{"id":8945,"date":"2015-05-07T10:25:39","date_gmt":"2015-05-07T14:25:39","guid":{"rendered":"http:\/\/www.constructionspecifier.com\/?p=8945"},"modified":"2016-12-21T14:25:13","modified_gmt":"2016-12-21T19:25:13","slug":"specifying-wall-cladding-fasteners","status":"publish","type":"post","link":"https:\/\/www.constructionspecifier.com\/specifying-wall-cladding-fasteners\/","title":{"rendered":"Specifying wall cladding fasteners"},"content":{"rendered":"<figure id=\"attachment_8946\" aria-describedby=\"caption-attachment-8946\" style=\"width: 289px\" class=\"wp-caption alignright\"><a href=\"http:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_NH_ServiceCreditUnion_GregWest-Kawneer.png\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-8946 \" src=\"http:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_NH_ServiceCreditUnion_GregWest-Kawneer.png\" alt=\"clad_NH_ServiceCreditUnion_GregWest-Kawneer\" width=\"289\" height=\"237\" srcset=\"https:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_NH_ServiceCreditUnion_GregWest-Kawneer.png 480w, https:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_NH_ServiceCreditUnion_GregWest-Kawneer-300x246.png 300w\" sizes=\"auto, (max-width: 289px) 100vw, 289px\" \/><\/a><figcaption id=\"caption-attachment-8946\" class=\"wp-caption-text\"><span style=\"font-family: arial,helvetica,sans-serif; font-size: 8pt;\">Photo \u00a9 Greg West Photography. Photo courtesy Kawneer Company<\/span><\/figcaption><\/figure>\n<p><strong>by Dean Lewis<br \/>\n<\/strong>Curtain walls are often the focal point of aesthetic design for a multi-story building. Behind the attractive fa\u00e7ade are the pedestrian, yet arguably more important, functional components that ensure safety and reliability\u2014fasteners that transfer loads both imposed and experienced by the assembly to the building\u2019s structural framework.<\/p>\n<p>Being key elements of the load path, all fasteners should be analyzed to ensure their material, thickness, and quantity are adequate. In doing so, designers must quantify both dead and live loads on the wall system\u2014which translate to bending, shear, bearing, and pull-out loads on the connections.<\/p>\n<p>Fasteners must have the hardness, along with the yield, tensile, and shear strength to appropriately withstand these loads without compromising the wall\u2019s integrity and weathertightness. Different anchorage configurations are also required for the various substrates typically encountered in commercial or institutional-type structures, featuring concrete, masonry, or steel frame.<\/p>\n<p><strong>Fastener guidelines<br \/>\n<\/strong>Numerous organizations have developed specifications, performance testing methods, and design guides for wall cladding fasteners, including:<\/p>\n<ul>\n<li>Aluminum Association;<\/li>\n<li>American Institute of Steel Construction (AISC);<\/li>\n<li>American Iron and Steel Institute (AISI);<\/li>\n<li>ASTM International;<\/li>\n<li>Industrial Fasteners Institute (IFI); and<\/li>\n<li>Society of Automotive Engineers (SAE).<\/li>\n<\/ul>\n<p>Compiling, applying, and in some cases reconciling the data from these various sources to produce a viable fastener specification is a formidable task.<\/p>\n<p>That task is made easier by the American Architectural Manufacturers Association (AAMA) Technical Information Report (TIR)-A9-14, <em>Design Guide for Metal Cladding Fasteners<\/em>, which provides the data necessary to select fasteners for anchoring the curtain wall to the building structure. Metals used in fasteners covered by TIR-A9 include various types of carbon steel and stainless steel alloys. It should be noted aluminum fasteners are not recommended for curtain wall anchoring systems.<\/p>\n<p>A complete specification must include fastener size and type, as well as material, calculated minimum mechanical properties (<em>e.g.<\/em> bending, shear, bearing and pull-out loads, thickness), and type of protective coating required. Fastener quality and corrosion resistance also should be addressed by specifiers.<\/p>\n<p>\u201cFastener Specification Checklist\u201d adequately defines the parameters for a given application including proposed anchorage arrangement, which defines the number and location of the fasteners, as well as determination of the forces acting on the attachments and the maximum design load per attachment.<\/p>\n<figure id=\"attachment_8948\" aria-describedby=\"caption-attachment-8948\" style=\"width: 369px\" class=\"wp-caption alignright\"><a href=\"http:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_CO_MeasJusticeCtr_BobPerzel-Kawneer.png\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-8948 \" src=\"http:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_CO_MeasJusticeCtr_BobPerzel-Kawneer.png\" alt=\"clad_CO_MeasJusticeCtr_BobPerzel-Kawneer\" width=\"369\" height=\"246\" srcset=\"https:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_CO_MeasJusticeCtr_BobPerzel-Kawneer.png 480w, https:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_CO_MeasJusticeCtr_BobPerzel-Kawneer-300x200.png 300w\" sizes=\"auto, (max-width: 369px) 100vw, 369px\" \/><\/a><figcaption id=\"caption-attachment-8948\" class=\"wp-caption-text\"><span style=\"font-family: arial,helvetica,sans-serif; font-size: 10pt;\">The Dennis Maes Pueblo Judicial Building in downtown Pueblo, Colorado opened in October 2014.<\/span> <span style=\"font-family: arial,helvetica,sans-serif; font-size: 8pt;\">Photo \u00a9 Bob Perzel Photography. Photo courtesy Kawneer Company<\/span><\/figcaption><\/figure>\n<p>A recommendation of attachment devices to resist the determined forces should also be included as the number and spacing must be sufficient to meet the loads. Additionally, fastener length should be sufficient to penetrate the substrate to a depth designed to meet applicable building codes, manufacturer recommendations, and structural calculations.<\/p>\n<p>Confirmation the curtain wall frame can resist the forces at the attachment points is required. The installation of fasteners or fastening systems must limit distortion of any framing member and must not in any way impede the action of operable components. It is also necessary to specify the required anchorage and\/or fastener quantity, spacing, type, material, strength, embedment, edge distances, and other parameters as appropriate.<\/p>\n<p>The mode of potential failure for the material and fasteners along the load path should be considered. This includes the fastener itself, as well as the material being fastened to the substrate, which can fail by bending, buckling, or pull-out (<em>i.e.<\/em> the force required to pull the fastener out of the base material), and\/or pullover (<em>i.e.<\/em> the force to pull the material over the head of the fastener). TIR-A9 tables give allowable pull-out values for different aluminum thicknesses of various alloy designations (<em>e.g.<\/em> 3003-H14, 5005-H34, 6061-T6, 6063-T5, 6063-T6, and 6005A-T61) for UNC (<em>i.e.<\/em> threads designated as \u2018coarse\u2019 under the <em>United <\/em><em>Thread Standard<\/em> [<em>UTS<\/em>]) and spaced threads for different screw diameters.<!--nextpage--><\/p>\n<figure id=\"attachment_8950\" aria-describedby=\"caption-attachment-8950\" style=\"width: 326px\" class=\"wp-caption alignleft\"><a href=\"http:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_TIR-A9-14_Fig23-2_Eg2.png\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-8950 \" src=\"http:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_TIR-A9-14_Fig23-2_Eg2.png\" alt=\"clad_TIR-A9-14_Fig23-2_Eg2\" width=\"326\" height=\"399\" srcset=\"https:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_TIR-A9-14_Fig23-2_Eg2.png 480w, https:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_TIR-A9-14_Fig23-2_Eg2-245x300.png 245w\" sizes=\"auto, (max-width: 326px) 100vw, 326px\" \/><\/a><figcaption id=\"caption-attachment-8950\" class=\"wp-caption-text\"><span style=\"font-family: arial,helvetica,sans-serif; font-size: 10pt;\">This figure, taken from American Architectural Manufacturer&#8217;s Association&#8217;s (AAMA) Technical Information Report (TIR)-A9-14, Design Guide for Metal Cladding Fasteners, shows an example of anchorage connection.<\/span> <span style=\"font-family: arial,helvetica,sans-serif; font-size: 8pt;\">Image courtesy AAMA<\/span><\/figcaption><\/figure>\n<p>The basic information needed to analyze the anchorage includes the following elements.<\/p>\n<p><em>Material properties<br \/>\n<\/em>This includes properties of the frame profiles, parts, and anchors and specifications for the surrounding wall conditions at the product perimeter. For metals, the thickness, alloy, temper, and strength are needed. Equivalent information for concrete and masonry substrates must be provided.<\/p>\n<p><em>Project-specific design pressure<br \/>\n<\/em>The proposed anchorage system must provide a load resistance equal to or greater than the project-specific design pressure. Of primary concern are the dynamic, or \u2018live,\u2019 that cause building movement, such as those imposed by wind, thermal expansion, and (in appropriate location-dependent cases) seismic activity, impact of hurricane wind-borne debris, or potential for blast waves. Wind loading is determined based on the expected maximum wind velocity that is likely to be experienced at the building location, as typically derived from the current, or code-cited, American Society of Civil Engineers\/Structural Engineering Institute (ASCE\/SEI) 7, <em>Minimum Design Loads for Buildings and Other Structures<\/em>.<\/p>\n<p>A contributing factor will be the weight of the glass of the type and thickness required to resist the wind loading, as determined by ASTM E1300, <em>Standard Practice for Determining Load Resistance of Glass in Buildings<\/em>. A rule of thumb is to use a glass type and thickness that just exceeds the required strength of the glazing.<\/p>\n<p><em>Design load-bearing capacities<br \/>\n<\/em>Design load-bearing capacity of fasteners for the surrounding wall substrate material should be considered. With respect to loads, a fastener system is primarily exposed to either tension, shear, or a combination of the two, depending on the configuration.<\/p>\n<p>Load-bearing analysis equations presented in TIR-A9 are the basis for determination of the values used in the document\u2019s load tables, which provide allowable tension, shear, and bearing loads for a range of different fastener sizes, carbon steel, and stainless steel alloys. A total of 21 fastener sizes are covered, ranging from #6-32 through 1-8.<\/p>\n<figure id=\"attachment_8953\" aria-describedby=\"caption-attachment-8953\" style=\"width: 380px\" class=\"wp-caption alignright\"><a href=\"http:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_Wausau_SLC-PSB_No4_WayneGillman.png\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-8953 \" src=\"http:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_Wausau_SLC-PSB_No4_WayneGillman.png\" alt=\"clad_Wausau_SLC-PSB_No4_WayneGillman\" width=\"380\" height=\"253\" srcset=\"https:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_Wausau_SLC-PSB_No4_WayneGillman.png 480w, https:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_Wausau_SLC-PSB_No4_WayneGillman-300x200.png 300w\" sizes=\"auto, (max-width: 380px) 100vw, 380px\" \/><\/a><figcaption id=\"caption-attachment-8953\" class=\"wp-caption-text\"><span style=\"font-family: arial,helvetica,sans-serif; font-size: 10pt;\">The public &#8216;face&#8217; of Salt Lake City&#8217;s Public Safety Building features serpentine glass curtain wall that slopes from one wing to the other and cants in multiple directions.<\/span> <span style=\"font-family: arial,helvetica,sans-serif; font-size: 8pt;\">Photos \u00a9 Wayne Gillman. Photos courtesy Wausau Window and Wall Systems<\/span><\/figcaption><\/figure>\n<p>The tensile strength or pull value of a connection is the amount of force required to pull a fastener apart by securing one end and pulling up on the other end. The shear strength of a connection is the force required to pull the base material in one direction and the top material in the other direction (a shearing motion) until failure.<\/p>\n<p>AAMA TIR-A9 walks through the derivation of equations used to calculate these and other parameters when different substrate material and thickness and various fastener types and sizes are used, as well as different hole thread configurations (<em>e.g.<\/em> UNC and SAE spaced threads).<\/p>\n<p>Since a fastener\u2019s load capacity depends on its size and the material of which it is made, the easiest way to evaluate the loaded performance of various size fasteners and fastener metals is from a load table, such as those published in this revised TIR. Additionally, many manufacturers publish load tables specific to their own fasteners.<\/p>\n<p>TIR-A9 also provides:<\/p>\n<ul>\n<li>expanded information in the allowable bearing at bolt holes section, which includes screws and screw tilting in various thicknesses and substrates;<\/li>\n<li>updated information in the pull-out strength section to include equations for thick, thin, and transition regions and include thread stripping of internal and external threads;<\/li>\n<li>tables showing hole and drill size for spaced threads tapping screws for Type A, C, AB, B, BF, BP, BT, D, F, and T steel in various substrates; and<\/li>\n<li>minimum spacing and edge distance guidelines for bolts and screws, with separate information noted for those that are intended for use with aluminum substrates.<\/li>\n<\/ul>\n<p><!--nextpage--><\/p>\n<table border=\"0\">\n<tbody>\n<tr>\n<td style=\"padding: 5px;\" bgcolor=\"#483d8b\">\u00a0<strong><span style=\"font-family: georgia,palatino; font-size: 12pt; color: #ffffff;\">Fastener Specification Checklist<\/span><\/strong><\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 5px;\" bgcolor=\"#f5f5f5\">\n<p style=\"text-align: left;\"><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">To aid in the fastener selection process, American Architectural Manufacturers Association (AAMA) Technical Information Report (TIR)-A9-14, <em>Design Guide for Metal Cladding Fasteners<\/em>, provides the following suggested fastener specification checklist.<\/span><\/p>\n<p><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"><strong>Mechanical properties <\/strong><\/span><\/p>\n<ol>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Description (including drawing)<\/span><br \/>\n<span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"> a. Size (nominal diameter and thread count [per inch])<\/span><br \/>\n<span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"> b. Length<\/span><br \/>\n<span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"> c. Head style<\/span><br \/>\n<span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"> d. Thread type<\/span><br \/>\n<span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"> e. Point type<\/span><br \/>\n<span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"> f. Special features (<em>e.g.<\/em> undercut head)<\/span><br \/>\n<span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"> g. Other<\/span><\/li>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Metal<\/span><\/li>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Minimum yield strength<\/span><\/li>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Minimum tensile strength<\/span><\/li>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Hardness<\/span><\/li>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Other (manufacturer proprietary coating or plating)<\/span><\/li>\n<\/ol>\n<p><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"><strong>Finish<\/strong><\/span><\/p>\n<ol>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Clear or natural<\/span><\/li>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Colored<\/span><br \/>\n<span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"> a. Painted<\/span><br \/>\n<span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"> b. Burned<\/span><\/li>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Other<\/span><\/li>\n<\/ol>\n<p><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"><strong>Corrosion protection<\/strong><\/span><\/p>\n<ol>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">As fabricated<\/span><\/li>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Plated (refer to appropriate ASTM standards)<\/span><br \/>\n<span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"> a. Zinc<\/span><br \/>\n<span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"> b. Cadmium<\/span><br \/>\n<span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"> c. Nickel<\/span><br \/>\n<span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"> d. Chromium<\/span><\/li>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Black oxide<\/span><\/li>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Waxed<\/span><\/li>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Other<\/span><\/li>\n<\/ol>\n<p><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\"><strong>Fastener exposure<\/strong><\/span><\/p>\n<ol>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Outside face of building<\/span><\/li>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Inside exterior cover (but high exposure)<\/span><\/li>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Inside glazing pocket<\/span><\/li>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Behind inner seal line<\/span><\/li>\n<li><span style=\"color: #000000; font-family: georgia,palatino; font-size: 10pt;\">Visible inside building<\/span><\/li>\n<\/ol>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><strong>Safety factors<br \/>\n<\/strong>A safety factor (SF) is used in the allowable strength design (ASD) method. This method was used to determine the allowable values presented in TIR-A9, which have been determined after a study of several industry standards. There is also another design approach\u2014the load and resistance factor design (LRFD) method\u2014in which the combined use of a load factor \u2018m\u2019 (greater than 1) and a resistance factor \u2018j\u2019 (less than 1) is the equivalent of using a safety factor. That is, SF= m\/j. Load factors are given in the governing building code. Resistance factors, also termed strength-reduction or capacity factors, are given in the specification for the structural material\/components being connected.<\/p>\n<p>For fasteners of 6.35 mm (0.25 in.) or less in diameter, a SF of 3.0 is used to generate allowable values. This value is used in both the <em>North American Specification for Cold-formed Steel <\/em><em>Structures<\/em> (2007 and 2001) and the 2010 <em>Specification for Aluminum Structures<\/em> for this size range of tapping screws.<\/p>\n<p>For fastener diameters exceeding 6.35 mm, but are 25 mm (1 in.) or less, a SF of 2.5 is used. This is more conservative than the safety factors recommended by others, especially for the 12.7 to 25 mm (0.5 to 1 in.) range, by the cold-formed steel specification, <em>Specification for Cold-formed Stainless Steel <\/em>(ASCE-8), and the AISC <em>Specification for Structural Steel Buildings<\/em> ranging between 2 and 2.42.<\/p>\n<p><strong>Protection from corrosion, hydrogen embrittlement<br \/>\n<\/strong>It is essential fasteners have adequate protection against corrosion to prevent eventual failures due to moisture from rain and condensation. Additionally, a defense must also be provided against galvanic corrosion, which occurs when dissimilar metals are in contact in the presence of moisture, especially in harsh environments such as seacoast locations.<\/p>\n<p>Stress corrosion is the effect of corrosion on a metal under stress. When metals are under constant or cycling stress (the latter of which causes metal fatigue), the effect of corrosion can be much more severe than when metals are not stressed. Stress corrosion failures can occur shortly after the load is applied, but may not occur for months or years later. Such failures occur without warning and can be dangerous.<!--nextpage--><\/p>\n<figure id=\"attachment_8957\" aria-describedby=\"caption-attachment-8957\" style=\"width: 261px\" class=\"wp-caption alignleft\"><a href=\"http:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_Wausau_SLC-PSB_Int2_WayneGillman.png\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-8957 \" src=\"http:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_Wausau_SLC-PSB_Int2_WayneGillman.png\" alt=\"clad_Wausau_SLC-PSB_Int2_WayneGillman\" width=\"261\" height=\"392\" srcset=\"https:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_Wausau_SLC-PSB_Int2_WayneGillman.png 480w, https:\/\/www.constructionspecifier.com\/wp-content\/uploads\/2015\/05\/clad_Wausau_SLC-PSB_Int2_WayneGillman-200x300.png 200w\" sizes=\"auto, (max-width: 261px) 100vw, 261px\" \/><\/a><figcaption id=\"caption-attachment-8957\" class=\"wp-caption-text\"><span style=\"font-family: arial,helvetica,sans-serif; font-size: 10pt;\">The building&#8217;s glass exterior needed to meet seismic and ballistic requirements, as well as contribute to the building&#8217;s Leadership in Energy and Environmental Design (LEED) and net-zero energy objectives. <\/span><\/figcaption><\/figure>\n<p>To forestall corrosion, carbon steel fasteners should be plated or coated with zinc, cadmium, nickel, or chromium in accordance with the specifications in TIR-A9 Section 4, \u201cProtection against Corrosion and Hydrogen Embrittlement.\u201d<\/p>\n<p>The specifier and purchaser must be aware of these matters and make the best compromise, all factors considered, in the selection of the fasteners. Designs for curtain wall anchoring systems must account for the stresses for which fasteners must be selected and the coatings to be employed to eliminate problems due to galvanic action and stress corrosion.<\/p>\n<p>Various ASTM standards govern coatings or platings in terms of class, service condition, and type, which dictate acceptance testing such as duration of salt-spray application. Class designation relates to the coating thickness, while service condition indicates the severity of the exposure for which the coating is intended (ranging in four steps from mild or indoor to very severe). The type indicates the composition of the coating, such as whether chromate or phosphate layers are added.<\/p>\n<p>Stainless steel offers better corrosion protection than plated carbon steel, but can present difficulties in terms of matching finishes to the framing.<\/p>\n<p>Hydrogen embrittlement is a condition of low ductility in metals resulting from the absorption of hydrogen, which typically occurs during the manufacturing process (particularly electroplating), although it also can occur through in-service corrosion. Bolts and screws\u2014with a hardness of C35 or greater on the Rockwell C scale\u2014are particularly subject to embrittlement. Hydrogen embrittlement can cause unpredictable and potentially disastrous failure, especially of a fastener under tensile load. Tests are available to assess whether hydrogen embrittlement is present<br \/>\nin a batch of fasteners.<\/p>\n<p><strong>Conclusion<br \/>\n<\/strong>Beyond developing a thorough specification, it is essential the fastener purchaser has a means for determining the fasteners that are received meet the specifications.<\/p>\n<p>ASTM standards provide chemical and mechanical requirements for the steels used in fasteners, as well as quality control procedures for shipment lot testing, source inspection, alloy control, heat control, permeability, manufacturer\u2019s identification, and material identification. Additionally, the end user should consider adding a requirement that fasteners be produced under a recognized quality assurance (QA) program, such as that governed by the quality management system standard International Organization for Standardization (ISO) 9001, <em>Quality Management Systems\u2013Requirements<\/em>.<\/p>\n<table border=\"0\">\n<tbody>\n<tr>\n<td style=\"padding: 5px;\" bgcolor=\"#483d8b\"><strong><span style=\"font-family: georgia,palatino; font-size: 12pt; color: #ffffff;\">\u00a0AAMA curtain wall design references<\/span><\/strong><\/td>\n<\/tr>\n<tr>\n<td style=\"padding: 5px;\" bgcolor=\"#f5f5f5\"><span style=\"font-family: georgia,palatino; font-size: 10pt; color: #000000;\">Additional American Architectural Manufacturers Association (AAMA) curtain wall design references for design professionals and specifiers include:<\/span><\/p>\n<ul>\n<li><span style=\"font-family: georgia,palatino; font-size: 10pt; color: #000000;\">AAMA CW-DG-1-96, <em>Curtain Wall Design Guide Manual<\/em>;<\/span><\/li>\n<li><span style=\"font-family: georgia,palatino; font-size: 10pt; color: #000000;\">AAMA CWG-1-89, <em>Installation of Aluminum Curtain Walls<\/em>;<\/span><\/li>\n<li><span style=\"font-family: georgia,palatino; font-size: 10pt; color: #000000;\">AAMA MCWM-1-89, <em>Metal Curtain Wall Manual<\/em>;<\/span><\/li>\n<li><span style=\"font-family: georgia,palatino; font-size: 10pt; color: #000000;\">AAMA CW-11-85, <em>Design Windloads for Buildings and Boundary Layer Wind Tunnel Testing<\/em>;<\/span><\/li>\n<li><span style=\"font-family: georgia,palatino; font-size: 10pt; color: #000000;\">AAMA TIR A11-04, <em>Maximum Allowable Deflection of Framing Systems for Building Cladding Components at Design Wind Loads<\/em>;<\/span><\/li>\n<li><span style=\"font-family: georgia,palatino; font-size: 10pt; color: #000000;\">AAMA TIR-A14-10, <em>Fenestration Anchorage Guidelines<\/em>;<\/span><\/li>\n<li><span style=\"font-family: georgia,palatino; font-size: 10pt; color: #000000;\">AAMA 501.1-05, <em>Standard Test Method for Water Penetration of Windows, Curtain Walls, and Doors Using Dynamic Pressure<\/em>;<\/span><\/li>\n<li><span style=\"font-family: georgia,palatino; font-size: 10pt; color: #000000;\">AAMA 501.2-09, <em>Quality Assurance and Diagnostic Water Leakage Field Check of Installed Storefronts, Curtain Walls, and Sloped Glazing Systems<\/em>;<\/span><\/li>\n<li><span style=\"font-family: georgia,palatino; font-size: 10pt; color: #000000;\">AAMA 501.4-09, <em>Recommended Static Test Method for Evaluating Curtain Wall and Storefront Systems Subjected to Seismic and Wind Induced Interstory Drift<\/em>, and <em>AAMA <\/em><em>501.6-09, Recommended Dynamic Test Method for Determining <\/em><em>the Seismic Drift Causing Glass Fallout from a Wall System<\/em> (combined document);<\/span><\/li>\n<li><span style=\"font-family: georgia,palatino; font-size: 10pt; color: #000000;\">AAMA 501.5-07, <em>Test Method for Thermal Cycling of Exterior Walls<\/em>;<\/span><\/li>\n<li><span style=\"font-family: georgia,palatino; font-size: 10pt; color: #000000;\">AAMA 501.7-11, <em>Recommended Static Test Method for Evaluating Windows, Window Wall, Curtain Wall, and Storefront Systems Subjected to Vertical Inter-story Movements<\/em>;<\/span><\/li>\n<li><span style=\"font-family: georgia,palatino; font-size: 10pt; color: #000000;\">AAMA 503-14, <em>Voluntary Specification for Field Testing of Newly Installed Storefronts, Curtain Walls, and Sloped Glazing Systems<\/em>; and<\/span><\/li>\n<li><span style=\"font-family: georgia,palatino; font-size: 10pt; color: #000000;\">AAMA 507-12, <em>Standard Practice for Determining the Thermal Performance Characteristics of Fenestration Systems Installed in Commercial Buildings<\/em>.<\/span><\/li>\n<\/ul>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><em>Dean Lewis currently serves as American Architectural Manufacturers Association\u2019s (AAMA\u2019s) educational and technical information manager, bringing his knowledge of technical training to advance the Fenestration Masters professional certification program. Lewis began his career <\/em><em>in the fenestration industry at PPG Industries with positions in project engineering, product design, and sales and customer technical support. He has served on committees of ANSI, ASTM, and ASHRAE. Further experience includes teaching in the industrial and military sectors, and 35 years of managing technical training, publishing, and certification. Lewis can be contacted by e-mail at <a title=\"dlewis@aamanet.org\" href=\"mailto:dlewis@aamanet.org\" target=\"_blank\">dlewis@aamanet.org<\/a>.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Curtain walls are often the focal point of aesthetic design for a multi-story building. Behind the attractive fa\u00e7ade are the pedestrian, yet arguably more important, functional components that ensure safety and reliability\u2014fasteners that transfer loads both imposed and experienced by the assembly to the building\u2019s structural framework.<\/p>\n","protected":false},"author":5,"featured_media":8946,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[520,179,449,185,254,489,460],"tags":[852,910,614,1210,1198,1543,526],"class_list":["post-8945","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-features","category-masterformat","category-uniformat","category-05-00-00-metals","category-05-50-00-metal-fabrications","category-b2010exterior-walls","category-b20exterior-vertical-enclosures","tag-08-44-00-curtain-wall-and-glazed-assemblies","tag-aama","tag-curtain-wall","tag-division-05","tag-division-08","tag-fastener","tag-metal-panels","entry"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.8 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Specifying wall cladding fasteners - The Construction Specifier<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.constructionspecifier.com\/specifying-wall-cladding-fasteners\/\" \/>\n<link rel=\"next\" href=\"https:\/\/www.constructionspecifier.com\/specifying-wall-cladding-fasteners\/2\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Specifying wall cladding fasteners - The Construction Specifier\" \/>\n<meta property=\"og:description\" content=\"Curtain walls are often the focal point of aesthetic design for a multi-story building. 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