How Well Do You Know Building Science?

This post first appeared on the Green Building Advisor Website.

The International Builders Show took place from February 27th through the 29th, 2024 in Las Vegas, NV.  The past couple years, Huber Engineered Wood has held a building science trivia game in their booth.  The game is played using an app on a cell phone, questions are answered by contestants and their score is based both on how quickly the question is answered and whether the question was answered correctly.  The game is just for fun, though there are some bragging rights if you are able to beat the on-stage contestants.  This year, the on-stage players were Jake Bruton, Steven Baczek, Peter Yost, and Ben Bogie with Tate Hudson from Huber asking the questions.  (Jake has this year’s bragging rights.)

I thought it might be fun to have a version of building science trivia here on the Northern Built Blog.  Some of the questions being asked are from the game played in the Huber booth, others are questions that were asked during another building science trivia game played a recent BS and Beer-Northern Minnesota meeting.  The game is just for fun, you keep track of how many you get right.  The answers (along with a little more in-depth information about the answer) will follow the quiz.  Here we go.

1. The climate zone map located in Chapter 11 (Energy Efficiency) of the 2021 International Residential Code Book contains how many different climate zones?
   1. 8
   2. 9
   3. 14
   4. 19

2. What is the average value of Carbon Dioxide in outdoor air?
   1. 250 ppm
   2. 425 ppm
   3. 675 ppm
   4. 1000 ppm

3. Changing one pound of water from a liquid to a solid will require how many British Thermal Units (Btu’s) be removed?
   1. 970 Btu
   2. 32 Btu
   3. 144 Btu
   4. 1 Btu

4. When calculating the volume of a house for a blower door test using the ANSI/RESNET/ICC 380 standard, what area is not included in the conditioned space volume calculation?
   1. A conditioned basement
   2. A conditioned attic
   3. The space between interior partition walls
   4. An attached, conditioned garage

5. A vapor diffusion port is:
   3. Only allowed by code in climate zones 1-3.
   4. Designed to allow water vapor to escape from an unvented roof assembly.
   5. Is typically located at the ridge, or highest point of the roof.
   6. All of the above.

6. One kilowatt, or 1,000 watts is equal to how many British Thermal Units (Btu’s)?
   34. 12 Btu
   35. 2 Btu
   36. 3,412 Btu
   37. 34,120 Btu

7. Long term exposure to radon can be detrimental to human health. According to the EPA, what is the radon threshold where radon mitigation may be needed?
   1. 148 becquerels per cubic meter
   2. 4 picocuries per liter
   3. 016 WL
   4. All of the above

8. Residential homes are typically blower door tested at 50 Pascals; a commercial structure is tested at 75 Pascals. How many inches of water column is 75 Pascals?
   1. 30
   2. 0
   3. 0
   4. 300

9. What is deposition frost?
   1. Frost that forms when strong, damp winds blow across a surface that is above freezing (32°F).
   2. When bulk water accumulates on a surface, then freezes.
   3. A phase transition in which gas transforms into a solid without passing through the liquid phase.
   4. The process of frost changing from a solid to a liquid.

10. With regards to construction, permeance (perm) is how easily water vapor flows through a material, the smaller the number, the slower the rate at which water vapor moves. Building codes recognize different classes of vapor retarders, which of the following is true?
    1. Class I-vapor impermeable: 0.1 perm or less
    2. Class II-vapor semi-impermeable: 1.0 perm or less and greater than 0.1 perm
    3. Class III-vapor semi-permeable: 10 perm or less and greater than 1.0 perm
    4. All of the above

ANSWERS

1. The climate zone map located in Chapter 11 (Energy Efficiency) of the 2021 International Residential Code Book contains how many different climate zones?
   1. 8
   2. 9
   3. 14
   4. 19

This is a tricky question.  The 2021 Energy Code added a new climate zone, climate zone 0 to the existing list of zones 1 through 8 giving us a total of 9.  Then there are the moisture zones of A, B, and C with A being moist, B being dry, and C being marine.  All 19 zones are listed in figure N1101.7 (R301.1) Climate Zones in Chapter 11, Energy Efficiency.  The map shows every climate found in the US but does not include zones 0A, extremely hot humid, 0B, extremely hot dry or 1B, very hot dry, which are not found in the US…yet.

2. What is the average value of Carbon Dioxide in outdoor air?
   1. 250 ppm
   2. 425 ppm
   3. 675 ppm
   4. 1000 ppm

According to the Climate.gov website, carbon dioxide levels in outdoor air have been steadily increasing.  In 1960, levels were around 320 ppm, in 2000, levels had climbed to around 375 ppm. The annual rate of increase over the past 60 years is about 100 times higher than the increases that occurred at the end of the last ice age, 11,000 – 17,000 years ago.  The ocean has absorbed enough CO to decrease its pH level by 0.1 units, a 30% increase in acidity.

3. Changing one pound of water from a liquid to a solid will require how many British Thermal Units (Btu’s) be removed?
   1. 970 Btu
   2. 32 Btu
   3. 144 Btu
   4. 1 Btu

One pound of water will lose 1°F of temperature for each Btu that is removed until it reaches the point where the water changes from a liquid to a solid.  At that point, an additional 144 Btu’s will need to be removed for the phase change.  It takes 970 Btu’s to change one pound of liquid water to steam.

4. When calculating the volume of a house for a blower door test using the ANSI/RESNET/ICC 380 standard, what area is not included in the conditioned space volume calculation?
   1. A conditioned basement
   2. A conditioned attic
   3. The space between interior partition walls
   4. An attached, conditioned garage

According to the 380 standards, the volume of an attic that is not both air sealed and insulated at the roof deck, vented crawlspaces, attached garages even when conditioned, and thermally isolated sunrooms shall be excluded from the conditioned space volume calculation.  Additionally, an attic that is both air sealed and insulated at the roof deck, the volume of an unvented crawlspace, and the volume of a basement are only included if they are verified to be conditioned space (have heating and/or cooling systems designed to maintain 78°F for cooling and/or 68°F for heating.)

5. A vapor diffusion port is:
   3. Only allowed by code in climate zones 1-3.
   4. Designed to allow water vapor to escape from an unvented roof assembly.
   5. Is typically located at the ridge, or highest point of the roof.
   6. All of the above.

Vapor diffusion ports are discussed in Chapter 8 Roof-Ceiling Construction of the International Residential Codes (beginning with the 2018 code).  The section for vapor diffusion ports is found at R806.5.2

6. One kilowatt, or 1,000 watts is equal to how many British Thermal Units (Btu’s)?
   34. 12 Btu
   35. 2 Btu
   36. 3,412 Btu
   37. 34,120 Btu

Both kilowatt-hours of electricity and Btus of heat are measurements of energy.  When performing energy audits and assessment, I use the conversion of the watts to Btu’s often.  As an example, an electric baseboard heater consumes approximately 250 watts per hour, a four-foot baseboard heater, 1,000 watts per hour, or kilowatt hour (kWh).  The heat produced by this four-foot heater is 3412 Btu.

7. Long term exposure to radon can be detrimental to human health. According to the EPA, what is the radon threshold where radon mitigation may be needed?
   1. 148 becquerels per liter
   2. 4 picocuries per liter
   3. 016 WL
   4. All of the above

According to the EPA, radon test results can be reported using three different metrics, picocuries per liter (pCi/l), working levels (WL), and becquerels per liter (bq/L).  Becquerels per liter can also be denoted as becquerels per cubic meter, using this metric, the recommended threshold is 148 bq/m³.

8. Residential homes are typically blower door tested at 50 Pascals; a commercial structure is tested at 75 Pascals. Approximately how many inches of water column is 75 Pascals?
   1. 0.30
   2. 3.0
   3. 30.0
   4. 300

One inch of water column is equal to 249.082 Pascals (or 1/28 pounds per square inch (psi)).  75 Pascals is equal to 0.3014 inches of water column.

9. What is deposition frost?
   1. Frost that forms when strong, damp winds blow across a surface that is above freezing (32°F).
   2. When bulk water accumulates on a surface, then freezes.
   3. A phase transition in which gas transforms into a solid without passing through the liquid phase.
   4. The process of frost changing from a solid to a liquid.

Deposition frost, sometimes called hoar or white frost, occurs when water vapor changes directly to ice without first moving through the liquid phase.  Deposition frost is often what we see in cold climate attics with high rates of air leakage from the conditioned space below.  Frost begins forming on the coldest surfaces first, often the nail heads used to fasten the roof shingles, eventually moving throughout the roof sheathing.  If warming occurs slowly, the frost can change back to water vapor without passing through the liquid phase, this is called sublimation.

10. With regards to construction, permeance (perm) is how easily water vapor flows through a material, the smaller the number, the slower the rate at which water vapor moves. Building codes recognize different classes of vapor retarders, which of the following is true?
    1. Class I-vapor impermeable: 0.1 perm or less
    2. Class II-vapor semi-impermeable: 1.0 perm or less and greater than 0.1 perm
    3. Class III-vapor semi-permeable: 10 perm or less and greater than 1.0 perm
    4. All of the above

Vapor retarder materials and classes are found in the International Residential Code, Chapter 7, Wall Covering, Table R702.7(1).  With the continuous insulation requirements being adopted in more areas around the country, we need to be familiar with section R702.7 Vapor Retarders, especially the footnotes included with the four tables found in R702.7.

So, what do you think?  Should building science trivia become a series?  Leave your comments below.