CBD Plumbing & Fixture Integration 2 — Questions and Answers
Question 1: What is the minimum recommended distance between the centerline of a toilet and an adjacent wall or obstruction per most US codes?
- 12 inches
- 15 inches (Correct answer)
- 18 inches
- 24 inches
Correct answer: 15 inches
Most US building codes require a minimum of 15 inches from the toilet centerline to any side wall or obstruction.
Question 2: A pressure-balance valve in a shower is required by US plumbing codes primarily to:
- Increase water pressure
- Prevent scalding when toilets flush (Correct answer)
- Reduce water consumption
- Filter sediment from the supply line
Correct answer: Prevent scalding when toilets flush
Pressure-balance valves maintain a set ratio of hot to cold water to prevent scalding when pressure fluctuates due to toilet flushing or other draws.
Question 3: Which drain configuration is most appropriate for a freestanding soaking tub installed away from the wall?
- Wall-mounted drain with chrome escutcheon
- Floor-mounted drain with flexible drain connector (Correct answer)
- Overhead ceiling drain
- P-trap mounted inside the tub apron
Correct answer: Floor-mounted drain with flexible drain connector
A floor-mounted drain with a flexible drain connector accommodates the freestanding tub's position away from wall plumbing.
Question 4: When specifying a vessel sink, the designer must ensure the rough-in drain height is set at:
- The same height as an undermount sink drain
- Floor level only
- A height that accounts for the vessel's depth above the counter (Correct answer)
- 18 inches above finished floor
Correct answer: A height that accounts for the vessel's depth above the counter
Vessel sinks sit on top of the countertop, so drain rough-in must account for the added height of the vessel bowl above the deck surface.
Question 5: The ADA-compliant reach range for faucet controls at an accessible lavatory is:
- No higher than 34 inches AFF
- Between 15 and 48 inches AFF for side reach (Correct answer)
- At least 36 inches AFF
- No restriction as long as it is operable with one hand
Correct answer: Between 15 and 48 inches AFF for side reach
ADA guidelines allow a maximum high side reach of 48 inches and minimum low reach of 15 inches above finished floor.
Question 6: In a wet-wall (plumbing wall) design, the standard wall thickness to accommodate drain and supply lines is typically:
- 2×4 framing (3.5" cavity)
- 2×6 framing (5.5" cavity) (Correct answer)
- 2×8 framing (7.25" cavity)
- Thickness varies only by pipe diameter
Correct answer: 2×6 framing (5.5" cavity)
A 2×6 framing cavity (5.5 inches) is standard for wet walls to accommodate 3- or 4-inch drain pipes along with supply lines.
Question 7: When a walk-in shower has no door or curtain (zero-threshold), which slope specification is critical to prevent water migration onto the bathroom floor?
- 1/8 inch per foot slope toward the drain inside the shower only
- A linear drain positioned at the shower entry threshold
- A secondary perimeter drain at the shower border
- Both a minimum 1/4 inch per foot slope and a sufficient distance from entry to drain (Correct answer)
Correct answer: Both a minimum 1/4 inch per foot slope and a sufficient distance from entry to drain
A doorless shower requires at minimum 1/4 inch per foot slope to drain combined with adequate depth so water travels toward the drain before reaching the opening.
CBD Plumbing & Fixture Integration 2
What is the minimum recommended distance between the centerline of a toilet and an adjacent wall or obstruction per most US codes?