METAL CURTAIN WALL FASTENERS
FORWARD
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2. 1. INTRODUCTION TO METAL CURTAIN WALL FASTENERS APPLICABLE DOCUMENTS3. 4. PROTECTIONAGAINST CORROSION QUALITY CONTROL N5. 6. FASTENERLOAD TABLES COMMENTARY PREVENTION OF FASTENER LOOSENING 67. ALLOWABLE BEARING AT BOLT HOLES 01 78. STANDARD AND SLOTTED BOLT HOLES PULLOUTSTRENGTH............ 1110. 9. 12 1311. 12. SLIDING FRICTION IN SCREW CHASE SCREW ENGAGEMENTINSCREW CHASE 14 1614. 13. FASTENER SPECIFICATION CHECK LIST FASTENERAVAILABILITY 1715. 16. SYMBOLS SAMPLE CALCULATIONS FOR LOAD TABLES 81 1718. 17. SELECTING FASTENER MATERIALS STAINLESS STEEL BOLTS HEX CAP SCREWS AND STUDS 20 21(Abstract of ASTM F 593-1985) 2219 20. FASTENER LOAD TABLES FASTENER SELECTION EXAMPLES 23 8621. APPENDIX . 45
AAMAasadvisoryinformstion andpubisbedasapubicadaptation of materials published herein. service. AAMA disclaims all liability for the use applicaticn or
1.INTRODUCTIONTO METALCURTAINWALLFASTENERS
The pupose of thisTchical IfomationReporis toprovidemetal curtain waldesigers wih tbcdataneccaryosclctfasteersfrcurainwalframingmemersandpoentsandfor anchoring the curtain wall to the building structure.
Technical information and data assembied in this report were drawm from a number of'Applicable Documents'
Uniform coarse machine threaded fastcners and spaced thrcaded fasteners are covered in thisreport.The Uifed TareadSerlesare generallyusedineitherclcarholes withmatingnuts or in tapped holes. Thread cutting screws with machine threads are used to cut their own thrcadsinpredlldldteaddfanandarralusdnys tapping screw This subject is covered in detail in Section 6 Fastener Load TablesCommentary.'
Metals used in fastnes on whih the datain this report is based includ tw group of carbon sleelandvgoupfstalstelallTfalnfsntndfor curtainwallanchoringsstmsandnodataalinumfstns isncludedCarbnslfasteners must be plated or coated in acordance with the specifications in Sectice 4 Protection Against Corrosion.'
Tables giving allowablc tnsion shearandbearing loads forfourten diferent fastener sizes forcarbnsandstileeallyinledintsrfuatmd of the size rangc in ascending rder are designated #632 #8-32 #10-24 and 12-24.Forfasteners deignated in this manner the number preceding thehyphcnis related to the fastener dEquations nceded to calculate the allowable ioads are included with the tables.
2.APPLICABLEDOCUMENTS
‘Specifications for Aluminum Structures * Fifth Edition
(AISC)AMERICANINSTITUTE OF STEEL CONSTRUCTION “Manual of Steel Construction Allowabie Stress Design ” Ninth Edition
(AISI) AMERICAN IRONAND STEELINSTITUTEAugust 19 1986 Edition
*“Stainless Steel Cold-Formed Structural Design Manual " 1974 Edition
(ANSI)AMERICANNATIONALSTANDARDSINSTITUTEANSI/ASME B1.1 *Unified Inch Screw Thrcads (UN and UNR Forms)
(ASTM) AMERICAN SOCIETY FOR TESTING AND MATERIALS
Volume 15.08 *Annual Book of ASTM Standards Fasteners*
ASTM A 143 *Remended Practice for Safeguarding Agains Embritlement of Hox-DipGalvanized Structural Steel Products and Procedure for Detecting Embrittlement*
ASTM A 1S3 *Specification for Zinc Coeting (Hot-Dip) o Iron and Steei Hardware
ASTMA 49 *Specification for Hea-Treatd Steel Structural Bolts 150 ki Minimum TensieStrength"
ASTM A 563 *Specification for Carbon and Alloy Steel Nuts*
ASTM B 201 *Practice for Testing Chromate Coetings on Zinc and Cadmium Surfaces*
ASTM B456 Specification for Electrodeposited Coatings of Copper Plus Nickel Plus Chromium and Nickel Plus Chromiuma
ASTM B 633 *Specification for Electrodepcsited Coatings of Zinc ce Iroe and Steel
AS'TM B 695 Specification for Coetings of Zinc Mechanically Deposited on Iroe and Stcel*
ASTM B 69%6 *Specification for Coetings of Cadmium Mechanically Depoited*
ASTM B 766 *Specification for Electrodeposited Coatings of Cadmium*
ASTM F s93 *Specification for Stainless Steel Bolts Hex Cap Scrcws and Studs*
ASTM F 594 *Specification for Stainless Steel Nuts”
ASTM F 606 *Method for Condueting Tests to Determine the Mechanical Properties of Exiernally and Internally Threaded Fasteners Washers and Rivets*
(IFI) INDUSTRIAL FASTENERS INSTITUTE*Fastener Standards * Sixth Edition
o Ande s pen
INDUSTRIAL PRESS INC."Machinery’s Handbook*
MCGRAW-HILLBOOK COMPANY *Marks’ Mechanical Engineers Handbook*
(SAE) SOCIETY OF AUTOMOTIVE ENGINEERS“Standards for Grades 2 and 5 Stcel*
3.QUALITYCONTROL
The sclection and use of proper fasteners is criticallyimportant to the safe and satisfactoryproperfasteandtosify thm.Beyond thispointhweveritisessetialtht manufacturers of fastenersmaintain excellentquality control procedures in theirplants to ensurethattheirdtsmet ifiatisfihthyarsiedpasspecifitonsfrtatelyreaseealagufinfrltsingoldinhisouty which have been fraudulently idcntified as bolts having quality which they do not poses.Inadvertcnt use of such inferior bolts could have disastrous results.
Manyfastenersmaybefound to be suttandardmechanicallyand dimensionaly whenchecked even though marked as high performance gradcs. Protective coatings on fasteners may also bepressurrmanfterappingadquatingsqualyandhickf a problem.As result ofmore stringentenvironmental requirements and tighteningeconomicInorder bectain that the fastenerncded omet dsignririais rvided the designer protectitingsndysmarktpartiuarlynlwricastrsis smat reliae.must ot onlypeciy fastnerize and type must al secifymatrial minimummcchanical properishickessandtyeofrototingrquire.Seth suggstdFastSpeification Checklit page 17 for items to be included in fastener specificatios.
AS'TM standards give the chemical and mechanical requirements for the steels used in fasteners.In addition they set forthrequirements whch the purchaser ffstenersmay specilyfor qualityonrlrouretfolwdinetioithhioderinldshiptidentification andmaterial identicationASTMF 606 scts forth in detail the testmethods for deteminingthemechanicalproperts ofexeallyandinterallythreadedfstenersAppropriate refrece tths adads an prdhbasis freaie qualityan progrms.
4.PROTECTIONAGAINSTCORROSION
prviddfluresntonsmayultlyccururainwlfringsysmaytand channel considerablc amounts of water both from rain and condensation of water vapor. This would tend to acclerate corrosive action where satisfactory protection did not cxist and thiswould be thc case with unprotected carbon steel fasteners. In additioe to corrosion resulting from atmospheric conditions andmoisture protection must also be provided against gahanicprotectagainstbothtypesof corroiveaction carbon steelfaseners platedinacoordancewith corrosion which occurs when dissimilar metals are in contact in the presence ofmoisture. Tothc specifications listed below or stainlcs stecl fasteners are reommended for usc withaluminum curtain wall systems.
seem that specifying the higerresistance aod typesofsainle stel foralfastners woulddesignsaretmanfacturednalltpessailesssteelbcausfthencedforhardening address these concerns withorrosionUfortunatly thisisnotecessarily trueomefasterfastenershigheresanc tpesftailssstl gerallyatve hnishesalidwhichmathanodidfraingwitoutreoinpintinPaningfscrwadsxpivand of dubious durabiliry. Many types of fastencrs are only available in stainless steels having lowerresistance ocorrosionSmallorder quantitiesless than 00000fastners errunmayalslimitalliyffastreiedretesitocifnd purchasermustbeawaref thesmattes ndmake th bstpromise poiblealfactrsconsidered in the selection of the fasteners.
resistance to corrosion. Thc severity of the service conditions to which the fastcners willbeexosed mus be considered in the specification.For zinc and cadmium coatings tbe followingspecifications are remended:
Zinc plated fasteners shall meet the requiremcnts of ASTM B 633 for Class FE/ZN 5 corrosion resistance requirements after a 12-hour salt spray test.
Zinc plated fasteners shall meet the requirements of ASTM B 633 for Class FE/ZN 8 corrosion resistance requirements after a 96-bour salt spray test.
Mechanicallydeposited zinccoated fastners shallmeet therequrements ofASTMB695 forClass5coting5μm thick withType IIfinish orClass 8 coeting8μm thickrequirements after a 72-hour salspray test.(Thicker costings meeting this ASTMstandard are availabie if required.)
Cadmium plated fasteners shall mcet the requirements of ASTM B 766 for Class 5 5μm thick Type Il coating meeting corrosion resistance requrements affer a 12-hour saltspray test.
Cadmium platd fasteners shallmet the requireents ofASTMB766forCass88μm thick Type II coating meeting corrosion resistancc requirements affer a 96-hour saltspray test.
