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Changes in the 2021 International Residential Code (IRC)

jar546

jar546

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A quick overview of the changes:
  • Braced wall lines must be placed on a physical wall or placed between multiple walls.
  • The rated separation for two-family dwellings is 1 hour whether or not a lot line exists between units.
  • Emergency escape and rescue openings require a clear 36-inch-wide path to a public way.
  • An engineered design is required for storm shelters.
  • A habitable attic is limited to one-half the area of the story below and the dwelling requires sprinklers.
  • Updated Wind Speed maps match IBC and ASCE 7 maps.
  • Deck design now considers snow load, tributary area for footing and post height, and guard details.
  • Specific requirements for deck guardrails were added.
  • Component and cladding wind pressures in Table R301.2(2) are updated for new design wind speeds and hip or gable roof profiles.
  • Minimum footing size tables are revised to more accurately reflect current practice.
  • Cripple wall requirements apply only to exterior cripple walls.
  • New appendices for cob construction and 3D printed construction are added.
  • A 30 percent reduction of airflow is permitted for balanced ventilation systems.
  • Commercial gas cooking appliances are prohibited.
  • The head pressure for a water test of DWV systems increased to 10 feet.
  • Air vacuum testing is now permitted for plastic piping DWV systems.
  • Section P2904 for dwelling sprinklers is expanded to more closely align with NFPA 13D.
  • An emergency service disconnect is required in a readily accessible outdoor location.
  • A surge-protective device (SPD) is now required at the service panel.
  • The number of receptacle outlets required for peninsular and island countertops in kitchens is determined by the area of the countertop surface.
  • GFCI protection is now required for damp and wet locations not included in the other 10 areas requiring GFCI protection.
 
I am not sure where you get the first bullet, "Braced wall lines must be placed on a physical wall or placed between multiple walls."

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Don't forget this gem:

N1102.4.6 (R402.4.6) Electrical and Communication Outlet Boxes (Air-Sealed Boxes)​


Electrical and communication outlet boxes installed in the building thermal envelope shall be sealed to limit air leakage between conditioned and unconditioned spaces. Electrical and communication outlet boxes shall be tested in accordance with NEMA OS 4, Requirements for Air-Sealed Boxes for Electrical and Communication Applications, and shall have an air leakage rate of not greater than 2.0 cubic feet per minute (0.944 L/s) at a pressure differential of 1.57 psf (75 Pa). Electrical and communication outlet boxes shall be marked "NEMA OS 4" or "OS 4" in accordance with NEMA OS 4. Electrical and communication outlet boxes shall be installed per the manufacturer's instructions and with any supplied components required to achieve compliance with NEMA OS 4.

That will make your electricians happy....
 
This is true, but now you must use tested and rated boxes. Even if I use air-impermeable spray foam in a 2x6 wall cavity, I must now use these special boxes in exterior walls under the 2021 IRC. Seems a bit redundant.
 
You do not have to do a number of things that are required in the energy code to meet the allowable air changes per hour permitted by the energy code.

After all isn't that all the code requires to measure compliance with is the allowable air changes per hour.

N1102.4.1.2 (R402.4.1.2) Testing.
The building or dwelling unit shall be tested and verified as having an air leakage rate of not exceeding five air changes per hour in Climate Zones 1 and 2, and three air changes per hour in Climate Zones 3 through 8. Testing shall be conducted in accordance with RESNET/ICC 380, ASTM E779 or ASTM E1827 and reported at a pressure of 0.2 inch w.g. (50 Pascals). Where required by the building official, testing shall be conducted by an approved third party. A written report of the results of the test shall be signed by the party conducting the test and provided to the building official. Testing shall be performed at any time after creation of all penetrations of the building thermal envelope.
 
The IRC does not even require an inspection for Chapter 11 code compliance.

The residential portion of the energy code does and specifies what to look for.
My point is that the energy code has mandates that if not met the structure will still pass the blower door test and therefore meet the intent of the energy code.

N1101.2 (R101.3) Intent.
This chapter shall regulate the design and construction of buildings for the effective use and conservation of energy over the useful life of each building. This chapter is intended to provide flexibility to permit the use of innovative approaches and techniques to achieve this objective. This chapter is not intended to abridge safety, health or environmental requirements contained in other applicable codes or ordinances.
 
The IRC does require inspection for Chapter 11 compliance, only a portion of which is done by third party. Our jurisdiction even uses different colored permit cards to remind the inspectors which energy compliance path the builder has chosen so they know what to review and the documentation to access.

By a similar analogy, I should not have to bother draftstopping penetrations to my attics because I plan on coating the entire attic floor with 4" of spray foam. They still make me do it anyway. If the code requires something, it is required. The energy code is only different in that it offers 4 different paths to compliance that each have different requirements. Still, many of the requirements are common to all.
 
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