Exam Cheat Sheet · Quick Reference
ICC F27 Master 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
80
Passing score
70%
Exam time
240 min
Administered by
Pearson Vue
Format
Reference materials allowed
National State Portion 80 questions
Administration
3 Q · 4%
Scope and applicability of the IPC and IFGC (systems, appliances, and exclusions)Duties and powers of the code official (enforcement, interpretations, right of entry, identification)Permit requirements, application process, and exempt workPermit issuance, validity, expiration, extension, and revocationConstruction document requirements and retentionRequired inspections (underground, rough-in, and final) and testing proceduresViolations, stop work orders, penalties, and unsafe installation authorityBoard of appeals composition, qualifications, procedures, and decision-makingScope and Administration
General Regulations
7 Q · 9%
Key plumbing definitions and terminology (IPC Chapter 2)Prohibited locations and connections for plumbing systemsMaterial identification, approval, and third-party certification requirementsProtection of pipes from corrosion, freezing, and physical damageTrenching, bedding, and backfill requirements for buried pipingPiping support intervals and hanger spacing by material typeRequired tests and inspections for drainage, vent, and water supply systemsAlternative engineered design submittal and approval processGeneral Regulations
Fixtures
4 Q · 5%
Minimum number of required plumbing fixtures by occupancy classificationFixture installation requirements (spacing, clearances, and alignment)Prohibited fixtures and connectionsFixture material standards and quality requirementsFaucets and fixture fittings (approval, shower valves, and temperature limits)Flushing devices for water closets and urinalsIndividual fixture requirements (bathtubs, showers, urinals, water closets, sinks, and specialty fixtures)Accessible plumbing fixture requirements
Water Heaters
3 Q · 4%
Temperature and pressure relief valve requirements and installationRelief valve discharge piping requirementsWater heater installation location and access requirementsSafety devices: antisiphon, vacuum relief, and shutdown provisionsDrain valves and required pans for leak protectionWater temperature limits and thermostatic mixing valves for combination systemsWater heater labeling, pressure marking, and third-party certificationAttic installation passageway and clearance dimensions
Water Supply & Distributions
9 Q · 11%
Water distribution system design criteria: minimum flow rates and pressures at fixture supply outletsMaximum flow rates and water consumption limits for plumbing fixtures and fixture fittingsApproved pipe and fitting materials for water service and water distribution systemsJointing methods by pipe material type (soldering, solvent cementing, heat fusion, mechanical, brazed)Backflow prevention devices and assemblies: types, applications, hazard classifications, and installation requirementsProtection of potable water supply: cross-connection control, air gaps, and nonpotable water system identificationValve placement requirements: full-open valves, shutoff valves, pressure-reducing valves, and water hammer arrestorsHot water supply system requirements: temperature limits, recirculation systems, thermal expansion control, and disinfection of new systemsWater Supply and Distribution
Sanitary Drainage
7 Q · 9%
Drainage fixture unit values and system sizing tablesSlope and installation requirements for horizontal drainage pipingApproved materials and standards for above-ground, underground, and building sewer pipePipe joint types and requirements by materialCleanout placement, sizing, and access requirementsSumps, sewage ejectors, and below-grade subdrain systemsBackwater valve installation and requirementsIndirect waste piping, air gaps, air breaks, and waste receptorsSanitary Drainage
Vents
10 Q · 12%
Trap seal protection and pressure differential limitsVent terminal location and clearance requirementsVent pipe sizing using fixture units and developed lengthTypes of venting methods (individual, common, wet, circuit, combination waste and vent, single stack)Air admittance valve installation and restrictionsVent stack and stack vent requirements for multi-story buildingsFrost closure and exterior vent protection requirementsVent pipe grading, rise, and connection to drainage system
Traps, Interceptors, & Separators
3 Q · 4%
Fixture trap requirements and prohibited trap typesTrap seal depth requirements and protection methodsGrease interceptor and automatic grease removal device requirementsOil separator design and capacity requirementsSand, solids, and specialty interceptors for commercial establishmentsInterceptor and separator venting, access, and maintenanceTrap sizing and installation requirements
Storm Drainage
2 Q · 2%
Sizing of vertical conductors, leaders, and horizontal storm drains using 100-year rainfall rate and flow tablesPrimary and secondary (emergency overflow) roof drains and scuppers — requirements and sizingApproved materials for inside conductors, underground storm drain pipe, building storm sewer pipe, and subsoil drain pipeRoof drain installation, flow rate determination, and ponding/roof design requirementsStorm drainage traps — when required, sizing, material, and cleanout provisionsSump pits and pumping systems — capacity, pit dimensions, piping, and check valve requirementsSubsoil drains and building subdrains — pipe type, minimum size, backwater valve, and discharge requirementsProhibited drainage connections and restrictions on conductor pipe use
Plan Reading
17 Q · 21%
Reading and interpreting water supply system drawings (pipe sizing, fixture supply, and distribution layouts)Interpreting drainage system plans including pipe slopes, stack configurations, and fixture unit loadsReading vent system diagrams including vent stack sizing, developed length, and vent termination requirementsIdentifying pipe materials and joint types for water supply, drainage, and vent systems from plan specificationsLocating required valves, cleanouts, and backflow prevention devices on plumbing drawingsInterpreting fixture unit tables and drainage sizing tables (Tables 709.1, 710.1, 906.1) from construction documentsReading plans for required clearances, access provisions, and code-mandated separation distancesWater Supply and DistributionSanitary DrainageVents
Gas
15 Q · 19%
Gas piping materials and fittings (steel, copper, CSST, polyethylene, aluminum)Gas pipe sizing methods and sizing tables (longest length, branch length, hybrid pressure)Gas piping installation requirements (burial depth, prohibited locations, protection, support)Pressure testing and purging of gas piping systemsShutoff valves and flow controls (regulators, excess flow valves, appliance shutoff valves)Combustion and dilution air requirements for gas appliancesVenting systems for gas appliances (vent types, sizing, termination, connectors)Specific gas appliances (furnaces, boilers, water heaters, unvented room heaters, cooking appliances, clothes dryers)Gas Piping InstallationsChimneys and Vents
Key Distinctions
Indirect waste by air gap (IPC 802.1.1, 802.1.3, 802.1.4)vsIndirect waste by air break (IPC 802.1.5)
Food storage/preparation/handling equipment and fixtures, potable clear-water waste (relief valves, sterilizers) and swimming pool waste/filter backwash all require an air gap, while devices and equipment such as process tanks, filters, drips and boilers discharging nonpotable water are permitted to connect through an indirect waste pipe by means of an air break or an air gap.
IPC 2015 Sections 802.1.1, 802.1.3, 802.1.4 and 802.1.5Longest length method (IFGC 402.4.1)vsBranch length method (IFGC 402.4.2)
The longest length method uses the single meter-to-most-remote-outlet length (rounded up to the next longer table row) to size every section, while the branch length method sizes each branch on its own meter-to-outlet length (mains still being sized on the longest run).
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 test of drainage and vent system (IPC 312.2)vsAir test (IPC 312.3)
A PVC (plastic) drainage and vent system 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 312.3Gravity building sewer test (IPC 312.6)vsForced sewer test (IPC 312.7)
A gravity sewer is tested with a 10-foot head of water, while a building sewer served by a sewage pump is plugged at the public sewer connection and tested at 5 psi greater than the pump rating, maintained for 15 minutes.
IPC 2015 Section 312.7Steel shield plates (IPC 305.6)vsProtective sheathing/wrapping through concrete or cinder walls (IPC 305.1)
Shield plates protecting piping other than cast-iron or galvanized steel installed through holes or notches in studs, joists, rafters or similar members less than 1 1/2 inches from the nearest edge of the member must be not less than 0.0575 inch (No. 16 gage) thick, whereas sheathing or wrapping for pipes passing through concrete or cinder walls and floors must have a wall thickness of not less than 0.025 inch (and a nonmetallic auxiliary drain pan minimum is 0.0625 inch).
IPC 2015 Section 305.6Tempered water (IPC 202)vsHot water (IPC 202)
Tempered water has a temperature range between 85°F and 110°F, while water at or above 110°F is defined as hot water.
IPC 2015 Section 202 (Tempered Water)Metallic pipe field bend (IFGC 405.2)vsPlastic pipe bend (IFGC 405.3)
A metallic gas pipe bend must have an inside radius not less than six times the outside diameter of the pipe (and be limited to an arc of 90 degrees), while the 25-times-the-inside-diameter figure applies to plastic pipe bends.
IFGC 2015 Section 405.2Building drain (IPC 202)vsBuilding sewer
The building drain is the lowest piping receiving discharge from soil, waste and other drainage pipes inside the building and extends 30 inches in developed length beyond the exterior walls, where the building sewer begins.
IPC 2015 Section 202 (Building Drain)Vent stack connected at base of drainage stack (IPC 904.4)vsVent stack connected to the building drain (IPC 904.4)
A vent stack may connect to the base of the drainage stack at or below the lowest horizontal branch, or instead to the building drain downstream of the drainage stack within a distance of 10 times the diameter of the drainage stack (40 inches for a 4-inch stack).
IPC 2015 Section 904.4Appeal filing deadline (IPC 109.1)vsBoard meeting deadline (IPC 109.3)
The application for appeal must be filed on a form obtained from the code official within 20 days after the notice of violation was served, while the board of appeals must meet within 10 days of the filing of an appeal.
IPC 2015 Section 109.1Ventilated metal thimble, 2 inches larger (IFGC 503.7.7, Item 1)vsThimble 4 / 6 / 12 inches larger
For listed appliances with draft hoods and appliances listed for Type B gas vents the thimble must be at least 4 inches larger in diameter, but where there is a run of not less than 6 feet of metal pipe in the open between the draft hood outlet and the thimble it is permitted to be not less than 2 inches larger; 6 inches applies to unlisted appliances with draft hoods and 12 inches to residential and low-heat appliances.
IFGC 2015 Section 503.7.7Floor drain outlet in public coin-operated laundry (IPC 412.4)vsGeneral floor drain minimum (IPC 412.3)
Floor drains in public coin-operated laundries and central washing facilities of multiple-family dwellings must have an outlet of not less than 3 inches in diameter, larger than the 2-inch general minimum.
IPC 2015 Section 412.4Separate-sex exception for mercantile occupancies (IPC 403.2, Exception 3)vsGeneral small-occupancy exception (IPC 403.2, Exception 2)
Separate facilities are not required in mercantile occupancies with a maximum occupant load of 100 or fewer, while the general exception for any structure or tenant space applies at an occupant load of 15 or fewer including employees and customers.
IPC 2015 Section 403.2Key Terms
Branch interval (IPC 202) 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.
Circuit vent (IPC 202) 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.
Tempered water (IPC 202) IPC 2015 Section 202 (Tempered Water)
Water having a temperature range between 85°F (29°C) and 110°F (43°C).
Backpressure, low head (IPC 202) 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.
Building drain (IPC 202) 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.
Water heater safety pan drain to exterior (IPC 504.7.2) IPC 2015 Section 504.7.2
A pan drain extended full size to the exterior of the building must terminate not less than 6 inches and not more than 24 inches above the adjacent ground surface.
Nonpotable rainwater identification tape (IPC 608.8.2.3) IPC 2015 Section 608.8.2.3
Tape at least 3 inches wide with white or black lettering on a purple field, installed on top of nonpotable rainwater distribution pipes, fastened at least every 10 feet to each pipe length and run continuously the entire length of the pipe.
Chemical waste vent terminating to an air admittance valve (IPC 901.3) IPC 2015 Section 901.3
Permitted where the valve complies with ASSE 1049, is constructed of materials approved under Section 702.5, and is tested for chemical resistance in accordance with ASTM F 1412.
Special atmosphere generator piping (IFGC 101.2.4) IFGC 2015 Section 101.2.4
Raw material (feedstock) applications are outside the scope of the fuel gas code except for piping to special atmosphere generators, which remains regulated.
Mechanical test gauge (IFGC 406.4) IFGC 2015 Section 406.4
A mechanical gauge used to measure test pressures must have a range whose highest end of scale is not greater than five times the test pressure.
Board of appeals vote (IFGC 109.5, 109.6) IFGC 2015 Sections 109.5 and 109.6
The board modifies or reverses the code official's decision by a concurring vote of three members; the appellant may request a postponement when five members are not present, but proceeding still requires three concurring votes.
Water service and sewer in a common trench, vertical-offset allowance (IPC 603.2) IPC 2015 Section 603.2
The required 5-foot horizontal separation may be waived where the bottom of the water service pipe located within 5 feet of the sewer is not less than 12 inches (305 mm) above the highest point of the top of the building sewer.
Appliance shutoff valve at a manifold (IFGC 409.5.3) IFGC 2015 Section 409.5.3
Permitted where the valve is within 50 feet of the appliance served, readily accessible and permanently identified, with piping from the manifold to within 6 feet of the appliance designed, sized and installed per Sections 401 through 408.
Pipe sleeve through a foundation wall (IPC 305.3) IPC 2015 Section 305.3
A pipe passing through a foundation wall must have a relieving arch or a pipe sleeve built into the wall, the sleeve being two pipe sizes greater than the pipe passing through.
Strainer plates on drain inlets (IPC 304.2) IPC 2015 Section 304.2
Must be designed and installed so that all openings are not greater than 1/2 inch (12.7 mm) in least dimension, to exclude rodents.
Auxiliary drain pan with separate drain (IPC 314.2.3, Item 1) IPC 2015 Section 314.2.3
A corrosion-resistant pan not less than 1 1/2 inches deep and not less than 3 inches larger than the unit or coil dimensions in width and length, draining to a conspicuous point of disposal.
Condensate waste and drain line (IPC 314.2.2) IPC 2015 Section 314.2.2
Shall be not less than 3/4-inch internal diameter and shall not decrease in size from the drain pan connection to the point of disposal.
Wall (sidewall) vent terminal (IPC 903.6) IPC 2015 Section 903.6
Must be not less than 10 feet from a lot line and not less than 10 feet above average ground level, and shall not terminate under the overhang of a structure with soffit vents.
Vent rough-in for future fixtures (IPC 905.6) IPC 2015 Section 905.6
Where drainage piping is roughed-in for future fixtures, a vent rough-in connection not less than one-half the diameter of the rough-in drain served must be installed and identified as a vent.
Full-open valve at base of water riser (IPC 606.1, item 4) IPC 2015 Section 606.1
Required at the base of every water riser except in multiple-family residential occupancies two stories or less in height and in one- and two-family dwellings.
Test gauge increments (IPC 312.1.1) IPC 2015 Section 312.1.1
Tests of 10 psi or less require gauge increments of 0.10 psi or less; tests greater than 10 psi but not more than 100 psi require increments of 1 psi or less; tests greater than 100 psi require increments of 2 psi or less.
Formulas to Know
Convert appliance input to gas demand (natural gas, 1,000 Btu per cubic foot)
cfh = Btuh ÷ 1,000; e.g., 50,000 + 40,000 + 100,000 = 190,000 Btuh ÷ 1,000 = 190 cfh total meter demandLoad carried by a pipe section
Section load = sum of the inputs of all outlets downstream of that section ÷ 1,000; e.g., section B serving outlets 2 and 3 = (65,000 + 40,000) ÷ 1,000 = 105 cfhLongest length method table row
Find the distance from the meter to the most remote outlet, then use the next longer length row in Table 402.4(2) for sizing every section; e.g., 68 ft → 70-ft row, 75 ft → 80-ft rowBranch length method table row
For each branch, length = main run from meter to its tee + branch length, then use the next longer table row; e.g., 30 + 20 + 15 = 65 ft → 70-ft row (mains on the longest run use that run's row)Selecting minimum pipe size from Table 402.4(2)
In the applicable length row, choose the smallest diameter whose listed capacity equals or exceeds the section demand; e.g., 140 cfh in the 40-ft row: 1/2 in. = 81 cfh (too small), 3/4 in. = 170 cfh (OK)Capacity margin of a selected pipe
Margin = table capacity − demand; e.g., 1 in. in the 70-ft row = 237 cfh − 150 cfh demand = 87 cfh marginBtuh served by a given pipe capacity
Btuh = cfh × 1,000; e.g., 137 cfh × 1,000 = 137,000 BtuhMaximum full-scale range of a mechanical test gauge (IFGC 406.4)
Gauge top of scale ≤ 5 × test pressure; e.g., 3 psig test × 5 = 15 psig gaugeVent stack connection to building drain (IPC 904.4)
Maximum distance downstream of the drainage stack = 10 × stack diameter; e.g., 10 × 4 in. = 40 in.Vent rough-in size for future fixture (IPC 905.6) and other proportional rules
Vent size ≥ 1/2 × rough-in drain diameter (3 in. drain → 1 1/2 in. vent); urinal partition extends the greater of 18 in. or outermost front lip + 6 in. (14 + 6 = 20 in.); group wash-up: every 20 in. of rim space = 1 lavatory (100 ÷ 20 = 5); continuous/semicontinuous flow: 1 gpm = 2 dfu (12 gpm × 2 = 24 dfu)