ICC P2 Exam Flashcards

Q: What does this ICC P2 flashcard set cover?

This 50-card set follows the ICC P2 Commercial Plumbing Inspector content distribution: Water Supply and Distribution (10 cards), Sanitary Drainage (9), Fixtures, Faucets, and Fixture Fittings (7), Vents (7), Water Heaters (5), Traps, Interceptors, Separators, Special Piping & Storage (5), Storm Drainage (3), General Requirements (2), Piping Installation (1), and Piping Protection (1) — proportional to ICC's published domain weights.

Q: Which code edition does this ICC P2 set use?

This set targets the current 2024 code cycle: the 2024 International Plumbing Code (IPC) as the primary reference, plus the 2024 International Fuel Gas Code (IFGC) for water heater venting and combustion air, and ICC A117.1-2017 for accessible fixture clearances. Confirm the exact edition on your ICC exam bulletin before purchasing references, since ICC also offers a 2021 cycle option.

Q: How does the ICC P2 exam differ from the ICC P1 exam?

P2 is the Commercial Plumbing Inspector exam, based on the International Plumbing Code (IPC) and scoped to commercially installed plumbing, storm drainage, special waste, and medical gas/oxygen piping systems. P1 is the Residential Plumbing Inspector exam, based on the International Residential Code (IRC) plumbing provisions and scoped to one- and two-family dwellings. They are separate certifications with separate content outlines.

Q: What score do I need to pass the ICC P2 exam?

ICC national certification exams require a scaled score of 75, which ICC states is not a fixed percentage or raw question count — scaling accounts for differences between exam forms, though it is commonly approximated as roughly 75% correct (about 45 of 60 questions). ICC does not publish a P2 pass rate.

Q: Is the ICC P2 exam open book, and how long do I have?

Yes, ICC P2 is open book: 60 multiple-choice questions in a 2-hour-30-minute limit, delivered through Pearson VUE test centers or ICC's PRONTO remote proctoring. Only the exam's listed approved references (2024 IPC, 2024 IFGC, ICC A117.1-2017) may be used — tab and highlight them, since exam questions are drawn only from those approved texts.

Q: What is ICC's retake policy if I fail the P2 exam?

You must wait 10 days between attempts, and you may attempt the same exam up to six times within a rolling six-month period. After a sixth attempt, you must wait until six months from your first attempt before registering again. You pay the exam fee for every attempt, and jurisdictions may add their own additional retest requirements.

Question 1

Who has authority to enforce the IPC and issue plumbing permits in a jurisdiction?

Accepted Answer

The code official (building official). Per IPC Section 103, the code official administers and enforces the code, issues permits, conducts inspections, and renders interpretations — not the master plumber, design professional, or contractor.

Question 2

When must plumbing construction documents be submitted with a permit application?

Accepted Answer

When required by the code official (IPC 106.3). The code official may waive documents for minor repair or replacement work while still requiring them for significant installations.

Question 3

How must plumbing pipe be protected where it runs through framing near an edge that could be penetrated by fasteners?

Accepted Answer

Install an approved steel shield plate (minimum 0.0575 inch, 16 gauge) covering the area where the pipe is close enough to the framing member's edge to be vulnerable to nails or screws.

Question 4

What are the two acceptance test methods for a DWV system before concealment, and their key parameters?

Accepted Answer

Water test: fill to at least 10 feet of head above the highest fitting, hold 15 minutes, no visible leakage. Air test: pressurize to 5 psi (or 10 in Hg), hold 15 minutes with no added air. Plastic DWV piping may not be air-tested.

Question 5

Under IPC Table 403.1, how many water closets does a 150-occupant business occupancy need?

Accepted Answer

4 water closets — the tiered ratio applies 1 per 25 for the first 50 occupants (2 WC) plus 1 per 50 for the remaining 100 occupants (2 WC).

Question 6

When can a business occupancy skip separate-sex plumbing facilities?

Accepted Answer

When the occupant load is 25 or fewer, a single combined-use toilet room is permitted under the IPC 403.1 exceptions.

Question 7

When is a service sink not required in a business occupancy?

Accepted Answer

When the occupant load is 15 or fewer, IPC 403.1 exempts the space from providing a service sink.

Question 8

What are the minimum clearances around a water closet under IPC 405.3.1?

Accepted Answer

At least 21 inches of clear space in front of the fixture; centerline at least 15 inches from any side wall or obstruction; and at least 30 inches center-to-center between adjacent water closets.

Question 9

What A117.1 clearances apply to an accessible water closet?

Accepted Answer

Centerline set 16-18 inches from the side wall, with a 60-inch clear floor space provided for a side transfer, matching the accessible stall dimensions referenced by the IPC for accessible fixtures.

Question 10

What knee clearance does A117.1 require under an accessible lavatory?

Accepted Answer

At least 27 inches high and 8 inches deep at the front of the clearance, allowing forward wheelchair approach without contacting the underside of the lavatory.

Question 11

What are the maximum fixture flow and flush rates referenced by the IPC (WaterSense/EPAct limits)?

Accepted Answer

Water closets: 1.6 gallons per flush. Urinals: 1.0 gallon per flush. Private lavatory faucets: 2.2 gpm at 60 psi. Public, non-metering lavatory faucets: 0.5 gpm at 60 psi.

Question 12

What are the maximum temperature and pressure settings for a water heater T&P relief valve (IPC 504.4)?

Accepted Answer

Temperature setting not more than 210°F. Pressure setting not more than the tank's rated working pressure or 150 psi, whichever is less.

Question 13

What are the discharge-piping rules for a T&P relief valve (IPC 504.6)?

Accepted Answer

Full size of the valve outlet with no reduction, no valve or threaded end, cannot connect directly to the drainage system, and must discharge through an air gap to a floor, pan, waste receptor, or outdoors, terminating not more than 6 inches and not less than 2x the pipe diameter above the receptor, at a point that is readily observable.

Question 14

When is a water heater safety pan required, and what size drain does it need?

Accepted Answer

Required where a leak would cause damage to the structure. The pan drains by an indirect waste pipe not less than 3/4 inch in diameter, discharging to an approved indirect waste receptor or extending to the building exterior.

Question 15

Where are seismic straps placed on a water heater in a high seismic zone?

Accepted Answer

Two straps: one in the upper third and one in the lower third of the tank's height, with the lower strap located at least 4 inches above the tank's controls.

Question 16

How much free area does each indoor combustion-air opening need using the two-permanent-opening method (IFGC 304.5.3)?

Accepted Answer

At least 1 square inch of free area per 1,000 Btu/h of total appliance input, minimum 100 sq in per opening, with one opening starting within 12 inches of the enclosure's top and one within 12 inches of the bottom.

Question 17

What is the minimum fixture supply pipe size for a lavatory versus a flushometer-valve water closet (IPC Table 604.5)?

Accepted Answer

Lavatory: 3/8 inch minimum. Water closet with a flush valve (flushometer): 1 inch minimum. A tank-type water closet needs only 3/8 inch.

Question 18

How is a building's water distribution piping sized under the IPC?

Accepted Answer

By converting each fixture to water supply fixture units (WSFU) and applying the demand curve in IPC 604.3 (based on Hunter's curve) to find design flow, then sizing pipe for that flow at an acceptable velocity.

Question 19

What is the difference between an RPZ and a double-check (DC) backflow assembly?

Accepted Answer

A reduced-pressure zone (RPZ) assembly protects against high-hazard, health-hazard backpressure and backsiphonage. A double-check (DC) assembly is rated only for low-hazard, non-health conditions.

Question 20

What is the minimum required air gap for potable water protection (IPC Table 608.15.1/608.16.1)?

Accepted Answer

At least twice the diameter of the effective opening, and never less than 1 inch, measured from the outlet to the flood-level rim of the fixture.

Question 21

What is a cross-connection under the IPC?

Accepted Answer

Any actual or potential physical connection between the potable water supply and a source of contamination or pollution (IPC 608.1); each one must be protected by a backflow preventer sized to the degree of hazard.

Question 22

What backflow protection does an exterior hose bibb (sillcock) require?

Accepted Answer

A non-removable hose-bibb-type backflow preventer or an atmospheric vacuum breaker, since an attached hose can create a submerged inlet and a backsiphonage path.

Question 23

When must a pressure-reducing valve be installed on a building water supply (IPC 604.8)?

Accepted Answer

When static water pressure exceeds 80 psi, an approved pressure-reducing valve with strainer must reduce building distribution pressure to 80 psi or less.

Question 24

When are water hammer arrestors required (IPC 604.9)?

Accepted Answer

On fixture supplies with quick-closing valves, such as dishwashers, clothes washers, and flushometer valves, sized and located per the manufacturer's instructions or ASSE 1010.

Question 25

What standard must all potable water distribution materials and fittings meet?

Accepted Answer

They must be third-party certified to NSF/ANSI/CAN 61 for contact with drinking water (IPC 605.1), in addition to conforming to the listed material standards in Tables 605.3 and 605.4.

Question 26

How must nonpotable, reclaimed water piping be identified from potable piping?

Accepted Answer

By distinct color, typically purple or violet, and labeling such as 'CAUTION: NONPOTABLE WATER — DO NOT DRINK,' marked at regular intervals so it cannot be mistaken for the potable system.

Question 27

What DFU value does a private 1.6 gpf water closet carry versus a public one, per IPC Table 709.1?

Accepted Answer

Private water closet: 3 DFU. Public water closet: 4 DFU (both rated at 1.6 gallons per flush).

Question 28

What DFU value do a lavatory and a kitchen sink, bathtub, shower, or floor drain carry?

Accepted Answer

Lavatory: 1 DFU. Kitchen sink, bathtub, shower, and floor drain: 2 DFU each.

Question 29

What DFU load does a full bathroom group (water closet + lavatory + tub/shower, 1.6 gpf) carry?

Accepted Answer

5 DFU total for the group, per IPC Table 709.1.

Question 30

What is the minimum slope for horizontal drainage piping by size (IPC 704.1)?

Accepted Answer

2.5 inches and smaller: 1/4 inch per foot (2%). 3 to 6 inches: 1/8 inch per foot (1%). 8 inches and larger: 1/16 inch per foot (0.5%).

Question 31

What minimum slope applies to drainage piping upstream of a grease interceptor, regardless of pipe size?

Accepted Answer

1/4 inch per foot (2% slope) — the standard small-pipe slope is required no matter the pipe diameter, to keep grease moving before it cools and solidifies.

Question 32

How often must cleanouts be provided on horizontal DWV piping?

Accepted Answer

At intervals not exceeding 100 feet, plus at each change of direction greater than 45 degrees, at the base of each stack, and near the building drain/building sewer connection.

Question 33

When is a backwater valve required on a building drain or branch (IPC 715.1)?

Accepted Answer

When the fixtures served are at an elevation lower than the elevation of the manhole cover of the next upstream manhole in the public sewer, making the branch subject to backflow during a surcharge.

Question 34

What must an indirect waste receptor provide (IPC 802)?

Accepted Answer

It must be trapped, vented, and accessible, and receive the discharge through an air gap or air break rather than a direct sewer connection — used for equipment like dishwashers, ice machines, and steam equipment.

Question 35

What is required of a sump receiving sewage that needs a pump or ejector (IPC 712)?

Accepted Answer

The sump must be gastight with a vented, sealed cover, and the ejector must be sized to handle the anticipated discharge and pass solids typical of sewage.

Question 36

What is the minimum size of a fixture vent under the IPC?

Accepted Answer

At least one-half the diameter of the drain it serves, but never smaller than 1-1/4 inch.

Question 37

How does slope limit the developed length from a trap weir to its vent?

Accepted Answer

The total fall caused by the fixture drain's slope cannot exceed the diameter of the fixture drain — once that allowable fall is used up, the vent connection must occur.

Question 38

Which fixtures are exempt from the trap-to-vent developed-length limit, and why?

Accepted Answer

Self-siphoning fixtures, such as water closets — their high discharge velocity clears the trap without relying on a limited vent distance, so the IPC places no developed-length limit on them.

Question 39

What is a wet vent?

Accepted Answer

A vent pipe that also serves as the drain for one or more fixtures, commonly a bathroom group, sized to handle both the venting function and the DFU load it carries.

Question 40

What is a common vent, and how is it sized?

Accepted Answer

A single vent connecting two fixture drains at the same level, such as back-to-back or side-by-side fixtures; it is sized for the larger of the two drains it serves.

Question 41

What installation limits apply to an air admittance valve (AAV) used as a vent terminal (IPC 917)?

Accepted Answer

It must be installed at least 4 inches above the horizontal branch or fixture drain served, remain accessible, and cannot serve as the sole vent for the entire building — a vent must still extend to open air.

Question 42

When must a vent pipe be upsized for length?

Accepted Answer

Any vent with a developed length exceeding 40 feet must be increased one nominal pipe size for its entire developed length.

Question 43

What is the required trap seal depth range under the IPC?

Accepted Answer

Not less than 2 inches and not more than 4 inches, deeper only for special accessible-fixture designs, per IPC 1002.4.

Question 44

Are S-traps permitted, and how many traps can serve one fixture?

Accepted Answer

S-traps are prohibited because they self-siphon. Each fixture must have its own trap, with very limited exceptions for specifically permitted combination fixtures.

Question 45

How is a gravity grease interceptor's required capacity calculated?

Accepted Answer

Total DFU of connected fixtures multiplied by the flow rate in gpm and the required retention time. Hydromechanical units are instead sized to ASME A112.14.3/.4, CSA B481.3, or PDI G101.

Question 46

What must precede a food waste grinder that discharges into a grease interceptor?

Accepted Answer

A solids interceptor, sized and rated for the grinder's discharge, to separate solids before the flow reaches the grease interceptor.

Question 47

What extra standard applies to nonflammable medical gas and non-medical oxygen piping systems beyond the IPC?

Accepted Answer

They must also comply with NFPA 99, in addition to the IPC's special piping and storage-system provisions inspected under this domain.

Question 48

What design storm does the IPC use to size roof drains and storm piping?

Accepted Answer

The 100-year, 1-hour rainfall rate for the site, from IPC Figure 1106.1/Appendix B or approved local weather data, applied against the flow-rate limits in Table 1106.2 (horizontal) and Table 1106.3 (vertical leaders).

Question 49

How is a secondary, emergency roof drainage system sized relative to the primary system?

Accepted Answer

Independently, at the same design rainfall rate, while assuming the primary drains are completely blocked — flow through the primary system is not credited when sizing the secondary system.

Question 50

Where must secondary or overflow roof drainage discharge?

Accepted Answer

At a location separate from the primary drainage piping and clearly observable, such as a through-wall scupper or an overflow drain terminating to daylight — never tied into the primary storm system.

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