Student Discussion: The 2021 International Residential Code® (IRC®) Exam Study Course

This in ref to the irc 2021 course. The question was whats the difference between a live load and a dead load. As i understand, a liveload is has an effect on the design for anticipated weight and dead load deals with the stregnth of the load.

What is the minimum required hight in a habitable space. Its 7ft

Where are smoke alarms supposed to be installed? On every floor, outside in the hallway and in every bedroom. They are allowed to be battery operated

At what minimum height is a masonry chimney required to terminate?

Chimneys shall extend not less than 2 feet (610 mm) higher than any portion of a building within 10 feet (3048 mm), but shall be not less than 3 feet (914 mm) above the highest point where the chimney passes through the roof.

How high above a floor in a garage is an appliance with an ignition source required to be located?

18 inches

  • When there is a conflict between a general requirement and a specific requirement, which provision shall be applicable?

Answer: Specific requirements

Dwellings separation requirements from garages can be done in a few different ways. One option is 1/2” gypsum board can be installed on the garage side of the wall from the foundation to the roof deck. Another option is 1/2” drywall to be installed on the garage wall side and also on the ceiling. If habitable space is above the garage, 5/8” is required on the garage ceiling. Doors must be self closing and meet one of the types in R302.5.1. Penetrations must be sealed. Duct penetrations must be 26 gauge sheet metal and not have an opening in the garage.

Escape and rescue openings are required in basements, habitable attics, and every sleeping room of a dwelling unit. A basement with a sprinkler system can omit emergency escape openings under prescribed conditions. Minimum dimensions are 20” width, 24” height, and 5.7 square feet of opening area. Area can be reduced 5’ if one grade floor or basements. Maximum sill height of 44” above finished floor. Windows should be operable without a tool, keys, or special knowledge.

Shingles should not be applied on slopes of 2/12 or less. slopes of 2/12 and less than 4/12 require two layers of underlayment material. Roofs less than 8/12 require ice and dam material for the first 24" inches of horizonal heated space, Roofs of 8/12 or more require ice and dam material over the first 36 inches of heated space.

The scope of the 2021 IRC is to govern construction of one and two family dwelling and townhouses not more than 3 stories in height with separate egress and other accessory buildings such as garages and out buildings.

How must a private garage be separated from the residence? Garages should be separated from dwelling units as outlined in R302.6 and Table R302.6. Minimum 1/2" drywall should be used to separate garage walls from interior walls. 5/8" type-X drywall should be used in garages below living space.

  • What is the minimum required size of the largest habitable room in a dwelling unit?
    The minimum size of a habitable room in a dwelling unit is 70SF with the exception of the kitchen area.
  • What is the minimum ceiling height permitted for a living room or bedroom?
    The Minimum height of ceilings for living and bedrooms is 7 feet as outlined in R305.1 Minimum height. The minimum height of Bathrooms water closets and laundry rooms is 6 feet 8 inches.

How is handrail height measured? What is the minimum height permitted? The maximum height? Handrail heights are measured vertically from the top of the slope along the leading edge of the treads, handrail heights should be between 34 inches and 38 inches.

How must lots be graded? Lot grading should slope away from the foundation a minimum 6 inches within the first 10 feet of the structure. Where lot size does not permit swales or drainage should be utilized to move water away from the foundation.

What is the minimum permitted thickness for concrete slab-on-ground floors? Three and one half inches is the minimum thickness for concrete slab on grade. There should be no vegetation of foreign material in the base fill. The base should be properly compacted.

  • What is the criteria for the installation of weep screeds in exterior plaster applications? Weep screed on wood/metal framed walls should be a minimum of 4" above the ground and a minimum of 2 inches above hardscape. Weep screed should be corrosion resistant and extend a minimum of 3 1/2" vertically.

  • What are the installation requirements for asphalt shingles? Roof shingles should be installed per the manufacturer’s installation instructions R905.2 and in my area Florida Department of Business and Professional Regulation Product Approvals.

Writing assignment #18: Arc-fault circuit interrupters are required for branch circuits that supply 120 v single phase 15 and 20 ampere outlets installed in kitchens, family rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas and similar rooms or areas. Unlike GFCI’s they are not required for bathrooms, garages, or outside.
AFCI protection is required also where branch circuit wiring is modified, replaced, or extended. An exception to this is the extension of branch circuit conductors is 6 ft. or less and does not include any additional outlets or devices other than splicing devices

Writing Assignment Chapter 28, 29, 30

Question: When is a water heater required to be installed in a pan? What type of pan is mandated? How big must it be? How shall it be drained?

Answer: 2801.6 Where a storage tank type water heater is installed in a location where water leakage from the tank will cause damage, the tank shall be installed in a pan.

Pan. Galvanized steel not less than .0236-inch thickness

Pan. Plastic pan not less than .036 inches thickness

The pan shall be a minimum of 1 ½ inches deep and shall be drained by a waste pipe no less than ¾ inches in diameter.

P2801.6.2 The pan drain shall extend full size and terminate over a suitably located indirect waste receptor or shall extend to the exterior of the building and terminate not less than 6 inches and not more than 24 inches above the ground surface.

There is an error in the ICC class material Session 9 quiz question #32 the answer stated says minimum 14" for Rumford

The Code says 12" minimum depth


  • How are ducts to be insulated and sealed? Ducts in unconditioned space should be insulated to a minimum of R-8. All flex ducts should be properly stretched and sealed.

How is condensate from refrigeration cooling equipment to be addressed? Condensation drain lines should be a minimum of 3/4 inch, sloped 1/8" per foot to the exterior or a suitable drain. Condensate drain lines should be insulated. Auxiliary drain pans should have a 3/4 inch drain line that drain to a conspicuous location. Condensate lines should be trapped per manufacturer installation instructions.

Where must mechanical exhaust air terminate? Mechanical exhaust air must terminate at the exterior of the structure. Duct terminations should be provided with backdraft dampers and screens (dryer vents should not have screens). Ducts should not terminate in attics, crawlspaces or soffits. Ducts should not terminate within 3’ of operable or inoperable openings to the structure.

  • What special conditions apply to the installation of a solar energy system?
    Solar thermal energy systems should have insulated piping, service area access, be equipped with pressure and temperature relief valves. Components subjected to a vacuum should be equipped with a vacuum relief valve.

What is the maximum permitted length for an appliance fuel connector serving a range or domestic clothes dryer?

Gas appliance connectors should not exceed 6 feet only one connector per appliance should be installed. Connectors are permitted to be longer than 6 feet if the connecting pipe is sized as part of the pie system.

  • What is the temperature limit for water supplied to a shower? A bathtub? A whirlpool bathtub? A bidet?

The temperature limit for a shower 120 degrees F, bathtubs 120 degres F, whirlpool bathtub 120 degrees F. A bidet temperture limit is 110 degrees F.

When is a water heater required to be installed in a pan? A water should be installed in a pan when installed at a location where leakage could cause damage. The pan should be a minimum of 1.5 inches deep and drain to the exterior or a suitable drain.

At what minimum height must an open vent pipe terminate above a roof? Plumbing vents must terminate at least 6" above the surface of the roof. Plumbing vent installed under items such as solar voltage power panels are permitted to be a minimum of 2". Plumbing vents that terminate at areas where persons may commonly be present should be a minimum of 7 feet.

What minimum working clearances are required for energized equipment and panelboards? The minimum working space for electrical panelboards and disconnects should be free and clear 36" deep by 30" wide (or minimum the width of the panelboard) and 6’ 6" H.

What method is used to determine the minimum spacing requirements for convenience receptacles? Wall space should have an outlet within 6 feet, including fixed glass panels. Bathroom sinks should have an outlet installed with 36". Countertop space should have an outlet within 24".

After straining my eyes for almost half of the course I realized there was a full screen button.

YAAAAAWWWWN :rofl: :wink:

IRC Chapters 31, 32, 33 Writing Assignment

Question: At what minimum height must an open vent pipe terminate above a roof? What if the roof is used for a purpose other than weather protection?

P3103.1.1 Open vent pipes shall terminate no less than 6 inches above roof surface or 6 inches above expected snow accumulation.

P3103.1.2 Where the roof is used for recreational purposes or gathering, the vent pipe shall end not less than 7 feet above the roof surface.

  • Which sources of outside or return air are prohibited?

R303.5.1 Intake openings.

Mechanical and gravity outdoor air intake openings shall be located not less than 10 feet (3048 mm) from any hazardous or noxious contaminant, such as vents, chimneys, plumbing vents, streets, alleys, parking lots and loading docks.

For the purpose of this section, the exhaust from dwelling unit toilet rooms, bathrooms and kitchens shall not be considered as hazardous or noxious.


  1. The 10-foot (3048 mm) separation is not required where the intake opening is located 3 feet (914 mm) or greater below the contaminant source.

  2. Vents and chimneys serving fuel-burning appliances shall be terminated in accordance with the applicable provisions of Chapters 18 and 24.

  3. Clothes dryer exhaust ducts shall be terminated in accordance with Section M1502.3.

When is a permit required? What types of work are exempted from permits?

As stated in R105.1:
“Any owner or owner’s authorized agent who intends to construct, enlarge, alter, repair, move,
demolish or change the occupancy of a building or structure, or to erect, install, enlarge, alter, repair, remove convert or replace any electrical, gas, mechanical or plumbing system, the installation of which is regulated by this code, or to cause any such work to be performed, shall first make application to the building official and obtain the required permit.”

“Exemption from permit requirements of this code shall not be deemed to grant authorization for any work to be done in any manner in violation of the provisions of this code or any other laws or
ordinances of this jurisdiction.”

The code then goes on to a long list of items that do not require a permit. They are categorized by building, electrical, gas, and mechanical. As an example, the building exemptions are listed below.

  1. Other than storm shelters, one-story detached accessory structures, provided
    that the floor area does not exceed 200 square feet (18.58m²).
  2. Fences not over 7 feet (2134 mm) high.
  3. Retaining walls that are not over 4 feet (1219 mm) in height measured from the
    bottom of the footing to the top of the wall, unless supporting a surcharge.
  4. Water tanks supported directly upon grade if the capacity does not exceed 5,000
    gallons (18 927 L) and the ratio of height to diameter or width does not exceed 2
    to 1.
  5. Sidewalks and driveways.
  6. Painting, papering, tiling, carpeting, cabinets, counter tops and similar finish
  7. Prefabricated swimming pools that are less than 24 inches (610 mm) deep.
  8. Swings and other playground equipment.
  9. Window awnings supported by an exterior wall that do not project more than 54
    inches (1372 mm) from the exterior wall and do not require additional support.
    10.Decks not exceeding 200 square feet (18.58 m²) in area, that are not more than
    30 inches (762 MM) above grade at any point, are not attached to a dwelling and
    do not serve the exit door required by Section R311.4.
  • What are the general provisions related to hydronic piping systems? How must floor heating systems be tested?

M2101.1 General.

Hydronic piping shall conform to Table M2101.1. Approved piping, valves, fittings and connections shall be installed in accordance with the manufacturer’s instructions. Pipe and fittings shall be rated for use at the operating temperature and pressure of the hydronic system. Used pipe, fittings, valves or other materials shall be free of foreign materials.

M2103.4 Testing.

Piping or tubing to be embedded shall be tested by applying a hydrostatic pressure of not less than 100 psi (690 kPa). The pressure shall be maintained for 30 minutes, during which the joints shall be visually inspected for leaks.