.
Despite its strength, ETFE can be cut through with, for instance, a sharp knife. For this reason, the product is generally not used in windows or on exterior walls unless a foundation is created roughly 15 ft off the ground.
Other challenges arise from acoustics. Though the sound of rain pattering on a roof may conjure up a cozy feeling for some, it could be difficult to settle in with a good book under an
ETFE roof structure. The cushion system, in effect, acts like a drum and can intensify noise levels dramatically. And when it is used in an interior application, more sound is transmitted than with glass or even wood construction, so privacy can be an issue.
Although the material is capable of adapting to complex environmental and architectural pressures, it’s still best to assess the motivation behind incorporating ETFE before automatically ruling out other products. Be sure to consider transparency, energy efficiency, and architectural design needs. In general, Foiltec recommends avoiding the resin in residential applications. But more innovations may be on the horizon. The company confirms, among other things, it is exploring ways to boost thermal properties and absorb noise.
For more info on ETFE, please visit: www.acsa-arch.org/plastic.
Lisa Marquis Jackson is a freelance writer based near Dallas, Texas.
Plastic Lumber Possibilities Home
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Plastic Lumber Possibilities
Traditional applications find progressive results
By Cathy Cirko
As a substitute for treated lumber, plastic lumber products resist insects, rot, moisture, and many chemicals. There are two different types of plastic-lumber products—the “composites” (wood products made from a mix of plastics and natural fibers) and the “wood-like” products made solely from plastics. Many of these products use recycled plastics, diverting waste from the landfills1— a potential benefit to the environment. Indeed, the plastic lumber industry largely owes its inception to finding a use for plastic scrap and post-consumer plastic waste. In some applications, these new products are now displacing traditional building materials.2 Global demand for these plastic lumber products is rising, due in part to an increase in their possible construction applications.
The difference is in the mix Wood–plastic composites (WPCs) consist of fibers combined with some sort of polymer. For example, natural fiber composites combine plastic with flax or hemp. In Western Europe, this material first became popular with German automotive manufacturers. For companies like BMW and Daimler Chrysler, natural composites now average between 7 and 10 kg (15 and 22 lb) per vehicle in nonstructural applications such as interior panels, headliners, seat panels, parcel shelves, and acoustic panels.
Wood composites, on the other hand, are products manufactured from a combination of wood fibers and plastics. Their various qualities (including durability and weather resistance) make them suitable for exterior building applications including decking/railing systems, window/door profiles, shingles, sound barriers for roadways, and infrastructure products such as boardwalks, picnic tables, and park benches.
Both natural fiber and wood composite products can be made with either new plastic or post-consumer/industrial recycled material. Virgin polymers offer additional aesthetic options, including pigmenting choices and reproducible patterns, but can also cost more. Potentially less expensive composites incorporating recycled plastic may use specialty additives/pigments to improve aesthetics, such as color retention and ultraviolet (UV) ray resistance.
In North America, polyethylene (PE) is the most widely used polymer in composite applications. However, post-consumer supply is tightening due to increased use of the material and rising exports overseas. This, along with ongoing research into new polymer combinations and processing methods (i.e. injection molding), could increase demand for other plastic materials, such as polypropylene (PP). When this happens, these new materials could offer their own distinctive properties and characteristics, further changing how WPCs are viewed by specifiers and other design professionals. (For example, polypropylene may be oriented to provide greater stiffness.)
Durability and other characteristicsPlastic lumber products can offer several advantages over their more traditional counterparts. According to a study from the U.S. Army Corps of Engineers, composite products are durable, stable, resilient, and resistant to weather, rot, mildew, and termites (without chemical pressure-treatment). Additionally, plastic lumber products do not require regular repainting or restaining. These types of products are also workable with conventional carpentry tools and, for the most part, are low-maintenance.
The limitations of plastic lumber products include their viscoelasticity. The material’s mechanical properties are time–temperature-dependent and subject to permanent deformation (i.e. creep) under sustained loads. The rate of this creep depends on the magnitude and duration of the stress and the temperature at which it is applied. Furthermore, plastic lumber can undergo significant dimensional changes due to temperature.
Another critical issue inherent to the material has been its relatively low stiffness and flexural strength. This may explain why most of the extruded plastics or WPC boards produced have been used for deck and boardwalk surfaces, where flexibility is less important. However, recently introduced oriented wood polymer composites offer increased stiffness and flexural strength.
Single-polymer systems rely on continuously extruded, structurally foamed high-density polyethylene (HDPE). Extrusion flow molding allows the use of even heavily contaminated recycled plastics, resulting in the potential for lower raw material costs and increased benefit to the environment. New flow mold systems are being developed that promise greater potential in producing largedimension plastic timber products at high throughput.
Fiberglass-reinforced recycled composites can provide components for demanding structural applications, such as deck joists, marine break walls, and bulkheads/pilings. Vinyl extrusion profiles, on the other hand, are being used primarily in railing and deck board systems.
Increased application and awareness Plastic lumber products have the potential to go beyond the traditional applications already mentioned. The Canadian Plastics Industry Association’s Environment, and Plastics Industry Council sponsored a study, Reviewing the Potential for Plastic Railroad Ties in Canada,
exploring the development, performance, production, and pricing of plastic railway ties.3 It points to the possibility of increased demand for the material within the North American rail industry, particularly for regional and short-line railroads. Factors contributing to this potential include the growing environmental concern within the United States over the disposal of creosote-treated wooden ties.
While railway ties may seem an esoteric field, it seems more than likely that plastic lumber products will also be incorporated into a growing number of residential and nonresidential construction products. As new applications for these products continue to evolve, so will demand for the material. The material’s success lies not only in its durability and potential use of recycled materials, but also in larger numbers of architects/engineers and specifications writers (re)discovering its applications.
Indeed, plastic lumber has come a long way from the novelty material applauded by environmentalists and largely ignored by the construction industry. With a greater understanding of the material’s performance through standard test methods and specifications and the construction industry’s growing comfort with its use, it could one day be an integral part of the built environment, from landscaping components to interior applications.
Codes and StandardsOne key factor driving the growth of wood plastic lumber use is the increasing number of ASTM International standards. Over the past five years, numerous standards have defined test procedures and helped engineers in designing structures. Most of the current standards were developed by the Plastic Lumber Trade Association (PLTA) and focus on single-polymer products. The following are a list of active standards pertaining to composite products:
ASTM D 6108-03, Compressive Properties of Plastic Lumber and Shapes ASTM D 6109-03, Flexural Properties of Unreinforced and Reinforced Plastic Lumber ASTM D 6111-03, Bulk Density and Specific Gravity of Plastic Lumber and Shapes by Displacement ASTM D 6112-97, Compressive and Flexural Creep and Creeprupture of Plastic Lumber and Shapes ASTM D 6117-97, Mechanical Fasteners in Plastic Lumber and Shapes ASTM D 6341-98, Linear Coefficient of Thermal Expansion of Plastic Lumber and Plastic Lumber Shapes between [–34.3 and 60 C] –30 and 140 F ASTM D 6435-99, Shear Properties of Plastic Lumber and Plastic Lumber Shapes ASTM D 6662-01, Standard Specification for Polyolefin-based Plastic Lumber Decking Boards
Further standards currently under development for plastic lumber include:
ASTM WK 2843, Polyolefin-Based Outdoor Structural-Grade Plastic Lumber ASTM WK 2501, Polymeric Piles ASTM WK 1202, Guidelines for Evaluating the Mechanical and Physical Properties of Wood-Plastic Composite Products ASTM WK 1203, Establishing Performance Ratings for Wood- Plastic Composite
Deck Boards and Guardrail SystemsNotes
1Recycling is not available in all regions of the country. 2For example, Wood Composites in Decking Structures: Building of Outdoor Living Areas, a report from consulting firm, Principia Partners, predicts WPC use in deck boards and railings will double between 2000 and 2005, with annual consumption growing from approximately 27.4 million to 60.4 million meters (90 million to 198 million ft) in the United States alone. 3The report can be accessed through http://www.plastics.ca/epic by selecting Publications and Special Reports.Cathy Cirko is the director general of the Environment and Plastics Industry Council (EPIC) of the Canadian Plastics Industry Association (CPIA).
Energy Efficiency, Sustainable Design, and XPS Home
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Energy Efficiency, Sustainable Design, and XPS
by Susan Herrenbruck
Relative to a building’s environmental impact, decisions about energy efficiency can be among the most important ones to make. The use of extruded polystyrene (XPS) foam plastic insulation can play an effective and important role in achieving this sort of efficiency, thanks to its ability to maintain insulating power.
Extruded polystyrene (XPS) foam plastic insulation uses highly efficient blowing agents specifically selected for low thermal conductivity and diffusivity—this helps the insulation retain its properties.1 The durability of extruded polystyrene foam plastic insulation is perhaps its most important environmental consideration. The closed-cell structure and lack of voids in extruded polystyrene foam plastic insulation not only impart the material’s durability and strength, but also help the foam resist moisture penetration—without the use of a facer or laminate—better than some other types of insulating materials.
Extruded polystyrene foam plastic insulation is dimensionally stable and products are available in a wide range of compressive strengths (from 103 to 689.5 kPa [15 to 100 psi]) to suit a variety of application requirements, including residential (e.g. foundations, walls, ceilings), commercial (e.g. roofs, belowgrade, waterproofing), and beyond (e.g. soil stabilization, pipe insulation, utility lines).2
Long-term benefitsTo truly assess the environmental impact of a building or application, the effect of material changes in foam formulations should also be analyzed in terms of the resulting thermal performance. Used to insulate commercial buildings and residences, the energy efficiency payback from insulation with high R-values over a long period far exceeds any marginal contribution of ozone-depletion potential (ODP). This analysis was done for estimated emissions until the Montreal Protocol’s phaseout date of 2010.3
Energy efficiency and conservation relative to global climate change (GCC) should also be considered when assessing the environmental impact of materials. In May 1999, technical
experts working on both the Montreal and Kyoto Protocols collaborated in Petten, Netherlands, at the Joint Intergovernmental Panel on Climate Change/Technology and Economic Assessment Panel (IPCC/TEAP) Expert Meeting on Options for the Limitation of Emissions of HFCs and PFCs.
Among several conclusions, the report stated the use of foams such as extruded polystyrene foam plastic insulation enabled high levels of energy efficiency. It also noted an average increase in global energy efficiency of one percent in buildings equated to a net annualized reduction of CO2 emissions by some 50,000 to 80,000 tons.
The Alliance for Responsible Atmospheric Policy (ARAP) conducted a study that included a life-cycle climate performance (LCCP) and provided an analysis of insulating sheathing for residential wood-framed walls.5
It concluded:
These results show far more energy is saved than consumed by manufacturing the plastic foam and that far more greenhouse gas emissions due to space condition energy consumption are avoided than are emitted in the manufacture of the plastic foam.
For an accurate environmental assessment, the impact of material changes in plastic foam formulation should be analyzed in terms of their resulting thermal performance.
Moisture resistanceA critical factor affecting long-term thermal performance is extruded polystyrene foam plastic’s aforementioned ability to resist the intrusion of moisture. Moisture can come in contact with insulation not only during construction, but also throughout the building’s life. To the extent moisture is absorbed by a product, its effect is to drastically reduce thermal efficiency (i.e. R-value).
Extruded polystyrene foam plastic insulation’s ability to resist moisture absorption has been confirmed repeatedly in laboratory tests and validated by actual application use in the field. Extruded polystyrene foam plastic insulation’s manufacturing process forms a natural ‘skin’ surface not conducive to moisture absorbency. Without the need for a facer or laminate, extruded polystyrene foam plastic insulation products only absorb 0.3 percent by weight.6 When installed in walls, extruded polystyrene foam plastic insulation shifts damaging dewpoints, which helps minimize the potential for condensation to occur within. This helps keep the insulating power in the wall and prevent degradation over time due to moisture intrusion—helping keep its energy-efficient properties intact.
Exterior wall sheathingWith a long-term thermal resistance ranging from R-3 (for 13-mm [0.5-in.] thick boards) to R-5 (for 25-mm [1-in.] thick boards), extruded polystyrene foam plastic insulation sheathing products increase the energy efficiency of the entire wall. (The higher the R-value, the greater the insulating power—suppliers can provide fact sheets on R-values.) extruded polystyrene foam plastic insulation sheathing products provide a continuous layer of protection against water moisture infiltration while guarding against thermal bridging. (Thermal bridging occurs due to wood studs and other uninsulated parts of the wall, such as framing, ducts, wiring, and plumbing.)
When properly installed, extruded polystyrene foam plastic insulation sheathing also forms a continuous air barrier that minimizes convection currents and air infiltration, the leading cause of energy loss. When moisture gets into a wall assembly, it compromises components made from traditional materials and can then reduce the overall R-value of the building envelope.
Cold storage applicationsIn 1997, the U.S. Army Corps of Engineers (USACE) Cold Regions Research and Engineering Laboratories (CRREL) conducted a survey of the moisture content in the roofing systems of existing cold storage buildings for an extruded polystyrene foam plastic insulation manufacturer.7 As discussed in the report issued by CRREL, rooftop nighttime and indoor daytime infrared (IR) moisture surveys were performed. Areas of wet insulation (various product types, including both traditional and plastic materials) were noted in eight of the 10 roofs evaluated.
Core sampling of the membranes and insulation were collected for laboratory evaluation. The specimens were evaluated for dry density, moisture content, and thermal resistance (both as sampled and after drying). The conclusions reached by CRREL suggest the intense vapor drive, air infiltration, and propensity of the cold storage roofs to exhibit water infiltration meant extruded polystyrene foam plastic insulation is among the most suitable roof insulation for freezers and coolers.
Frost-protected shallow foundations
Extruded polystyrene foam plastic insulation is a code-approved product for use in horizontal configurations in code-compliant frost-protected shallow foundation (FPSF) applications.8 The concept of FPSF involves the placement of rigid foam insulation in a way that raises the frost penetration depth around a building. This permits foundation footing depths as shallow as 406 mm (16 in.), even in cold climates.
According to the Department of Housing and Urban Development’s (HUD’s) FPSF Design Guide, the technology not only improves energy efficiency for completed projects, but it also allows a reduction in material use and earth excavation during construction, cutting down on energy consumption.
Although relatively new in the United States, FPSF has been prevalent in Scandinavia for more than 40 years. FPSF is commonly used in monolithic slab-on-grade, independent slab and stem wall, and permanent wood foundation applications. Moisture resistance is extremely important in FPSF due to the insulation’s placement in potentially wet soil and because of the possibility of freeze-thaw cycles.
Protected membranesA protected membrane roof assembly (PMRA) differs from a conventional roof design in that the membrane is placed under the insulation layer, helping to maximize membrane life by protecting it from temperature extremes, freeze-thaw cycles, ultraviolet (UV) ray degradation, and traffic wear. A PMRA begins with the application of the ethylene propylene diene monomer (EPDM) membrane, followed by the extruded polystyrene foam plastic insulation boards, the protective scrim, and finally, the ballast.
Extruded polystyrene foam roofing boards are the only type of insulation recommended for use and approved by many building codes in PMRA systems. Again, this is because extruded
polystyrene foam plastic insulation resists moisture absorption and crushing from foot or equipment traffic so thoroughly. The end result of a successful PMRA system is a great shield against unwanted airflow, and further reduction in the heat escaping from the building, which translates into lowered energy consumption.
ConclusionThe current initiative toward green building is manifesting itself throughout the built environment, as design teams seek ways to keep their projects as energy-efficient as possible. One method for helping achieve adequate thermal protection is the specification of insulation in appropriate applications. At several locations within the building, extruded polystyrene foam plastic insulation can offer these energy-efficient benefits.
Notes1 Due to this gas movement, the overall thermal resistance of an insulation product may change over time. This phenomenon is typically called ‘aging.’ Foam aging is not new and has been discussed in numerous papers over the years. Recent data on extruded polystyrene foam plastic insulation products and long-term performance demonstrate the excellent long-term thermal performance of extruded polystyrene foam plastic insulation products in the laboratory. See Chau Vo and Andrew Paquet’s “An Evaluation of the Thermal Conductivity for Extruded Polystyrene Foam Blown with HFC 134a or HCFC 142b” in the 2004 edition of Journal of Cellular Plastics.
2 For more on XPS applications, visit the XPSA Web site at www.xpsa.com.
3 See “Energy and Environmental Benefits of Extruded Polystyrene Foam and Fiberglass Insulation Products in U.S. Residential and Commercial Buildings,” by Merle F. McBride, PhD, PE.
5 See A.D. Little’s “Global Comparative Analysis of HFC and Alternative Technologies for Refrigeration, Air Conditioning, Foam, Solvent, Aerosol Propellant, and Fire Protection Applications”
6 This information takes into account the following ASTM International standards: ASTM C 578-06, Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation; ASTM 1289-06, Standard Specification for Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board; and ASTM C 1029-05a, Standard Specification for Spray-applied Rigid Cellular Polyurethane Thermal Insulation.
7 See “Development of Experimental Data on Extruded Polystyrene Roofing Insulation under Simulated Winter Exposure Conditions” (Report #SPI-6443, Energy Materials Testing Laboratory). See also “U.S. Army Cold Regions Research and Engineering Laboratories Report: Moisture in the Roofs of Cold Storage Buildings,” by Wayne Tobiasson and Alan Greatorex.
8 For more on FPSF technology, see “Frost-protected Shallow Foundations,” by Elizabeth M. Steiner in the November 2004 issue of Modern Materials.
Susan Herrenbruck is the executive director of the Extruded Polystyrene Foam Association (XPSA), a trade association representing manufacturers of XPS insulation products and its raw material suppliers.
Plastics Takes Improvement To The Wall Home
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Plastics Takes Improvement To The Wall
New NAHB Research Center Wall Study About Heat Flow—R-Value Not The Whole Story
By Craig Drumheller, NAHB Research Center
“Plastic building products can reduce heat flow an average of 18 to 25 percent over baseline wall under windy conditions.”
In an effort to more realistically quantify the energy performance of a variety of wall system alternatives under simulated ‘real-world’ conditions, the National Association of Home Builders (NAHB) Research Center, through the labs of Architectural Testing Inc., conducted a series of residential wall panel tests during 2005 and 2006. The purpose was to compare the most common ‘baseline wall’ (i.e. fiberglass batt insulation between 2x4 wooden studs finished with interior drywall) against several walls containing plastic building products (including foam plastic insulating materials).
R-value represents resistance to conductive heat flow, where higher numbers indicate increased thermal resistance. (In other words, the higher the R-value, the greater the insulating power.) Although R-value has been traditionally used in building codes for decades to quantify minimum insulation requirements for standard wall construction, it does not provide a complete accounting of the overall wall system’s energy performance. Effects such as thermal bridging of framing members, air and wind infiltration resistance, and stack effect on the building shell under normal, ‘real-world’ operating conditions are not considered in the R-value.
This study is unique in its evaluation of overall wall system performance. It was designed to characterize the energy consequences of wall construction and insulation material choices under simulated wind pressure conditions. To more accurately represent various climates and ‘real-world’ conditions, each wall system was tested under two conditions:
in a ‘static state’ condition with no additional atmospheric wind pressures at one outdoor temperature; and
with a 24-km/h (15-mph) ‘wind loading’ at three different outdoor temperatures.Testing showed all the wall systems performed similarly (within the statistical accuracy of the testing apparatus) under no-wind conditions. Of course, all walls under wind conditions performed less well than with no wind. Nonetheless, once simulated ‘real-world’ wind loading was applied, the wall systems with plastic panel building products performed between 14 and 29 percent better, with performance, relative to the baseline wall,
increasing as the outside temperature rose. This indicates air infiltration plays an important role in the thermal performance of a wall system in ‘real-world’ conditions.
This study addressed the net effect of temperature and wind pressure differences across a variety of residential walls, comparing them to the most common ‘stick and batt’ wall construction. The testing shows how a wall assembly would be expected to perform thermally while actually in use.
The test protocol was designed so the performance tests would be equitable for all the wall assemblies; additionally, the testing process was designed in such a manner to be repeatable. No two walls are made of exactly uniform materials due to factors such as wood warping, oriented strand board (OSB) thickness variations, and nail placement.
As such, special effort was made to ensure framing leakage through OSB sheathed walls was both reasonable and consistent (ASTM International E 283, Standard Test Method for Determining Rate of Air Leakage through Exterior Windows, Curtain Walls, and Doors Under Specified Pressure Differences Across the Specimen). Also, benchmarking was performed on each wall sample. The R-value of each individual material was tested (ASTM C 518, Standard Test Method for Steady-state Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus, at 24 C [75 F] mean temperature) and from the material test results, a theoretical whole wall R-value was calculated for each wall that became its benchmark.
The benchmark was then compared to the actual whole wall test results at Architectural Testing Inc. of York, Philadelphia (ASTM C 1363, Standard Test Method for Thermal Performance of Building Materials and Envelope Assemblies by Means of a Hot Box Apparatus). The ratio of actual performance of a wall system over a wall’s benchmark became the basis of comparison between the wall types. This enabled reasonable comparison of walls with differing R-values. This method fairly handicaps walls of various R-values to capture differences in performance of a wall system under different conditions. Conditions were representative of both typical and extreme ‘real-world’ conditions in various climates.
Five wall types were assembled for whole-wall thermal testing. Plastic building products such as plastic building wrap, plastic spray-inplace foam insulation, rigid foam plastic insulation, and structural insulated panels (SIPs) of foam plastic were compared to the baseline wall’s benchmark construction (Table 1). Note: the R-value of spray polyurethane foam (SPF) may degrade after installation. Generally, most degradation occurs within the first couple of months after application. To account for this possible change, the spray polyurethane foam (SPF) panels tested were warehoused nearly a year prior to the study.
The tested baseline wall represented the most common wall construction used in home building today (NAHB Research Center): a 2.4-m (8-ft) high, 101.6-mm (4-in.) overall thickness, wood-studframed wall with studs spaced 406.4 mm (16 in.) on-center (oc), sheathed with OSB, R-13 kraft-faced fiberglass batt (KFB) insulation, and 12.7-mm (0.5-in.) drywall covering the inside. Furthermore, best installation practices and the manufacturers’ specifications were used. Individual insulation products were thermally characterized through alternate testing to validate the overall wall and material performance designations.
Since each plastic-insulated wall performed better than the baseline under windy conditions, it was concluded the supposed performance values based on traditional R-value
measurements and calculations are not a complete indicator of how well a wall system will resist the loss or gain of energy.
Summary
This laboratory testing clearly demonstrated the benefits of using plastic building products (including plastic foam insulation) by showing significantly improved energy performance of residential wall systems under ‘real-world,’ wind-loaded conditions at various temperatures, compared to the baseline wall construction, as specified below.
No wind and moderate temperature (static state)
When there is no wind at 21 C (70 F) inside and −4 C (25 F) outside, all wall systems performed similar to their expected calculated benchmark. Compared to a typical batt insulation baseline, wall systems with plastic building products had a heat flow reduction of only three percent (not statistically significant).
Wind and extremely cold temperature
Under a 24-km/h (15-mph) wind pressure, at 70 F inside and a temperature of −26 C (−15 F) outside, plastic building products and foam plastic-insulated wall panel systems reduced heat flow an average of 18 percent better than the baseline.
Wind and moderate temperature
Under a 15-mph wind, at 70 F inside and a temperature of 25 F outside, the performance results changed significantly. The wall systems with plastic building products overall reduced heat flow an average of 20 percent better than the baseline.
Wind and extremely hot temperature
Under a 15-mph wind, at 70 F inside and a temperature of 46 C (115 F) outside, wall systems with plastic building products reduced heat flow an average of 25 percent better than the baseline. One panel sample performed 29 percent better in this category.
ConclusionAn important finding is all the walls containing plastic building products performed similarly to the baseline wall with respect to reducing heat flow in the ‘no-wind’ conditions. Interestingly, though, when ‘real-world’ wind conditions were applied, the research found all wall systems with plastic building products performed similarly better than the baseline. It also found that, as the temperature changed, all wall systems with plastic building products performed similarly better as a group to the baseline wall at each new temperature level.
An important implication of this research indicates in order for a typical (i.e. stick and batt) wall to meet the performance of a ‘plastic’ wall under windy conditions, it would need to perform at least 15 percent better. This is equivalent to upgrading the wall insulation from R-13 to R-15. As mentioned earlier, the higher the R-value, the greater the insulating power. (Design professionals should ask an insulation seller for a fact sheet on R-values.) Nonetheless, without considering changes in air infiltration between the batt types, this means approximately 85 percent more fiberglass material would need to be inserted in the
same 88.9-mm (3.5-in.) cavity to achieve similar performance results to plastic building products in this study, according to the NAHB Research Center.
About the Author Craig Drumheller is a senior engineer with the National Association of Home Builders (NAHB) Research Center.
Bringing 'do no harm' to building materialsHoward WilliamsMonday, May 6, 2013 - 5:00am
CC license by La Citta Vita/Flickr
What will it serve if we halt global warming, restore our natural environment and transition to alternative energy only to find we left humanity behind to deal with its chronic illnesses?
We expect our “place” — home, school, store, hospital, office or place of worship — to be healthy and safe.
But buildings are made of stuff that contains chemicals, some of which are chemicals of concern. Chronic diseases are on the rise, with seven out of 10 deaths among Americans each year attributed to them. Those diseases are also increasingly linked to chemical exposure.
We spend over 90 percent of our lives indoors. Buildings either can be the cause of illness or consciously designed and built in ways that contribute to better health.
The Green Guide for Health Care states, “Imagine cancer treatment centers built without materials linked to cancer,” but we should not only do that, but imagine all buildings built with materials safe for humans and the environment.
Overcoming challenges
Immunologist and allergist Dr. Claudia Miller suggests that the architectural community may have a greater influence on human health than physicians. Physicians can recommend behavioral changes that will lead to better health and wellness, but the results will depend on an individual’s willingness to change their habits. Architects and designers face the same behavior change challenge when designing wellness
features into a building or site. But when it comes to healthy building materials, no behavior change is required; just a firm hand on the specification is needed.
Architecture always has sought to design in ways that enable people to interact favorably with their built environment.
Interestingly, when we turn that traditional view 180 degrees, we begin creating built environments that interact favorably in terms of health and wellness with people.
Some began to engage in this introspective work over a decade ago, while others have waited for a more audible market to form around the premise that buildings should be health-positive and wellness-active.
Image credit: CC license by La Citta Vita/Flickr
The idea of being health positive is grounded in the belief that building materials should be free of chemicals of concern. All stakeholders have the right to expect this beneficial interaction with their built environment. Health positive is a hazard-based concept that respects not only the site boundary, but also the full length of the supply chain. (End users may be at risk if the hazardous chemical escapes from the material, whereas many others along the supply chain may have dealt directly with the hazardous chemical.)
The drivers of this change are varied and many, and we may never know when the tipping point naturally would have occurred. We know only that at GreenBuild 2012, Rick Fedrizzi, CEO of the U.S. Green Building Council, played the ball from where it lay and healthy buildings gained a bodyguard through a highly resolved commitment to LEED v4, Materials & Resources. Wasting no time, the USGBC held a Green Building and Human Health Summit in January because, in Fedrizzi’s words, “Healthy places are a human right.” The NIH reconvened the Health in Buildings Roundtable in April for the purpose of building a body of research from which additional evidence-based strategies may be drawn and acted upon in a series of continuous improvement cycles.
I participated in both meetings and although additional research was discussed, I don’t recall anyone suggesting the buildings industry currently lacks actionable findings or sufficiently informed consumers willing to use their buying power to pull new, safer building materials into the market.
Joining the leaders
So who is answering the consumer’s call for healthy buildings materials?
Building owners in the healthcare, education, commercial and residential markets are making materials a key consideration.
Architects and designers such as Perkins+Will, HKS, HOK and HDR Architecture are recognizing material health as a vital subset of sustainability.
The USGBC is responding to its customers by introducing LEED v4’s Materials & Resourcestransparency, avoiding chemicals of concern in materials and supply chains.
Building product manufacturers are responding to their consumers through transparency, labeling and avoidance/removal of chemicals of concern.
Rigorous multi-attribute third-party product certification, such as the Cradle-to-Cradle Product Innovation Institute’s C2C Certification, addresses the full spectrum of sustainability and all of its stakeholders. The Cradle to Cradle Certified Products Program rates products across five critical quality categories and recognizes achievement and a commitment to continuous improvement. The five critical categories are the sustainability primaries: material health (chemistry), reutilization (recycle), water (use reduction), energy (renewables instead of fossil) and social responsibility. The five are inseparable aspects of sustainability.
To get started on using or making safe building materials:
1. Bring to all your business decisions William McDonough’s insight: “Design is the first signal of human intention.”
2. Contact the Cradle to Cradle Products Innovation Institute.3. Contact McDonough Braungart Design Chemistry.4. Establish a chemicals policy governing products and processes. 5. Do it.
There are many ways to characterize and define sustainability, but I’ve found none so compelling as what Dwight D. Eisenhower, the 34th U.S. President, said in his farewell address:
“As we peer into society’s future, we – you and I, and our government – must avoid the impulse to live only for today, plundering, for our own ease and convenience, the precious resources of tomorrow. We cannot mortgage the material assets of our grandchildren without asking the loss also of their political and spiritual heritage.”
Toxic Building Materials in Residential ConstructionA reporter from Angie’s List Magazine just asked for my opinion on toxic building
materials in residential construction… and while writing my response I realized there
was some valuable information to share. Hopefully Angie’s List Magazine will decide to
run the piece.
Here is my response to some great questions from Brittany Paris:
1) What do you consider to be the most toxic building materials used in
residential construction today – and why?
PVC, lead, mercury, and halogenated flame retardants would be top my list. Each of
these common building components have known health and toxicity problems, and can
become deadly under the wrong conditions.
PVC: Polyvinyl Chloride has a tremendous upstream toxicity impact (chemical
manufacturing in “cancer alley”), releases phthalates during it’s use phase of life, and
releases dioxin when burned. Dioxin is one of the most toxic substances known to exist.
PVC and PVC-byproducts contain known carcinogens, and developmental and
reproductive toxicants.
Lead: We’re learning that lead exposure – at even lower rates than previously known –
has negative effects in the form of cancer, and developmental and reproductive toxicity.
Around the country you can still buy faucets and lead-containing solder to be used for
potable water. In fact, in the US, even “lead-free” solder and flux is allowed to contain
lead! So you have to specify “100% lead-free” if you’re serious about eliminating lead.
Mercury: There is still mercury in some electronics and thermostats, but the most
significant source in the residential sector is in lighting. Since the massive rollout of
Compact Fluorescent Lights (CFLs), several states and the EPA have published clean-up
protocols for broken CFLs. Mercury is a known developmental toxicant, and it’s
suspected of many other health effects.
Halogenated Flame Retardants: HFRs are added to too many building materials – even
when they are not needed. Fire scientists, toxicologists, and even firefighters are raising
alarm bells around the world. There is no significant fire safety benefit from HFRs in
foam or wiring behind walls or under concrete slabs, yet current US codes requires HFRs
in these applications. Sadly, during a fire, HFRs release significantly more smoke and
very toxic gases that harm/kill occupants and firefighters. The European Union has
already banned some HFRs, but the US lags behind. There is currently a concerted
effort in the green building movement to remove HFRs from materials when there is no
added fire safety benefit.
2) Are you seeing a shift in the green building community to phase out some
of these noxious materials?
Absolutely. There are numerous green building rating systems that now “give points”
for avoiding these known hazards. At last week’s GreenBuild Conference – the largest
green building conference in the country – CA Governor Jerry Brown really hammered
home the point that “green buildings” need to be healthy, and not just energy efficient.
Major architecture and engineering firms are voluntarily specifying alternatives to these
chemicals, and huge companies (e.g., Google) are going through great extremes to
reduce their use in buildings. So forward thinking designers are meeting more
conscientious consumers – and a major shift is taking place in the design/build industry.
3) What are some alternative building materials for those you listed above?
PVC piping for potable water can easily be swapped out with copper, PEX or
polypropylene, and there are even less expensive alternatives for non-potable water
piping.
Lead in potable water plumbing should be avoided where possible. Most brass fittings
and valves do contain trace amounts of lead, but eliminating lead from flux and solder
is low hanging fruit.
Light Emitting Diodes (LEDs) are far more energy efficient than CFLs, and they do not
contain mercury.
Halogenated Flame Retardants (HFRs) are in all foam products in the US, and now the
only avoidance strategy available is to not specify foam. There are alternatives to PVC-
and HFR-jacketed wiring, but the cost premium to avoid these toxins is so high it is out
of the reach of most American home builders.
4) Do you encounter clients who are sickened by the effects of toxic
construction materials?
Yes, every day! Half of our business focuses on green building consulting for new
buildings or remodels, and the other half is devoted to environmental testing (industrial
hygiene) for existing buildings. The number of people sick and suffering in buildings is
alarming, and the stories we hear every day are heartbreaking. It doesn’t have to be
this way, but sick buildings are contagious, and our jobs are secure for the foreseeable
future.
5) How can a consumer find out what a building product contains?
I wish there was an easy answer. Unlike food labeling laws that require full ingredient
disclosure, intellectual property rights provide a corporate veil of secrecy over many
common building materials in the US. Most products disclose their primary ingredients
on mandated Material Safety Data Sheets (MSDS), but it’s not required they post all
ingredients. It’s a two-pronged movement toward healthy building materials: on one
side there are growing precautionary lists of chemicals to avoid, and on the other side
are people demanding more transparency!
Pharos is an online database of materials and their ingredients, but it’s voluntary and
therefore doesn’t have enough materials cataloged to be very useful when evaluating
the material palette for an entire building.
The push for transparency is from many diverse stakeholders. But just last week the
Health Product Declaration Collaborative made it’s big debut, and moving forward this
non-profit lead by respected industry leaders will undoubtedly become the de facto
umbrella group organizing the push for transparency. Keep an eye out for many major
product manufacturers to start completing Health Product Declarations (HPDs) and
disclosing more ingredients.
6) Anything else you’d like to mention?
Healthy building is about much more than air quality. Light quality, acoustics,
electromagnetic fields, and connections to nature are all part of a truly healthy building.
So many green building consultants focus primarily on energy efficiency, and some
energy efficiency measures can actually harm occupant health.
We frequently use two images to remind people of how important health is: 1) from the
American Lung Association, “when you can’t breathe, nothing else matters,” and 2) If
you were driving your kid uphill to the hospital and he was having an asthma attack –
would you drive your Prius slow to improve your fuel economy?
I like to think these help people frame the importance of healthy buildings. Without our
health – what do we have?
Harmful substances in building materialsContaminated Building Materials
PCB (Polychlorinated Biphenyls) and asbestos are some of the substances damaging to health in building materials. Today the use of building materials containing PCB and asbestos is illegal, but prior to changes in the law the harmful affects of these substances were unknown and they were often used in construction within the law.
Today we know that PCB and asbestos can cause a number of serious problems and health hazards to people through contamination of the indoor climate in buildings that contain them. In addition, the presence of harmful substances may make renovation and demolition projects far more expensive than expected.
How can the Danish Technological Institute help you?
Preliminary Screening/Mapping of Harmful Substances in Buildings Determination of Extent of Sample Extraction and Building Inspection Technical Measurements of Indoor Climate and Consultancy Hazard Assessment of the Effects of Harmful Substances on Users Preparation of Action Plans
Even though both asbestos and PBC are substances damaging to health, they are very different in the sense that they have completely different properties and affect our health in different ways too. In the 60s and the 70s, PCB, one of the world’s most dangerous environmental toxins, was used as a softening agent in building materials – e.g. in fillers and in the sealing of doubled-glazed windows. These substances disrupt hormones and are difficult to break down, thereby accumulating in the food chain.
Contamination from asbestos primarily occurs when materials containing it are damaged during renovations and repairs or when buildings are demolished. Asbestos is non-flammable with good insulating capacities and has therefore been used for things like ceiling sheets and technical insulation, for example. Asbestos fibres easily split into very thin fibres, which can be inhaled and, in the long term, can cause diseases such as lung cancer.
Unsuitable use of other materials can also result in damaging effects on the indoor climate, for example, earlier use of mineral wool in ventilation systems and surface treatment with leaded paints.
At The Danish Technological Institute we have extensive consultancy and guidance experience and also in arranging courses concerning the handling of harmful substances that may be contained in building materials. It may be beneficial to involve our experts at an early stage of a renovation or demolition job where there is a risk that such harmful substances could be present.
The Danish Technological Institute analyses PCB and asbestos content in materials and air in our own laboratories. PBC analyses of building materials.
FormaldehydeFormaldehyde is used widely to manufacture building materials and numerous household products. It is also a by-product of combustion and certain other natural processes. Thus, it may be present in substantial concentrations both indoors and outdoors. In homes, the most significant sources of formaldehyde are likely to be pressed wood products made using adhesives that contain urea-formaldehyde (UF) resins. Pressed wood products made for indoor use include particleboard, hardwood plywood paneling, and medium density fiberboard, which contains a higher resin-to-wood ratio than any other UF pressed wood product and is generally
recognized as being the highest formaldehyde-emitting pressed wood product.
Formaldehyde is also used to add permanent-press qualities to clothing and draperies, as a component of glues and adhesives, and as a preservative in some paints and coating products. Formaldehyde, a colorless, pungent-smelling gas, is a known respiratory irritant and carcinogen. It can cause watery eyes, burning sensations in the eyes and throat, nausea, and difficulty in breathing in some humans exposed at elevated levels (above 0.1 parts per million).
Phthalates
Phthalates, called “plasticizers,” are a group of industrial chemicals used to make plastics like polyvinyl chloride (PVC) more flexible or resilient. Building materials are the largest end use for PVC. Major uses of flexible PVC in buildings include carpet backing, resilient flooring, wall coverings, acoustical ceiling surfaces, upholstery textiles, roof membranes, waterproofing membranes, and electrical cord insulation. Phthalates are nearly ubiquitous in modern society, and can also be found in toys, food packaging, hoses, raincoats, shower curtains, vinyl flooring, adhesives, detergents, hair spray, and shampoo. Certain phthalates are known or suspected endocrine disruptors, meaning they impact and alter the human hormone system. Phthalates are also suspected to be potent reproductive toxins, especially in boys.
Polybrominated diphenyl ethers (PBDEs)PBDEs are used as flame retardants in plastic building materials and are particularly widespread in polyurethane foam products (insulation and cushions). In May, 2010, the EPA released an exposure assessment for PBDEs, providing information on the extent to which humans are exposed to and have a body burden of the chemicals. Key routes of human exposure are thought to be from their use in household consumer products, and their presence in house dust, and not from dietary routes. PBDEs have been associated in animal studies with liver toxicity, thyroid toxicity, developmental and reproductive toxicity, and developmental neurotoxicity.
Since many people spend much of their time indoors, long-term exposure to VOCs in the indoor environment can contribute to sick building syndrome.[17] In offices, VOC results from new furnishings, wall coverings, and office equipment such as photocopy machines, which can off-gas VOCs into the air.[18][19] Good ventilation and air-conditioning systems are helpful at reducing VOCs in the indoor environment.[18] Studies also show that relative leukemia and lymphoma can increase through prolonged exposure of VOCs in the indoor environment.[20]
In the United States, there are two standardized methods for measuring VOCs, one by the National Institute for Occupational Safety and Health (NIOSH) and another by Occupational Safety and Health Administration (OSHA). Each method uses a single component solvent; butanol and hexane cannot be sampled, however, on the same sample matrix using the NIOSH or OSHA method.[21]
The aromatic VOC compound benzene, emitted from exhaled cigarette smoke is labeled as carcinogenic, and is ten times higher in smokers than in nonsmokers.[18]
The United States Environmental Protection Agency (EPA) has found concentrations of VOCs in indoor air to be 2 to 5 times greater than in outdoor air and sometimes far greater. During certain activities indoor levels of VOCs may reach 1,000 times that of the outside air.[22] Studies have shown that individual VOC emissions by themselves are not that high in an indoor environment, but the indoor total VOC (TVOC) concentrations can be up to five times higher than the VOC outdoor levels.[23] New buildings especially, contribute to the highest level of VOC off-gassing in an indoor environment because of the abundant new materials generating VOC particles at the same time in such a short time period.[17] In addition to new buildings, we also use many consumer products that emit VOC compounds, therefore the total concentration of VOC levels is much greater within the indoor environment.[17]
VOC concentration in an indoor environment during winter is three to four times higher than the VOC concentrations during the summer.[24] High indoor VOC levels are attributed to the low rates of air exchange between the indoor and outdoor environment as a result of tight-shut windows and the increasing use of humidifiers.[25]
