Windows and Doors reports that several major requirements were set forth in the published 2018 I-codes for windows, doors, skylights, and other fenestration products in single family homes, duplexes, and townhouses three stories or less in height. The 2018 editions of the International Residence Code (IRC) and the International Energy Conservation Code (IECC) are the most recent addressing changes to design loads, installation, and energy performance for fenestration products. Windows and Doors breaks down several of the major changes in the most recent code requirements.
Wind Loads
The design wind pressure values obtained from the 2018 IRC are to be multiplied by 0.6 for the purposes of comparison to the Design Pressure rating of the fenestration product obtained by testing in accordance with the 2017 edition of AAMA/WDMA/CSA 101/I.S.2/A440 (NAFS-17).
In most of the central U.S., the design wind speeds were reduced from the 2010 edition of American Society of Civil Engineers (ASCE) 7 to the 2016 edition. Design wind speeds are used to calculate the design wind pressures.
For vertical glazing, this reduction in design wind speed in ASCE 7-16 results in a reduction in design wind pressure. For skylights and sloped glazing, however, other factors used to calculate design wind pressure were increased. In some cases, this increase results in a higher design wind pressure.
Window Installation
Flashing requirements found in Section R703.4 did not change in the 2018 IRC; however, the editions referencing some AAMA standards for flashing were updated. Section R703.4 of the 2018 IRC requires self-adhered membranes used as flashing to comply with AAMA 711-13 and fluid-applied flashing to comply with AAMA 714-15. Item 1 of Section R703.4 requires mechanically applied flashing to comply with AAMA 712-14.
Energy Performance Compliance Paths
In the 2018 IECC, there continues to be four energy conservation compliance paths for residential construction:
- The prescriptive path,
- The UA (area weighted average) alternate method,
- The whole building performance path, and
- The Energy Rating Index (ERI) path.
The prescriptive path is the simplest to use. It provides one set of energy efficiency requirements for each component of the building envelope.
For more details on the code provisions and other code requirements, click through for Window and Door's comprehensive roundup of 2018 code changes.
Read More
