ICC G29 Master Mechanical Exam (2018 IMC/IFGC)
Practice at the real exam's pace
Every practice exam shows your time per question against the real exam's clock (2:24 here), and each topic lands in one of these:
What's on the exam
Questions per topic, out of 100Topics
Administration General Regulations
Key Concepts
Scope and applicability - Detached one- and two-family dwellings and multiple single-family dwellings (townhouses) not more than three stories high with separate means of egress follow the International Residential Code (101.2 Exception). - A specific requirement governs over a general requirement; "most restrictive governs" applies only where different sections specify different materials/methods (102.1). - Building/structural additions, alterations, renovations or repairs → International Existing Building Code (102.2.1). - The owner or owner's authorized agent is responsible for maintenance; HVAC maintenance inspection per ASHRAE/ACCA/ANSI Standard 180 (102.3). - Where a code provision is less restrictive than the listing conditions or manufacturer's installation instructions, the listing and instructions apply (304.2 Exception; parallel exception in 102.8).
Permits - Exempt: self-contained refrigeration systems with 10 pounds or less of refrigerant, or actuated by motors of 1 horsepower or less (106.2, Item 7). Exemption does not authorize code violations. - Annual permit: applicant regularly employing one or more qualified tradespersons; detailed record of alterations required (106.1.1, 106.1.2). - Construction documents for buildings more than two stories must indicate penetration locations and the materials/methods maintaining structural safety, fire-resistance rating and fireblocking (106.3.1). - Permit is null and void if work is **not commenced within…
Appliances & Mechanical Equipment
Key Concepts
Listing/testing standards (IFGC Ch. 6) - Vented gas fireplaces (decorative): ANSI Z21.50/CSA 2.22 (604.1). Vented gas fireplace heaters: ANSI Z21.88/CSA 2.33, plus a flame safeguard device per 602.2 (605.1). - Decorative appliances in approved solid fuel-burning fireplaces: ANSI Z21.60/CSA 6.26 (602.1); the flame safeguard device must automatically shut off fuel to the main burner when the means of ignition becomes inoperative (602.2). - Vented wall furnaces and floor furnaces: ANSI Z21.86/CSA 2.32 (608.1, 609.1). Forced-air warm-air furnaces: ANSI Z21.47/CSA 2.3 or UL 795 (618.1). Unit heaters: ANSI Z83.8/CSA 2.6 (620.1).
Clearances and placement (IFGC) - Vented wall furnace: no door may swing within 12 inches of an air inlet or outlet, measured at right angles; doorstops/closers shall not be used to obtain it (608.4). - Floor furnace register, horizontal outlet: not less than 18 inches from two adjoining sides to walls; remaining sides not closer than 6 inches; doors/draperies not nearer than 12 inches (609.2). Grade clearance 6 inches, reduced to not less than 2 inches where the lower 6-inch portion is sealed by the manufacturer against water; excavated pit 12 inches all sides, 18 inches control side (609.4). - Suspended unit heaters: 18 inches sides, 12…
Exhaust and Ventilation Systems
Key Concepts
Exhaust discharge location (IMC 2018, Section 501.3.1, Pages 41–42) - Item 1 — ducts conveying explosive or flammable vapors, fumes or dusts: 30 ft from property lines; 10 ft from operable openings into buildings; 6 ft from exterior walls and roofs; 30 ft from combustible walls and operable openings into buildings in the direction of the exhaust discharge; 10 ft above adjoining grade. - Item 2 — other product-conveying outlets: 10 ft from property lines; 3 ft from exterior walls and roofs; 10 ft from operable openings; 10 ft above adjoining grade. - Item 3 — all environmental air exhaust: 3 ft from property lines; 3 ft from operable openings into buildings other than Group U; 10 ft from mechanical air intakes. - Section 501.3.2: exhaust openings terminating outdoors get corrosion-resistant screens, louvers or grilles with openings not less than 1/4 inch and not larger than 1/2 inch, protected against local weather.
Duct Systems
Key Concepts
Return air openings (601.5, p. 70). Return air openings shall not be located less than 10 feet, measured in any direction, from an open combustion chamber or draft hood of another appliance in the same room or space. Return air from a kitchen is permitted where openings serve the kitchen and are not less than 10 feet from the cooking appliances.
Corridors (601.2, p. 69). Corridors shall not serve as supply, return, exhaust, relief or ventilation air ducts. Exception 3 permits corridors to convey return air where located within tenant spaces of 1,000 square feet or less. Under 601.2.1 (p. 69), the corridor ceiling space may be a return air plenum where, among other listed conditions, the corridor is not required to be of fire-resistance-rated construction.
Plenums (602.1, p. 70). Plenums are limited to one fire area; air systems shall be ducted from the boundary of the fire area served directly to the air-handling equipment. Fuel-fired appliances shall not be installed within a plenum.
Combustion Air
2018 IFGC Chapter 3 (General Regulations) / 2018 IMC Chapter 7 (Combustion Air)
Key Concepts
Scope and general rules - Combustion, ventilation and dilution air for appliances in buildings shall be provided by one of the methods in Sections 304.5 through 304.9. Where Section 304.5 is not met, outdoor air shall be introduced per Sections 304.6 through 304.9 (IFGC 304.1). - Combustion and dilution air for gas-fired appliances is governed by IFGC Section 304; for fuels other than fuel gas, by the International Mechanical Code (IFGC 301.1.1; IMC 701.1). Solid fuel-burning appliances follow the manufacturer's instructions; oil-fired appliances follow NFPA 31 (IMC 701.1). - Appliances shall be located so as not to interfere with proper circulation of combustion, ventilation and dilution air (IFGC 304.2). - Where exhaust fans, clothes dryers and kitchen ventilation systems interfere with appliance operation, makeup air shall be provided (IFGC 304.4).
Chimneys and Vents
Key Concepts
Termination heights (vertical). A Type B or L gas vent shall terminate not less than 5 feet in vertical height above the highest connected appliance draft hood or flue collar; a Type B-W gas vent not less than 12 feet above the bottom of the wall furnace (503.6.6). Chimneys for residential-type or low-heat appliances shall extend not less than 3 feet above the highest point where they pass through a roof and not less than 2 feet higher than any portion of a building within 10 feet horizontally; chimneys for medium-heat appliances shall extend not less than 10 feet higher than any portion of any building within 25 feet; chimneys shall extend not less than 5 feet above the highest connected draft hood outlet or flue collar (503.5.4, Page 88). Single-wall metal pipe: 5 feet above the highest connected draft hood outlet/flue collar, 2 feet above the roof penetration, 2 feet above any portion of a building within 10 feet (503.7.3).
Fuel Supply Systems
Key Concepts
Materials (IFGC Section 403) - Cast-iron pipe shall not be used (403.4.1). Steel, stainless and wrought-iron pipe shall be not lighter than Schedule 10 (403.4.2). - Copper and copper alloy pipe/tubing shall not be used if the gas contains more than an average of 0.3 grains of hydrogen sulfide per 100 standard cubic feet (403.4.3, 403.5.3). - Copper tubing joints shall be brazed with material having a melting point in excess of 1,000°F (538°C); brazing alloys shall not contain more than 0.05-percent phosphorus (403.10.2). - PVC and CPVC shall not be used to supply fuel gas; PE pipe shall conform to ASTM D2513 and be marked "Gas" (403.6). - For other than steel pipe, exposed piping shall be identified by a yellow label marked "Gas" in black letters at intervals not exceeding 5 feet; not required in the same room as the appliance served (401.5).