Plan for Successful Door Installation
Building use, site location, and weather patterns affect the specifying and installation of commercial doors and windows.
Ken Brenden, American Architectural Manufacturer
The performance of a door or window is only as good as its installation. The installation, in turn, depends upon three things: the level of understanding and communication among the architect, contractor, and installer; the quality of the manufacturer’s installation instructions; and the installer’s expertise. Architects and contractors know that once the specification is written and the product selected, the need for planning and oversight has begun.
To foster uniform and reliable installation practices in the commercial sector, the American Architectural Manufacturers Association (AAMA), Schaumburg, IL, published Standard Practice for the Installation of Windows and Doors in Commercial Buildings (IPCB-08). This detailed methodology for the installation of exterior glass doors and windows in commercial buildings provides information for new construction and replacement projects. The publication addresses hinged and sliding commercial exterior doors incorporating large-glass vision.
Designing for installed performance begins with meeting the application’s requirements as set forth in standards and codes. In commercial buildings, live loads typically take precedence over dead loads (the weight of the stationary building components). Live loads are those that come and go or that change over time. Examples include wind loading, thermal expansion, seismic drift, and even the building’s occupants. Live loads typically induce movement involving interaction among multiple building elements that extend beyond the glazed unit itself.
When specifying doors to withstand these and other conditions specific to the job site, remember that doors have distinct functional differences and application realities compared to windows. These differences stem from accessibility requirements, operating frequency, and water penetration.
|During the design phase, it is imperative to consider proper installation and appropriate accessories so fenestration units function effectively and efficiently. This reduces rework, and saves time and money in the long run. Specifiers should also consider using pre-installation and final-quality checklists.|
Standards, codes, and regulations
AAMA wrote a material-neutral and harmonized (i.e. suitable for both the United States and Canada) performance standard for window, door, and unit skylights. AAMA also established performance specifications for exterior side-hinged doors This standard and the most recent version (NAFS-08) also reference separate AAMA standards for operating-cycle performance and resistance from forced entry, vertical load, hardware load, and water penetration. These standards pioneered the limited water (LW) rating concept, which recognizes that entry doors typically are installed in weather-protected areas, such as under an overhang or opening into a portico. Thus, significant leakage problems are rare.
NAFS-08 establishes levels of performance for various classes of windows, doors, and unit skylights. Successfully meeting these requirements provides a gateway into one of four performance classifications:
- R, commonly used in one- and two-family dwellings
- LC, used in low- and mid-rise multi-family dwellings and other buildings where larger sizes and higher loading requirements are expected
- CW, used in low-rise and mid-rise buildings where larger sizes, higher loading requirements, limits on deflection, and heavy use are expected
- AW, used in mid-rise and high-rise buildings to meet increased loading requirements and limits on deflection, and in buildings where frequent and extreme use of the fenestration products is expected.
The 2009 International Building Code (IBC), which references NAFS-08 for window and door performance, governs commercial construction in local jurisdictions where it has been adopted. Other codes governing the performance of commercial doors and windows include the IECC, ADA, and CPSC.
The International Energy Conservation Code (IECC) sets forth thermal-performance requirements.
The Americans with Disabilities Act [ADA] Accessibility Guidelines (referenced in Chapter 11 of the IBC) require that public buildings and multi-family dwellings include certain features of accessible design. A key requirement is that exterior-door thresholds and sliding-door tracks are not to exceed a height of 1/2 to 3/4 in. This limitation on threshold heights can have an impact on a system’s resistance to water penetration. Door specifiers and installers must be aware of ADA requirements, and must understand this trade-off and the role of the LW rating.
The Consumer Product Safety Commission (CPSC) enforces safety-glazing regulation 16 CFR Part 1201 (codified in the IBC), which mandates use of tempered or laminated safety glazing in any operable door with a glass panel or a fixed-panel adjacent to a door.
Weather barrier concerns
The weather-barrier system and the means of integrating it with doors and windows is one of the most important for long-term performance. Two weather-barrier systems are commonly used in commercial construction: surface-barrier systems and membrane/drainage systems.
A surface-barrier system uses the outermost surface of a wall as its sole barrier to shed and control water penetration. Walls considered to be surface-barrier systems are often solid walls; for example, single-width masonry, poured concrete, glass fiber-reinforced concrete, concrete block, and others that do not include wall cavities. These walls have drainage planes, such as direct-applied exterior insulation and finish systems (EIFS).
Window or door products are integrated into a surface-barrier system with a sealant joint, which becomes the sole method for joining the various materials. The joint serves as the weather barrier (the only defense) for the completed assembly.
A membrane/drainage system uses a weather-resistant barrier (building paper, house wrap, sheathing, or other water-shedding material) behind the exterior surface of a wall. Walls sided with some types of EIFS, stucco, brick, or stone veneer are considered membrane/drainage systems. Walls built with a membrane/drainage system may allow incidental water to enter behind the outer-most surface of the building, but they are designed to control and divert this water back out to the exterior.
The integration of the window/door framing, the installation accessories, and the weather-resistant barrier with flashing and sealant is critical. Installation of windows and glass doors in membrane/drainage wall systems may require special attention and coordination with the building contractor to ensure that the weather-shedding integrity of the building is maintained.
|A Checklist for Site Constraints
When possible, the architect should meet with the contractor or installer prior to installation to ensure that a preliminary site inspection is conducted. The parties should determine if conditions exist that could cause installation problems. American Architectural Manufacturers Association’s (Schaumburg, IL) IPCB-08 document provides sample site-inspection checklists for replacement work and new construction. These checklists provide information on:
Specifying flashing, sealants, anchors, and accessories
Flashing in commercial applications consists of a waterproof material that bridges the joint between the interior construction and the exterior building components. It diverts moisture from above or below the opening back to the exterior.
There are two basic types of flashing products (flexible and rigid) used in conjunction with windows and doors. Flexible flashing is a formable, waterproof sheet material, typically applied to the substrate prior to the window or door installation. As an example, flexible flashing is often used above the head of the window on top of the steel lintel in brick or stone applications. Rigid flashing is typically galvanized metal, stainless steel, and aluminum or copper sheet metal. It is used at the head and sill to carry incidental water from the interior to the exterior.
Often, the architect is expected to specify the sealants used for installation. Joint sealant is usually required to prevent infiltration of air and water around working joints that accommodate movement or non-working joints secured by fasteners. The size of the sealant joint and the sealant compound must accommodate the maximum thermal expansion and contraction of surrounding materials, as well as building movement.
Wall anchors must have the hardness, yield, and tensile strength to bear the weight of the door unit itself. In addition, anchors must withstand the forces imposed by dynamic loads, while allowing thermal movement. Fastening requirements should be thoroughly understood to ensure that the units are installed to meet and/or exceed the expected performance criteria. Avoid penetrating the flashing with attachment fasteners. Selection of the appropriate fastening method is the responsibility of the architect or contractor, in cooperation with the installer.
Special accessories include panning, receptors, and receivers. These are often used to accommodate transitions and allow for movement. They can be used to cover existing building components, allow for ease of installation, and provide a finished condition after installation.
Panning materials are used on the exterior of doors and windows in new construction and replacement. In replacement installations, panning materials typically cover existing framing or trim and are often designed to provide the same profiles as the materials they cover. Sealing is generally accomplished by the use of gaskets, sealant, or a combination.
Receptor systems, also known as comp channels, are an effective way to accommodate excessive building movement due to live loads. They are generally one- or two-piece extruded members used at the head and jambs of doors or windows. Receptors are usually shaped as a channel and typically include gaskets that form a compression seal against the framing system.
Some substrate materials (stucco, EIFS, and metal panels) require a receiver, often a J-shaped molding that is applied after window installation. The weathering joint occurs between the receiver and the window or door and eliminates the need for sealing the product directly to the substrate material.
Most common to commercial applications is extruded aluminum trim, usually designed in two pieces that are snapped together to form a rectangle or square. For retrofit applications, aluminum trim can be extruded in profiles that resemble the old trim. In commercial applications, trim occasionally serves as a device for anchoring the window to the building. If the trim is at least two pieces, the first piece can be secured to the existing structure and the new window frame. The second piece is snapped over the first, hiding any fasteners from view.
If the architect has project-management or inspection authority, the contractor or installer should notify him or her when the job is ready for the initial inspection. Usually, this is when the first few units are properly installed. The installer should leave anchor conditions exposed so the architect can perform a visual inspection. Access to the interior and exterior side of the units should be preserved.
After all windows, doors, and associated trim pieces have been installed, the architect can perform the final quality-control inspection. It is a good idea to use a checklist (such as the one found in AAMA’s Standard Practice document IPCB-08) to verify that an installer has performed each step of the installation process completely, correctly, and in accordance with the prescribed installation practices. When an item on the quality-control checklist is not part of the installer contract, the architect or contractor typically assumes this responsibility.
By specifying and ensuring the use of appropriate accessories, and by using quality-control checklists, the architect, contractor, and installer ensure that door and window units will function effectively and efficiently. This reduces re-work and saves time and money in the long run.