In the exciting industry of building and remodeling residential, commercial and institutional structures, there are terms and phrases that builders, designers and architects use that they are familiar with but you may not be. We have captured many of them here with the intent to create a resource that you may use whether you are building with us or just curious about a process or term. If we have missed something you want more information about, please send your inquiry to email@example.com. We’ll do our best to get back to you.
- Energy Conservation
- Solar Related
- Environmental Impact
- Other Construction/Building Related Terms
ENERGY STAR® is an international standard for energy efficient consumer products originated in the United States of America. It was first created as a United States Environmental Protection Agency program during the early 1990s, but Australia, Canada, Japan, New Zealand, Taiwan and the European Union have also adopted the program. Devices carrying the ENERGY STAR® logo, such as computer products and peripherals, kitchen appliances, buildings and other products, generally use 20%–30% less energy than required by federal standards.
The ENERGY STAR® program was intended to reduce energy consumption and greenhouse gas emission by power plants. Developed by John S. Hoffman, inventor of the Green Programs at EPA, working closely with the IT industry, and implemented by Cathy Zoi and Brian Johnson, the program was part of a series of voluntary programs, such as Green Lights and the Methane Programs, that would demonstrate the potential for profit in reducing greenhouse gases and facilitate further steps to reducing global warming gases.
Beginning with labels for computer and printer products, the program was significantly expanded in 1995, introducing labels for residential heating and cooling systems and new homes. Currently there are tens of thousands of ENERGY STAR® products available in a wide range of items including major appliances, office equipment, lighting, home electronics, and more. ENERGY STAR® strategies are available for new homes, and commercial and industrial buildings as well as small businesses and congregations.
Wright Builders, Inc. is an ENERGY STAR® partner and are part of the EPA’s airPLUS Program. This program recognizes newly built homes that include a comprehensive set of indoor air quality measures, further differentiating our new homes from others. We are 100% on board with building to the ENERGY STAR® standard, upholding our commitment to save energy, reduce global warming and create healthy homes that also are less expensive to operate.
You can visit the ENERGY STAR website to learn more about products, building an ENERGY STAR home and about how to start saving with ENERGY STAR.
Did you know:
If every TV, DVD, and sound bar purchased in the U.S. were certified, we would save more than $220 million and prevent 2.8 billion pounds of greenhouse gas emissions each year.
ENERGY STAR qualifying dryers use 20 percent less energy and ENERGY STAR partners sponsor rebates on certified products.
LED stands for light emitting diode. LED lighting products produce light approximately 90% more efficiently than incandescent light bulbs.
Tablets use 4 x less energy than a laptop.
Efficient energy use, sometimes simply called energy efficiency, is the goal of efforts to reduce the amount of energy required to provide products and services. For example, insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature. Installing fluorescent lights or natural skylights reduces the amount of energy required to attain the same level of illumination compared to using traditional incandescent light bulbs. Compact fluorescent lights use two-thirds less energy and may last 6 to 10 times longer than incandescent lights. Improvements in energy efficiency are most often achieved by adopting a more efficient technology or production process.
There are various different motivations to improve energy efficiency. Reducing energy use reduces energy costs and may result in a financial cost saving to consumers if the energy savings offset any additional costs of implementing an energy efficient technology. Reducing energy use is also seen as a key solution to the problem of reducing emissions. According to the International Energy Agency, improved energy efficiency in buildings, industrial processes and transportation could reduce the world’s energy needs in 2050 by one third, and help control global emissions of greenhouse gases.
A Home Energy Rating (HERS) is a measurement of a home’s energy efficiency, used primarily in the United States. Home energy ratings can be used for either existing homes or new homes. A home energy rating of an existing home allows a homeowner to receive a report listing options for upgrading a home’s energy efficiency. The homeowners may then use the report to determine the most effective ways in which to upgrade the home’s energy efficiency.
Ratings provide a relative energy use index called the HERS Index – a HERS Index of 100 represents the energy use of the “American Standard Building” and an Index of 0 (zero) indicates that the building uses no net purchased energy (a Zero Energy Building). The lower the value, the better. Wright Builders, Inc.’s homes have an estimated HERS ratings of 45 or lower.
Leadership in Energy and Environmental Design (LEED) consists of a suite of rating systems for the design, construction and operation of high performance green buildings, homes and neighborhoods.
Developed by the U.S. Green Building Council (USGBC), LEED is intended to provide building owners and operators a concise framework for identifying and implementing practical and measurable green building design, construction, operations and maintenance solutions.
LEED has evolved since its original inception in 1998 to more accurately represent and incorporate emerging green building technologies. Today, LEED consists of a suite of nine rating systems for the design, construction and operation of buildings, homes and neighborhoods.
Wright Builders, Inc’s homes at Village Hill are eligible for LEED certification. Final ratings are applied once all requirements of the program have been fulfilled.
The efficiency of air conditioners is often rated by the Seasonal Energy Efficiency Ratio (SEER) which is defined by the Air Conditioning, Heating and Refrigeration Institute in its standard ARI 210/240, Performance Rating of Unitary Air-Conditioning and Air-Source Heat Pump Equipment.
The SEER rating of a unit is the cooling output in BTU (British thermal unit) during a typical cooling-season divided by the total electric energy input in watt-hours during the same period. The higher the unit’s SEER rating the more energy efficient it is.
The Energy Efficiency Ratio (EER) of a particular cooling device is the ratio of output cooling (in Btu/hr) to input electrical power (in watts) at a given operating point. EER is generally calculated using a 95F outside temp and an inside (actually return air) temp of 80F and 50% relative humidity.
The EER is related to the coefficient of performance (COP) commonly used in thermodynamics, with the primary difference being that the COP of a cooling device is unit-less: the cooling load and the electrical power needed to run the device are both measured using the same units, e.g. watts.
The Seasonal Energy Efficiency Ratio (SEER) has the same units of BTU, but instead of being evaluated at a single operating condition, it represents the expected overall performance for a typical year’s weather in a given location. The SEER is thus calculated with the same indoor temperature, but over a range of outside temperatures from 65 to 104 degrees F, with a certain specified percentage of time in each of 8 bins each spanning 5 degrees F. There is no allowance for different climates in this rating. It just gives an indication of how the actual EER is typically affected by different outside temperatures over the course of a cooling season.
Wright Builders, Inc. installs minimum 14.5 SEER air conditioning.
Insulated Window Glazing
Insulated glazing (IG) also known as double glazing are double or triple glass window panes separated by an air or other gas filled space to reduce heat transfer across a part of the building envelope.
Glass in windows is used to provide light and allow a view from either side to the other side. Its importance to the construction is its dimensional stability over a wide temperature range.
Insulated Glass Units (IGUs) are manufactured with glass in range of thickness from 3 mm to 10 mm or more in special applications. Laminated or tempered glass may also be used as part of the construction. Most units are manufactured with the same thickness of glass used on both panes but special applications such as acoustic attenuation or security may require wide ranges of thicknesses to be incorporated in the same unit.
The glass panes are separated by a “spacer”. A spacer is the piece that separates the two panes of glass in an insulating glass system, and seals the gas space between them. Historically, spacers were made primarily of metal, which manufacturers thought provided more durability.
Wright Builders, Inc typically installs triple glazed windows with an R value of 4.5 to ensure maximize energy savings and efficiency.
Low E Glass
Low emissivity (low e) – actually low thermal emissivity – is a quality of a surface that radiates, or emits, low levels of radiant thermal (heat) energy. All materials absorb, reflect and emit radiant energy.
Emissivity is the value given to materials based on the ratio of heat emitted compared to a blackbody, on a scale of 0 to 1. A blackbody would have an emissivity of 1 and a perfect reflector would have a value of 0.
Reflectivity is inversely related to emissivity and when added together their total should equal 1 for an opaque material. Therefore, if asphalt has a thermal emissivity value of 0.90 its thermal reflectance value would be 0.10. This means that it absorbs and emits 90% of radiant thermal energy and reflects only 10%. Conversely, a low-e material such as aluminum foil has a thermal emissivity value of 0.03 and a thermal reflectance value of 0.97, meaning it reflects 97% of radiant thermal energy and emits only 3%. Low-emissivity building materials include window glass manufactured with metal-oxide coatings as well as housewrap materials, reflective thermal insulations and other forms of radiant thermal barriers.
Energy recovery ventilation (ERV) is the energy recovery process of exchanging the energy contained in normally exhausted building or space air and using it to treat (precondition) the incoming outdoor ventilation air in residential and commercial HVAC systems. During the warmer seasons, the system pre-cools and dehumidifies while humidifying and pre-heating in the cooler seasons. The benefit of using energy recovery is the ability to meet the ASHRAE ventilation & energy standards, while improving indoor air quality and reducing total HVAC equipment capacity.
This technology, as expected, has not only demonstrated an effective means of reducing energy cost and heating and cooling loads, but has allowed for the scaling down of equipment. Additionally, this system will allow for the indoor environment to maintain a relative humidity of an appealing 40% to 50% range. This range can be maintained under essentially all conditions. The only energy penalty is the power needed for the blower to overcome the pressure drop in the system.
An energy recovery ventilator (also abbreviated ERV) is a type of air-to-air heat exchanger that not only transfers sensible heat but also latent heat. Since both temperature and moisture is transferred, ERVs can be considered total enthalpic devices. On the other hand, a heat recovery ventilator (HRV) can only transfer sensible heat. HRVs can be considered sensible only devices because they only exchange sensible heat. In other words, whereas all ERVs are HRVs, not all HRVs are ERVs, but many people use the terms HRV, AAHX (air-to-air heat exchanger), and ERV interchangeably.
Wright Builder’s uses ERVs in conjunction with their HVAC system designs to circulate fresh air throughout the home, recover heat and to control humidity.
Net Surplus Electricity
Net surplus electricity is the electricity generated by a solar PV system that exceeds the amount of electricity consumed by the customer in a given period. The systems that Wright Builders, Inc. installs in the homes and other buildings we construct strive to create a “net surplus electricity” environment.
Photovoltaics (PV) is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect. Photovoltaic power generation employs solar panels composed of a number of solar cells containing a photovoltaic material. Due to the growing demand for renewable energy sources, the manufacturing of solar cells and photovoltaic arrays has advanced considerably in recent years.
The total power output of the world’s PV capacity run over a calendar year is equal to some 80 billion kWh of electricity. This is sufficient to cover the annual power supply needs of over 20 million households in the world. More than 100 countries use solar PV. Installations may be ground-mounted (and sometimes integrated with farming and grazing) or built into the roof or walls of a building (building-integrated photovoltaics).
Driven by advances in technology and increases in manufacturing scale and sophistication, the cost of photovoltaics has declined steadily since the first solar cells were manufactured and the levelised cost of electricity (LCOE) from PV is competitive with conventional electricity sources in an expanding list of geographic regions. Net metering and financial incentives, such as preferential feed-in tariffs for solar-generated electricity have supported solar PV installations in the United States.
Photovoltaics are best known as a method for generating electric power by using solar cells to convert energy from the sun into a flow of electrons. The photovoltaic effect refers to photons of light exciting electrons into a higher state of energy, allowing them to act as charge carriers for an electric current. The Cave home in North Hadley, MA was constructed with a full array of Photovoltaics.
A solar panel (also solar module, photovoltaic module or photovoltaic panel) is a packaged, connected assembly of photovoltaic cells. The solar panel can be used as a component of a larger photovoltaic system to generate and supply electricity in commercial and residential applications.
Because a single solar panel can produce only a limited amount of power, many installations contain several panels. A photovoltaic system typically includes an array of solar panels, an inverter, and sometimes a battery and interconnection wiring.
Solar panels use light energy (photons) from the sun to generate electricity through the photovoltaic effect. The structural (load carrying) member of a module can either be the top layer or the back layer. The majority of modules use wafer-based crystalline silicon cells or thin-film cells based on cadmium telluride or silicon. The conducting wires that take the current off the panels may contain silver, copper or other non-magnetic conductive transition metals.
The cells must be connected electrically to one another and to the rest of the system. Cells must also be protected from mechanical damage and moisture. Electrical connections are made in series to achieve a desired output voltage and/or in parallel to provide a desired current capability.
A solar inverter or PV inverter is a critical component in a photovoltaic system. It converts the variable DC output of the solar panel into a utility frequency alternating current that can be fed into the commercial electrical grid or used by a local, off-grid electrical network. An inverter allows use of ordinary mains-operated appliances on a direct current system. Solar inverters have special functions adapted for use with PV arrays, including maximum power point tracking and anti-islanding protection.
Maximum power point tracking is a technique that solar inverters use to get the maximum possible power from the PV array. Solar cells have a complex relationship between solar irradiation, temperature and total resistance that produces a non-linear output efficiency known as the I-V curve. It is the purpose of the MPPT system to sample the output of the cells and apply a resistance (load) to obtain maximum power for any given environmental conditions. Essentially, this defines the current that the inverter should draw from the PV in order to get the maximum possible power (since power equals voltage times current).
The R-Value of Insulation
An R-value indicates an insulation’s resistance to heat flow. The higher the R-value, the greater the insulating effectiveness.
The R-value depends on the type of insulation and includes its material, thickness, and density. When calculating the R-value of a multilayered installation, add the R-values of the individual layers. Installing more insulation in your home increases the R-value and the resistance to heat flow.
The effectiveness of an insulation’s resistance to heat flow also depends on how and where the insulation is installed. For example, insulation that is compressed will not provide its full rated R-value. The overall R-value of a wall or ceiling will be somewhat different from the R-value of the insulation itself because some heat flows around the insulation through the studs and joists. Therefore, it’s important to properly install your insulation to achieve the maximum R-value.
The amount of insulation or R-value you’ll need depends on your climate, type of heating and cooling system, and the section of the house you plan to insulate.
The US Department of Energy has recommended R-values for given areas of the USA based on the general local energy costs for heating and cooling, as well as the climate of an area. There are four types of insulation: rolls and batts, loose-fill, rigid foam, and foam-in-place. Rolls and batts are typically flexible insulators that come in fibers, like fiberglass. Loose-fill insulation comes in loose fibers or pellets and should be blown into a space. Rigid foam is more expensive than fiber, but generally has a higher R-value per unit of thickness. Foam-in-place can be blown into small areas to control air leaks, like those around windows.
Wright Builders, Inc. Energy Star Tier III homes are built R value ratings include:
- R 16.5 insulated basement floor systems
- Basement walls with an R 31
- Triple Glazed windows with an R 4.5
- R 36 wall insulation in living spaces
- R 64 in ceiling insulation
Properly controlling moisture in your home will improve the effectiveness of your air sealing and insulation efforts, and vice versa. Thus, moisture control contributes to a home’s overall energy efficiency.
The best strategy for controlling moisture in your home depends on your climate and how your home is constructed. Before deciding on a moisture control strategy for your home, you may first want to understand how moisture moves through a home.
Moisture control strategies typically include the following areas of a home:
- Crawl space
- Slab-on-grade floors
In most U.S. climates, you can use vapor diffusion retarders in these areas of your home to control moisture. Proper ventilation should also be part of a moisture control strategy.
A deep energy retrofit is a whole-building analysis and construction process that uses integrative design to achieve much larger energy savings than conventional energy retrofits. Deep energy retrofits can be applied to both residential and non-residential (“commercial”) buildings. A deep energy retrofit typically results in savings of 30 percent or more, perhaps spread over several years, and may significantly improve the building value.
The term “deep energy retrofit” is often used interchangeably with “deep green retrofit” and “deep retrofit”. A deep green retrofit may have less focus on energy efficiency and may emphasize obtaining certification from a green building rating system, such as LEED. The definition of the term continues to be refined and debated.
A deep energy retrofit combines energy efficiency measures such as energy efficient equipment, air sealing, moisture management, controlled ventilation, insulation, and solar control so that dramatic energy savings are achieved alongside optimal building performance.
Durability, good interior air quality and energy efficiency are attained by sound building science practices. In a deep energy retrofit, filling a wall cavity with effective insulation also requires careful consideration of how that wall will dry if moisture does happen to get past its skin. Using very high R-value insulation systems on the exterior of the building enclosure is often one of the hallmarks of a deep energy retrofit. Where exactly the dewpoint will fall in (or out) of those thickened walls—and in what climate zone—becomes crucial. Careful detailing, flashing and air sealing of windows and other building penetrations is also key to a successful deep energy retrofit.
Wright Builders, Inc. specializes in deep energy retrofits (DERs) and works closely with the local entities and the sponsoring utilities to help home owners take advantage of financial assistance programs and subsidies available through these programs.
Drywall, also known as plasterboard, wallboard or gypsum board is a panel made of gypsum plaster pressed between two thick sheets of paper. It is used to make interior walls and ceilings. Drywall construction became prevalent as a speedier alternative to traditional lath and plaster.
A wallboard panel is made of a paper liner wrapped around an inner core made primarily from gypsum plaster. The raw gypsum, (mined or obtained from flue-gas desulfurization must be calcined before use to produce the hemihydrate of calcium sulfate (CaSO4·½ H2O). This is done in kettle or flash calciners, typically using natural gas today.
The plaster is mixed with fiber (typically paper and/or fiberglass), plasticizer, foaming agent, finely ground gypsum crystal as an accelerator, EDTA, starch or other chelate as a retarder, various additives that may increase mildew and/or fire resistance (fiberglass or vermiculite), wax emulsion or silanes for lower water absorption and water. This is then formed by sandwiching a core of wet gypsum between two sheets of heavy paper or fiberglass mats. When the core sets and is dried in a large drying chamber, the sandwich becomes rigid and strong enough for use as a building material.
Light supplied by the sun, as opposed to artificial light from light bulbs.
What are preliminary plans? Preliminary plans are the initial design phase in preparing the commercial construction bidding or residential building documents.
These documents are developed from the information contained in the budget package. Typically the preliminary plans are developed in two distinct steps referred to as schematics and design development. The two-step process allows Wright Builders to interact before the design is developed, helping to ensure a mutual understanding of the design objectives, limitations and budget.
- Schematic documents: Schematic documents are the initial architectural and engineering plans prepared during the preliminary plan phase, depicting the designer’s conceptual solution to project needs. The major difference compared with design documents is the amount of detail.
- Design documents: These are the final documents which result from the preliminary plan phase, and may include a site plan, architectural floor plans, elevations and a cost estimate. For each utility, site development, conversion, and remodeling project, the drawings must be sufficiently descriptive to convey accurately the location, scope, cost, and the nature of the improvement being proposed.
As part of Wright Builders, Inc. process, we develop preliminary plans at no cost to you after our initial visit and fact finding. These plans are not intended to be used to build the structure, but more as a guideline and planning tool towards creating a preliminary budget and as a means to move to the next step of design development and eventually into hard pricing of the project. These preliminary plans are owned by Wright Builders, Inc. and are not intended to be shared with other builders for the purpose of estimating.
Construction Project Management
Construction Project Management is the overall planning, coordination and control of a project from inception to completion aimed at meeting a client’s requirements in order to produce a functionally and financially viable project that will be complete management.
Sustainable energy is the sustainable provision of energy that meets the needs of the present without compromising the ability of future generations to meet their needs. Technologies that promote sustainable energy include renewable energy sources, such as hydroelectricity, solar energy, wind energy, wave power, geothermal energy, and tidal power, and also technologies designed to improve energy efficiency.
Zero Net Energy
Zero-net-energy building is defined as “a building that is designed, constructed, and operated to require a greatly reduced quantity of energy to operate, meet the balance of energy needs from sources of energy that do not produce greenhouse gases, and therefore result in no net emissions of greenhouse gases and be economically viable.”
A zero-energy building, also known as a zero net energy (ZNE) building, Net-Zero Energy Building (NZEB), or Net Zero Building, is a popular term to describe a building with zero net energy consumption and zero carbon emissions annually. Zero energy buildings can be independent from the energy grid supply. Energy can be harvested on-site—usually through a combination of energy producing technologies like Solar and Wind—while reducing the overall use of energy with extremely efficient HVAC and lighting technologies. The zero-energy design principle is becoming more practical to adopt due to the increasing costs of traditional fossil fuels and their negative impact on the planet’s climate and ecological balance.
Energy use can be measured in different ways (relating to cost, energy, or carbon emissions). Different views are taken on the relative importance of energy harvest and energy conservation to achieve a net energy balance. Although zero energy buildings remain uncommon in developed countries, they are gaining importance and popularity. The zero net energy approach has potential to reduce carbon emissions, and reduce dependence on fossil fuels.
A building approaching zero net energy use may be called a “near-zero energy building” or “ultra-low energy house”. Buildings that produce a surplus of energy during a portion of the year may be known as “energy-plus buildings”. Wright Builders, Inc. suggests to all customers that they consider the benefits of zero net energy construction.
VOC – Volatile Organic Compounds
VOCs are organic chemicals that have a high vapor pressure at ordinary, room-temperature conditions. Their high vapor pressure results from a low boiling point, which causes large numbers of molecules to evaporate or sublimate from the liquid or solid form of the compound and enter the surrounding air. An example is formaldehyde, with a boiling point of –19 °C (–2 °F), slowly exiting paint and getting into the air.
Many VOCs are dangerous to human health or cause harm to the environment. VOCs are numerous, varied, and ubiquitous. They include both man-made and naturally occurring chemical compounds. VOCs play an important role in communication between plants. Anthropogenic VOCs are regulated by law, especially indoors, where concentrations are the highest. VOCs are typically not acutely toxic, but instead have compounding long-term health effects. Because the concentrations are usually low and the symptoms slow to develop, research into VOCs and their effects is difficult.
Wright Builders, Inc uses only very low or no VOC paints and finishes.
The term “sustainable” is now widely applied to a host of materials – steel, plastics, concrete and aluminium for example – that obviously aren’t sustainable. Sustainable wood is different. It comes from sustainably managed forests. These are not only a renewable resource, but are also managed so as to prevent damage to eco-systems, watersheds, and other forest values.
The first effort to define sustainability came in the 1987 report of the World Commission on Environment and Development chaired by Prime Minister Brundtland of Norway. This report defined sustainable development as “Meeting the needs of the present without compromising the ability of future generations to meet their own needs”.
The Brundtland definition was expanded on and applied in depth to forests at the 1992 United Nations Earth Summit. In fact, even now, the forest sector remains the only major international commodity sector where there is worldwide international agreement on the key elements of sustainable production. The forest sector has led the way to translate “sustainability” from a nice idea on paper into a fundamental determinant of action on the ground.
Most other sectors are still at the “nice idea on paper” stage, or worse, they have simply adopted the term when marketing their efforts to chip away at their considerable environmental burdens. “Sustainable wood” is much more than this. Through its increased use, it can make a major positive contribution to the world’s environment.
A gas at room temperature, formaldehyde is colorless and has a characteristic pungent, irritating odor. It is an important precursor to many other chemical compounds, especially for polymers. In 2005, annual world production of formaldehyde was estimated to be 23 million tons. Commercial solutions of formaldehyde in water, commonly called formalin, were formerly used as disinfectants and for preservation of biological specimens.
Formaldehyde is a naturally occurring substance in the environment made of carbon, hydrogen and oxygen. Natural processes in the upper atmosphere may contribute up to 90 percent of the total formaldehyde in the environment. Formaldehyde is an intermediate in the oxidation (or combustion) of methane as well as other carbon compounds, e.g. forest fires, in automobile exhaust, and in tobacco smoke. When produced in the atmosphere by the action of sunlight and oxygen on atmospheric methane and other hydrocarbons, it becomes part of smog. Formaldehyde has also been detected in outer space.
Formaldehyde, as well as its oligomers and hydrates, are rarely encountered in living organisms. Methanogenesis proceeds via the equivalent of formaldehyde, but this one-carbon species is masked as a methylene group in methanopterin. Formaldehyde is the primary cause of methanol’s toxicity, since methanol is metabolised into toxic formaldehyde by alcohol dehydrogenase. Formaldehyde does not accumulate in the environment, because it is broken down within a few hours by sunlight or by bacteria present in soil or water. Humans metabolize formaldehyde quickly, so it does not accumulate, and is converted to formic acid in the body.
Other Construction/Building Related Terms
A regulation or law which sets out, in each jurisdiction to which it applies, the standards and technical provisions for the construction of new buildings or the renovations or demolition of existing buildings.
Compliance to a building code is usually supervised by local officers who issue building permits and who have the power in the event of suspected construction or renovation which is contrary to the relevant code, to shut down the building.
Wright Builders, Inc. works closely with local officials, through pre-planning, to make certain that all necessary permits can be acquired prior to construction. We then secure the permits required for your project. These can include: zoning, wetland preservation, historical preservation, commercial districts, state and local building codes.
Stack effect is the movement of air into and out of buildings, chimneys, flue gas stacks, or other containers, and is driven by buoyancy. Buoyancy occurs due to a difference in indoor-to-outdoor air density resulting from temperature and moisture differences. The result is either a positive or negative buoyancy force. The greater the thermal difference and the height of the structure, the greater the buoyancy force, and thus the stack effect. The stack effect is also referred to as the “chimney effect”, and it helps drive natural ventilation and infiltration.
Since buildings are not totally sealed (at the very minimum, there is always a ground level entrance), the stack effect will cause air infiltration. During the heating season, the warmer indoor air rises up through the building and escapes at the top either through open windows, ventilation openings, or other forms of leakage. The rising warm air reduces the pressure in the base of the building, drawing cold air in through either open doors, windows, or other openings and leakage. During the cooling season, the stack effect is reversed, but is typically weaker due to lower temperature differences.
Radon is a chemical element with the atomic number 86, and is represented by the symbol Rn. It is a radioactive, colorless, odorless, tasteless noble gas, occurring naturally as the decay product of uranium or thorium. Its most stable isotope, Rn, has a half-life of 3.8 days. Radon is one of the densest substances that remains a gas under normal conditions. It is also the only gas that only has radioactive isotopes, and is considered a health hazard due to its radioactivity. Intense radioactivity also hindered chemical studies of radon and only a few compounds are known.
Radon is formed as part of the normal radioactive decay chain of uranium and thorium. Uranium and thorium have been around since the earth was formed and their most common isotope has a very long half-life (4.5 billion years). Uranium and thorium, radium, and thus radon, will continue to occur for millions of years at about the same concentrations as they do now. As the radioactive gas of radon decays, it produces new radioactive elements called radon daughters or decay products. Radon daughters are solids and stick to surfaces such as dust particles in the air. If contaminated dust is inhaled, these particles can stick to the airways of the lung and increase the risk of developing lung cancer.
Radon is responsible for the majority of the public exposure to ionizing radiation. It is often the single largest contributor to an individual’s background radiation dose, and is the most variable from location to location. Radon gas from natural sources can accumulate in buildings, especially in confined areas such as attics and basements. It can also be found in some spring waters and hot springs.
Fire Rated Foam
Fire Rated Foam is an expanding, fire-rated polyurethane foam designed to prevent room-to-room fire and smoke spread through gaps or voids in fire-rated walls and floors. Fire Rated Expanding Foam provides an insulating seal on and between concrete, brick, wood, metal, aluminum and steel.
In short, wall cavities require the presence of an air-impermeable barrier to enclose the building cavities. The EPA’s Thermal Bypass Checklist (TBC) further specifies that insulation shall be installed in full contact with sealed interior and exterior air barrier, except in climate zones 1 through 3, (covering most of Texas) where sealed exterior air barrier aligned with RESNET Grade 1 insulation is fully supported.
An EPA technical ruling states that “an air barrier is any solid material that blocks air flow.” The only caveat noted is that if building paper is applied directly to the framing, without sheathing, then the material would have to be taped or otherwise sealed to effectively function as the air barrier. EPA noted that, for some products, it may be “unrealistic” to achieve an air seal that will remain effective throughout the expected lifetime of the building.
The U-value (or U-factor), more correctly called the overall heat transfer coefficient, describes how well a building element conducts heat. It measures the rate of heat transfer through a building element over a given area, under standardized conditions. The usual standard is at a temperature gradient of 24 °C, at 50% humidity with no wind (a smaller U-value is better at reducing heat transfer).