M2 International Code Council Commercial Mechanical Inspector Free Practice Exam Questions (2026 Updated)

For indoor combustion air openings, one opening must commence within 12 inches of the top of the enclosure and one within 12 inches of the bottom . That corresponds to 1 foot of the ceiling and 1 foot of the floor , so Option A is correct.

The ICC mechanical code requires the lowest portion of a floor furnace to have not less than 6 inches (152 mm) clearance from grade level . Therefore, the correct choice is the option corresponding to 6 inches , which is C based on your answer set.

In the IMC hydronic piping provisions for ground-source heat pump loop systems, shutoff valves are required on both sides of a pressure-reducing valve . That matches D . Heat-fusion joints and change-in-material joints do not trigger this two-sided shutoff-valve requirement.

The IMC requires air removed by a mechanical exhaust system to be discharged outdoors to an approved location and not be readily drawn back into the building. That makes D correct. The code does not permit general exhaust air to terminate in an attic, and it does not make filtering or recirculation the default rule for mechanically exhausted air.

The IMC combustion-air provisions require openings used for combustion air to have a minimum cross-sectional dimension of 3 inches . Where ducts are used, they must be of the same cross-sectional area as the openings to which they connect. That makes 3 inches the correct answer, so Option B is correct.

The IMC requires fuel-burning units to be marked with the hourly rating, approved fuel type, and required clearances . That means the appliance marking/nameplate is the direct source for the required clearance information for listed fuel-burning appliances. This is why B is the correct answer.

For appliances on roofs, ICC access provisions require a level platform at the appliance. The platform must be not less than 30 inches in any dimension . For the choices provided, that makes 30 inches the correct answer, which is Option C .

For this type of continuously ventilated exhaust shaft serving a multifamily building, the code requires the kitchen exhaust connection to penetrate the shaft and extend vertically not less than 22 inches without a fire damper. That matches Option D .

This is also an exhibit-reading question. From the equipment schedule in the image, CEF-5 is listed as a Nutone unit, so Option D is correct. This falls under reading commercial mechanical drawings and equipment schedules related to exhaust/ventilation components.

The IMC specifically provides that Type I hoods used over extra-heavy-duty cooking appliances shall not cover other appliances requiring fire-extinguishing protection and shall discharge to an independent exhaust system . Therefore, D is correct.

Hazardous exhaust systems are regulated under the IMC provisions for special exhaust because they handle potentially dangerous fumes, vapors, dusts, or other contaminants. The code requires the duct system and its support components to be suitable for that hazard level, and supports for hazardous exhaust duct must be constructed of noncombustible material . That is why Option C is correct. Plastic and fibrous supports would not satisfy the required fire and safety performance, and UL 181 applies to certain factory-made air ducts and connectors, not as the governing support-material rule for hazardous exhaust duct supports.

The IMC requires access openings for fire dampers to be of a size that allows maintenance and resetting of the damper . The code does not set the answer as same-as-duct, half-diagonal, or a universal 12-inch by 12-inch opening. So Option C is correct.

The fuel gas venting provisions state that the exit terminals of mechanical draft systems shall be not less than 7 feet above grade where located adjacent to public walkways. Therefore, A is the correct answer.

Under the ICC administrative provisions used with the mechanical code, one approved set is retained by the code official, and one approved set is returned to the applicant. The returned set must be kept on the site of the building or job while the authorized work is in progress. That directly matches Option A . It does not require return to the architect, filing with the county clerk, or retention for one year after completion.