curtain wall design guide manual
Pressure-equalized rain screen systems function by blocking all of the forces that can drive water across a barrier. The American Architectural Manufacturers Association (AAMA) has developed a new manual providing guidelines for the design of curtainwalls. With a properly designed system the water that enters the system at the gasket corners will weep out through the snap cover weep holes. Therefore the connections to anchor the curtain wall must be designed to allow differential movement while resisting the loads applied. These systems frequently include gaskets that are placed between the pressure bar and mullions and function as thermal breaks and help with acoustic isolation. Common curtain wall durability problems include the following: Glazing failures (see Glazing). Either way, the cavity may be at temperatures significantly above or below interior conditions with only thermally conductive aluminum between them. Manual and other related technical literature and standards with a commitment to revise and republish them as AAMA documents. The stack joint is designed to resist lateral loads while the two floor anchors resist gravity and lateral loads. Shadow box construction creates the appearance of depth behind a transparent lite of glass by incorporating a metal sheet into the curtain wall behind the lite. thermal break). Shop drawing coordination: Require curtain wall installation shop drawings showing all adjacent construction and related work, including flashings, attachments, interior finishes, and indicating sequencing of the work. Details are not provided for interior glazed systems because air infiltration is a concern with interior glazed systems. Systems whose connecting legs lock also compromise the ability of the system to accommodate movement. Knock-out panels are identified by a non-removable reflective dot (typically two inches in diameter) located in the lower corner of the glass and visible from the ground by the fire department. The units are connected with a field applied splice sleeve that contains an index clip to align the next unit above the joint horizontally as it is being set. Designed to help our members excel in a dynamic and fast-moving future, the Fenestration and Glazing Industry Alliance, or FGIA, is focused on building better industry synergies from glass to framing. Unitized systems are frequently structural silicone glazed, especially if four-side SSG is desired. Glass and metal curtain walls (Best practice guide, building technology) Issued also in French under title: Murs-rideaux en verre et métal. In large areas of stick framed curtain wall, a split vertical mullion will be introduced periodically to allow thermal movement. This elevation shows a typical stick-built curtain wall set in a punched opening in a masonry cavity wall. Do not use vertical mullions as drain conductors. The interlocking legs of the horizontal mullions are the most critical interface of a unitized system. There isa wide range of systems on the market from manufacturers that provide varying levels of reliability. These interior air temperatures are inputs for the thermal modeling software. Steel can be added to a unitized system to increase its spanning capability. For high rise construction the building should be designed for swing stage access for window cleaning, general maintenance, and repair work, like glass replacement. Laboratory-tested fire rated assemblies may be required in unsprinklered buildings by some codes as Perimeter Fire Containment Systems when the floor assemblies are required to be fire-resistance rated. Lateral load resistance requirements (wind loads, spans) generally dictate frame depth. Unitized systems generally rely on rain screen design principles and gaskets and/or the interlock of mating frames for moisture protection at joints between adjacent modules. Designers should be aware that the CRF is a weighted average number for a curtain wall assembly. Functional / Operational—Ensure Appropriate Product/Systems Integration, Building Envelope Design Guide—Glazing, Building Envelope Design Guide—Windows, See appropriate sections under applicable guide specifications: Unified Facility Guide Specifications (UFGS), VA Guide Specifications (UFGS), Federal Guide for Green Construction Specifications, MasterSpec®. "Smart" Curtain Walls, like smart windows, control visible light transmittance by employing electrochromic or photochromic glass coatings; see the discussion in Glazing. This is best scheduled prior to the release of shop drawings for window production, so that there is an opportunity to make design changes based on the test performance of the field mock-up. Curtain wall perimeters should have flashings (sill, jambs and head) that are sealed to the air and water barrier at adjacent walls. The interlocking leg in the plane of the glazing pocket will be sealed by gaskets and is the primary line of defense against water and air infiltration. AAMA and IGMA, two industry leaders, have unified to form an exponentially stronger alliance. Curtain walls and perimeter sealants require maintenance to maximize the service life of the curtain walls. Require additional testing to be performed if initial tests fail. A curtain wall is defined as thin, usually aluminum-framed wall, containing in-fills of glass, metal panels, or thin stone. Blocks should be gapped 1/8-inch from the edge of the glazing unit. The long-term reliability of such seals is extremely suspect and such systems should be avoided. Interior and exterior glazed systems offer different advantages and disadvantages. In exterior glazed systems, glass and opaque panels are installed from the exterior of the curtain wall. Have a curtain wall consultant present to document mock-up curtain wall construction and verify mock-up performance. The challenge is to strive for the highest visible light transmittance (VT) and the lowest solar heat gain coefficient (SHGC) while not preventing the glass from being too reflective when viewed from both the exterior and the interior, while controlling glare.