NOMENCLATURE
C.S.F - (hundred square feet) the
unit of measure for price and weight.
DIAMOND OR OPENING - This is the
description of the open area formed by strands and bonds. Normally
the open area is diamond shaped.
BOND - The point where adjacent strands
intersect. The bond is always twice the width of the strand.
SWD OR SWO - Short way of diamond
or short way of opening is the dimension measured across the sheet
in a direction parallel to the smallest dimension of the diamond.
LWD OR LWO - Long way of diamond
or long way of opening is the dimension measured across the sheet
in a direction parallel to the largest dimension of the diamond.
MESH - This is the nominal distance
from the mid-point of one bond to the mid-point of the next bond
measured across the SWD. Mesh is expressed in inches.
OPENING SIZE - The area enclosed
by bonds and strands.
OVERALL THICKNESS - This is the finished
thickness and often determines the
selection of framing members.
PERCENT OF OPEN AREA - These important
relative percentages are used by designers to calculate the degree
with which light and air can pass through a piece of expanded
metal.
PITCH - The measurement from a point
on one diamond to the same point on an adjacent diamond.
STRAND - The single metal strip which
forms the border of the diamond, or opening. Strand width is the
amount of material advanced for expanding as differentiated from
strand thickness which is the thickness of metal from which the
expanded metal is produced.
STYLE - Is the guage or thickness
of metal from which expanded metal
is made. Usually, but not always, this conforms to manufacturer’s
standard guages. Style is expressed by a number. Expanded metal
grating style is expressed in lbs. per square foot.
FORMABILITY - Each piece should be
able to withstand a 90 degree bend with a 1/4 in. inside radius
in either direction, without fracture.
LEVELING - All
expanded metal products except grating are leveled after having
been expanded.
OUT OF SQUARE - Expanded
metal sheets are generally not perfectly square when finished.
Sheets must be resquared by shearing on all sides for perfect
squareness. Reshearing at the mill is not usually done since most
sheets are sheared to size to be within tolerance.
CAMBER - Bow
in sheet. It is measured by placing a straight edge along
the concave side of the sheet parallel to LWD, touching both
ends of the sheet. The maximum distance
between the edge of the expanded
metal and the straight edge is the camber. A sheet maybe within
a width tolerance and still have camber.
PRODUCT DEFINITION
REGULAR EXPANDED METAL is sheet simultaneously slit and
stretched into a rigid, non-raveling open mesh. It is readily
available in carbon steel, aluminum and stainless steel.
FLATTENED EXPANDED METAL is manufactured by processing
regular expanded metal in a rolling mill. This rolling reduces
the thickness of the sheet and provides a smooth flat sheet.
EXPANDED METAL GRATING is produced from heavier plate,
usually low-carbon steel, with larger diamonds. It is typically
used for walkways and platforms.
DECORATIVE EXPANDED METAL is manufactured with unique
shaped openings which possess great appeal for architects and
designers.
STAIR TREADS - Expanded Metal Grating Stair Treads are
fabricated using 4.0# Grating, angles and bars. They are shipped
ready for installation on the job.
FINISHING - Limited finishes can be accomplished at manufacturing
plants. This includes hot-dip galvanizing and pre-galvanizing.
Special finishing such as anodizing, enameling, and plastic coating
can be arranged by contacting your steel service center.
SHEET SIZE - While expanded metal can be manufactured
in many varying sheet sizes, practical limitations are such that
it is wise to select sheet sizes shown in the catalog. Availability
of sizes can be determined by contacting your steel service center.
DISTRIBUTION - expanded metal products are readily available
from large stocks maintained by your local steel service center.
PRODUCT SELECTION
The first step in the design of a product or fabricated
assembly incorporating expanded metal is to select the appropriate
expanded metal pattern, keeping in mind various product
characteristics.
The strength and rigidity of expanded metal material is determined
by Long Way of Design. On a walkway, for example, the LWD should
run perpendicular to the walkway support.
Diamond direction also affects air deflection and diffusion,
concealment properties and aesthetic appearance. Consult your
supplier for suggestions.
Most manufacturers can and do routinely furnish expanded
metal in special ("non-standard") sheet sizes when requested.
In this event, it is important for the specifier to give some
consideration to the edge configuration of the sheet as
it relates to any particular requirement since the cost may be
affected by the manufacturing operations necessary to shear the
edge desired.
|
GRATING
