Significant changes to dwelling unit rated penetrations in the 2021 International Residential Code

A clarification to Section R302.4 (Dwelling Unit Rated Penetrations) of the 2021 International Residential Code (IRC) states that water-filled fire sprinkler piping of any approved material joins the list of metal penetrating items that do not require a firestop system provided the annular space is filled with the prescribed materials.

When items such as pipes or ducts penetrate one or both sides of the fire-resistance-rated wall assembly separating dwelling units, both the penetrating item and the space around it must be protected to maintain the integrity of the fire-resistant assembly. In general, penetrations by metal pipe require that the space around the pipe be filled with approved materials to prevent the passage of flame and hot gases. Other penetrating materials, such as plastic pipe, must be protected by an approved penetration fire-stop system. Such a system often consists of intumescent material that expands when heated by fire conditions, filling the penetration as the plastic pipe melts and preserving the fire-resistance rating of the wall assembly.

Listed nonmetallic fire sprinkler piping is ignition resistant and will not sustain combustion. The IRC now permits water-filled fire sprinkler piping to penetrate a fire-resistance-rated membrane or both membranes of a through penetration without a listed firestop system provided that the annular space is filled using an approved material. This matches the installation requirements for metal piping penetrations. Exception 1.2 of Section R302.4.1 sets the criteria for the material filling the annular space of the membrane or through penetration.

Read the full significant change.

The 2021 Significant Changes guides are available for the International Building, Fire, Residential, Energy Conservation, Plumbing, Mechanical and Fuel Gas Codes. This valuable series can help any code user save time by zeroing in on the most critical changes in the 2021 International Codes. The Code Council’s technical experts provide summaries, analysis and graphics for these changes making them clear and easy to understand. Each edition provides a comprehensive analysis of significant changes since the 2018 edition, offering key insights into its contents and implications. Each change analysis features the affected code sections and identifies the change with strikethroughs and underlines to show modifications to the existing language. Each change is accompanied by a quick summary, detailed illustrations, and a discussion of its significance, which brings the technical jargon of the code to life in a real-world setting.

Significant Changes to the International Residential Code, 2021 Edition, is available in the ICC Store or through Digital Codes Premium.