MBG 532 –00
ANSI/NAAMM MBG 532-005 GRATINGvision of
THE NATIONAL ASSOCIATION OF ARCHITECTURAL METAL MANUFACTURERS
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This standard was developed by representative members of the Metal Bar Grating Division (MBG) of the National Association of Architectural Metal Manufacturers (NAAMM) to provide their opinion and guidance on the specification and use of metal bar gratings. This standard contains advisory information only and is published as a public service by NAAMM. NAAMM and its Divisions disclaim all liability of any kind for the use, application, or adaptation of material published in this standard.
Current information on all NAAMM Standards is available by calling or writing the National Association of Architectural Metal Manufacturers or by going to www.naamm.org.
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National Association of Architectural Metal Manufacturers
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The NAAMM Heavy Duty Metal Bar Grating Manual provides architects and engineers with current technical data on heavy duty bar gratings of structural carbon steel and stainless steel. The data includes descriptions of the most frequently used types of gratings, the methods used in their fabrication, dimensional standards, load tables giving allowable uniform and concentrated loads for spans from one foot (305 mm) through eight feet (2440 mm), installation practices, specifications, code of standard practice and glossary. The information is concerned primarily with bar gratings capable of supporting heavy loads. Architects and engineers interested in lighter walkway gratings are referred to the current edition of NAAMM’s Metal Bar Grating Manual. (ANSI/NAAMM MBG 531). The first three editions of the manual have been widely used by the design professions. In preparing this fourth edition, the Metal Bar Grating Division of NAAMM has reviewed its contents in detail and has made revisions to reflect current practices. NAAMM believes that the scope of this manual makes it an excellent reference source for those concerned with the design of structures incorporating heavy duty metal bar gratings. The load tables in this edition are based on the design formulas and procedures found in MBG 534, Metal Bar Grating Engineering Design Manual, which was developed to provide a clearer understanding of the procedures used in the design of grating. Also included are metric equivalents to reflect the current trend toward metrication as an aid to designers who must use the metric system.The system of metric measurement used is from IEEE/ASTM SI 10-1997, “Standard for Use of the International System of Units (SI): the Modern Metric System”. The values stated in inch-pound units are to be regarded as the standard.
This manual presents the common heavy duty gratings manufactured by NAAMM members. NAAMM recognizes the many special designs that embody the use of special steel shapes and/or larger structural members that are used under the same conditions. Because these designs are so varied, they are not covered in this publication but can be manufactured according to the principles within this manual. Consult the manufacturers of these specialty items for technical information.
a) Steel Gratings Steel used in bearing bars, cross bars and reticuline bars of rectangular section shall conform to ASTM A 1011/A 1011M, Commercial Steel (CS Type 2) for hot rolled carbon steel sheet and strip and ASTM A 36/A 36M for structural steel bars. Cross bars made of wire rod shall conform to ASTM A 510 (A 510M) for carbon steel wire rods and coarse round wire, except that permissible tolerance on diameter of course round wire shall be +0.005 in. (+0.13 mm). Combinations of these steels are not prohibited from being welded together. Rivets shall be of a steel as prescribed in ASTM A 575, 1/4 In. (6.4 mm) minimum diameter, flat head type.
b) Stainless Steel Gratings Stainless steel used in bearing bars, cross bars and reticuline bars shall be Type 304, 304L, 316, or 316L alloy conforming to ASTM A 666. Rivits shall be of a Type 300 series alloy as prescribed in ASTM A 493.