Using materials recovered from the waste stream typically results in less waste, pollution, and energy use than using virgin materials. From an environmental standpoint, post-consumer is typically considered preferable to pre-consumer recycled content because post-consumer recycled materials are more likely to have been diverted from landfills.
In some cases, we consider products with recycled content green but with some caveats regarding where they should be used. For example, rubber flooring made from recycled automobile tires should not be used in most fully enclosed indoor spaces due to the likelihood of VOC emissions.
Recycling can have downsides. For example, some studies show that curbside collection programs and some recycling processes use more energy than they save. Closed-loop recycling is generally preferable to “down-cycling,” in which a lower-grade material is produced—but due to contamination of waste streams and the difficulty of extracting high-value ingredients, down-cycling may be as good as it gets. At times recycling can re-introduce hazardous components. Some products, like copper and aluminum, include a high level of recycled content as a matter of course—which we applaud, but don’t consider justification for listing in GreenSpec. As more complete life-cycle information on recycled materials and processes becomes available, we use that to increase our scrutiny of recycled products.
EcoCore Phase Change Panel
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Pre-consumer (also called “post-industrial”) recycling refers to the reuse of industrial by-products, as distinguished from material that has been in consumer use. The iron-ore slag used to make mineral wool insulation and the fly ash used to make concrete are examples of post-industrial recycled materials. While post-consumer recycled content is preferable, a product that uses pre-consumer content or recycles a seldom-used waste product, especially in an area where recycled products are hard to find, can be considered green.
Excluded from this category, by FTC definitions, is the use of scrap within the same manufacturing process from which it was generated—material that would typically have gone back into the manufacturing process anyway. -
Some products help us use other products or materials more efficiently. For example, drywall clips allow the elimination of corner studs, engineered stair stringers reduce lumber waste, and concrete pigments and polishing systems can turn concrete slabs into attractive finished floors. We also recognize some products, like vacuum plumbing systems, which use less material than their conventional counterparts. Many products with this attribute are fairly unique, so we bring a skeptical eye to manufacturer claims, but not a specific standard.
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Before specifying efficient heating and cooling equipment, it’s important to do what we can to reduce heating and cooling loads. Insulation is one of the key products to consider here, but because there are so many insulation products on the market, we look for additional benefits. Examples include cellulose insulation with recycled content, mineral wool insulation with no flame retardants, and fiberglass insulation with no formaldehyde binders. Other products in this area are high-performance windows and glazings, products that contribute to building airtight envelopes, products that reduce thermal bridging, and window-retrofit products.
With products in this area under constant development, we are always refining our approach. For example, as we have learned about insulation products with hazardous flame retardants and blowing agents that have high global warming potential, we have removed those products from GreenSpec, pending manufacturing changes. We encourage building professionals to pressure manufacturers for those changes through specification language and purchasing decisions. -
Once we’ve considered low-emitting products and those that prevent moisture problems, we also consider green ventilation products, filters, radon mitigation equipment, and other equipment and devices that help to remove pollutants or introduce fresh air. Because ventilation equipment is standard, we only recognize products that are particularly efficient or quiet or which have other benefits, such as heat recovery.
Tate Access Floors has developed EcoCore access panels that have a cementitious fill with small capsules with a phase change material (PCM) paraffin core. These flooring panels are installed on supports and provide a space for underfloor air delivery and electrical and communications cabling. The PCM in EcoCore panels has a phase-change temperature of 75.2°F. The panels are available in two sizes. The 24" square, 1-5/8" deep panels contain 2.3 lbs of PCM and absorb up to 141 Btu of thermal energy and weigh 8.2 lbs/ft2. Each 24" square panel absorbs an additional 6.7 Btu/°F. The 60 cm square, 1.28" deep panels contain 2.4 lbs of PCM and absorb up to 147 Btu of thermal energy and weigh 9.6 lbs/ft2. Each 60 cm square panel absorbs an additional 7.4 Btu/°F. By comparison, four square feet of 4-inch-thick concrete slab provides about 360 Btu of heat storage over a 10°F rise in temperature. An electrically conductive epoxy paint finish protects the panel from corrosion. The panel and understructure system contain a minimum of 30% recycled content. According to the manufacturer, the PCM has a lifespan of over 100,000 phase changes.
Thermal storage materials are used in buildings to store heat and reduce temperature cycling, and thus, maintain more even temperatures. By maintaining more constant temperatures and storing heat that is released later in the day (or year), thermal storage materials can improve comfort in a building interior, as well as reduce heating and cooling loads.
A wide range of materials can provide thermal storage, including concrete, brick, tile, stone, plaster, wood, and water. Effectiveness in heat storage is a function of the “heat capacity” of a material and the ability of heat to move into and out of the material. This can be a function of thermal conductivity or, with fluids, convection. These common “thermal mass” materials are all solids or liquids that store and release heat without changing phase.
Some materials can store and release very large amounts of heat as they change phase—absorbing heat as the solid melts and releasing that heat as the liquid freezes. This heat storage relies on the physical principle of “latent heat” capacity. These so-called “phase change materials” (PCMs) can be paraffins, salt hydrates, or eutectic salts. Water also can serve as a PCM, and it is widely used in ice-based Thermal Energy Storage (TES) HVAC systems.
Access flooring greatly simplifies renovation or reconfiguration of office spaces, dramatically reducing "churn" costs.
In addition to providing a plenum for electrical and communications cabling, access flooring with appropriate height can be used for underfloor air delivery (UFAD)—an economically and environmentally attractive combination of floor and air duct.
Compared to conventional ceiling-located air-supplies, displacement ventilation from access flooring systems more effectively diffuses conditioned air into the occupied space to displace stale air, which leaves via ceiling-mounted return ducts.
More effective air distribution leads to other efficiencies as well: air handlers can be downsized, and conditioned air does not have to be chilled as much to provide the same levels of comfort. Often, ceiling height can also be increased, improving daylighting potential.
LEED Credits
EAc1: Optimize Energy Performance
EAp2: Minimum Energy Performance
EAp2: Minimum Energy Efficiency Performance
EQc2: Increased Ventilation
EQp1: Minimum IAQ Performance
IEQc2: Increased Ventilation
IEQc2: Increased Ventlilation
IEQp1: Minimum IAQ Performance
MRc4: Recycled Content
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