Next: Fenestrations Richard L. Cook Jr., FRCI, RRC, RWC, REWC, RBEC, CCS, CSRP, LEED AP ADC Engineering, Inc. 1226 Yeamans Hall Road, Hanahan, SC 29410 Phone: 843-566-0161 • Fax: 843-566-0161 • E-mail: rickc@adcengineering.com 2 9 t h RC I I n t e r n a t i o n a l C o n v e n t i o n a n d T r a d e S h ow • Ma rc h 2 0 – 2 5 , 2 0 1 4 C o o k • 7 3 Abstract This paper will examine the research, learning, and development process and provide the basic fundamentals of fenestrations: 1. Terminology 2. Types 3. Industry standards 4. Code requirements 5. Developing in-house standards a. Specifications b. Details/sections c. Construction administration This should be considered Fenestrations 101, basics and fundamentals, focused on commercial buildings. Speaker Richard L. Cook Jr. FRCI, RBEC, REWC, RWC, RRC, CCS, LEED AP, CSRP – ADC Engineering, Inc. Rick Cook received a BS in civil engineering from The Citadel in 1984 and was selected the “Outstanding Engineer” that year. He has been a Professional member of RCI since 1988 and is a past president. He has chaired committees, published articles in Interface, received Outstanding Volunteer awards, and has developed and taught dozens of courses for RCI. Cook has authored numerous papers on the subject of the building envelope and has presented papers at national symposia and conferences, including the American Society of Civil Engineers, the Construction Specifications Institute, RCI’s Building Envelope Symposia, RCI’s conventions, the Federal Construction Committee in Washington, DC, as well as before dozens of local and regional industry meetings and conferences. 7 4 • C o o k 2 9 t h RC I I n t e r n a t i o n a l C o n v e n t i o n a n d T r a d e S h ow • Ma rc h 2 0 – 2 5 , 2 0 1 4 Intr oducti on The term fenestration comes from the Latin word “fenestra” or “window.” This, combined with the fact that the most common wall opening in a building is a window, explains why most people think of windows when the term fenestration is used. Glazing, which derives its meaning from the Middle English for “glass,” is part of a wall or window made of glass. The term is also used to describe the work completed by a professional “glazer,” or window/fenestration work in general. The earlier windows were just holes in a wall. Later, windows were covered with animal hide, cloths, and wood. Shutters that could be opened and closed came next. Over time, windows were built that both protected the inhabitant from the elements and transmitted light: mullioned glass windows, which joined multiple small pieces of glass with leading; paper windows; flattened pieces of translucent animal horn; and plates of thinly sliced marble. In the Far East, paper was used to fill windows. The Romans were the first known to use glass for windows, a technology likely first produced in Roman Egypt. In Alexandria, ca. 100 AD, cast-glass windows, albeit with poor properties, began to appear; but these were small, thick productions— little more than blown glass jars (cylindrical shapes) flattened out into sheets with circular striation patterns throughout. It would be over a millennium before a window glass became transparent enough to see through clearly, as we think of it now.1 Today, the term fenestration means “openings in the wall of a structure.” Fenestration refers to the design, construction, or presence of openings in a building. Fenestrations include windows, doors, louvers, vents, wall panels, skylights, storefront, curtain wall, and sloped glazing systems. Obviously, in some structures, some of the systems listed would not be “openings in the wall of a structure” and may be considered the wall assembly (i.e., curtain wall, sloped glazing system). Even with continual technological advances in materials, water continues to create unnecessary problems. This is most often due to an envelope’s inability to act as an integrated system preventing water and pollutant infiltration. All too often, several systems are designed into a building, chosen independently and acting independently rather than cohesively. Detailing transitions from one system to another or terminations into structural components are often overlooked. Product substitutions that do not act integrally with other specified systems create problems and leakage. Inadequate attention to movement characteristics of a structure can cause stress to in-place systems that they are not able to withstand. All these situations acting separately or in combination will eventually cause water intrusion.2 Fundame ntals of Exteri or Walls Wall assemblies, like other components of the building envelope, serve three important functions: 1) They are part of the structural system, 2) they offer protection from weather (heat, cold, rain, etc.), and 3) they contribute to the exterior finish or aesthetics of the building. The “function” of weatherproofing is the most problematic and, when the assembly fails to perform, can also affect the structural and aesthetics functions of the wall. Fenestrations play similar roles as part of the exterior skin of the façade. It is not a big secret that wall assemblies leak when three basic conditions exist simultaneously on a wall assembly: 1) Water (most likely rain) is on the wall, 2) openings exist within or between wall assemblies through which the water can pass, and 3) forces (gravity, surface tension, capillary action, pressure differential, and/or kinetic) exist that cause the water to enter the openings. The five forces are: 1. Gravity. The most common leaks are from penetrations in horizontal and low-sloped surfaces, whereby water drips in. 2. Surface tension. Water’s high surface tension (its ability to cling to itself and surfaces) can cause it to follow a surface, even turning 90 degrees around corners, such as at soffits, sills, or ledges. This can cause leaks in areas typically considered “protected,” like under overhangs (at ledges and metal caps). 3. Capillary action. The propensity for water to “wick” in through very narrow openings, such as hairline cracks, is due to capillary action, which also results from water’s high surface tension. Capillary action is the action by which liquids in contact with solids—as in a capillary tube—rise or fall. 4. Pressure differential. If the air pressure is higher outside than inside, water will readily pass from the outside area of higher pressure through the smallest holes in the waterproofing materials to the inside area of low pressure. A building’s HVAC system can cause the pressure to be lower inside than outside, which makes it nearly impossible to maintain waterproof systems; water can be drawn through any defects. Next: Fenestrations 2 9 t h RC I I n t e r n a t i o n a l C o n v e n t i o n a n d T r a d e S h ow • Ma rc h 2 0 – 2 5 , 2 0 1 4 C o o k • 7 5 Wind can also create this pressure differential from one building face to the other. 5. Kinetic. Wind-driven rain has a velocity that will carry it through openings, such as improperly designed and installed windows, under copings or flashings, through louvers, or through voids or cracks in the wall assemblies. The location of a building can make this potential greater than normal. In blowing rains, walls facing winds and corners get wetter because of wind patterns in these locations. If any of the three conditions in 5 above (water, openings, or force) is eliminated, rainwater will not penetrate the wall assembly. The wall assembly of a facility is composed of one or more wall systems—both barrier and redundant (such as backup or rain screen assemblies)—and a variety of fenestrations (or wall openings such as windows, store fronts, doors, louvers) and penetrations (mechanical, electrical, and plumbing penetrations). A critical relationship exists among the various systems that comprise the exterior wall of the building envelope. Fenestrations (windows, storefronts, curtain wall, and other wall openings) are similar to wall systems in that some systems are designed as “barriers” (shedding 100% of the water), while other systems incorporate redundant flashings to provide a secondary drainage mechanism. Depending on the type of wall systems and wall openings, transition or through-wall flashings may be incorporated. In many cases, the common thread that has to “hold” these various systems together is simply the sealant joint. In the introduction of his chapter on sealants, William T. Kubal, in his book, The Construction Waterproofing Handbook, states, “Sealants are not only the most widely used waterproofing materials, but are also the most incorrectly used.” Realizing the critical role sealants provide with all building envelope systems, a design professional must have a clear understanding of the criteria, standard specifications, terminology, and methods for calculating movement and designing joints. Experience with renovation projects provides the design professional first-hand experience of where, how, and why joints fail. This knowledge not only helps the designer correct the specific renovation project, but also assists in designing new construction projects. Exterior wall assemblies and fenestrations must complement each other or “marry” to one another. A wall assembly can contain four “barriers”: 1) thermal, 2) moisture, 3) vapor, and 4) air. Window systems have similar infiltration-related requirements: 1) air, 2) thermal (solar heat gain, conductance, and correction), 3) water infiltration, and 4) acoustical. In both wall and window systems, the aesthetics, structural performance, security performance, cost, and warranty are also primary considerations. In addition to aesthetics, fenestrations must meet basic performance requirements such as structural loading, water penetration, air infiltration, thermal efficiency, and resistance to forced entry. When determining performance requirements, factors such as geographic, ground roughness, orientation, and wind speeds— as well as hail, flying debris (and golf balls), and hurricane-prone regions—must be considered. Finally, the effect that the building itself can have on fenestrations must be considered. Those effects include the following: 1. Stack effect 2. Positive and negative pressures created by mechanical systems All of these factors are critical to the building envelope’s success, but the transitions between the wall assemblies and the fenestration systems are of the greatest concern. INDUSTRY STANDARDS/ FENESTRATION TERMINO LOGY National Fenestration Rating Council (NFRC) • A nonprofit organization that administers an independent, uniform rating and labeling system for the energy performance of fenestration products. • NFRC is the “engine” that drives virtually every window energy-efficiency program in the country, including Energy Star (the U.S. governmentsponsored initiative). • For residential construction, the rating is the certified products directory (or CPD). For nonresidential energy certifications and ratings, it is the component modeling approach (or CMA). • The NFRC is often considered to be like the mpg rating sticker on a car. American Architectural Manufacturers’ Association (AAMA) • Trade organization that administers an accredited American National Standards Institute (ANSI) certification program for aluminum and vinyl fenestration products Window and Door Manufacturers’ Association (WDMA) • A trade organization that runs the Hallmark certification program for wood fenestration products. The North American Fenestration Standard/Specification for Windows, Doors and Skylights (NAFS – 2011) is a joint document by AAMA, CSA, and WDMA. It replaces the 2008 edition of the joint standard. The International Energy Conservation Code (IECC) references the following: • NFRC 100 for U values • NFRC 200 for solar heat gain coefficient (SHGC) • AAMA/WDMA/CSA 101/1.5.2/A C440, third edition; and the NFRC 400 for air leakage Whole-product ratings. Protocols involve testing of the full window, including glass, frame, spacers, and any other component that is a permanent part of the complete product. 1. U factor 2. Solar heat gain 3. Visible transmittance 4. Air leakage 5. May contain information on air leakage and condensation resistance 6. Fixed set of environmental conditions and specific product size U Factor 1. Measures how well a product prevents heat from escaping a home or building. 2. Ratings for windows generally range from 0.15 – 1.20 (the lower the better). 3. U factor versus R-value: U factor measures the rate of heat transfer (or loss), while R-value measures the resistance to heat loss. 7 6 • C o o k 2 9 t h RC I I n t e r n a t i o n a l C o n v e n t i o n a n d T r a d e S h ow • Ma rc h 2 0 – 2 5 , 2 0 1 4 4. R-value is a measure of conductance and thermal resistance. A product with a high conductance will conduct heat quickly, like a hot pan on a stove or a single pane of glass. 5. U Factor, on the other hand, takes into account more than conductance. It also is affected by airflow (convection) around the window and the emissivity (radiated or reflected heat) of the glass. SHGC 1. Measures how much heat from the sun is blocked. 2. Expressed as a number between 0 and 1 (the lower the SHGC, the more a product is blocking solar heat gain). 3. Particularly important during summer cooling season in hot, southern climates. By contrast, people in northern climates may want solar heat gain during the cold winter months to lessen the cost of heating. Visible Transmittance (VT) 1. Measures how much light comes through a product. 2. Expressed as a number between 0 and 1. 3. The higher the VT, the higher the potential (ability) for day lighting. Two optional ratings sometimes provided on the label are: • Air leakage. Measures how much outside air comes into a home or building through a product. Air leakage rates typically range between 0.1 and 0.3 (the lower, the better at not permitting air leakage). • Condensation resistance measures how well a product resists the formation of condensation. Expressed as a number between 0 and 100. (The higher the number, the better the resistance.) Condensation Resistance Factor Tool The Condensation Resistance Factor (CRF) tool is intended to provide general guidance on suggesting a minimum CRF based on a project-specific set of environmental conditions. While not an absolute value, the CRF is a rating number obtained under specified test conditions to allow a relative comparison of the condensation performance of the product. It will provide a comparative rating of similar products of the same configuration and permit the determination of the conditions beyond which an objectionable amount of condensation may occur. Some interpretative allowances may need to be made in comparing products of dissimilar type or configuration (e.g., wall sections versus operating windows or versus fixed glazing). Condensation in the field can be a result of many variables. Thermal conductivity of surrounding building construction, interior/exterior trim, humidification control, and the method of heat distribution on the interior plane of the assembly will impact its overall performance. Conditions that may affect interior surface temperatures include (but are not necessarily limited to) the following: • Type of wall construction and material(s) used therein • For cavity walls, location of thermal barrier in the product with respect to the wall cavity • Closed drapes and/or shades • Depth of reveal (recess at sill, jambs, and head) • Positive exterior wind pressure or negative pressure within the building that may increase infiltration of cold air — H eight of product above grade — Location of surrounding buildings and type of surrounding terrain — Wind velocity • Solar radiation and orientation • Water vapor pressure and temperature indoors • Water vapor pressure and temperature outdoors • Rate and amount of water vapor released to interior The calculations used to determine the CRF rating are based on the procedures outlined in AAMA 1503-09, “Voluntary Test Method for Thermal Transmittance and Condensation Resistance of Windows, Doors, and Glazed Wall Sections.”3 In addition to the ratings noted above (as well as cost and warranty), some facilities may have other applicable special ratings, such as: 1. Water infiltration. Measures the amount of water and pressure that a window can resist to keep the water from leaking through it (the higher the rating, the better the window is at resisting water leakage). 2. Structural performance rating. Measures the amount of air pressure (wind load) a window can resist before failing. The amount of structural pressure ratings required for windows in an area is often determined by local code requirements. The higher the rating, the more wind load that can be resisted. 3. Acoustical performance rating. Measures the amount of sound transmission through a window. The higher the ratings, the better at blocking noises from coming through the window. 4. Security performance ratings. Measures the ability of a window to resist different types of forces, such as burglar-resistant, bullet-resistant, windborne-debris-resistant, and many others. Fenestration Types Various window configurations exist, and their names are predominantly selfdescriptive. Common examples include: 1. Single- and double-hung windows 2. Vertical and horizontal sliding windows 3. Casements 4. Side-hinged, top-hinged (awning), and bottom-hinged (hopper) windows 5. H inged escape/rescue/egress windows 6. Pivoted and parallel openings 2 9 t h RC I I n t e r n a t i o n a l C o n v e n t i o n a n d T r a d e S h ow • Ma rc h 2 0 – 2 5 , 2 0 1 4 C o o k • 7 7 Figure 1 7. Dual-action windows 8. Greenhouse/garden windows 9. Bay and bow windows 10. Fixed windows 11. Secondary storm windows Door configurations are also descriptive and, naturally, more limited. 1. Side-hinged 2. H inged glass 3. Dual-action 4. Sliding Unit skylights include fixed-glass, acrylic domes, and operable configurations. Also included are tubular daylighting devices (TDD). The glass (or glazing) has various options that assist in meeting the various performance requirements: 1. Single-, double-, triple-, and quadglazed (and dual windows) 2. Space filled with various gases (argon, krypton, xenon, and others). These are odorless and harmless. 3. Glass Float glass (annealed) developed in 1959, is covered under ASTM C1036, Standard Specification for Float Glass. • Annealed (600-1,200 psi) • H eat-treated — H eat-strengthened glass (1,200-3,000 psi) — Fully tempered glass (2,400- 6,000 psi) • Chemically strengthened glass • Coated glass • Spandrel glass • Laminated glass • Insulating glass • Bent glass • Decorative glass • Mirrors Rolled glass is used to create wired glass, figured, or patterned glass, and other decorative glass (art, cathedral, etc). 4. Glass treatments can include: • Low E: Low-emissivity coating— typically with multiple-pane, high E, such as a clear piece of glass, will allow over 84% infrared energy from a warm room outside to the cold air. • Electrochromic glass (smart glass) refers to glass or glazing that changes light transmission properties when voltage, light, or heat is applied (thus controlling heat transmission). 5. Spacer: The component that separates and maintains the space between the glazing surfaces of an insulating glass unit (IGU). 6. Frame: The enclosing structure of a window, door, or skylight, which fits into the wall, glazing, sash, or vents. Code Requirement Highlights (IBC) 1. IBC 2012, Chapter 1 – Any exterior 7 8 • C o o k 2 9 t h RC I I n t e r n a t i o n a l C o n v e n t i o n a n d T r a d e S h ow • Ma rc h 2 0 – 2 5 , 2 0 1 4 Figure 2 – Anatomy of an aluminum-framed window, Part 1. Figure 3 – Anatomy of an aluminum-framed window, Part 2. wall (wall assemblies and fenestration systems) design must meet the applicable code requirements, which are minimum standards. The new IBC states the following: a. Section 1061.6, Exterior wall envelope. Construction documents for all buildings shall describe the exterior wall envelope in sufficient detail to determine compliance with this code. The construction documents shall provide details of the exterior wall envelope as required, including flashing; intersections with dissimilar materials; corners; end details; control joints; intersections at roof, eaves, or parapets; means of drainage; water-resistive membrane; and details around openings. The construction documents shall include manufacturers’ installation instructions that provide supporting documentation that the proposed penetration and opening details described in the construction documents maintain the weather resistance of the exterior wall envelope. The supporting documentation shall fully describe the exterior wall system that was tested, where applicable, as well as the test procedure used. b. Section 1043.2, Weather protection. Exterior walls shall provide the building with a weather-resistant exterior wall envelope. The exterior wall envelope shall include flashing as 2 9 t h RC I I n t e r n a t i o n a l C o n v e n t i o n a n d T r a d e S h ow • Ma rc h 2 0 – 2 5 , 2 0 1 4 C o o k • 7 9 Figure 4 – Anatomy of an aluminum-framed window, Part 3. Figure 5 – Anatomy of an aluminumframed window, Part 4. described in Section 1405.3. The exterior wall envelope shall be designed and constructed in such a manner as to prevent the accumulation of water within the wall assembly by providing a water-resistive barrier behind the exterior veneer, as described in Section 1040.2, and a means for draining water that enters the assembly to the exterior. Protection against condensation in the exterior wall assembly shall be provided in accordance with the International Energy Conservation Code. Exceptions: • A weather-resistant exterior wall envelope shall not be required over concrete or masonry wall designed in accordance with Chapters 19 and 21, respectively. • Compliance with the requirements for a means of drainage, and the requirements of Sections 1404.2 and 1405.3, shall not be required for an exterior wall envelope that has been demonstrated through testing to resist wind-driven rain, including joints, penetrations, and intersections with dissimilar materials, in accordance with ASTM E331 under the following conditions: — Exterior wall envelope test assemblies shall include at least one opening, one control joint, one wall/eave interface, and one wall sill. All tested openings and penetrations shall be representative of the intended enduse configuration. — Exterior wall envelope test assemblies shall be at least 4 feet by 8 feet (1219 mm by 2438 mm) in size. — Exterior wall envelope assemblies shall be tested at a minimum differential pressure of 6.25 pounds per square foot (psf) (0.297 kN/m2). • The exterior wall envelope design shall be considered to resist winddriven rain where the results of testing indicate that water did not penetrate control joints in the exterior wall envelope, joints at the perimeter of openings, or intersections of terminations with dissimilar materials. 2. The IECC references the National Fenestration Rating Council (NFRC) for the following: a. NFRC 100 for U values b. NFRC 200 for SHGC c. AAMA / WDMA / CSA 101 / 1.5.2 / A C440 Third Edition and the NFRC 400 for air leakage 3. The IBC and IRC 2012 also reference the 2011 North American Fenestration Standard/Specification for Doors, Windows, and Skylights (NAFS-11). 4. “Relating ASCE/SEI 7-2010 Design Wind Loads to Fenestration Product Ratings” is a technical bulletin jointly endorsed by AAMA, WDMA, the Fenestration Manufacturers Association (FMA), and the Door and Access Systems Manufacturers Association (DASMA). a. Cannot be intermixed with earlier versions. b. Not necessary to test exterior fenestration products differently due to 2010 update. c. Explains how design loads from 2010 relate to exterior fenestration product ratings and performance guides. 5. IEBC 2012, Section 406, Glass Replacement, 406.1 Conformance. The installation or replacement of glass shall be as required for new installations. DEVELOPING IN-HOU SE STANDARDS FOR THE CON SULTANT During Design The two primary elements in the design process are the technical specifications and the drawings: 1. Specification: The UFGS system is an excellent basis or starting place for developing guide specifications. 2. Drawings: Several independent sources exist for developing guide details for the various fenestration systems. Based on the wall assemblies and transitions required, standard details for window flashings, sealants, and other common denominators will also be needed. During Submittal Phase The submittal process is the least favorite work item in most offices and often falls to the low person on the totem pole. Defined procedures, a required submittal list, a defined administrative checklist for process, and standard comments for each technical specification can make the submittal process easier and more beneficial. Mock-ups—especially for renovation projects—provide the opportunity to ensure that the actual “crew” of each subcontractor understands the requirements and the owner understands the end results. During Construction The construction process is the key phase for achieving a successful wall system, including the coordination of the various barrier systems to perform as intended. 1. The surface/substrate must be suitable and prepared to receive the system(s). 2. The application process and a defined quality control/quality assurance program are key. Once the system is in place, it is “covered up” by the rest of the wall assembly, and access for investigation or modifications is very difficult and expensive. 3. The contractor needs to have a clear understanding of the system and the required details for the terminations, transitions, and penetrations. 4. In-place mock-ups completed at the preinstallation meeting are an excellent idea. This allows discussion, clarifications, and decisions to be completed prior to work commencing. 5. Use and application of sealant joints as part of the fenestration systems should be addressed specifically. (This is also true for the various wall assemblies for the building. How the various barrier [air, vapor, moisture, and thermal] transitions tie into these assemblies/systems is critical.) 6. Obviously, other trades have a coordinating role in the process. A waterproofing contractor will most likely be used for the application of the air 8 0 • C o o k 2 9 t h RC I I n t e r n a t i o n a l C o n v e n t i o n a n d T r a d e S h ow • Ma rc h 2 0 – 2 5 , 2 0 1 4 barrier system. Various other contractors will be providing systems that terminate, transition, or penetrate the air barrier: roof contractor, MEP contractors, glass/glazing (fenestration) contractors, and exterior wall contractors. 7. Testing – Ensure/verify that various testing requirements for the exterior walls, including the fenestrations, are clearly defined as laboratory tests (to be provided as part of the submittals) or field tests (to be completed in the field as part of the mock-ups or acceptance of the system/ assembly). Concl usi on Fenestrations—often thought of as selfconstrained or highly engineered “black boxes,” since there is a heavy reliance on the manufacturer and contractor and limited involvement by the design professional— truly require the entire design and construction team’s involvement. Further Fenestration Knowledge AAMA professional certifications: For individuals who want to further develop their knowledge specific to fenestrations, AAMA has programs for a Certified Fenestration Associate (CFA) and a Certified Fenestration Master (CFM). These programs have eligibility requirements, online courses, reference study materials, and exams. Know Your Limitations Understand and stress the importance of coordination of the various exterior wall assemblies and fenestration systems. For Your Information The Federal Trade Commission (FTC) has been involved in investigating window manufacturers’ marketing claims (including energy savings) and has “warned” several manufacturers. Understand the Forces Know the forces and how they can act on an exterior wall/fenestration system based on the types, orientation, geographic location, heights, etc. Focus on Coordination The various exterior wall systems, combined with the complexity of fenestrations and multiple subcontractors, require a building envelope preinstallation meeting with approved submittals in hand. Submittal and Mock-Ups The purpose and value of submittals,— including SDS (formerly MSDS) data sheets and mock-ups—cannot be overemphasized. Footnotes 1. Encyclopedia Britannica, 2012 2. Michael T. Kubal, Waterproofing the Building Envelope, McGraw-Hill, Inc., 1993 3. AAMA website, 2013 2 9 t h RC I I n t e r n a t i o n a l C o n v e n t i o n a n d T r a d e S h ow • Ma rc h 2 0 – 2 5 , 2 0 1 4 C o o k • 8 1
