NV Journeyman Plumber cheat sheet

Potable water: water free of impurities in amounts that could constitute a health hazard; must meet primary and secondary drinking water standards.

Fixture unit (f.u.): drainage fixture unit (dfu) rates a fixture's waste load; water supply fixture unit (wsfu) rates its demand. The two scales are independent.

A stack is any vertical line of pipe larger than 1-1/2 inches; a stack vent is the extension of a soil or waste stack above the highest horizontal drain connected to it.

A branch is any part of a piping system other than a main, riser, or stack; a fixture branch connects one fixture to a drain or supply line.

Code administration: the AHJ (authority having jurisdiction) enforces the adopted plumbing code; approved means accepted in writing by the AHJ, and listed/labeled means certified by an approved third-party agency.

Shall is mandatory; should/may are permissive. Where the code and manufacturer's installation instructions conflict on a listed appliance, the stricter requirement governs.

Developed length: total length of a pipe measured along its centerline, including fittings; fitting allowances are added to straight-run length when computing drain and vent sizes.

Reasonable interpretation rule: where the code is silent, the AHJ's written interpretation controls, and work must stop for correction when the AHJ rejects an installation.

A permit is required before installing, altering, repairing, or replacing any plumbing system; ordinary repairs such as clearing stoppages, replacing a faucet washer, or re-caulking a fixture do not require one.

Permit application must show the work's location, character, occupancy, and the name/address of the licensed contractor; permits expire if work does not start within the period set by the jurisdiction.

Required inspection sequence: rough-in (before concealment), then drain/waste/vent testing, then final. Concealed work must be inspected and approved before it is covered.

Drainage systems are tested with water to the highest point of the system (10 ft head minimum where practical) or with air at the pressure the code specifies; water supply piping is tested at working pressure plus a margin, typically 100 psi for at least 15 minutes.

Building sewer: the pipe from the building drain to the public sewer or private disposal; building drain is the lowest piping of the drainage system inside the building, extending 30 inches beyond the exterior wall.

Minimum air gap for a water-supply outlet: twice the effective opening of the outlet, never less than 1 inch, measured above the flood level rim of the receiving fixture.

A plumbing system must be installed with structural support, protection from freezing, and accessibility of cleanouts; no plumbing may be installed in an unsafe or unsanitary manner.

Change of occupancy or use that increases plumbing load requires a new permit and a re-evaluation of fixture counts and pipe sizing.

Water closet maximum flush: 1.6 gallons per flush; urinals 1.0 gpf; showerheads 2.5 gpm at 80 psi; kitchen faucets 2.2 gpm; lavatory faucets 2.2 gpm (public lavatories 0.5 gpm).

Fixture clearances: water closets need 15 inches clear from the centerline to any side wall or partition and 21 inches clear in front of the bowl; minimum compartment width is 30 inches.

Each fixture must have a water-supply connection protected against backflow, a smooth impervious surface, and a drain with a trap; fixtures must be accessible for cleaning.

Water heaters: a temperature and pressure relief (TPR) valve is required, sized to the heater's rated capacity, with a full-size discharge pipe draining by gravity to a safe point of disposal with no trapped section.

A water heater's TPR discharge pipe must terminate not more than 6 inches above the floor or waste receptor and must not be threaded or capped at the outlet.

Expansion tanks are required on closed water-supply systems to absorb thermal expansion from the water heater; a check valve or backflow preventer creates a closed system.

Floor drains, drinking fountains, and hose bibbs require backflow protection appropriate to the hazard: atmospheric vacuum breakers on hose bibbs, air gaps on receptors.

Fixtures must be set level and secured; a water heater in a garage must be elevated so the ignition source is at least 18 inches above the floor.

Minimum residual pressure: 8 psi at a fixture during flow where the supply is from a gravity tank or street main, and 15 psi for flushometer valves; static pressure above 80 psi requires a pressure-reducing valve.

Water supply fixture units (wsfu) convert to demand in gallons per minute through the Hunter curve; convert flush-tank and flushometer fixtures on separate curves before combining.

Developed length = straight pipe + equivalent lengths of fittings and valves; use the total to select pipe size from the demand/velocity tables.

Maximum velocity in water distribution is generally 8 fps for cold and 5 fps for hot water to limit noise and erosion.

Hot water distribution: a recirculation line or heat-traced system is needed where the developed length from the heater to the farthest fixture exceeds the code threshold (commonly 100 ft).

Supply lines must be protected from freezing, supported at intervals set by the code, and isolated with valves so fixtures can be serviced without shutting down the building.

A water service line must be buried below the local frost depth; in southern Nevada that depth is shallow, but the AHJ's adopted depth governs.

Parallel water-heating and booster systems must be sized so that the total demand does not exceed the source capacity; a pressure-reducing valve is required where street pressure exceeds 80 psi.

Slope rules: 2-1/2 inch and smaller drains at 1/4 inch per foot; 3 to 6 inch drains at 1/8 inch per foot; larger mains may use 1/16 inch per foot where velocity is adequate.

Drainage fixture units (dfu): water closet 3, lavatory 1, bathtub/shower 2, kitchen sink 2, floor drain 2, clothes washer 2, urinal 4 (flushometer).

A horizontal drain must change direction with 45-degree or gentler fittings; a 90-degree turn requires a long-sweep or two 45s; vertical-to-horizontal turns use a wye or combination.

Cleanouts: required at the base of each stack, at the end of each horizontal drain run, and at intervals not exceeding 100 ft in horizontal drains; cleanout must be accessible and gas-tight.

Venting: each trap must be protected by a vent; a vent stack extends to open air at least 6 inches above the roof, at least 3 ft from any window or air intake, and larger than the drain it serves.

A wet vent may serve only fixtures on the same floor and is limited in size and length; a common vent connects two fixture drains at the same level.

Storm drainage must be separate from sanitary; roof drains, area drains, and leaders discharge to a storm system or approved point, never to a sanitary sewer unless the AHJ allows combined flow.

A trap arm (fixture drain from trap to vent) must not exceed the developed length set by the trap arm table, and its slope must not exceed one pipe diameter.

Every trap must have a liquid seal of at least 2 inches and at most 4 inches; a trap must be self-cleaning and accessible for cleaning.

A trap may serve only one fixture (except where code permits a combination fixture); a floor drain trap must be protected against evaporation by a trap primer.

A grease interceptor is required for commercial kitchens and any discharge containing fats, oils, or grease; it must be sized to the fixture load, installed with flow control, and cleaned regularly.

A sand/oil interceptor serves vehicle service bays and garages; a lint trap serves laundry; a hair interceptor serves barber and beauty shops.

Special wastes (acid, chemical, photographic, medical) must be neutralized or treated before entering the drainage system, and the treatment equipment must be vented.

A backwater valve is required where a fixture's flood level rim is below the next upstream manhole cover, to prevent sewage backup.

Indirect waste receptors receive clear-water waste through an air gap; the waste pipe must terminate with an air gap of at least twice the pipe diameter above the receptor.

Traps must be protected from siphonage by venting; a trap that loses its seal by evaporation, oscillation, or back pressure is a cross-connection hazard.

Gas pipe sizing uses the longest-run method: total the connected load in Btu/hr, find the longest developed length from the meter, and read the required pipe size from the capacity table for the gas's specific gravity and pressure.

Natural gas heating value is about 1,000 Btu per cubic foot; propane is about 2,500 Btu per cubic foot. Convert appliance input ratings to cubic feet per hour before sizing.

Gas piping must be installed with a sediment trap (drip leg) at each appliance, with the trap below the appliance connection and the gas flow turning upward into the appliance.

A shutoff valve must be installed in the same room and within 6 feet of each appliance, and a union or flanged connection must allow removal of the appliance.

Gas pipe must be supported at intervals of 6 ft for horizontal runs and 10 ft for vertical runs, and must be protected from physical damage and corrosion.

A gas piping system is tested with air or inert gas at not less than 10 psi for 10 minutes (or the pressure the code specifies for the pipe type), with the gauge visible and no pressure drop.

Combustion air and venting: appliances must have adequate combustion air and a vent that terminates safely away from windows, doors, and air intakes; a Category IV appliance needs a sealed, sloped vent.

Gas piping must not be concealed in a way that prevents inspection, and no gas piping may pass through a duct, chimney, or elevator shaft.

Cross-connection: any actual or potential connection between potable water and a non-potable source; it must be eliminated or protected by an approved backflow assembly.

Backflow is caused by backpressure (downstream pressure exceeds supply) or backsiphonage (negative pressure in the supply).

Air gap is the highest level of protection (an air gap of twice the effective opening, minimum 1 inch); an RPZ (reduced pressure zone) assembly is used for high-hazard protection and must be tested annually.

A double check valve assembly protects against low hazards only; a pressure vacuum breaker protects against backsiphonage only and cannot be used where backpressure exists.

An atmospheric vacuum breaker must be installed at least 6 inches above the highest downstream outlet and must not be subject to continuous pressure.

Hose bibbs, irrigation systems, boiler feed lines, and chemical dispensers require backflow protection; the assembly must be accessible for testing and repair.

The potable water system must be protected during construction and repair; a new main must be disinfected and flushed before being placed in service.

Backflow assemblies must be tested by a certified tester at installation and at the interval the AHJ sets, with results filed with the water purveyor.

An isometric drawing shows length, width, and height on three axes 120 degrees apart; vertical lines stay vertical, and horizontal lines run at 30 degrees from the horizontal.

Isometric symbols: a circle becomes an ellipse; a right angle in plan appears as 60 or 120 degrees; pipe runs are drawn parallel to the three axes.

On an isometric, a change in direction is shown by a fitting symbol at each turn; the drawing must show the vent, drain, and supply in the correct relative positions.

Plan views show the building layout in two dimensions; a riser diagram shows the vertical relationship of stacks and vents; a section shows the vertical relationship of buried and overhead lines.

A material takeoff lists pipe by size and length, fittings by size and type, and fixtures by count; add a waste factor (commonly 5-10 percent) to pipe and fittings.

Scale: a 1/4 inch = 1 ft plan means 1/4 inch on the drawing equals 12 inches in the field; convert drawing measurements to actual lengths before ordering.

When counting fittings for a takeoff, count each change of direction, each branch, and each transition; include valves, cleanouts, and hangers in the takeoff.

A bill of materials must match the approved plans; a substitution of pipe material or fitting type requires AHJ approval before installation.

Confined-space entry requires a permit, atmospheric testing (oxygen, flammable gas, hydrogen sulfide), a standby attendant, and rescue equipment; never enter a sewer manhole without these.

Trench safety: any trench 5 ft or deeper requires a protective system (shoring, sloping, or shielding); a competent person must inspect trenches daily and after any change.

Ladder safety: maintain a 4:1 slope for extension ladders, secure the top, and keep three points of contact; never stand on the top two rungs.

Soldering and brazing require a fire watch, a fire extinguisher, and removal of combustibles; a hot-work permit may be required by the site.

Personal protective equipment for plumbing work includes safety glasses, gloves, hearing protection when cutting, and respiratory protection when working with solvents or in dusty areas.

Tool use: a pipe wrench is sized to the pipe (14-inch for 1-inch pipe), a tubing cutter leaves a square end that must be reamed, and a press tool must be calibrated to the fitting manufacturer's spec.

Lockout/tagout: isolate and tag energy sources before servicing equipment; verify zero energy before work begins.

Housekeeping and jobsite practice: cap open pipe ends, protect potable water from contamination, and keep the work area clear of tripping hazards.

Plumbing contracting in Nevada is licensed by the Nevada State Contractors Board (NSCB); a journeyman plumber works under a licensed plumbing contractor.

Nevada plumbing classifications include the C-1 (plumbing and heating) and C-2 (plumbing) contractor licenses; the license must be held by the qualifying party who passes the trade exam.

The Nevada Plumbing Code is adopted by the state and enforced by local building departments; the Southern Nevada Health District and local water purveyors add backflow and cross-connection requirements.

Journeyman plumber certification in Nevada is administered through the state's plumbing examiner/apprenticeship framework; a journeyman must work under a licensed contractor and may supervise apprentices.

Contractors must carry workers' compensation and a surety bond, and must display the license number on contracts, bids, and advertising.

Unlicensed contracting is a misdemeanor for a first offense and can escalate; the NSCB can fine, suspend, or revoke a license for violations.

Nevada requires written contracts for residential work above a set dollar amount, with a three-day right to cancel and specific notice provisions.

Local amendments: jurisdictions such as Las Vegas, Henderson, and Clark County adopt the state code with local amendments, so the AHJ's amendment package must be checked before design.

Potable water: water free of impurities in amounts that could constitute a health hazard; must meet primary and secondary drinking water standards.

Fixture unit (f.u.): drainage fixture unit (dfu) rates a fixture's waste load; water supply fixture unit (wsfu) rates its demand. The two scales are independent.

A stack is any vertical line of pipe larger than 1-1/2 inches; a stack vent is the extension of a soil or waste stack above the highest horizontal drain connected to it.

A branch is any part of a piping system other than a main, riser, or stack; a fixture branch connects one fixture to a drain or supply line.

Code administration: the AHJ (authority having jurisdiction) enforces the adopted plumbing code; approved means accepted in writing by the AHJ, and listed/labeled means certified by an approved third-party agency.

Shall is mandatory; should/may are permissive. Where the code and manufacturer's installation instructions conflict on a listed appliance, the stricter requirement governs.

Developed length: total length of a pipe measured along its centerline, including fittings; fitting allowances are added to straight-run length when computing drain and vent sizes.

Reasonable interpretation rule: where the code is silent, the AHJ's written interpretation controls, and work must stop for correction when the AHJ rejects an installation.