NITC Journey Level Plumber cheat sheet

Plumbing is defined as the practice, materials, and fixtures used in installing, maintaining, and altering piping, fixtures, appliances, and appurtenances in connection with sanitary drainage or storm drainage facilities, venting systems, and public or private water supply systems.

Water supply systems are classified as either public (municipal) or private (well or other non-municipal source); drainage systems are classified as sanitary, storm, or combined.

Confined-space entry requires atmospheric testing for oxygen (19.5-23.5 percent), flammable gas, hydrogen sulfide, and carbon monoxide before entry and continuous monitoring during occupancy.

Personal protective equipment for plumbing work typically includes safety glasses or goggles, hard hat, gloves, steel-toe boots, hearing protection, and respiratory protection when soldering, cutting, or working in contaminated environments.

Backflow prevention protects potable water from contamination; an air gap provides the highest level of protection, followed by a reduced-pressure-zone assembly and then a double check valve assembly.

Fall protection is required when working at heights of 6 feet or more in construction; guardrails, personal fall arrest systems, and safety net systems are acceptable methods.

Before cutting or drilling, verify the location of concealed utilities using as-built drawings, locate markings, and safe-digging practices; the universal color code marks gas as yellow, water as blue, sewer as green, and electric as red.

Lockout/tagout procedures require de-energizing equipment, applying a lock and tag, releasing stored energy, and verifying isolation before maintenance or repair.

Copper tubing is sized by nominal size with type K, L, and M indicating wall thickness; type K has the thickest wall, type M the thinnest, and type L is the common plumbing choice.

Nominal pipe size (NPS) and iron pipe size (IPS) refer to approximate inside diameter for standard-weight steel pipe; schedule number indicates wall thickness relative to NPS.

PEX is joined with insert fittings and copper crimp rings, stainless steel clamp rings, or compression fittings; PEX cannot be solvent cemented and must be protected from UV exposure.

CPVC is joined with solvent cement specifically rated for CPVC; PVC cement and CPVC cement are not interchangeable, and primer is required for PVC in most codes.

Soldering copper requires cleaning the tube and fitting, applying flux, heating the joint, and feeding lead-free solder; lead-free solder is required for potable water systems.

Brazing copper uses filler metals melting above 840 degrees Fahrenheit and produces stronger joints than soldering; it is used for high-temperature or high-pressure applications.

Threaded steel pipe joints require cutting threads with a die, applying thread sealant or PTFE tape to male threads, and tightening to the correct engagement.

Dielectric unions or dielectric nipples separate dissimilar metals such as copper and steel to prevent galvanic corrosion in piping systems.

Press-connect fittings for copper and steel use a mechanical crimp with an O-ring seal; they require a calibrated pressing tool and cannot be used with damaged or misaligned tubing.

A water closet is a fixture that receives human waste and discharges it to the drainage system through a trap; a bidet is a fixture for personal hygiene and is not a water closet substitute.

Fixture units (FU) are a measure of the load-producing effect of a fixture on the drainage or water supply system; a private water closet typically counts as 3 drainage fixture units.

Water heater temperature and pressure relief (TPR) valves must be piped to a safe point of discharge, typically within 6 inches of the floor, with no reduction in pipe size and no trap or valve downstream.

Shower valves must be of the pressure-balancing or thermostatic type to prevent scalding from sudden pressure changes in the water supply.

Water closets must be set level and secured to the flange; the closet flange connects the fixture to the drainage system, and wax or waxless seals provide the watertight connection.

A faucet with a 2.2 gallon per minute maximum flow rate at 60 psi meets the common federal standard for lavatory and kitchen faucets; water closets are limited to 1.6 gallons per flush.

Dishwashers must have a backflow prevention device such as an air gap or a high-loop, and the discharge must connect to the drainage system through an indirect waste or air gap.

Floor drains require a trap and a trap primer where the trap may evaporate; trap seal protection is required for infrequently used drains.

A trap seal must be a minimum of 2 inches and a maximum of 4 inches deep; the developed length of the trap arm is limited to protect the trap seal from siphonage.

A vent stack provides air to the drainage system and extends through the roof; the vent terminal must be at least 6 inches above the roof and at least 10 feet from any window, door, or air intake.

A soil stack carries the discharge of water closets; a waste stack carries the discharge of other fixtures; a stack vent is the extension of a soil or waste stack above the highest fixture connection.

A wet vent is a vent that also serves as a drain for one or more fixtures; a dry vent carries only air and does not receive drainage.

The building drain is the lowest piping of a drainage system that receives the discharge from soil, waste, and other drainage pipes inside the walls and conveys it to the building sewer.

The building sewer is the pipe that conveys sewage from the building drain to the public sewer or private sewage disposal system, beginning outside the building wall.

Cleanouts are required at the base of each stack, at each horizontal drainage pipe at intervals not exceeding 100 feet, and at changes in direction greater than 45 degrees in buried piping.

Drainage piping must slope at a minimum of 1/4 inch per foot for pipe 2.5 inches and smaller, and 1/8 inch per foot for pipe 3 inches and larger, unless otherwise specified by code.

Air admittance valves (AAVs) are one-way vents that admit air to the drainage system but do not allow sewer gas to escape; they must be installed in accessible locations and per manufacturer instructions.

Water supply system components include the service line, water meter, main shutoff valve, distribution piping, and fixture supply stops; the service line is the pipe from the public main to the building.

A pressure-reducing valve (PRV) is required when the incoming water pressure exceeds 80 psi; typical residential water pressure should be between 40 and 80 psi.

Water supply distribution systems are classified as upfeed (street pressure or booster pump) or downfeed (roof tank or gravity); upfeed systems are common in low-rise buildings.

A water hammer arrestor absorbs hydraulic shock caused by sudden valve closure; it is installed near the fixture or appliance that causes the shock.

Backflow prevention devices are required on connections between potable water and non-potable systems, including irrigation systems, boilers, and chemical feed lines.

The minimum size of a water service line is typically 3/4 inch for a single-family dwelling, and fixture supply stops are typically 3/8 inch compression or 1/2 inch nominal.

Water supply pipe sizing uses fixture units and equivalent length of pipe; the Hunter curve converts fixture units to probable demand in gallons per minute.

Hot water distribution piping should be insulated, and recirculation systems reduce wait time and water waste in large buildings.

Fixture units are converted to probable demand in gallons per minute using published tables; for example, 1,000 fixture units correspond to roughly 150 gpm in many code tables.

Drainage pipe slope: total fall equals pipe length times slope. A 40-foot run at 1/4 inch per foot falls 10 inches (40 x 0.25 = 10).

A 45-degree offset in drainage piping has a horizontal offset equal to the vertical rise; a 22.5-degree offset is half that. For a 45-degree fitting, offset = rise.

An isometric drawing shows plumbing piping in three dimensions along axes at 30, 90, and 150 degrees; vertical pipes are drawn vertically, and horizontal pipes are drawn at 30 degrees.

On an isometric, a horizontal branch drawn to the left or right represents a pipe running east-west or north-south depending on the orientation; a vertical line represents a vertical pipe.

Pipe volume: volume = area x length. For a 4-inch diameter pipe, area = pi x (2 inches)^2 = 12.56 square inches; per foot, volume = 12.56 x 12 = 150.7 cubic inches, or about 0.65 gallons per foot.

A scale of 1/4 inch = 1 foot means 1 inch on the drawing equals 4 feet in reality; a 3-inch line on the drawing represents 12 feet.

Plot plan symbols: a circle with a cross represents a floor drain, a square with a circle represents a water closet, and a triangle represents a cleanout.

The Uniform Plumbing Code (UPC) and International Plumbing Code (IPC) are the two model codes most commonly adopted in the United States; local jurisdictions adopt and amend one of these.

A permit and inspection are typically required before installation, alteration, or repair of plumbing systems, and inspections occur at rough-in, top-out, and final stages.

A rough-in inspection verifies piping installation before concealment; a final inspection verifies fixtures, trim, and operational testing.

A hydrostatic test of the drainage system is conducted by filling the system with water and holding it for a specified period, typically 15 minutes to 1 hour, with no drop in level.

A water supply system test is conducted at a pressure of at least the working pressure or 100 psi, whichever is greater, for a specified duration.

A trap primer is required where a floor drain or other trap may lose its seal through evaporation; the primer maintains the trap seal.

Vent terminals must extend above the roof and be located away from operable windows, doors, and air intakes; a common minimum is 10 feet horizontally or 2 feet above.

Potable water piping must not be installed in contact with soil or in areas subject to contamination; underground potable piping must be protected from contamination and corrosion.

A running toilet is commonly caused by a faulty flapper, a worn fill valve, or a misadjusted float; the flapper is the most common cause of a leaking water closet.

A clogged drain can be cleared with a plunger, a drain snake, or a hydro-jetter; chemical drain cleaners are discouraged because they can damage piping and create hazards.

A water hammer condition is diagnosed by banging noise when a valve closes; the fix is to install or recharge a water hammer arrestor and secure loose piping.

A leaking faucet is commonly caused by a worn cartridge, O-ring, or seat; repairing or replacing the cartridge resolves most single-handle faucet leaks.

A water heater that produces insufficient hot water may have a failed lower heating element, a broken dip tube, or a failed thermostat; a leaking TPR valve indicates excessive temperature or pressure and requires immediate attention.

A frozen pipe is thawed by applying heat gradually, starting from the fixture end toward the frozen section, and never with an open flame; the pipe should be inspected for cracks after thawing.

A sewer odor in a building is commonly caused by a dry trap, a broken vent, or a failed wax ring; the trap seal and vent system should be inspected first.

A water pressure complaint is diagnosed by measuring static and residual pressure; low pressure may be caused by a partially closed valve, a clogged aerator, or a failing pressure-reducing valve.