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2026 Statistics

Key Facts: OBC HVAC - House Exam

Total Questions

Humber Exam Specifications

70%

Passing Score

Humber Guidelines

3 Hours

Time Limit

Humber Guidelines

$150

Fee (CAD)

Humber Fee Schedule

Part 9 & 12

OBC 2024 Scope

Exam Syllabus

The OBC HVAC - House exam consists of 70 multiple-choice questions with a 3-hour time limit. It is an open-book exam administered by Humber Polytechnic on the 2024 Ontario Building Code, requiring a 70% score to pass.

Sample OBC HVAC - House Practice Questions

Try these sample questions to test your OBC HVAC - House exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Under the 2024 Ontario Building Code, what is the minimum normal operating exhaust capacity of the principal ventilation fan for a 3-bedroom dwelling unit?

A.18 L/s

B.22 L/s

C.26 L/s

D.32 L/s

Explanation: OBC 2024 Table 9.32.3.3 specifies a normal operating exhaust capacity range of 22 to 32 L/s for a 3-bedroom dwelling unit. The minimum value in this range is 22 L/s (approximately 44 cfm). The 2024 OBC replaced the former single fixed value with a min/max range to allow design flexibility.

2Under the 2024 OBC, what is the minimum normal operating exhaust capacity of the principal ventilation fan for a 1-bedroom dwelling unit?

A.10 L/s

B.16 L/s

C.22 L/s

D.24 L/s

Explanation: OBC 2024 Table 9.32.3.3 specifies a range of 16 to 24 L/s for a 1-bedroom dwelling unit. The minimum normal operating exhaust capacity is 16 L/s (approximately 32 cfm). Note that the 2024 OBC values differ from the former 2012 OBC fixed value of 15 L/s.

3Under the 2024 OBC, what is the minimum normal operating exhaust capacity of the principal ventilation fan for a 4-bedroom dwelling unit?

A.22 L/s

B.26 L/s

C.32 L/s

D.38 L/s

Explanation: OBC 2024 Table 9.32.3.3 specifies a range of 26 to 38 L/s for a 4-bedroom dwelling unit. The minimum normal operating exhaust capacity is 26 L/s (approximately 52 cfm).

4For a 5-bedroom dwelling unit, what is the minimum normal operating exhaust capacity of the principal ventilation fan under the 2024 OBC?

A.26 L/s

B.30 L/s

C.38 L/s

D.45 L/s

Explanation: OBC 2024 Table 9.32.3.3 specifies a range of 30 to 45 L/s for a 5-bedroom dwelling unit. The minimum normal operating exhaust capacity is 30 L/s (approximately 60 cfm).

5A new dwelling unit is designed with 6 bedrooms. Under the 2024 OBC, how is the principal ventilation capacity determined?

A.The system must comply with Clause 9.32.3.1.(1)(a), requiring design to Part 6 or CSA F326

B.By adding 7.5 L/s for each bedroom over 5 to the baseline of 45 L/s

C.A flat rate of 60 L/s is applied to any house with more than 5 bedrooms

D.It must be sized based on the total heated volume of the building rather than bedrooms

Explanation: OBC 2024 Table 9.32.3.3 states that for dwelling units with more than 5 bedrooms, the system must comply with Clause 9.32.3.1.(1)(a), which allows design in accordance with Part 6 or good practice such as CSA F326. The former 2012 OBC rule of adding 7.5 L/s per bedroom over 5 no longer applies.

6Under the 2024 OBC, what is the minimum rated capacity required for a supplemental exhaust fan installed in a residential kitchen?

A.25 L/s

B.40 L/s

C.50 L/s

D.100 L/s

Explanation: OBC 2024 Division B Article 9.32.3.7 requires that a supplemental exhaust fan in a kitchen have a rated capacity of not less than 50 L/s (equivalent to 100 cfm). This is intended to rapidly exhaust heat, steam, grease, and combustion products from cooking.

7What is the minimum rated capacity required by the 2024 OBC for a supplemental exhaust fan in a bathroom?

A.15 L/s

B.25 L/s

C.35 L/s

D.50 L/s

Explanation: Under Article 9.32.3.7 of the 2024 OBC, supplemental exhaust fans in bathrooms and water closet rooms must have a rated capacity of at least 25 L/s (50 cfm). This is sized to effectively clear humidity and odors from the space.

8Under the 2024 OBC, what is the minimum external static pressure at which a principal ventilation fan with ducts connected on both sides (e.g., an HRV) must be rated?

A.25 Pa

B.50 Pa

C.62 Pa

D.100 Pa

Explanation: OBC 2024 Table 9.32.3.10.A requires that fans with ducts connected on both sides, such as an HRV or central exhaust fan, be rated at a minimum external static pressure of 100 Pa (0.4 inches w.c.). This is a significant increase from the previous 50 Pa requirement, improving real-world performance.

9What is the minimum height above the finished ground level (grade) required for an outdoor air intake of a residential mechanical ventilation system under the 2024 OBC?

A.150 mm

B.300 mm

C.450 mm

D.600 mm

Explanation: Under the OBC, outdoor air intakes must be located at least 300 mm (12 inches) above the finished ground level. This elevation helps prevent the intake from drawing in snow, ponded water, dirt, leaves, or crawl space contaminants.

10What is the minimum horizontal separation required between an outdoor air intake and a gas vent or high-moisture exhaust outlet under the 2024 OBC?

A.1.0 m

B.1.2 m

C.1.5 m

D.1.8 m

Explanation: OBC 2024 Division B requires a minimum separation distance of 1.8 m (approximately 6 feet) between an outdoor air intake and any contaminant source, such as a furnace gas vent, bathroom exhaust, or clothes dryer vent. This prevents exhaust air from being drawn back into the house.

About the OBC HVAC - House Exam

The Ontario Building Code HVAC - House Examination is a professional licensing exam for designers, inspectors, and HVAC contractors seeking BCIN certification under Ontario's Building Code Act. The exam covers the technical requirements for heating, ventilation, and air conditioning systems in low-rise residential houses. The curriculum focuses on mechanical ventilation system sizing (OBC Section 9.32), forced-air systems (Section 9.33), heat recovery ventilators (HRVs), duct design and sizing, and space heating load calculations in compliance with CSA F280. The 2024 version aligns with the National Building Code (NBC) 2020 structure with Ontario-specific amendments.

Assessment

70 multiple-choice questions (Open-book, computer-based)

Time Limit

3 hours

Passing Score

70%

Exam Fee

$150.00 CAD (Humber Polytechnic / Ontario Ministry of Municipal Affairs and Housing (MMAH))

OBC HVAC - House Exam Content Outline

35%

Part 9 Mechanical Ventilation

Principal exhaust fan capacity, supplemental exhaust (kitchens and bathrooms), outdoor intakes, exhaust outlets, duct sizing, and ventilation controls.

25%

Forced-Air Systems & Duct Sizing

Duct configuration, installation standards, supply and return air inlet locations, carbon monoxide alarms, and furnace room clearances.

20%

HRVs & ERVs

Heat recovery and energy recovery ventilator specifications, coupling with forced-air systems, condensate drains, and performance standards.

20%

Heating and Cooling Load Calculations

Determining appliance capacity under CSA F280, heat loss/gain calculations, insulation levels (SB-12), and general engineering practice.

How to Pass the OBC HVAC - House Exam

What You Need to Know

Passing score: 70%
Assessment: 70 multiple-choice questions (Open-book, computer-based)
Time limit: 3 hours
Exam fee: $150.00 CAD

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

OBC HVAC - House Study Tips from Top Performers

1Familiarize yourself with OBC Section 9.32 for ventilation rates and Table 9.32.3.3. Sizing principal exhaust fans by bedroom count is a guaranteed exam topic.

2Understand the clearance requirements in Section 9.33 for fuel-fired appliances, chimneys, and vents, as well as where return air is prohibited.

3Know how to navigate Supplementary Standard SB-12 for energy efficiency requirements, including heat recovery ventilator (HRV) requirements.

4Learn the difference between direct-vent (sealed combustion) and non-direct-vent appliances, and how they affect combustion air supply and return air restrictions.

5Time management is key: with 70 questions in 180 minutes, you have about 2.5 minutes per question. Use tabs to find key tables in your code book quickly.

Frequently Asked Questions

Is the OBC HVAC - House exam open book?

Yes, the exam is open book. Candidates are allowed to have a physical or approved digital copy of the 2024 Ontario Building Code Compendium during the test.

What is the passing score for the HVAC - House exam?

The passing score is 70%. Candidates must answer at least 49 out of 70 questions correctly to pass.

What standard is used for heat loss and heat gain calculations under the OBC?

Under Article 9.33.2.2 of the Ontario Building Code, all heating and cooling load calculations must be performed in accordance with the CSA F280-12 standard, 'Determining the required capacity of residential space heating and cooling appliances'.

Can I take the exam online?

Yes. Humber Polytechnic offers online virtual proctoring, allowing candidates to take the exam from their home or office, as well as in-person testing at various Ontario College Test Centres.

100+ Free OBC HVAC - House Practice Questions

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