IA Plumber study plan

Label every segment of a drain, waste and vent (DWV) system by its code name: fixture drain, fixture branch, soil stack, waste stack, stack vent, building drain, building sewer.

Compute drain fixture units (DFU) for a mixed fixture load by looking up each fixture type and summing branch and stack totals.

Apply minimum slope and sizing rules to horizontal drainage pipe, distinguishing 2-1/2 in. and smaller from 3 in. and larger.

Identify prohibited drainage fittings and connections, including the restrictions on sanitary tees, double fittings, and horizontal-to-vertical turns.

Locate required cleanouts by pipe size, run length, and change of direction.

Determine when a trap is required to be vented and select an acceptable vent type (individual, common, wet, circuit, island) for each fixture group.

Size vent stacks and vent branches from connected DFU using the vent sizing table.

Apply rules for vent termination height, distance from openings, and clearance above the roof.

Explain the function of a stack vent versus a vent stack in a multi-story building and where each is required.

Verify trap seal depth and trap arm length limits, and identify prohibited traps such as S-traps, bell traps, and traps with moving parts.

Select and size a grease interceptor for a restaurant and explain when a sand or oil interceptor is required.

Describe how special wastes (chemical, corrosive, high-temperature, dental, or photographic) must be handled before discharge.

Explain the purpose and placement of each fixture's vent relative to the trap weir.

Convert water supply fixture units (WSFU) to probable demand in gallons per minute using the demand curve.

Size a water service main, building supply, and branch lines from WSFU and available pressure.

Compute developed length and apply it to friction loss and pressure-loss calculations.

Determine required residual pressure at fixtures and where a pressure-reducing or booster system is needed.

Calculate velocity and pressure loss in copper and PEX lines using standard friction tables, and select a pipe diameter that satisfies both.

Lay out a public water main, meter, service line, and distribution tree with valves, and justify each valve location.

Solve plumbing math problems involving volume, capacity, slope as a percentage, and unit conversions (psi to feet of head, gallons to cubic feet).

Explain thermal expansion control and the placement of shock arrestors, water hammer arrestors, and air chambers.

Define key code terms (approved, listed, fixture branch, plumbing system, accessible) and apply them to scenario questions.

Outline the permit, inspection, and testing sequence for new plumbing work, including the water test and air test requirements.

State required fixture clearances, spacing, and installation requirements for water closets, lavatories, sinks, and showers.

Identify fixture-fitting requirements including backflow protection at hose bibs and the correct use of fixture stops and escutcheons.

Specify temperature and pressure relief valve sizing, placement, and discharge piping for storage and tankless water heaters.

Apply water heater installation rules for seismic strapping, drip pans, combustion air, and venting of gas-fired units.

Size gas piping by the longest-length method and identify required sediment traps, shutoff valves, and appliance connectors.

Explain combustion air requirements and the prohibition on installing gas appliances in bedrooms and bathrooms without the required safeguards.

Rank backflow prevention assemblies (air gap, reduced pressure zone, double check, pressure vacuum breaker, atmospheric vacuum breaker) by degree of hazard and apply each to a scenario.

Identify cross-connection risks in typical residential and commercial installations and specify the correct device.

Review all ten domains using a missed-question log and re-drill the two weakest domains.

Complete full-length practice exams under timed conditions.