Exterior windows and doors are covered in Section 1710.5 of the 2012 International Building Code (IBC) and Section R612 of the 2012 IRC. A summary of the current code provisions related to these products is as follows:
- Exterior swinging doors can be tested and labeled in accordance with AAMA/WDMA/CSA 101/I.S.2/A440-11 (NAFS-11) or tested to 1.5 times allowable stress design load in accordance with ASTM E330-02. NAFS-11 contains provisions for some types of exterior swinging doors. AAMA has also put into place a program to certify these types of products for compliance with this standard. This program depends upon testing of each proposed door assembly, rather than the component-based approach offered by ANSI A250.13 and others.
- The 2012 International Building Code references the 2010 edition of ASCE7 for design loads. The 2010 edition of ASCE 7 provides design wind load provisions that are based upon Strength Design of building components. This method provides loads that have a lower likelihood of occurring during the service life of the building. The building components are then designed not to fail (rupture) when subjected to that load.
- In comparison, the 2012 International Residential Code retains use of the more traditional Allowable Stress Design methodology. This methods provides loads that have a higher likelihood of occurring during the service life of the building and the building components are then designed to remain serviceable (not require replacement) when subjected to those loads.
- Beginning with the 2012 International Codes, the energy conservation provisions of Chapter 11 of the IRC are an exact duplicate of the provisions of the IECC for the same building.
The prescriptive paths for both residential and commercial construction establish maximum permitted U-factors (and solar heat gain coefficients) for fenestration. U-factor is to be determined in accordance with NFRC 100-09 or by use of a default table in the 2012 IECC.
The other two compliance paths for residential construction in the 2012 IECC permit some tradeoffs in levels of energy efficiency from one building component to another. One of these—designated the UA alternate method—only permits tradeoffs between different elements of the building envelope. The other method—performance-based design of the whole building—permits tradeoffs among some components of the residence that impact energy use. The amount of tradeoff that is permitted for fenestration when following the UA alternate or whole building performance compliance paths is capped for different climate zones in the 2012 IECC.
The U-factor requirements for vertical fenestration also apply to exterior doors. This include both glass doors and opaque doors
Glass doors, by definition in the IECC, are considered to be doors which are more than 50 percent glass in area. These doors must meet the criterion for vertical glazing in the IECC.
If the door is equal to or less than 50 percent glass in area, it is considered to be an opaque door. Opaque doors are included in the definition of fenestration area in the 2012 IECC and 2012 IRC. They are assigned a maximum U-factor of 0.35, separate from the U-factor requirements for glazing area. According to Table R303.1.3 of the IECC, this criterion is met by any insulated, nonmetal edge opaque door with glazing less than 45 percent of the door area, if any glazing that does occur in the door is double pane. Also, one opaque door up to 24 square feet in area is exempt from the maximum U-factor requirement in the 2012 IECC and 2012 IRC.
- The 2012 IECC and IRC require air leakage resistance of windows, door assemblies and unit skylights to be determined in accordance with NAFS-11 or NFRC 400-09, similar to the requirements in the 2009 IECC and IRC. The 2012 IECC also requires air-leakage resistance of curtain wall, storefront glazing and commercial doors to be determined in accordance with ASTM E283-04.
- The requirements for sizes, locations, etc., for emergency escape and rescue openings are set forth in Section 1029 of the 2012 IBC and Section R310 of the 2012 IRC. It is important to note that the required opening size of 24 inches high, 20 inches wide and 5.0 or 5.7 square feet in area must be met by “normal” operation of the window, door or skylight without the use of keys, tools or special knowledge, and without the removal of a second sash from the opening. Typically the emergency escape and rescue opening requirements are met with operable windows or doors. Section R311 of the 2012 IRC and Section 1021 of the 2012 IBC require all buildings to have at least one exit door. Dependent upon the occupancy rating of the building, Section 1021 of the 2012 IBC may require more than one exit door. Section R311.3 of the 2012 IRC and Section 1008.1.7 of the 2012 IBC restrict the threshold height of the required exit door in residences to 1½ inches or ¾ inch, depending upon the type of door, from the top of the threshold to the floor or landing on each side of the door. Section R311.3 of the 2012 IRC also specifies that the dimensions of the clear opening provided by the required exit door are to be at least 32 inches wide and 78 inches high.
The Next Round of Changes
Heading into 2014, most states and local jurisdictions are still referencing older editions of the IRC, IBC and IECC. Adoption and reinforcement of a new edition of a model construction code traditionally occurs most significantly in the second and third year after its publication. Some states, however, have specifically opted to skip the 2012 edition of the International Codes and will continue to use the 2009 or earlier edition until the 2015 edition becomes available. We can expect to see continued adoption of the 2012 International Codes, however, by some jurisdictions in 2014 as other states complete the rather arduous process of putting an updated code into place.
The development of the 2015 editions of the I-Codes is now well underway. All of the door-related proposals that follow have been approved and will be contained in the 2015 edition of the IRC (RBxx proposals) or the 2015 edition of the IECC (RExx or CExx proposals).
Construction-Related Provisions of the 2015 International Residential Code
- RB39 – Revises the wind load provisions of the IRC from Allowable Stress Design to Ultimate, for consistency with the IBC. Although AAMA supported the approval of this proposal as submitted, we were opposed to revising the text of ASTM E1996 to define Wind Zone 4 (WZ4) as more than 170 mph. The proposal was approved with that revision.
- RB40 – Adds reference to AAMA/NSA/NPEA 2100-12 to the IRC and requires sunroom additions to single family homes to comply with it. It requires all fenestration in the sunroom addition, including doors, to be tested and labeled in accordance with NAFS-11.
- RB117 – Reorganizes the Emergency Escape and Rescue Opening (EERO) provisions of the IRC, and clarifies certain provisions. Among the items clarified was that doors that do not necessarily meet the criteria for a means of egress door, such as a sliding glass door, can be used as an EERO if it meets the applicable size and operational criteria
- RB198 – Requires doors that serve as the entrance to a home, which are at the top of stairs on a floodplain, to comply with the performance requirements of Section R612 for exterior doors.
- RB340 – Adds ANSI/AMD 100-13 to the list of standards to which exterior residential swinging doors are to be tested and labeled as described in Section R612. The ANSI/AMD 100-13 edition of this standard requires door systems to be retested or reevaluated whenever more than one component is substituted into a previously tested door system.
Energy-Related Provisions of the 2012 International Energy Conservation Code
- RE58 – Clarifies that vertical doors between crawl spaces and conditioned spaces are to meet the criteria of the IECC for vertical fenestration and do not have to be insulated to the R-value of the attic floor.
- RE188 – Adds a new compliance path to the IECC for residential construction, based upon an Energy Rating Index that is similar to the HERS rating provided by RESNET. This option is in addition to the “performance-based design” method that permitted whole-building tradeoffs among some building components. Hence, three sets of criteria for fenestration in residential construction have been l established for the 2015 IECC. The applicable criterion depends upon which compliance path the builder is using. The requirements apply to “glass doors” (contain more than 50% glazing area).
The maximum U-factor for glass doors in residential buildings in the 2015 IECC will be as follows:
b. Max U-factor = 0.65 for impact rated fenestration
- CE88, in a similar fashion, adds an alternative building envelope compliance path to the IECC that permits the trading off of building envelope UA, thermal conductance (CA), perimeter heat loss (FL), window area and skylight area.
- CE75 – Requires replacement glazing in commercial buildings to comply with the prescriptive requirements for new construction.