Exam Cheat Sheet · Quick Reference
ICC F28 Journeyman Plumber with Gas Exam (2015 IPC/IFGC)
National · Pearson Vue
Verified, not estimated. Every figure below is drawn from the official exam structure we maintain — question counts, passing standard and topic weighting. Practice questions are grounded in the source law with statute citations. We omit any figure we can't verify rather than guess at it.
Total questions
70
Passing score
70%
Exam time
180 min
Administered by
Pearson Vue
Format
Reference materials allowed
National State Portion 70 questions
Plumbing Fixtures and Terminology
3 Q · 4%
Definitions of plumbing fixtures, fittings, and appurtenancesMinimum number of required plumbing fixtures by occupancy typeFixture installation requirements (clearances, spacing, and setting)Prohibited fixtures and connectionsFixture material and quality standardsFaucets, fixture fittings, and shower valve requirementsFlushing devices for water closets and urinalsIndividual fixture requirements (bathtubs, showers, water closets, urinals, sinks, bidets, and specialty fixtures)Fixtures, Faucets and Fixture Fittings
Plumbing Fundamentals
10 Q · 14%
Code scope, intent, and applicability (IPC Chapter 1)Permit requirements, application, issuance, expiration, and exempt workCode official authority, duties, inspections, and right of entryViolations, stop work orders, penalties, and unsafe plumbing abatementBoard of appeals process and qualificationsRequired plumbing system tests (water, air, smoke, gravity sewer, forced sewer, shower liner)Protection of pipes from corrosion, freezing, physical damage, and structural membersPipe support intervals, hangers, anchorage, and sway bracing by material typeScope and AdministrationGeneral Regulations
Traps, Cleanouts, and Interceptors
3 Q · 4%
Fixture trap requirements and prohibited trap typesTrap seal depth requirements and seal protection methodsCleanout placement intervals and location requirementsCleanout sizing, access clearance, and plug specificationsGrease interceptor requirements, sizing, and capacityOil separators and sand interceptors for commercial applicationsVenting, access, and maintenance of interceptors and separatorsSpecialty interceptors for clothes washers, bottling plants, and slaughterhousesSanitary Drainage
Special Requirements
2 Q · 4%
Nonpotable water storage tank requirements (location, access, venting, overflow, testing)On-site nonpotable water reuse systems (permitted/prohibited sources, collection piping, disinfection, valves)Nonpotable rainwater collection and conveyance systems (collection surface, roof washer, debris excluders, filtration)Reclaimed water system design and distribution piping requirementsSubsurface landscape irrigation system design, sizing, and installation (percolation tests, seepage trenches, absorption area)Indirect waste piping requirements (air gap, air break, waste receptors, food-handling equipment)Special wastes — neutralization and treatment of corrosive wastes
Drainage Requirements
10 Q · 14%
Sanitary drainage pipe materials and applicable standards (above-ground, underground, and building sewer)Slope and installation requirements for horizontal drainage pipingDrainage fixture unit values and system sizing tablesCleanout placement, sizing, access, and clearance requirementsJoints and connections for sanitary drainage piping by material typeSumps, sewage ejectors, and below-grade subdrain pumping systemsStorm drainage system sizing using rainfall rates, roof drain flow rates, and conductor/leader tablesSecondary (emergency) roof drains, scuppers, and backwater valve requirementsSanitary DrainageStorm Drainage
Venting Requirements
10 Q · 14%
Trap seal protection and maximum allowable pressure differentialVent terminal location and height requirements (roof, wall, and proximity to openings)Frost closure and cold-climate vent sizing requirementsVent pipe sizing using developed length and drainage fixture units (Table 906.1)Maximum distance of fixture trap from vent (Table 909.1)Venting methods: individual, common, wet, circuit, combination waste-and-vent, and waste stack ventAir admittance valve installation, location, size, and prohibited applicationsRelief vent requirements for stacks exceeding 10 branch intervals and circuit-vented branches
Water Distribution
8 Q · 12%
Water service pipe sizing and separation requirementsPipe and fitting materials for water service and distribution (approved standards)Fixture supply pipe sizing and minimum flow rates/pressures at outletsMaximum flow rates and water consumption limits for fixtures and fittingsBackflow prevention devices and cross-connection controlPressure regulation, water hammer arrestors, and booster systemsValve placement requirements (full-open and shutoff valves)Water heater safety devices, relief valves, and discharge piping requirementsWater Supply and Distribution
Plan Reading
10 Q · 14%
Interpreting drainage fixture unit (DFU) values and pipe sizing tables for sanitary drainage systemsReading water distribution system design criteria tables (flow rates, pressures, and fixture supply pipe sizes)Identifying pipe slope requirements for horizontal drainage piping from plan specificationsLocating and interpreting cleanout placement requirements on drainage plan drawingsReading vent pipe sizing tables (stack vents, vent stacks, and individual vents) from developed length and fixture unit dataIdentifying required valve locations (full-open and shutoff) on water distribution system plansInterpreting building drain and sewer sizing tables based on slope and fixture unit loadReading trap-to-vent distance requirements and vent connection configurations from plan layoutsWater Supply and DistributionSanitary DrainageVents
Gas
14 Q · 20%
Gas piping sizing using tables and equations (longest length, branch length, and hybrid pressure methods)Piping materials, fittings, and joining methods (metallic pipe, copper tubing, CSST, polyethylene plastic)Piping installation requirements (prohibited locations, burial depth, underground protection, support, and identification)Pressure testing, inspection, and purging of gas piping systemsShutoff valves and flow controls (appliance shutoff valves, pressure regulators, excess flow valves)Appliance connections and connector requirements (flexible connectors, maximum length, prohibited locations)Combustion air requirements (indoor air, outdoor air openings, mechanical air supply methods)Venting of gas appliances (vent types, vent connector sizing, chimney requirements, vent termination locations)Gas Piping InstallationsChimneys and Vents
Key Distinctions
Longest length method (IFGC 402.4.1)vsBranch length method (IFGC 402.4.2)
Longest length method sizes every section of the system from the single table row for the distance from the meter to the most remote outlet, while the branch length method sizes each branch from its own meter-to-outlet length (e.g., branch 1 at 15 ft uses the 20-ft row under branch length but the 60-ft row under longest length).
IFGC Section 402.4.1, Longest Length Method; Table 402.4(2), Schedule 40 Metallic Pipe (natural gas, 0.5 in. w.c. drop)Water supply air test (IPC 312.5)vsDrainage and vent air test (IPC 312.3)
The water supply system air test, for piping systems other than plastic, is not less than 50 psi held not less than 15 minutes, whereas the 5 psi air test belongs to the drainage and vent system test.
IPC 2015 Section 312.5DWV water test (IPC 312.2)vsDWV air test (IPC 312.3)
Plastic DWV piping must be water tested with no section tested at less than a 10-foot head of water held not less than 15 minutes, because Section 312.3 states plastic piping shall not be tested using air (the 5 psi air test applies only to nonplastic piping).
IPC 2015 Sections 312.2 and 312.3Plumbing appurtenancevsPlumbing appliance / plumbing fixture
An appurtenance is an adjunct to the basic piping system that demands no additional water supply and adds no discharge load, while a plumbing appliance depends on energized components for its operation and a plumbing fixture is a receptacle or device connected to the water supply or drainage system.
IPC 2015 Section 202 (definitions of "Plumbing Appurtenance," "Plumbing Appliance," "Plumbing Fixture")Tempered watervsHot water
Tempered water has a temperature range between 85°F and 110°F; water at or above 110°F is defined as hot water (IPC 2015, Section 202).
IPC 2015 Section 202 (Tempered Water)Outdoor combustion air through vertical ducts or direct openingsvsOutdoor combustion air through horizontal ducts
Openings communicating directly with the outdoors or through vertical ducts require 1 square inch per 4,000 Btu/h, while horizontal ducts require 1 square inch per 2,000 Btu/h (IFGC 2015, Section 304.6.1).
IFGC 2015 Section 304.6.1Trench bottom in solid rock (IPC 306.2.2)vsTrench bottom in soft, poor load-bearing material (IPC 306.2.3)
Rock must be removed to not less than 3 inches below the bottom of the pipe and the trench backfilled to pipe bed level with tamped sand (pipe and joints shall not rest on rock at any point), whereas soft poor load-bearing soil has its own separate remedy under Section 306.2.3; supporting pipe on blocks to grade is prohibited by Section 306.2.
IPC 2015 Section 306.2.2Vent stack connected at base of drainage stackvsVent stack connected to the building drain
The vent stack may connect at the base of the drainage stack at or below the lowest horizontal branch, or to the building drain downstream of the drainage stack within 10 times the diameter of the drainage stack (40 inches for a 4-inch stack).
IPC 2015 Section 904.4Forced sewer test (IPC 312.7)vsGravity building sewer test (IPC 312.6)
A forced (pumped) building sewer is plugged at the public sewer connection and tested at 5 psi greater than the pump rating maintained for 15 minutes, while the 10-foot head test applies to gravity sewer tests.
IPC 2015 Section 312.7Protective sheathing for pipe through concrete/cinder walls (IPC 305.1)vsSteel shield plates at bored/notched framing (IPC 305.6)
Sheathing or wrapping protecting pipe against corrosion in concrete or cinder walls and floors must have a wall thickness not less than 0.025 inch, while piping other than cast-iron or galvanized steel run less than 1 1/2 inches from the nearest edge of a stud, joist or rafter must be protected by steel shield plates not less than 0.0575 inch (No. 16 gage) thick.
IPC 2015 Section 305.1Rigid support sway bracing (IPC 308.6)vsRestraints at changes in direction/diameter (IPC 308.7.1)
Sway bracing is required at changes in direction greater than 45 degrees for pipe sizes 4 inches and larger, while Section 308.7.1 separately requires restraints for pipe sizes greater than 4 inches at all changes in direction and at changes in diameter greater than two pipe sizes.
IPC 2015 Section 308.6IPC scopevsInternational Residential Code scope (IPC 101.2 exception)
Detached one- and two-family dwellings and multiple single-family dwellings (townhouses) not more than three stories in height with separate means of egress, and their accessory structures, are removed from the IPC scope and comply with the IRC instead.
IPC 2015 Section 101.2Key Terms
Branch interval IPC 2015 Section 202 (Branch Interval)
A vertical measurement of distance, 8 feet or more in developed length, between the connections of horizontal branches to a drainage stack, measured down the stack from the highest horizontal branch connection (IPC 2015, Section 202).
Tempered water IPC 2015 Section 202 (Tempered Water)
Water having a temperature range between 85°F (29°C) and 110°F (43°C) (IPC 2015, Section 202).
Circuit vent IPC 2015 Section 202 (Circuit Vent)
A vent that connects to a horizontal drainage branch and vents two traps to a maximum of eight traps or trapped fixtures connected into a battery (IPC 2015, Section 202).
Building drain IPC 2015 Section 202 (Building Drain)
The lowest piping of a drainage system that receives discharge from soil, waste and other drainage pipes inside the building and extends 30 inches in developed length of pipe beyond the exterior walls (IPC 2015, Section 202).
Backpressure, low head IPC 2015 Section 202 (Backpressure, Low Head)
A pressure less than or equal to 4.33 psi (29.88 kPa), or the pressure exerted by a 10-foot column of water (IPC 2015, Section 202).
Plumbing appurtenance IPC 2015 Section 202 (definitions of "Plumbing Appurtenance," "Plumbing Appliance," "Plumbing Fixture")
A manufactured device, prefabricated assembly or on-the-job assembly of component parts that is an adjunct to the basic piping system and plumbing fixtures, demanding no additional water supply and adding no discharge load (IPC 2015, Section 202).
Plumbing appliance IPC 2015 Section 202 (definitions of "Plumbing Appurtenance," "Plumbing Appliance," "Plumbing Fixture")
A plumbing device that depends on energized components for its operation (IPC 2015, Section 202).
Plumbing fixture IPC 2015 Section 202 (definitions of "Plumbing Appurtenance," "Plumbing Appliance," "Plumbing Fixture")
A receptacle or device connected to the water supply or drainage system (IPC 2015, Section 202).
Crown vent (prohibited) IPC 2015 Section 909.3
A dry vent installed within two pipe diameters of the trap weir, which is prohibited by IPC 2015, Section 909.3 (maximum trap-to-vent distances are separately governed by Table 909.1).
NSF 14 IPC 2015 Section 303.3
The standard to which all plastic pipe, fittings and components installed in a plumbing system must be third-party certified (IPC 2015, Section 303.3).
ASTM F 1412 IPC 2015 Section 901.3
The standard for chemical-resistance testing of an air admittance valve serving a chemical waste vent system (IPC 2015, Sections 901.3 and 918.8).
ASSE 1049 IPC 2015 Section 901.3
The air admittance valve standard a chemical waste vent system terminal must comply with, versus ASSE 1050 which covers stack-type air admittance valves (IPC 2015, Section 901.3).
Wall (sidewall) vent terminal IPC 2015 Section 903.6
A vent terminal that must be not less than 10 feet from a lot line and not less than 10 feet above average ground level, and that shall not terminate under the overhang of a structure with soffit vents (IPC 2015, Section 903.6).
Longest length method IFGC Section 402.4.1, Longest Length Method; Table 402.4(2), Schedule 40 Metallic Pipe (natural gas, 0.5 in. w.c. drop)
Gas pipe sizing in which the table length row for the distance from the meter to the most remote outlet (next longer row if the exact length is not listed) is used to size every section of the system (IFGC Section 402.4.1 / Appendix A103.1).
Branch length method IFGC Section 402.4.2, Branch Length Method; Table 402.4(2), Schedule 40 Metallic Pipe (natural gas, 0.5 in. w.c. drop)
Gas pipe sizing in which each branch is sized using its own length measured from the meter to that outlet, while mains are sized on the longest run (IFGC Section 402.4.2).
Forced sewer test IPC 2015 Section 312.7
A test of a building sewer served by a sewage pump, made by plugging the end of the building sewer at the point of connection with the public sewer and applying 5 psi greater than the pump rating for 15 minutes (IPC 2015, Section 312.7).
Formulas to Know
Gas demand and capacity conversion (1,000 Btu per cubic foot natural gas)
cfh = Btuh ÷ 1,000 (e.g., 40,000 ÷ 1,000 = 40 cfh; 65,000 + 40,000 + 50,000 = 155,000 ÷ 1,000 = 155 cfh); conversely Btuh capacity = table cfh × 1,000 (e.g., 247 cfh = 247,000 Btuh; 44 cfh = 44,000 Btuh; 117 cfh = 117,000 Btuh).Selecting the table length row in Table 402.4(2)
Use the listed length row equal to the run; if the exact length is not listed, use the next longer row (55 ft → 60-ft row; 95 ft → 100-ft row; 75 ft → 80-ft row; 68 ft → 70-ft row; 23 ft → 30-ft row).Longest length method row selection
Row length = distance from the meter to the most remote outlet (sum of all main sections plus branch), rounded up to the next listed row; that one row sizes every section (e.g., 30 + 25 + 20 = 75 ft → 80-ft row; 10 + 20 + 25 + 15 = 70 ft → 70-ft row).Branch length method row selection
Branch row length = main length from the meter to the branch tee + branch length (15 + 5 = 20 ft → 20-ft row; 15 + 8 = 23 ft → 30-ft row; 30 + 15 = 45 ft → 50-ft row); mains are sized on the longest run (e.g., 90-ft row).Pipe section load and spare capacity
Section load = sum of the Btuh of all outlets downstream ÷ 1,000; spare capacity = table capacity − demand (247 − 35 = 212 cfh; 170 − 60 = 110 cfh; 322 − 150 = 172 cfh; 137 − 135 = 2 cfh).Vent stack connection to the building drain (IPC 904.4)
Maximum distance downstream of the drainage stack = 10 × stack diameter (4-inch stack: 10 × 4 = 40 inches).Maximum range of a mechanical test gauge (IFGC 406.4)
Highest end of gauge scale shall be not greater than 5 × test pressure (3 psig test × 5 = 15 psig gauge).Vent sizing (IPC 906.2 individual vents; 905.6 future-fixture rough-in)
Vent size = not less than one-half the required diameter of the drain served (1/2 of 3 inches = 1 1/2 inches); where the individual vent's developed length exceeds 40 feet, increase one nominal pipe size for the entire developed length (1 1/2 inches → 2 inches at 46 feet).Drainage fixture units for continuous/semicontinuous flow (IPC 709.3)
dfu = gpm × 2 (12 gpm × 2 = 24 dfu).Combustion air sizing (IFGC 304)
All air from outdoors, two permanent openings: each opening = total input ÷ 4,000 Btu/h per sq in for openings direct to outdoors or through vertical ducts (120,000 ÷ 4,000 = 30 sq in each), or ÷ 2,000 Btu/h per sq in for horizontal ducts; all air from indoors, standard method: volume = 50 cu ft per 1,000 Btu/h of total appliance input (120,000 ÷ 1,000 × 50 = 6,000 cu ft).