CNST 251 Exam 3
"Which of the following steel stud wall assemblies gives a higher overall R-value? In both assemblies, the total amount of insulation is R-15"
"Assembly A has an exterior insulating sheathing of R-5 and within-stud insulation of R-10"
"Which of the following plastic foam insulation contains air within its voids?"
"Expanded polystyrene (EPS) board (bead board) "
"For energy conservation, materials with high thermal mass are effective in climates in which the heat flow through the building envelope is"
"bidirectional within a 24-h period during a large part of the year."
"The test specimen used for determining the compressive strength of concrete in the United States is a "
"cylinder measuring "
"In a simple three-member truss consisting of two rafters and a tie, each member is in"
"either tension or compression."
"The U.S. Department of Energy's climate zones are based on"
"the exterior air temperature and the exterior humidity." ( a and b )
"When we determine the strength of concrete using the test specimens, we determine the concrete's "
"ultimate compressive stress."
"The U-value and R-value of an assembly are related to each other by which relationship?"
(U)(R)=1.0
"The R-value of a single glass sheet, without considering the film resistances, is approximately"
0
"The emissivity of a material lies between"
0 and 1
"A 20-ft-high column shortens by 0.6 in. under a load. What is the resulting strain in the column? "
0.0025
"The unit for the measure of energy in the U.S. system of units is"
Btu
"Which gives greater warning before failure?"
Ductile material
"Which of the following insulating materials contain HCFC gas within their voids?"
Extruded polystyrene Polyisocyanurate Polyurethane ALL OF THE ABOVE
"Which of the following beam cross sections is structurally more efficient in bending?
I-section
IECC is an acronym for
International Energy Conservation Code.
"The unit for the measure of energy in the SI system of units is"
Joule
"A rectangular column measuring 12 in.×12 in. in cross section carries a load of 18 kips. What is the stress in the column?"
NONE OF THE ABOVE
"The approximate R-value of an air space in a wall is"
R-1
"The approximate R-value of an air space in a wall with an aluminum foil lining is"
R-2.5
"A wall assembly ( totalarea=100 ft2) consists of 80 ft2 of opaque wall with an R-value of R-20 and a 20 ft2 of window whose R-value is R-2. The effective (overall) R-value of the entire wall assembly is approximately"
R-7
"The R-value of a building assembly in the SI system is referred to as the "
RSI-Value
"The F-factor relates to heat flow through"
a concrete slab-on-ground
"Apart from the climate of the location, the other factors that affect energy-conscious building design are "
all of the above
The unit of modulus of elasticity is
all of the above
"Concrete is"
an elastic material
"Low-carbon (mild) steel is"
an elastic-plastic material
"In which of the following locations is blown-in insulation most commonly used?"
attic space
"The horizontal blocking in wood studs helps prevent"
buckling of studs
The material in an arch is primarily in
compression
"The bearing strength of a material is closely related to its"
compressive strength
"Within a solid, the mode of heat transfer is by"
conduction
"In which of the following buildings will heat flow occur unidirectionally?"
continuously heated or cooled buildings
"Within an air space (cavity), the mode of heat transfer is primarily by"
convection and radiation
"Which of the following insulations is combustible?"
extruded polystyrene (XPS) board
"In a steel column that rests on a concrete footing, the area of the bearing plate used is generally "
greater than the cross-sectional area from the column
"For the same thickness, which of the following materials has the smallest R-value?"
gypsum
"Which of the following materials has the smallest value of emissivity? "
highly polished metal
"Modulus of elasticity refers to how"
how stiff a material is
"The stirrups in a reinforced concrete beam are used to"
increase the strength of the beam in shear
"The concept of aged R-value is applicable to"
insulating materials that contain HCFC gas
"Aluminum foil is commonly used in building assemblies because it "
lowers heat transfer due to convection
"In relation to its compressive strength, the tensile strength of concrete is"
much lower
"Foamed concrete is generally used as insulation in"
none of the above
"One of the main reasons for using HCFC gas in some insulating materials is that it"
none of the above
"The R-value of a 1-in.-thick extruded polystyrene board is 5.0. If the R-value of a 1-in.-thick brick wall is 0.2, how thick should the brick wall be to equal the R-value of 1-in.-thick extruded polystyrene?"
none of the above
"The R-value of a 2-in.-thick material is 4.0. What is the R-value of the same material if its thickness is 1 in.?"
none of the above
"The coastal region of the western United States lies in"
none of the above
"What is the yield stress of grade 60 reinforcing steel?"
none of the above
"Which of the following insulating materials is available in the form of rigid boards?"
none of the above
"Insulation is most effective if it is placed"
on the outside face of the assembly
"In a suspension bridge, which member(s) is (are) in compression?"
support pylons
"Which of the following beam cross sections is structurally more efficient in bending?"
tubular section
"A material that is weak in tension is"
weak in bending
"A material that is weak in tension is"
weak in shear
"The bending stresses along the neutral axis of a beam are"
zero
"When a cable or rope is compressed by a force, what is the compressive stress in it?"
zero
"The R-value of a building assembly is influenced by the inside and outside air films. The sum of the R-values of these two films (Rsi+Rso) is approximately equal to"
1.0
"The R-value of a single glass sheet, including the film resistances, is approximately"
1.0
"A building assembly with a higher U-value is thermally more insulating than one with a lower U-value."
false
"A wall framed with wood or steel studs is a mass wall."
false
"A wet or moist material provides a higher R-value than if the same material is dry."
false
"Air is a good thermal insulator, provided that it exists in large volumes."
false
"In climates where a concrete slab-on-ground must be insulated, it should be insulated under its entire area."
false
"In most materials, the safety margin for compressive stress and bending stress is the same."
false
"The walls of a conditioned basement must be insulated over the entire depth of the wall."
false
"Which of the following insulating materials is available in the form of batts?"
fiberglass
"When an aluminum foil is used in attic spaces, it is"
laminated to inside-facing surface of roof sheathing
"The allowable stress in a material is generally "
less than its ultimate stress
"For the same thickness, which of the following materials has the highest R-value? "
polyisocyanurate
"The primary purpose of ties in a reinforced concrete column is to"
prevent the buckling of vertical reinforcement in the column
"The International Energy Conservation Code provides"
three alternative paths of compliance
"A concrete slab-on-ground does not require to be insulated in warm climates."
true
"In a typical stress-strain diagram of a material, the stress is generally plotted along the vertical axis. "
true
"Insulating materials that contain HCFC gas within their cells have a higher R-value than those that contain air within their cells. "
true
"Like color, emissivity is a property of the surface of the material, not of the entire body of the material."
true
"The primary purpose of longitudinal steel bars in a reinforced concrete beam is to overcome the weakness of concrete in tension."
true
"The stress-strain diagram of mild steel is nearly a straight line up to the yield point."
true
"The units of measurement of U-value and U-factor are the same."
true
"The use of aluminum foil in attics is more useful in warm climates than in cold climates."
true
