All posts by Daniel Overbey

The Health Impacts of Indoor Relative Humidity

Green Building

The Health Impacts of Indoor Relative Humidity

Originally published on October 1, 2018 by BNP Media through the Building Enclosure Blog.   In many parts of the U.S., homeowners with basements have to manage rising humidity levels for most of the cooling season. It is not uncommon for such individuals to have a dehumidifer running full-throttle in the basement from April through October. High indoor humidity levels has been associated with the growth of fungi, such as mold, among other irritants. The EPA suggests keeping indoor relative….

Read More

Clarifying Energy Simulation Aided Design: A Look at ASHRAE Standard 209

Green Building

Clarifying Energy Simulation Aided Design: A Look at ASHRAE Standard 209

Originally published on September 5, 2018 by BNP Media through the Building Enclosure Blog. ANSI/ASHRAE Standard 209-2018, Energy Simulation Aided Design for Buildings Except Low-Rise Residential Buildings is the product of a half-decade of inertia within the building design and construction community toward leveraging energy modeling a design tool through a project. Standard 209 outlines the minimum requirements for providing energy design assistance using building energy simulation and analysis. To this end, the standard defines a range of minimum criteria from energy modeling requirements,….

Read More

How to Make Building Energy Models More Accurate

Green Building

How to Make Building Energy Models More Accurate

Originally published on August 13, 2018 by BNP Media through the Building Enclosure Blog.   I’m asked regularly about the discrepancies between modeled and measured building performance. At first blush, one might suspect that the building energy model (BEM) itself contains bad information. That notion could very well be correct! BEM inputs require a certain level of synthesis, interpretation, and assumption. But there are many other reasons why the BEM results may vary significantly from measured performance outcomes on a completed project. In basic terms: Actual weather in….

Read More

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….

Read More

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….

Read More

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….

Read More

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….

Read More

Thermal Dynamics: Visualizing Sensible Versus Latent Heat

Green Building

Thermal Dynamics: Visualizing Sensible Versus Latent Heat

Originally published on March 12, 2018 by BNP Media through the Building Enclosure Blog. It’s the first law of thermodynamics. The Law of Conservation of Energy states that energy can neither be created nor destroyed; energy can only be transferred or changed from one form to another. This is the foundation of phase change in the physical environment. Molecular activity requires energy. The activity does not just magically happen. Phase Change When a material changes its state or phase (e.g., going….

Read More

Five Diagrams Every Design Team Should Know

Green Building

Five Diagrams Every Design Team Should Know

Originally published on February 7, 2018 by BNP Media through the Building Enclosure Blog. They might be considered cliché; however, they might also be very true. The following are five diagrams that frequently work their way into slide decks about green building design and construction. You should be familiar with all of these. Let’s unpack each one briefly – going back to primary source material and acknowledging attribution. Read more…

Read More

Tracking Energy Efficiency Improvements in ASHRAE Standard 90.1

Green Building

Tracking Energy Efficiency Improvements in ASHRAE Standard 90.1

Originally published on January 17, 2018 by BNP Media through the Building Enclosure Blog. It may be the most well-known standard in the building design and construction industry: ANSI/ASHRAE/IES Standard 90.1, Energy Standard for Buildings, Except Low-Rise Residential Buildings (or more commonly, ASHRAE Standard 90.1). It serves as the basis for many energy codes across the U.S. It is also the energy standard referenced by LEED and other green building certification systems. Every few years, Standard 90.1 is updated by….

Read More