Denver Master Gas Pipe Fitter Exam (ICC F33, 2015 IFGC)

Key Concepts

Scope and exclusions - The code's piping provisions cover natural gas at an operating pressure of 125 psig or less and LP-gas at 20 psig or less, except as provided in Section 402.6, extending from the point of delivery to the outlet of the appliance shutoff valves (Section 101.2.2). - Detached one- and two-family dwellings and multiple single-family dwellings (townhouses) not more than three stories high with separate means of egress, and their accessory structures, comply with the International Residential Code (Section 101.2, Exception). - Section 101.2.4 lists work outside the scope: raw material (feedstock) applications "except for piping to special atmosphere generators" (that piping stays regulated); atomic energy plant fuel gas piping; railroad switch heating LP-gas; and temporary LP-gas piping for buildings under construction that will not become part of the permanent system.

Permits, fees, inspections (Sections 105–110) - Tests to substantiate alternatives: required at no expense to the jurisdiction (105.3), performed by an approved agency (105.3.2), reports retained by the code official for the period required for retention of public records (105.3.3). - Annual permit may be issued instead of an individual construction permit for each alteration to an already approved system, to a person/firm regularly employing one or more qualified tradespersons (106.1.1); detailed records required (106.1.2). - Construction documents for buildings more than two stories must indicate penetration locations and the materials/methods for maintaining structural safety, fire-resistance…

Key Concepts

Installation and ignition source (Section 305) - Equipment/appliances having an ignition source shall be elevated so the ignition source is not less than 18 inches (457 mm) above the floor in hazardous locations and public garages, private garages, repair garages, motor fuel-dispensing facilities and parking garages (305.3). Exception: appliances listed as flammable vapor ignition resistant. - Public garages, motor fuel-dispensing facilities, repair garages or other areas frequented by motor vehicles: install not less than 8 feet (2438 mm) above the floor; where vehicles can pass under, install at manufacturer's clearances and not less than 1 foot (305 mm) higher than the tallest vehicle garage door opening (305.4). - Private garages: minimum clearance of 6 feet (1829 mm) above the floor (305.5), unless protected from motor vehicle impact and installed per 305.3. - At grade level: supported on a level concrete slab or other approved material extending not less than 3 inches above adjoining grade, or suspended not less than 6 inches above adjoining grade (305.7). - Clearances to combustibles must account for door swing, drawer pull, overhead projections, shelving, window swing; door stops/closers shall not be used to provide clearance (305.8).

Key Concepts

• Sizing methods (402.4.1–402.4.3). Longest length: size each section using the longest length from the point of delivery to the most remote outlet. Branch length: size the longest run first, then size each unsized branch using the length from the point of delivery to the most remote outlet in that branch. Hybrid pressure: size higher-pressure piping using the longest length from the point of delivery to the most remote line pressure regulator; size downstream piping from the regulator to the most remote outlet it serves.
• Altitude (402.2). The volumetric flow rate of gas provided shall be adjusted for altitude where the installation is above 2,000 feet (610 m). Total connected hourly load is the basis for sizing unless a diversity of load is established.
• Indoor operating pressure (402.6). Maximum design operating pressure inside buildings shall not exceed 5 psig, except where the system is welded; is in a ventilated chase; serves areas used exclusively for industrial processing or heating, research, warehousing, or boiler/mechanical rooms; is temporary construction piping; serves agricultural appliances; or is an LP-gas system over 20 psi complying with NFPA 58.
• Materials. Cast-iron pipe shall not be used (403.4.1). Steel/wrought iron shall be not less than Schedule 40 (403.4.2). Copper and copper alloy pipe/tubing shall not be used where the gas contains more than an average of **0.3 grains of hydrogen sulfide per 100 standard…

Denver Master Gas Pipe Fitter Exam (ICC F33, 2015 IFGC) — Section 304 (IFGS)

Key Concepts

Which appliances use the prescriptive methods (304.1). Air for combustion, ventilation and dilution shall be provided by one of the methods in Sections 304.5 through 304.9. However, 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 this air in accordance with the appliance manufacturer's instructions. Exception: Type 1 clothes dryers provided with makeup air per Section 614.6.

Indoor combustion air (304.5). 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 volumes required for all appliances in the space.

• Standard method (304.5.1): minimum 50 cubic feet per 1,000 Btu/h of appliance input rating.
• Known air-infiltration-rate method (304.5.2): Equation 3-1 for appliances other than fan-assisted; Equation 3-2 for fan-assisted appliances. An infiltration rate greater than 0.60 ACH shall not be used in Equations 3-1 and 3-2.

Key Concepts

Venting required / exempt appliances - Every appliance shall discharge products of combustion to the outdoors, except appliances exempted by Section 501.8 (501.2). - Where appliances listed in Items 5 through 11 of Section 501.8 (booster water heater, refrigerators, counter appliances, room heaters listed for unvented use, direct-fired makeup air heaters, other listed unvented appliances without flue collars, specialized limited-input appliances such as laboratory burners and gas lights) are installed so the aggregate input exceeds 20 Btu/h per cubic foot of room volume, one or more shall be vented so the remaining unvented aggregate does not exceed 20 Btu/h per cubic foot. Volume of an adjacent room connected by a doorway or archway that cannot be closed may be included (501.8).

Masonry chimneys - Connectors shall connect to a masonry chimney flue not less than 12 inches above the lowest portion of the interior of the flue (501.9). - Cleanout opening: minimum height 6 inches, upper edge not less than 6 inches below the lowest chimney inlet opening, tight-fitting noncombustible cover (501.15.3). - Residential/low-heat flue linings: ASTM C 315 clay liner, listed systems complying with UL 1777, or approved materials resisting flue gases up to 1,800°F (501.12).

Denver Master Gas Pipe Fitter Exam (ICC F33, 2015 IFGC) — 4 questions, 5%

Key Concepts

Decorative appliances & fireplaces - Decorative appliances for approved solid fuel-burning fireplaces: tested to ANSI Z21.60; manually lighted natural gas decorative appliances tested to ANSI Z21.84 (602.1). Vented gas fireplaces: ANSI Z21.50 (604.1); vented gas fireplace heaters: ANSI Z21.88 (605.1); log lighters: CSA 8 (603.1). - All decorative appliances except those tested to ANSI Z21.84 must use a direct ignition device, ignitor or pilot and be equipped with a flame safeguard device that shuts off fuel to the main burner when ignition becomes inoperative (602.2). Prohibited where Section 303.3 prohibits (602.3).

Unvented room heaters (621) - Maximum input of any unvented room heater: 40,000 Btu/h (621.3). - Prohibited in occupancy Groups A, E and I; location also per 303.3 (621.4). - Aggregate input of all unvented appliances limited to 20 Btu/h per cubic foot of room volume; volume of an adjacent space connected by an archway or similar opening that cannot be closed may be included (621.5). - Oxygen-depletion-sensitive safety shutoff: shuts off gas to main and pilot burners at the manufacturer's specified concentration, not lower than 18 percent; no field adjustment of the set point (621.6). - Unvented decorative room heater in a factory-built fireplace only if the fireplace system is tested, listed and labeled for that use to UL 127; ventless firebox enclosures listed…