ICC P3 cheat sheet

Plumbing permit drawings must be drawn to scale and show floor plans, elevations or sections, riser/isometric diagrams, fixture locations and types, pipe sizes, materials, and the occupancy classification.

A plumbing permit lapses where work has not commenced within 180 days of issuance, or where work is suspended or abandoned for 180 days; an extension may be granted in writing.

A permit is not required for clearing stoppages, repairing leaks in drains, water, soil, waste, or vent pipe, or reinstalling an existing water closet where the trap is not disturbed.

Minimum plumbing facilities are determined by occupancy classification and occupant load using the fixture-ratio table (IPC Table 403.1); fixture counts drive water, drain, and vent sizing shown on the plans.

Occupancy groups (A, B, E, F, I, M, R, S, U) come from the building code and control required fixtures, accessibility features, and the degree of plumbing protection.

The code official may require water tests, air tests, smoke tests, and rough-in and final inspections; a certificate of occupancy follows approval of the final plumbing inspection.

Alternate materials, methods, and designs require prior written approval supported by evidence of equivalent performance; unlisted materials are not permitted.

New work added to an existing building must comply with the code for new construction; existing systems may remain where they are not made less safe or sanitary.

Maximum fixture water use: water closet 1.6 gpf (1.28-gpf units also comply), urinal 1.0 gpf, showerhead 2.5 gpm at 80 psi, lavatory faucet 2.2 gpm at 60 psi.

Each fixture must be individually trapped and vented, except where the code permits a listed combination fixture or a single trap serving a set of fixtures.

Trap seals must be at least 2 inches and not more than 4 inches deep, and the fall of a trap arm must never exceed the depth of the trap seal.

Maximum trap-arm length from trap weir to vent: 1-1/4 in = 5 ft, 1-1/2 in = 6 ft, 2 in = 8 ft, 3 in = 12 ft, 4 in = 16 ft.

A private bathroom group (water closet, lavatory, bathtub or shower) is 5 drainage fixture units with a flush-tank water closet and 6 with a flushometer valve.

Minimum fixture supply sizes: 3/8 in for flush-tank water closets and lavatories, 1/2 in for bathtubs, showers, and sinks, 3/4 in for flushometer urinals, 1 in for flushometer water closets.

Accessible lavatories have a rim no higher than 34 inches above the floor with knee and toe clearance provided; accessible water closet compartments are at least 60 inches deep and 30 inches wide.

Traps subject to evaporation, such as floor drains in unused areas, must be protected by a trap primer or another approved method of maintaining the seal.

Fixtures and fittings must be listed and approved to recognized standards (for example, ASME A112.19.2/CSA B45.1 for vitreous china) and be installed per the manufacturer's instructions.

Every storage water heater requires a combination temperature and pressure relief valve, with the sensing element in the top 6 inches of the tank.

The relief valve discharge pipe must be full size (never reduced), gravity-drained, free of valves and traps, and terminate not more than 6 inches above the floor or outside the building.

Residential tank relief valves typically open at 210 degrees F or 150 psi; the setting must not exceed the pressure rating of the tank or system components.

A drain pan at least 1-1/2 inches deep with a drain of at least 3/4 inch is required where leakage would damage the structure, finish, or ceiling below.

Water heaters installed in private garages must be elevated at least 18 inches above the floor where the ignition source is within 18 inches of the floor.

Where seismic design category C or greater applies, tanks are strapped with two straps: one in the lower third and one in the upper third of the tank.

Attic or concealed-space installations require a 24-inch access opening, a level service platform, and a 30-inch working space at the controls; clearances to combustibles follow the listing.

A thermal expansion tank is required where a check valve, backflow preventer, or pressure-reducing valve creates a closed system with no means for expansion.

Hot water delivered to showers and public lavatories is limited by a listed mixing valve to a maximum of 120 degrees F (lower limits apply in health-care settings).

The building water service is not smaller than 3/4 inch; no individual fixture supply is smaller than 3/8 inch, and flushometer water closets require a 1-inch supply.

Piping is sized from fixture units and developed length using the fixture-unit/sizing tables; the governing run is the longest developed length from the source to the farthest outlet.

A pressure-reducing valve is required where static pressure exceeds 80 psi; the downstream setting is typically 50 to 60 psi, with no more than 80 psi at any fixture.

Water distribution piping must be tested and proved tight under hydrostatic pressure at or above the working pressure and inspected before being concealed.

Water service pipe laid in the same trench as the building sewer must be separated, and at crossings the water pipe must be at least 12 inches above the sewer.

An air gap provides complete backflow protection; hose bibbs, sill cocks, and connections to nonpotable systems require approved vacuum breakers or backflow preventers.

Water hammer arrestors of a listed type are required at quick-closing valves such as flushometer valves and at appliance connections in groups of five or more.

Design velocity in water distribution piping is generally limited to about 8 feet per second to control noise and erosion; pipe joints other than approved fittings must remain accessible.

Horizontal drain slope: 1/4 inch per foot for pipe 2-1/2 inches and smaller, and 1/8 inch per foot for 3-inch and larger pipe (1/4 inch is also permitted for larger pipe).

The building sewer is not less than 4 inches in diameter and is sized from the total drainage fixture units of the building, using the building drain and sewer sizing table.

Cleanouts are required at the base of each stack, at the upper end of each horizontal drain, at horizontal changes of more than 45 degrees, and at intervals not exceeding 100 feet.

A cleanout is the same size as the pipe it serves up to 4 inches; cleanouts on larger pipe are not less than 4 inches and must be accessible.

Every fixture trap must be vented; vent sizing and common-vent and wet-vent arrangements follow the vent tables based on fixture units and stack length.

A vent stack through the roof terminates at least 6 inches above the roof surface and must not be located under an overhang or near an air intake or operable window.

Storm drainage must be kept separate from the sanitary system; roof drains and leaders are sized from the local 100-year, 1-hour rainfall intensity.

Secondary (overflow) roof drainage by drains or scuppers is required in addition to primary drains where a parapet wall or similar condition could allow ponding if the primary drain blocks.

Fixtures draining to a point below the level of the next upstream manhole on the sewer require an automatically closing backwater valve.

Gas piping is sized by the longest-length method using the developed length of the run plus total connected Btu/hr input, 0.60 specific gravity gas, and 0.5-inch water column pressure drop for systems at 1/2 psi or less.

Fuel gas piping is tested at not less than 1-1/2 times the maximum working pressure and never less than 3 psi, with the test held a minimum of 10 minutes for low-pressure systems.

A shutoff valve is required in the same room and within 6 feet of the appliance, and a sediment trap (drip leg) is installed at the appliance inlet downstream of the shutoff.

Appliance connectors are limited to 6 feet in length, must not be concealed, and must not pass through walls, floors, or ceilings; unions are not permitted in concealed locations.

Combustion air: two permanent openings sized at 1 square inch per 1,000 Btu/hr for indoor air, 1 per 2,000 Btu/hr for horizontal outdoor ducts, and 1 per 4,000 Btu/hr for vertical ducts.

Food-service fixtures discharge through a grease interceptor sized to the fixture flow and grease retention capacity, with a vented, accessible cover and a solids-retaining compartment.

Garages and service bays require a sand or oil interceptor on floor drains, and below-grade fixtures require a sump with an ejector sized for the expected inflow and discharge head.