Exam Cheat Sheet · Quick Reference
ICC G33 Master Gas Pipe Fitter Exam (2018 IFGC)
National · Pearson Vue
National State Portion 75 questions
Key Distinctions
Per IFGC Section 202, 'pipe' is a rigid conduit of iron, steel, copper, copper-alloy or plastic, while 'tubing' is a semirigid conduit of copper, copper-alloy, aluminum, plastic or steel (aluminum appears only under tubing).
IFGC 2018 Section 202 (Piping definition)A pressure test verifies the gas-tight integrity of piping following installation or modification, while a leak check is performed to verify the system does not leak (typically during or after placing in service).
IFGC 2018 Section 202, DefinitionsFlue gases are products of combustion plus excess air in appliance flues or heat exchangers, whereas combustion products are constituents resulting from combustion of fuel with oxygen, including inert gases but excluding excess air.
IFGC 2018 Chapter 2 DefinitionsCombustion air is the air necessary for complete combustion of a fuel, including theoretical air and excess air; dilution air is air introduced into a draft hood and mixed with the flue gases.
IFGC 2018 Chapter 2 DefinitionsThe longest length method sizes every section using the longest length of piping from the point of delivery to the most remote outlet, while the branch length method sizes each branch using that branch's own length measured from the meter.
IFGC 2018 Section 402.4.1CSST not listed with an arc-resistant jacket or coating must be electrically continuous and bonded to the electrical service grounding electrode system with a jumper not smaller than 6 AWG copper, whereas arc-resistant-jacketed CSST is considered bonded where it connects to an appliance connected to the appliance grounding conductor of the circuit supplying that appliance.
IFGC 2018 Section 310.2.2Per the Section 404.7 exception, black steel and galvanized steel piping are not required to be protected against fastener penetration; other concealed piping that is less than 1-1/2 inches (38 mm) from the framing member face to which wall, ceiling or floor membranes will be attached must be protected by shield plates of steel not less than 0.0575 inch (No. 16 gage), extending not less than 4 inches to each side of the framing member.
IFGC 2018 Section 404.7.3A flared joint is a metal-to-metal compression joint in which a conical spread on the tube end is compressed by a flare nut against a mating flare, while a flanged joint is made by bolting together a pair of flanged ends.
IFGC 2018 Section 202 (Joint, Flared definition)Section 503.7.7 Item 1 requires the ventilated metal thimble to be not less than 4 inches larger in diameter than the pipe, but permits only 2 inches larger 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.
IFGC 2018 Section 503.7.7For listed draft-hood appliances the ventilated metal thimble must be not less than 4 inches larger in diameter than the pipe, while for unlisted draft-hood appliances it must be not less than 6 inches larger.
IFGC 2018 Section 503.7.7The LP-gas self-service switch must be within 100 feet of, but not less than 20 feet from, the dispensers, while the CNG facility requirement is the 75-foot/25-foot combination.
IFGC 2018 Section 412.9, Item 2Piping systems with a design operating gas pressure greater than 2 psig are required to be purged outdoors; indoor purging is only allowed for systems at 2 psig or less that also do not meet the size and length criteria of Table 406.7.1.1.
IFGC 2018 Section 406.7.1Detached one- and two-family dwellings and townhouses not more than three stories high with separate means of egress (and their accessory structures) fall under the International Residential Code; a four-story townhouse exceeds that limit and remains under the IFGC.
IFGC 2018 Section 101.2, ExceptionKey Terms
Formulas to Know
Demand (cfh) = Appliance input (Btu/h) ÷ 1,000; e.g., 50,000 + 40,000 + 100,000 = 190,000 Btuh ÷ 1,000 = 190 cfh. Reverse: capacity (cfh) × 1,000 = Btuh (e.g., 170 cfh × 1,000 = 170,000 Btuh).Spare capacity = Table capacity at the run length − appliance demand; e.g., 137 cfh − 80 cfh = 57 cfh spare; 44 cfh − 40 cfh = 4 cfh spare; 220 cfh − 155 cfh = 65 cfh margin.Round the run length up to the next listed row: 15 ft → 20-ft row; 35 ft → 40-ft row; 55 ft → 60-ft row; 110 ft → 125-ft row.Branch length = main length from meter to the branch tee + branch length; e.g., 30 + 15 = 45 ft (→ 50-ft row); 30 + 20 + 15 = 65 ft (→ 70-ft row); 20 + 15 = 35 ft (→ 40-ft row).Test pressure = not less than 1½ × proposed maximum working pressure, but not less than 3 psig irrespective of design pressure.Required volume (ft³) = (total appliance input Btu/h ÷ 1,000) × 50 ft³; worked example: (120,000 + 60,000) ÷ 1,000 × 50 = 9,000 ft³.Ratio of interior spaces = available volume ÷ required volume; Outdoor size reduction factor = 1 − ratio; worked example: 1 − 0.60 = 0.40, so outdoor openings are sized at 40% of the full size calculated per Section 304.6.Maximum straight duct = 35 ft total equivalent length − sum of fitting equivalent lengths; worked example: two 4-in. radius mitered 90° elbows at 5 ft each (10 ft) + one 4-in. radius mitered 45° elbow at 2 ft 6 in. = 12 ft 6 in.; 35 − 12.5 = 22 ft 6 in.Table values already include losses for four 90-degree bends and two end fittings; runs with more bends or fittings are increased by an equivalent length of tubing using L = 1.3n.Single-appliance vent tables include two 90° elbows; reduce listed maximum capacity 10% for each additional elbow greater than 45° up to and including 90° (Section 504.2.3). Reduce maximum common vent capacities 20% when sizing corrugated metallic liners in masonry chimneys (Section 504.3.19). Common vent area shall not be greater than seven times the smallest listed appliance categorized vent area, flue collar area or draft hood outlet area (Section 504.3.17). Maximum horizontal length of a single-wall connector = 75% of chimney or vent height (Section 503.10.8), except engineered systems.