ICC G34 Journeyman Gas Pipe Fitter Exam (2018 IFGC)

Longest length sizes every section from the table row for the longest run from the point of delivery to the most remote outlet, while branch length sizes each branch from its own length measured from the meter (e.g., 30 ft of main + 15 ft branch = 45 ft → 50-ft row).

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).

Combustion 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.

Per Section 402.4 (Equations 4-1 and 4-2) and Appendix A A.4, the low-pressure equation applies to systems operating at less than 1-1/2 psi and the high-pressure equation at 1-1/2 psi and above; the 2 psig value is the dividing point for the capacity tables, not for the equations.

Per Section 406.7.1, piping systems with a design operating pressure greater than 2 psig must be purged outdoors; indoor purging (such as through an appliance burner) is allowed only for systems at 2 psig or less that also do not meet the size and length criteria of Table 406.7.1.1.

Under the Section 404.7 exception, black steel and galvanized steel piping are not required to be protected from fasteners; other piping concealed in light-frame construction and located less than 1-1/2 inches from the framing member face to which the membrane attaches must be protected by steel shield plates not less than 0.0575 inch (No. 16 gage) thick (Sections 404.7.1 through 404.7.3).

Most appliances get combustion, ventilation and dilution air by the prescribed code methods, but 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 must follow the appliance manufacturer's instructions.

Single-wall metal pipe through a combustible exterior wall needs a ventilated thimble not less than 4 inches larger in diameter than the pipe for listed draft-hood appliances (2-inch allowance only where there is a run of not less than 6 feet of pipe in the open between draft hood outlet and thimble), but not less than 6 inches larger for unlisted draft-hood appliances.

A flared joint is a metal-to-metal compression joint where a conical spread on the tube end is compressed by a flare nut against a mating flare; a flanged joint is made by bolting together a pair of flanged ends.

A mechanical joint is a gas-tight joint made by positive-holding mechanical construction (press-connect, flanged, threaded, flared or compression), while a plastic heat fusion joint is made in thermoplastic piping by heating the parts enough to fuse the materials when pressed together.

Single-appliance venting tables already include two 90-degree elbows and the listed maximum capacity is reduced 10 percent for each additional elbow greater than 45 up to 90 degrees, whereas corrugated metallic liners in masonry chimneys require the maximum common vent capacities from Tables 504.3(1)/(2) to be reduced by 20 percent.

Section 309.1 prohibits using gas piping as a grounding electrode, while a bonding jumper is a conductor installed to electrically connect metallic gas piping to the grounding electrode system, and each above-ground portion of a gas piping system other than CSST likely to become energized must be electrically continuous and bonded to an effective ground-fault current path.

Per Section 624.1, gas water heaters are tested to ANSI Z21.10.1/CSA 4.1 and ANSI Z21.10.3/CSA 4.3 and installed per the manufacturer's instructions, while water heaters utilizing fuels other than fuel gas are regulated by the International Mechanical Code.