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These 10 free IL-PLUMBER questions are organized by exam domain, so you can see how each part of the Illinois Plumber License Exam blueprint is tested. Reveal the answer and explanation under each question.
A completed potable-water system will operate at 70 psi. The contractor proposes a 100-psi air test held for 10 minutes. Which test protocol complies with the Illinois Plumbing Code?
Correct answer: B - 105 psi hydrostatic for 15 minutes
During inspection of a hub-and-spigot cast-iron DWV joint, the oakum is firmly packed and the lead finishes 1/16 inch below the hub rim, but the lead depth is only 3/4 inch. No coating has been applied. The joint should be:
Correct answer: C - Rebuilt with at least 1 inch of lead
A commercial pot sink has inside liquid dimensions of 42 by 22 by 10 inches. Its grease interceptor will be installed on the floor below. Using 231 cubic inches per gallon, what minimum liquid-holding capacity is required?
Correct answer: B - 24 gallons, using the below-floor factor
Maintenance logs show sewer odor returning after about six weeks whenever a mechanical-room floor drain is unused; the odor disappears as soon as water is poured into the drain. A smoke test shows no leakage, and vent pressures are normal. Which correction addresses the failure mechanism without routine servicing?
Correct answer: D - Install an automatic trap primer
A restaurant tenant in an enclosed mall proposes to use shared public restrooms 80 feet from its entrance, but one floor above. The rooms are available whenever the restaurant is open or employees are present and are sized for the combined occupant load. The unresolved defect is that the restrooms:
Correct answer: A - Must be on the same floor as the food-service tenant
An athletic-club locker-room shower is specified with 1,224 square inches of outside-dimension floor area, a 34-inch shortest outside dimension, a 2-inch waste outlet, and a safety mixing device limited to 115°F. A compliant revised specification would:
Correct answer: D - Increase the outside-dimension floor area to 1,350 square inches
At a private residence, a dishwasher drain is carried up to the underside of the sink's spill rim, then connected to the inlet on the food-waste disposer. What change is required?
Correct answer: A - Discharge it separately into the sink trap or tailpiece
During commissioning of a correctional-facility security sink/lavatory, its self-closing control valve remains open for 46 seconds. The waste assembly is brass and all other components comply. The required adjustment is to:
Correct answer: C - Set the valve within a 5- to 40-second range
A pressurized make-up line serves a closed process tank containing a high-hazard corrosion-inhibitor solution. Process pressure can exceed potable-supply pressure, a fixed air gap is impractical, and the code permits a mechanical assembly for this application. Which device provides the required protection?
Correct answer: D - Reduced-pressure-principle backflow assembly
An over-rim potable-water outlet has an effective opening of 1 1/4 inches. An adjacent wall is close enough to create the Table C near-wall condition. What minimum vertical air gap is required?
Correct answer: C - 3 3/4 inches
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