Unit Skylights

Unit skylights are one of the many noteworthy inclusions in AAMA/WDMA/CSA 101/I.S.2/A440-05 Standard/Specification for Windows, Doors, and Unit Skylights. �It�s the first complete, performance-based fenestration standard that includes unit skylights,� said Roland Temple, Compliance and Certification Coordinator, VELUX America, Greenwood, S.C. Temple is a member of WDMA�s Exterior Fenestration Standards Committee and also served as the skylight representative to the U.S./Canadian Structural Harmonization Task Force. �This is the first complete guide for skylights. Previously, there was no single, unified standard on how unit skylights should perform,� he said. �There have been references in predecessor documents, but nothing as complete and encompassing as this. This standard/specification gives manufacturers one document to test to for all the performance requirements for skylights,� Temple added.

Unit skylights, said Temple, are defined as factory-assembled fenestration consisting of a single panel of glass or plastic installed in a sloped or horizontal orientation. Unit skylights are fixed (non-operable) or venting (operable). They are designed to allow for natural daylighting and ventilation in operable units.

The Standard/Specification gives manufacturers one document to test to for all the performance requirements for skylights. Photo courtesy of VELUX America

Temple added that the specification covers a range of applications, from residential to commercial. �The standard identifies different performance criteria, which allows manufacturers to have products rated for various levels, depending on the application,� he said. �For the building code community, it�s something they�ve been looking for � a way to identify different characteristics of skylights and other products and how they should perform,� he added.

Side-hinged Exterior Doors

Prior to the release of AAMA/WDMA/CSA 101/I.S.2/A440-05, there was some confusion in the construction community about what specific performance criteria were necessary for side-hinged doors. When ANSI/AAMA/WDMA 101/I.S.2-97 and AAMA/WDMA 101/I.S.2/-NAFS-02 were put into the IBC and IRC, an exemption was created for exterior side-hinged doors and other products outside the scope of the standards, allowing them to be tested using ASTM E330 structural testing only. This exemption created some confusion for code officials, especially regarding exterior side-hinged doors containing glazing. Some jurisdictions insisted any swinging door containing glazing should meet 101/I.S.2-97 or 101/I.S.2/NAFS-02 standards, while others exempted some types of swinging patio doors from the requirement.

The recently completed AAMA/WDMA/CSA 101/I.S.2/A440-05 includes a specification section specifically for side-hinged exterior doors, and it is hoped its inclusion in the 2006 edition of the IBC and IRC will rectify any remaining problems. AAMA and WDMA jointly developed a Technical Position Statement regarding �Exterior Side-Hinged Door Systems� to address concerns regarding the applicability of 101/I.S.2-97 and 101/I.S.2/NAFS-02 to side-hinged exterior door systems that contain glazing. They agreed that these specifications were intended to apply to sliding glass doors containing certain typical elements including framed lower track systems. These types of framed sliding glass doors operate in a manner consistent with horizontal sliding window units, and as such, it was determined reasonable to expect that they would be able to perform in a similar manner during water penetration testing. (This Technical Position Statement is available at www.wdma.com).

The requirements in AAMA/WDMA/CSA 101/I.S.2/A440-05 governing side-hinged exterior door systems clear up some of the ongoing confusion about side-hinged doors and what types are addressed by the Standard/Specification. The standard/specification includes side-hinged exterior doors, sliding doors (often referred to as patio doors), dual-action side-hinged doors, and fixed doors (not interior doors). More importantly, the standard makes specific recommendations based on the type of door and where it is used. As in this standard and others developed recently by WDMA, performance and applicability to the built environment are critical components of the documents.

One of the most significant changes is the inclusion of requirements for side-hinged exterior doors. Side-hinged exterior door systems have requirements that are quite different from window, sliding door, and unit skylight products, both in design and application. As the primary means of entry to a building, exterior doors are required to not only protect against the elements, but are also required to allow for ease of access and emergency escape and rescue. Issues concerning accessibility by the disabled also need to be addressed in product design. In addition, consideration must be given to escape during emergencies such as fire, and in some cases, the door system is required to act as a barrier to fire. An exterior door system can be expected to be operated a significantly greater number of times and to a greater severity during its design life than a typical window or unit skylight assembly. As a result, cycling performance is evaluated, as well as other criteria specific to these types of fenestration products. Finally, it is not always feasible or necessary for side-hinged door systems to meet the substantial water penetration resistance requirements of other fenestration products in cases such as but not limited to, accessibility requirements and/or the application of products in weather-protected areas.