CSI Construction Materials & Systems 3 — Questions and Answers
Question 1: What type of glass is produced by heating annealed glass and rapidly cooling it to create surface compression?
- Laminated glass
- Tempered glass (Correct answer)
- Heat-strengthened glass
- Insulating glass
Correct answer: Tempered glass
Tempered glass is produced through a thermal tempering process that creates surface compression, making it approximately four times stronger than annealed glass and causing it to dice into small fragments when broken.
Question 2: In masonry construction, what is the purpose of a relieving angle (shelf angle)?
- To anchor the masonry veneer to the structural backup
- To transfer accumulated masonry dead load to the building structure at each floor (Correct answer)
- To provide a weep hole drainage path at the base of the wall
- To control cracking caused by thermal expansion
Correct answer: To transfer accumulated masonry dead load to the building structure at each floor
Shelf angles transfer the accumulated dead load of masonry veneer above to the building's structural frame at each floor or intermediate level.
Question 3: Which insulation material has the highest R-value per inch among commonly used rigid insulation products?
- Expanded polystyrene (EPS)
- Extruded polystyrene (XPS)
- Closed-cell spray polyurethane foam (ccSPF)
- Polyisocyanurate (polyiso) (Correct answer)
Correct answer: Polyisocyanurate (polyiso)
Polyisocyanurate (polyiso) typically achieves R-6 to R-6.5 per inch, the highest among common rigid board insulations, though it can lose R-value at cold temperatures.
Question 4: What does the term 'galvanic corrosion' describe in the context of construction materials?
- Rust formation on steel exposed to moisture and oxygen
- Electrochemical corrosion when dissimilar metals contact each other in the presence of an electrolyte (Correct answer)
- Corrosion of aluminum cladding due to acid rain
- Oxidation of copper flashing over time
Correct answer: Electrochemical corrosion when dissimilar metals contact each other in the presence of an electrolyte
Galvanic corrosion occurs when two dissimilar metals are in electrical contact with an electrolyte (such as water), causing the less noble metal to corrode preferentially.
Question 5: In wood-frame construction, what is the structural purpose of a rim joist (band joist)?
- To provide lateral bracing for interior floor joists against overturning (Correct answer)
- To transfer loads from studs above down through the floor system
- To provide a nailing surface for sheathing and close off floor joist ends
- To act as a header over window and door openings
Correct answer: To provide lateral bracing for interior floor joists against overturning
Rim joists run perpendicular to floor joists at the perimeter and resist overturning (rotation) of the parallel floor joists while also capping the floor system.
Question 6: What is the primary function of a cavity (drainage) wall construction method in masonry systems?
- To increase the thermal mass of the wall assembly
- To provide a drainage path for water that penetrates the outer wythe (Correct answer)
- To eliminate the need for flashing at window sills
- To allow the use of non-weather-resistant brick at the exterior
Correct answer: To provide a drainage path for water that penetrates the outer wythe
Cavity walls include an air space between wythes that allows any water penetrating the outer masonry wythe to drain down and exit through weep holes at the base.
Question 7: Which property of steel is defined as the stress at which a material exhibits a specified limiting permanent set?
- Ultimate tensile strength
- Modulus of elasticity
- Yield strength (Correct answer)
- Ductility
Correct answer: Yield strength
Yield strength is the stress level at which steel undergoes a specified amount of permanent plastic deformation (typically 0.2% offset) rather than elastic recovery.
CSI Construction Materials & Systems 3
What type of glass is produced by heating annealed glass and rapidly cooling it to create surface compression?