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17800.711.4939www.directmetals.comBAR GRATINGGlossaryTerminologyANCHOR - A device by which grating isattached to its supports. BAND - A at bar welded to the end of a grating panel or along the line of a cutout and extending neither above nor below the bearing bars. Load-Carrying Band: A band used in a cutout to transfer the load from unsupported bearing bars to the supported bearing bars. Trim Band: A band which carries no load but is used chiey to improve appearance. BEARING BARS - Load-carrying bars made from steel strip, slit sheet or rolled or extruded aluminum, and extending in thedirection of the grating span. BEARING BAR CENTERS - The distance center to center of the bearing bars. CARRIERS - Flats or angles, which are welded to the grating panel and nosing of a stair tread, and are bolted to a stair stringer to support the tread. CLEAR OPENING - The distance between faces of bearing bars in a rectangulargrating or between a bent connecting bar and a bearing bar in a riveted grating. CROSS BARS - The connecting bars made from steel strip, slit sheet, rolled bars, or rolled or extruded aluminum, which extend across the bearing bars, usually perpendicular to them. They may be bent into a corrugated or sinuous pattern where they intersect, the bearing bars are welded, forged, or mechanically locked to them. CROSS BAR CENTERS - The distance center to center of the cross bars. CURVED CUT - A cutout following a curved pattern. CUTOUT - An area of grating removed to clear an obstruction or to permit pipes, ducts, columns, etc. to pass through the grating. ELECTRO-FORGED - A process combining hydraulic pressure and heat fusion to forge bearing bars and cross bars into a panel grid. FINISH - The coating, usually paint orgalvanizing, which is applied to the grating. FLUSH TOP GRATING - A type of pressure-locked grating, in which the cross bars and bearing bars are in the same plane relative to the top surface of the grating. GRATING - An open grid assembly of metal bars, in which the bearing bars running in one direction are spaced by rigid attachment to cross bars running perpendicular to them, or by bent connecting bars extending between them. HINGED PANELS - Grating panels which are hinged to their supports or to other grating parts. I-BAR - An extruded aluminum bearing bar having a cross sectional shape resembling the letter “I”. LENGTH - The dimension of a grating panel measured parallel to the bearing bars. Also referred to as span. LOAD-CARRYING BAND - see Band. NOSING - A special L-section member serving as the front or leading edge of a stair tread or of grating at the head of a stair. PRESSURE-LOCKED GRATING - Grating in which the cross bars are mechanically locked to the bearing bars at their intersections by deforming orswaging the metal. RADIALLY CUT GRATING - Rectangular grating which is cut into panels shaped as annular segments for use in circular or annular areas. RETICULINE BAR - A sinuously bent connecting bar extending between two adjacent bearing bars, alternately contacting and being riveted to each. RIVET CENTERS - The distance center to center of rivets along one bearing bar. RIVETED GRATING - Grating composed of straight bearing bars and bent connecting bars, which are joined at their contact points by riveting. SERRATED GRATING - Grating which has the top surfaces of the bearing bars, cross bars or both notched. SPAN OF GRATING - The distancebetween points of grating support or thedirection of the dimension. Also referred to as length. STRAIGHT CUT - That portion of the cut edge or cutout of a grating, which follows a straight line. SWAGING - A method of altering the cross-sectional shape of a metal bar by pressure applied through dies. TOEPLATE - A at bar attached against the outer edge of a grating or rear edge of a tread, and projecting above the top surface of grating or tread to form a lip or curb. TREAD - A panel of grating having carriers and nosing attached by welding, and designed specically to serve as a stair tread. WELDED GRATING - Grating in which the bearing bars and cross bars are joined at their intersections by a weld. WIDTH - The overall dimension of a grating panel, measured perpendicular to the bearing bars and in the same direction as the cross bars.This catalog uses a form of the NAAMM alpha-numeric designation for bar spacing and manufacturing identication. The rst number signies center-to-center bearing bar spacing in 1/16ths of an inch*. A letter designates method of manufacture. The last number details center-to-center cross bar spacing in whole inches (usually 4" or 2")or rivet spacing (usually 3-1/2", 5" or 7").Methods of manufacturing and their letter designations used in this catalog include: SG ........ Swaged Rectangular Bar SGF ...... Swaged Flush Top SGI ....... Swaged I-Bar W .......... Welded Steel R .......... Riveted (Steel) AR ........ Riveted (Aluminum)FOR EXAMPLE: 19-W-4 – Bearing Bars 19/16" (or 1-3/16") c.c. – Welded Steel Construction – Cross Bars 4" c.c. 15-SGI-2 – Bearing Bars 15/16" c.c. – Swaged I-Bar – Cross Bars 2" c.c.Other Bearing Bar Spacings commonly used throughout the industry are designated thus: 38-W-4 (or 2) Bearing Bars 38/16" c.c. (2-3/8" c.c.) 30-W-4 (or 2) Bearing Bars 30/16" c.c. (1-7/8" c.c.) 22-W-4 (or 2) Bearing Bars 22/16” c.c. (1-3/8” c.c.) 11-SG-4 (or 2) Bearing Bars 11/16" c.c. 7-SG-4 (or 2) Bearing Bars 7/16" c.c. 18-R-7 (or 3-1/2) Bearing Bars 18/16" face-to-face (1-1/8")* 37-R-5 Bearing Bars 37/16" face-to-face (2-5/16")* 12-R-7 (or 3-1/2) Bearing Bars 12/16" face-to-face (3/4")**Note: Riveted grating marking indicates space between bearing bars.