ICC G31 Journeyman Mechanical Exam (2018 IMC/IFGC) Practice Exam
Free Practice Exam
Test your knowledge with 10 questions from our pool of 20 free questions.
- 10 questions per attempt
- 30 minute time limit
- Unlimited attempts
- A new mix each time
- Instant results
Full Practice Exam
Complete exam simulation matching the real Pearson VUE test format.
- 50 questions (same as real exam)
- 180 minute time limit
- 7 topic areas covered
- 215 questions in pool
- Detailed explanations
Texts preferred · 9am–9pm Central
ICC G31 Journeyman Mechanical (2018 IMC/IFGC) Practice Exam Guide
What's on the exam
Questions per topic, out of 50This practice exam is built around the official content outline for the ICC G31 Journeyman Mechanical (2018 IMC/IFGC) exam: Administration General Regulations, Appliances & Mechanical Equipment, Exhaust and Ventilation Systems, Duct Systems, Combustion Air, Chimneys and Vents, Fuel Supply Systems.
There are two ways to practice. The free practice exam gives you 10 questions per attempt, and you can take it as many times as you like. The full practice exam gives you 50 questions on a 3 hours clock, with a new draw from our question bank each time.
Administration General Regulations 11 items
Our study plan for this topic: General Installation Requirements; Plan Reading; Permits and permit applications; Inspections and testing requirements; Code official duties and authority; Violations, stop work orders, and penalties; Means of appeal and board of appeals; Definitions of key mechanical code terms.
Appliances & Mechanical Equipment 11 items
Our study plan for this topic: Heating Equipment & Gen App Installation; Water Heaters and Boilers; Cooling and Refrigeration Systems; Hydronic and Other Systems; Refrigerant Classification & Safety Groups (ASHRAE 34 toxicity/flammability ratings); Machinery Room Requirements (construction, ventilation rates, refrigerant detectors, emergency controls); Refrigerant Piping Materials, Joints & Stop Valves; Maximum Allowable Refrigerant Quantities by Occupancy.
Exhaust and Ventilation Systems 7 items
Our study plan for this topic: Exhaust Fan & Product Conveying Systems; Commercial Hoods & Kitchen Ventilation; Clothes Dryer Exhaust Systems; Makeup Air Requirements for Exhaust Systems; Hazardous Exhaust Systems; Smoke Control Systems; Exhaust Discharge Location & Outlet Clearances; Mechanical Ventilation Rates by Occupancy.
Duct Systems 8 items
Our study plan for this topic: Duct Construction, Installation & Plenums; Smoke and Fire Dampers; Return Air System Requirements and Restrictions; Duct Insulation, Coverings, and Vapor Retarders; Air Filters in Duct Systems; Smoke Detection Systems for Air Distribution; Flexible Duct and Flexible Air Connector Requirements; Underground and Exterior Duct Installation.
Combustion Air 4 items
Our study plan for this topic: Venting of Fuel Burning Appliances; Indoor combustion air volume requirements (standard method and known air-infiltration-rate method); Outdoor combustion air opening methods (two-permanent-openings and one-permanent-opening); Combustion air opening sizing for louvers, grilles, and screens; Combustion air duct requirements and installation restrictions; Combination indoor and outdoor combustion air method; Mechanical combustion air supply systems and appliance interlock requirements; Makeup air provisions for exhaust fans and ventilation interference.
Chimneys and Vents 5 items
Our study plan for this topic: Venting of Fuel Burning Appliances; Chimney and Vent Connectors; Appliance venting categories and vent type selection (Table 503.4 / Table 802.2); Vent and chimney termination height and location requirements; Sizing of Category I appliance venting systems using tables (Section 504); Masonry chimney requirements including flue lining materials and cleanouts; Factory-built chimney listing, installation, and support requirements; Draft hoods, draft controls, and automatically operated vent dampers.
Fuel Supply Systems 4 items
Our study plan for this topic: Fuel Supply Installation, Testing and Sizing; Approved piping materials and tubing types (steel, copper, CSST, polyethylene, aluminum); Piping joints, fittings, and connection methods; Prohibited piping locations and installation restrictions; Underground piping installation, burial depth, and corrosion protection; Shutoff valves and pressure regulators; Overpressure protection devices and pressure limitations; Piping support intervals and spacing requirements.
Sample 1 — Administration General Regulations
Question: A hot-water heating assembly is composed of individually jacketed gas-fired modules installed as a unit without intervening stop valves. For the assembly to qualify as a modular boiler, each individual module is limited to a maximum input rating of what value?
- A. 400,000 Btu/h
- B. 300,000 Btu/h
- C. 150,000 Btu/h
- D. 200,000 Btu/h
Correct Answer: A
IMC 2018 Section 202, definition of 'Modular Boiler,' limits individual modules to a maximum input rating of 400,000 Btu/h gas, 3 gallons per hour oil, or 115 kW electric.
Reference: IMC 2018 Section 202 — Modular Boiler
Sample 2 — Appliances & Mechanical Equipment
Question: Field pressure tests of refrigerant-containing parts must be made with an inert dried gas. Air is allowed as the test medium for a system using which refrigerant, provided the system is evacuated before charging?
- A. R-410A
- B. R-744
- C. R-134a
- D. R-717
Correct Answer: D
IMC 2018 Section 1108.2 requires tests to be performed with an inert dried gas such as nitrogen or carbon dioxide; the exception permits air to test R-717 (ammonia) systems provided they are subsequently evacuated before charging with refrigerant.
Reference: IMC 2018 Chapter 11 — Section 1108.2, Book
Sample 3 — Duct Systems
Question: Ducts used for cooling are externally insulated with a wrap that is not itself a low-permeance product. The vapor retarder covering the insulation must have a maximum permeance of , or consist of aluminum foil having a minimum thickness of .
- A. 0.05 perm; 4 mils
- B. 0.1 perm; 2 mils
- C. 0.5 perm; 1 mil
- D. 0.05 perm; 2 mils
Correct Answer: D
IMC 2018 Section 604.11 requires externally insulated cooling ducts to be covered with a vapor retarder having a maximum permeance of 0.05 perm, or aluminum foil having a minimum thickness of 2 mils (0.051 mm). Insulation having a permeance of 0.05 perm or less need not be covered, and joints and seams must be sealed to maintain vapor retarder continuity.
Reference: IMC 2018 Chapter 6 — Section 604.11 Vapor retarders
Your first score is just a starting point. After every attempt, the results page shows how you did on each outline topic, so you can see what to work on next. Compare your score with the real exam's passing score, 70% correct, and keep at it until you pass consistently.
- Start with the questions you know. Go through the whole exam once and bookmark anything you're unsure about. Our practice exams let you bookmark and come back.
- Circle back to your bookmarks on the second pass.
- Keep an eye on your pace. The real exam works out to about 3 minutes 36 seconds per question.
- Turn every miss into a lesson. After each attempt, look up each missed question's reference in your book and read the section.
| Questions | 50 questions |
| Time limit | 3 hours |
| Passing score | 70% correct |
| Books in the exam room | Open book |
| Exam fee | $120 |
- Results for examinations taken electronically are available immediately after the examination is completed.
- You must wait 10 days before retaking a failed exam.
Source: National Contractor/Trades Examination Information Bulletin, PUBLISHED June 30, 2026; ICC Exam Catalog, checked October 6, 2026. Check the bulletin before test day: fees and rules can change.