ICC F31 Journeyman Mechanical Exam (2015 IMC/IFGC)

Key Concepts

Scope & applicability - The IMC regulates permanently installed mechanical systems; detached one- and two-family dwellings and townhouses not more than three stories high with separate means of egress comply with the IRC instead (§101.2 Exception). - Where this code conflicts with a referenced standard, the provisions of this code apply (§102.8.1; see also §102.8.2). - Existing and new systems shall be maintained; HVAC maintenance inspection is per ASHRAE/ACCA/ANSI Standard 180; the owner or owner's authorized agent is responsible (§102.3).

Code official authority - The code official is appointed by the chief appointing authority (§103.2); the code official appoints deputies, technical officers and inspectors with the appointing authority's concurrence (§103.3). - Expert opinion on unusual technical issues may be engaged subject to approval of the appointing authority (§104.3). - Modifications: details of the action granting a modification are recorded and entered in the files of the mechanical inspection department (§105.1). - Test…

Key Concepts

Water heaters - Gas-fired water heaters shall be tested in accordance with ANSI Z21.10.1 and ANSI Z21.10.3 and installed per the manufacturer's instructions; water heaters using fuels other than fuel gas are regulated by the International Mechanical Code (IFGC 2015, 624.1). - Water heater requirements for sizing, relief valves, drain pans and scald protection are in accordance with the International Plumbing Code (IFGC 624.1.1) — even though that text is not printed in the fuel gas code. - Combination potable water heating/space heating water heaters shall be listed and labeled for such service and installed per the manufacturer's instructions and the IPC (IFGC 624.2; IMC 1002.2). - Where such a system needs water for space heating higher than 140°F, an ASSE 1017 temperature-actuated mixing valve shall temper water to the potable hot water distribution system to 140°F (60°C) or less (IMC 1002.2.2). - Water heaters shall be removable without first removing a…

2015 International Mechanical Code — Chapter 4 (Ventilation) and Chapter 5 (Exhaust Systems)

Key Concepts

Exhaust outlet termination distances (IMC 2015, Section 501.3.1). The termination point of exhaust outlets and ducts discharging outdoors must meet these minimum distances:

• Ducts conveying explosive or flammable vapors, fumes or dusts (Item 1): 30 feet from property lines; 10 feet from operable openings into buildings; 6 feet from exterior walls and roofs; 30 feet from combustible walls and operable openings into buildings which are in the direction of the exhaust discharge; 10 feet above adjoining grade.
• Other product-conveying outlets (Item 2): 10 feet from the property lines; 3 feet from exterior walls and roofs; 10 feet from operable openings into buildings; 10 feet above adjoining grade.
• All environmental air exhaust (Item 3): 3 feet from property lines; 3 feet from operable openings into buildings for all occupancies other than Group U; and **10 feet from…

Key Concepts

Duct construction, materials and classification - Ducts are classified at positive or negative 0.5, 1.0, 2.0, 3.0, 4.0, 6.0 or 10.0 inches of water column; the classification must equal or exceed the system design pressure (§603.3). There is no 8.0-inch class. - Nonmetallic ducts must be Class 0 or Class 1 material complying with UL 181, and air temperature within them shall not exceed 250°F (121°C) (§603.5). - Gypsum board air shafts (ducts) are limited to return air systems where air temperature does not exceed 125°F (52°C), with board surface temperature kept above the airstream dew point; not permitted with evaporative coolers (§603.5.1). The same 125°F limit applies to gypsum board plenums (§602.2). - Flexible air connectors are limited in length to 14 feet (§603.6.2.1) and shall not pass through a wall, floor or ceiling (§603.6.2.2). Flexible air ducts are not limited in length (§603.6.1.1).

2015 International Mechanical Code / 2015 International Fuel Gas Code

Key Concepts

Which code governs which fuel (IMC 701.1; IFGC 301.1.1) - Solid fuel-burning appliances: combustion air per the appliance manufacturer's installation instructions. - Oil-fired appliances: combustion air per NFPA 31. - Gas-fired appliances: combustion and dilution air per the International Fuel Gas Code (IFGC Section 304). - The methods of providing combustion air in IMC Chapter 7 do not apply to fireplaces, fireplace stoves and direct-vent appliances. Note the distinction: solid fuel and oil-fired appliances are still within the chapter's scope — they are simply pointed to another standard. - IFGC 301.1.1: combustion and dilution air for appliances operating with fuels other than fuel gas is regulated by the International Mechanical Code.

Key Concepts

Which code governs. Gas-fired appliances are vented per the International Fuel Gas Code; IMC Chapter 8 governs chimneys, liners, vents and connectors for other fuels (IMC 801.1; IFGC 501.1). Masonry chimney construction is regulated by the International Building Code (IFGC 501.3).

Chimney entrance. Connectors shall connect to a masonry chimney flue at a point not less than 12 inches (305 mm) above the lowest portion of the interior of the chimney flue (IFGC 501.9; IMC 801.12).

Cleanouts. Masonry chimney flues require a cleanout opening with a minimum height of 6 inches, the upper edge not less than 6 inches below the lowest chimney inlet opening, with a tight-fitting noncombustible cover (IFGC 501.15.3; IMC 801.13).

Key Concepts

Scope and general piping rules (IFGC Chapter 4) - The code applies to piping systems from the point of delivery to the connections with the appliances, including design, materials, fabrication, installation, testing, inspection, operation and maintenance (IFGC 401.1). - When an additional appliance is served, existing piping must be checked for adequate capacity for all appliances served; if inadequate, enlarge the system or run separate piping of adequate capacity (IFGC 401.4). - For other than steel pipe, exposed piping is identified by a yellow label marked "Gas" in black letters, spaced at intervals not exceeding 5 feet; marking is not required on pipe in the same room as the appliance served (IFGC 401.5). - Where two or more meters on the same premises supply separate consumers, the piping systems shall not be interconnected on the outlet side of the meters (IFGC 401.6). Multiple-meter piping must be permanently identified by the installer (IFGC…

Key Concepts

Refrigeration — general and system requirements - Listed, labeled self-contained factory-built equipment is tested to UL 207, 412, 471 or 1995 and is deemed to meet design, manufacture and factory test requirements where installed per its listing and the manufacturer's instructions (1101.2). - The refrigerant type in a circuit containing more than 220 pounds (99.8 kg) of Group A1, or more than 30 pounds (13.6 kg) of any other group, shall not be changed without prior notification to the code official (1101.8). - Refrigerant circuit access ports located outdoors shall have locking-type tamper-resistant caps or be otherwise secured; exception for controlled areas such as roofs with locked access hatches or doors (1101.10, 1102.3). - Refrigerants with different ASHRAE 34 designations shall not be mixed, except where a second refrigerant is permitted by the manufacturer to improve oil return at low temperatures (1102.2.1). - Recovered refrigerants shall not be reused in other than…

Key Concepts

1. Electrical work follows NFPA 70 — IMC Section 301.10 Electrical wiring, controls and connections to equipment and appliances regulated by the IMC shall be in accordance with NFPA 70 (the National Electrical Code). Know the companion standards well enough to rule them out: NFPA 54 is the National Fuel Gas Code, NFPA 90A applies to air-conditioning and ventilating systems, and NFPA 31 applies to oil-burning equipment.

2. Nameplate basics — IMC Section 301.9 A permanent factory-applied nameplate(s) shall be affixed to appliances, showing in legible lettering: - the manufacturer's name or trademark, - the model number, - the serial number, and - the seal or mark of the approved agency.