Tag Archives: Building Envelope

Blue Roofs are Essential to Achieve Zero Rainwater Overflow

Green Building

Blue Roofs are Essential to Achieve Zero Rainwater Overflow

Originally published on November 30, 2018 by BNP Media through the Building Enclosure Blog. In their latest Infrastructure Report Card, the American Society of Civil Engineers (ASCE) gave our domestic wastewater infrastructure and average grade of D+ citing 772 communities in the US in which wastewater and stormwater drain into the same treatment system. These combined sewer systems can experience capacity issues following heavy rain events, resulting in overflows containing a combination of stormwater with untreated human and industrial waste, toxic substances, debris, and other….

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Beware of Galvanic Action (It’s a Thing)

Green Building

Beware of Galvanic Action (It’s a Thing)

Originally published on July 10, 2018 by BNP Media through the Building Enclosure Blog. The concept of “galvanic action” is confounding to many design professionals. In simple terms, galvanic action refers to the corrosive effect created when two electrochemically dissimilar metals are in direct contact with each other. Their contact creates a conductive path for electrons and ions to move from one metal to the other. As ions move from one metal to another, corrosion occurs. The remedy is to….

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The Psychrometric Chart Explained

Green Building

The Psychrometric Chart Explained

Originally published on June 13, 2018 by BNP Media through the Building Enclosure Blog. It is one of the intimidating charts for any building design professional: the psychrometric chart. At first blush, the “psych chart” looks very complicated. There are layers of axes and curved reference lines. However, a closer examination will reveal that – at its essence – the chart is visually conveying the answers to two related questions: How much sensible (dry-bulb) heat is in the air? (See….

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Dry-Bulb Temperature, Wet-Bulb Temperature and Enthalpy

Green Building

Dry-Bulb Temperature, Wet-Bulb Temperature and Enthalpy

Originally published on May 9, 2018 by BNP Media through the Building Enclosure Blog. There is energy in the air all around us. Some of it exists in the form of thermal energy that one can sense – heat in air that impacts one’s perception of thermal comfort. But there is also an energy embodied in the vapor present in the air. While this “hidden” heat is not experienced as warmth, it certainly has a bearing on thermal comfort as….

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Defining Humidity Ratio and Relative Humidity

Green Building

Defining Humidity Ratio and Relative Humidity

Originally published on April 4, 2018 by BNP Media through the Building Enclosure Blog. How does a hot-air balloon rise? Fire up the burner and the temperature of the air captured within the balloon increased. The molecules of the air take on the thermal energy and become more excited. The excited molecules create more space between them. As a result, the air expands as its temperature increases. Thus, one pound of air at 80-degrees Fahrenheit (°F) is a larger volume than….

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Effective Insulation R-Values in Steel vs. Wood Framing Types

Green Building

Effective Insulation R-Values in Steel vs. Wood Framing Types

Also published on May 29, 2017 by BNP Media through the Building Enclosure Blog. . The value of continuous insulation is a source of contention among some building design and construction professionals. Increasingly stringent energy code requirements are calling for minimal amounts of continuous insulation that some claim are prohibitively expensive, structurally complicated, or marginally impactful versus increased cavity insulation. Professionals are generally aware of the potential for thermal bridging in construction assemblies – the phenomenon by which heat conducts….

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BECx is Coming to a Project Near You

Green Building

BECx is Coming to a Project Near You

Originally published on January 11, 2017 by BNP Media through the Building Enclosure Blog. . In recent years, a growing demand for high-performance building envelope solutions has been evidenced by the increased attention paid to this topic throughout the building design and construction industry. Building Envelope Council (BEC) initiative Seeing this emerging priority, in 2004 the National Institute of Building Sciences (NIBS) Building Enclosure Technology and Environmental Council (BETEC) and the American Institute of Architects (AIA) signed an agreement to….

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Is a Vapor Retarder Necessary in a Low-Slope Roof Assembly?

Green Building

Is a Vapor Retarder Necessary in a Low-Slope Roof Assembly?

Originally published on October 7, 2016 by BNP Media through the Building Enclosure Blog. . If you have designed or built a low-slope roof with a single-ply membrane, at some point you will be confronted with this simple question: Is the vapor retarder necessary? With considerable costs at stake, the prospect of omitting a vapor retarder is always a precarious notion and one that merits careful consideration of the project-specific dynamics at play. Consider the Entire Assembly In order to….

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The Difference Between Permeance and Permeability

Green Building

The Difference Between Permeance and Permeability

Originally published on April 18, 2016 by BNP Media through the Architectural Roofing & Waterproofing Blog. All information presented in imperial (I-P) units. Water vapor transmission is a rather confusing issue. The difference in vapor pressure between two sides of a building envelope assembly is the driving force behind vapor transmission. (Although by comparison, gaps in the envelope account for vastly greater amounts moisture migration due to vapor-laden air infiltration.) Vapor = Latent Heat; Air Temperature = Sensible Heat The….

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Defining Mass Walls through Heat Capacity

Green Building

Defining Mass Walls through Heat Capacity

Originally published on February 12, 2015 by BNP Media through the Architectural Roofing & Waterproofing Blog. There are significant differences in the prescriptive requirements of mass walls versus other above-grade walls. Using ASHRAE 90.1-2007 as example, above-grade walls for a steel-framed nonresidential building in Climate Zone 5 will need a minimum of R-13 insulation AND a continuous insulation layer of at least R-7.5. However, the building’s mass wall assemblies would only be required to exhibit a continuous layer of R-11.4….

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