ICC G33 Master Gas Pipe Fitter Exam (2018 IFGC)

Key Concepts

Scope and administration - The code covers piping systems for natural gas at an operating pressure of 125 psig or less, and for LP-gas at 20 psig or less (Section 101.2.2). - Piping systems for mixtures of gas and air within the flammable range with an operating pressure greater than 10 psig are outside the scope (Section 101.2.4, Item 18). - Installations that are part of buildings or structures moved into or within the jurisdiction shall comply with the provisions for new installations (Section 102.7). - Underground inspection is made after trenches are excavated and bedded, piping is installed, and before backfill is put in place (Section 107.2, Item 1). The permit holder furnishes apparatus, instruments, material and labor for testing (Section 107.3.2).

Definitions (Section 202) - Bonding jumper: a conductor installed to electrically connect metallic gas piping to the grounding electrode system. - Piping system: fuel piping, valves and fittings from the outlet of the point of delivery to the outlets of the appliance shutoff valves. - Pipe: rigid conduit of iron, steel, copper, copper-alloy or plastic. Tubing: semirigid conduit of copper, copper-alloy, aluminum, plastic or steel. - Mechanical joint: press-connect, flanged, threaded, flared or compression joint. Flanged joint: made by bolting together a pair of flanged ends. Flared joint: metal-to-metal compression joint with a conical spread on the tube end compressed by a flare nut against a mating…

Section 624, Chapter 6, Specific Appliances

Key Concepts

1. Testing standards (IFGC 624.1). Water heaters shall be tested in accordance with ANSI Z21.10.1/CSA 4.1 and ANSI Z21.10.3/CSA 4.3 and shall be installed in accordance with the manufacturer's instructions. Both standards are cited together — the correct exam answer is the pair, not one alone.

2. Fuels other than fuel gas (IFGC 624.1). Water heaters utilizing fuels other than fuel gas shall be regulated by the International Mechanical Code. So an oil-fired replacement water heater falls to the IMC, not the IFGC, for the appliance installation.

3. Items deferred to the plumbing code (IFGC 624.1.1). The requirements for water heaters relative to sizing, relief valves, drain pans and scald protection shall be in accordance with the International Plumbing Code. Memorize these four items as a set. Venting of gas-fired water heaters is not in this list — vent sizing remains a fuel gas code requirement (IFGC Chapter 5, Chimneys and Vents).

4. Combined potable water and space heating (IFGC 624.2). Water heaters utilized both to supply potable hot water and provide hot water for space-heating applications shall be: - listed and labeled for such applications by the manufacturer, and - installed in accordance with the manufacturer's instructions and the International Plumbing Code.

Key Concepts

Clothes dryer exhaust (Section 614) - Exhaust ducts for domestic dryers: smooth interior, metal not less than 0.016 inch thick, 4 inches nominal in diameter (614.8.1). Supported at 4-foot intervals; fasteners shall not protrude more than 1/8 inch into the duct (614.8.2). - Transition ducts: a single length listed and labeled to UL 2158A, not more than 8 feet, and not concealed within construction (614.8.3). - Specified duct length: maximum 35 feet from the connection to the transition duct to the outlet terminal, reduced by fittings per Table 614.8.4.1 (614.8.4.1). - Where equivalent length exceeds 35 feet, identify it on a permanent label or tag located within 6 feet of the exhaust duct connection (614.8.5). - Makeup air: installations exhausting more than 200 cfm require makeup air; a closet designed for a dryer requires an opening of not less than 100 square inches, or other approved means (614.6). The terminal passageway must be undiminished and provide an open area not less than 12.5 square inches (614.4.1). - Ducts serving commercial (Type 2) dryers: minimum 6-inch clearance to combustible materials (614.9). Terminate outside with a backdraft damper; no screens; no fire dampers (614.4, 614.2).

Key Concepts

• General sizing intent. Piping systems shall be of such size and so installed as to provide a supply of gas sufficient to meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply pressure required by the appliance (Section 402.1).
• Maximum gas demand. The volumetric flow rate of gas to be provided shall be the sum of the maximum input of the appliances served. The total connected hourly load shall be used as the basis for pipe sizing, assuming that all appliances could be operating at full capacity simultaneously. Where a diversity of load can be established, pipe sizing shall be permitted to be based on such loads (Section 402.2).
• Altitude. The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2,000 feet (610 m) in elevation (Section 402.2).
• Permitted sizing approaches. Gas piping shall be sized by pipe sizing tables or sizing equations per Section 402.4 or 402.5, by the sizing tables in a listed piping system manufacturer's installation instructions, or by other approved engineering methods (Section 402.3).
• Longest length method. The pipe size of each section of gas piping shall be determined using the longest length of piping from the point of delivery to the most remote outlet and the load of the section (Section 402.4.1). -…

Key Concepts

General requirement (Section 304.1). Air for combustion, ventilation and dilution of flue gases for appliances installed in buildings shall be provided by one of the methods prescribed in Sections 304.5 through 304.9. Where the requirements of Section 304.5 are not met, outdoor air shall be introduced per Sections 304.6 through 304.9. Direct-vent appliances, gas appliances of other than natural draft design, vented gas appliances not designated as Category I, and appliances equipped with power burners shall be provided with combustion, ventilation and dilution air in accordance with the appliance manufacturer's instructions. Exception: Type 1 clothes dryers provided with makeup air in accordance with Section 614.6.

Indoor combustion air (Section 304.5). The required volume is determined by Section 304.5.1 or 304.5.2, except that where the air infiltration rate is known to be less than 0.40 ACH, Section 304.5.2 shall be used. The total required volume is the sum of the required volume calculated for all appliances in the space.

Key Concepts

General venting requirement. Every appliance shall discharge products of combustion outdoors except those exempted by Section 501.8 (Section 501.2). Appliances not required to be vented include ranges, hot plates, refrigerators, counter appliances, room heaters listed for unvented use, direct-fired makeup air heaters, and specialized limited-input appliances such as laboratory burners and gas lights (Section 501.8, Items 1–11).

Unvented aggregate input. Where appliances in Items 5 through 11 are installed so the aggregate input rating exceeds 20 Btu/h per cubic foot of room volume, one or more must be vented so the remaining unvented appliances do not exceed 20 Btu/h per cubic foot. Where the room is directly connected to another room by a doorway, archway or comparable opening that cannot be closed, the adjacent volume may be included (Section 501.8).

Terminations. - Type B or L gas vent: not less than 5 feet in vertical height above the highest connected appliance draft hood or flue collar; Type B-W: not less than 12 feet above the bottom of the wall furnace (Section 503.6.6). - Gas vents: not less than 3 feet above any forced-air inlet within 10 feet (Section 503.6.8). - Chimneys for residential-type or low-heat appliances: not less than 3 feet above the highest point of roof passage and not less than 2 feet higher than any portion of a building within 10 feet horizontally; medium-heat chimneys 10 feet higher…