NHIE Building Systems and Components 3 — Questions and Answers
Question 1: What is the function of a TPR (temperature-pressure relief) valve on a water heater?
- Regulate water temperature during normal use
- Release pressure and prevent explosion if temperature or pressure exceeds safe limits (Correct answer)
- Control the flow rate to fixtures
- Prevent backflow into the cold water supply
Correct answer: Release pressure and prevent explosion if temperature or pressure exceeds safe limits
The TPR valve is a safety device that automatically opens to discharge water when temperature exceeds 210°F or pressure exceeds 150 psi, preventing tank rupture or explosion.
Question 2: An inspector finds that the bathroom exhaust fan discharges into the attic. This is a deficiency because:
- It violates fire separation requirements
- It introduces moisture into the attic, promoting mold and structural damage (Correct answer)
- It reduces the fan's CFM capacity
- It creates negative pressure in the bathroom
Correct answer: It introduces moisture into the attic, promoting mold and structural damage
Exhausting humid bathroom air into the attic causes moisture accumulation that can lead to mold growth, insulation damage, and wood rot in the roof structure.
Question 3: What is the recommended minimum depth for a footing in a cold climate?
- 12 inches below grade
- Below the frost line (Correct answer)
- At least 24 inches below grade
- At the level of undisturbed soil
Correct answer: Below the frost line
Footings must be placed below the local frost depth to prevent frost heave, which can shift the foundation and cause structural damage.
Question 4: When inspecting a chimney, what does efflorescence on the exterior masonry indicate?
- Structural failure of the chimney cap
- Water is migrating through the masonry and depositing minerals on the surface (Correct answer)
- The mortar joints are properly sealed
- The flashing has failed completely
Correct answer: Water is migrating through the masonry and depositing minerals on the surface
Efflorescence is the white mineral deposit left behind as water evaporates after passing through masonry, indicating ongoing water infiltration.
Question 5: Which AFCI protection is required by the NEC for bedroom circuits in new construction?
- GFCI-only protection
- Arc-fault circuit interrupter (AFCI) breakers (Correct answer)
- Dual-function GFCI/AFCI receptacles only
- Whole-house surge protection
Correct answer: Arc-fault circuit interrupter (AFCI) breakers
The NEC requires AFCI breaker protection for bedroom circuits to detect dangerous arcing that can cause electrical fires from damaged wiring.
Question 6: What is the purpose of building wrap (housewrap) installed behind exterior cladding?
- Provide primary structural sheathing
- Act as a weather-resistive barrier while allowing vapor to escape (Correct answer)
- Serve as the primary insulation layer
- Replace the need for flashing at openings
Correct answer: Act as a weather-resistive barrier while allowing vapor to escape
Housewrap is a weather-resistive barrier (WRB) that blocks liquid water infiltration while remaining vapor-permeable to allow moisture in the wall assembly to dry outward.
Question 7: An inspector observes that a deck ledger is attached directly to the rim joist with no flashing. The primary concern is:
- Deck overloading the floor joists
- Water intrusion causing rot at the ledger-to-house connection (Correct answer)
- Inadequate fastener shear strength
- Thermal bridging through the rim joist
Correct answer: Water intrusion causing rot at the ledger-to-house connection
Without proper flashing, water is trapped between the ledger and the house rim joist, leading to wood rot, fastener corrosion, and potentially catastrophic deck collapse.
NHIE Building Systems and Components 3
What is the function of a TPR (temperature-pressure relief) valve on a water heater?