MHIC Building Codes and Standards 5 — Questions and Answers
Question 1: Under the International Residential Code (IRC), what is the minimum required width for a main hallway in a new residential construction?
- 28 inches
- 32 inches
- 36 inches (Correct answer)
- 42 inches
Correct answer: 36 inches
The IRC requires a minimum hallway width of 36 inches for main corridors in residential construction. This ensures adequate passage space for occupants and emergency egress.
Question 2: A homeowner wants to add a bedroom in the basement. According to IRC egress requirements, what is the minimum net clear opening area required for an egress window in that bedroom?
- 3.3 square feet
- 5.7 square feet (Correct answer)
- 7.5 square feet
- 8.0 square feet
Correct answer: 5.7 square feet
The IRC requires egress windows to have a minimum net clear opening of 5.7 square feet (with an exception of 5.0 sq ft at grade floor). This ensures occupants can escape or be rescued in an emergency.
Question 3: When installing a deck attached to a house in Maryland, which document typically governs the ledger board connection requirements?
- NFPA 70 (National Electrical Code)
- IRC Section R507 and local amendments (Correct answer)
- OSHA 1926 Subpart Q
- ANSI A117.1 accessibility standard
Correct answer: IRC Section R507 and local amendments
Attached deck construction, including ledger board connections, is governed by IRC Section R507 (Decks) along with any local Maryland amendments. The ledger connection is critical to prevent deck collapse and must meet specific fastener, flashing, and spacing requirements.
Question 4: A contractor is framing a load-bearing wall and needs to install a header over a 6-foot door opening. Under the IRC, what is the primary factor in determining the minimum required header size?
- The height of the ceiling above
- The type of lumber species used for framing
- The load the header must carry based on span and tributary area (Correct answer)
- The width of the door being installed
Correct answer: The load the header must carry based on span and tributary area
Header sizing is determined by the structural load the header must support, which depends on the span of the opening and the tributary area of roof, floor, or wall loads above. The IRC provides span tables that account for these loads to ensure structural adequacy.
Question 5: In Maryland, which agency is primarily responsible for adopting and enforcing the statewide building code for residential construction?
- Maryland Department of Natural Resources
- Maryland Department of Labor (through the Division of Labor and Industry) (Correct answer)
- Maryland State Highway Administration
- Maryland Department of Housing and Community Development
Correct answer: Maryland Department of Labor (through the Division of Labor and Industry)
The Maryland Department of Labor, through its Division of Labor and Industry, administers the Maryland Building Performance Standards and adopts the state building code, which is based on the IRC with Maryland-specific amendments.
Question 6: According to IRC smoke alarm requirements, where must a smoke alarm be installed in a home with a finished basement being converted to living space?
- Only at the top of the basement stairway
- Only inside the finished basement rooms
- On each level of the dwelling, including the basement, and inside each sleeping room (Correct answer)
- Only in rooms adjacent to the basement on the floor above
Correct answer: On each level of the dwelling, including the basement, and inside each sleeping room
The IRC requires smoke alarms to be installed on each level of the dwelling unit (including basements), inside each sleeping room, and outside each separate sleeping area. When a basement is converted to living space, smoke alarms must be placed in all these required locations.
MHIC Building Codes and Standards 5
Under the International Residential Code (IRC), what is the minimum required width for a main hallway in a new residential construction?