Bar Joist
A name commonly used for "Open Web Steel Joists".
Barrel Vault
A semi-cylindrical shaped roof.
X. Glossary Metal Building Systems Manual
Base Flashing
The lower flashing component of a two component metal flashing detail. The
component flashing details are often used either for expedience or to allow differential
thermal movement between building elements or accessories. The lower component is
the “base” flashing; the upper component is the “counter-flashing”.
Base Angle
An angle secured to a wall or foundation used to attach the bottom of the wall
paneling.
Base Plate
A plate attached to the bottom of a column that rests on a foundation or other support,
usually secured by anchor rods.
Base Tube
A continuous member imbedded in the edge of the foundation to which the wall panels
are attached.
Batten
A strip of wood common to non-structural panels that is used to support the vertical
ribs of adjacent metal panels.
Batten Cover
1) A separate strip of metal used to cover the wood batten, and join the vertical ribs of
adjacent metal panels on either side of the batten. 2) A strip of formed metal used to
span the void area and join the vertical legs of adjacent metal panels.
Batten Seam
1) A metal panel profile attached to and formed around a wood or metal batten, 2) A
metal panel profile that imitates the traditional batten seam system but omits the
wooden batten.
Bay
The space between the main frames measured normal to the frame.
Beam
A member, usually horizontal, that is subjected to bending loads. There are three types,
simple, continuous, and cantilever.
Beam and Column
A structural system consisting of a series of rafter beams supported by columns. Often
used as the end frame of a building.
Bearing End Frame
See "Beam and Column".
Bearing Plate
A steel plate that is set on the top of a masonry support on which a beam or purlin can
rest.
Bent
See "Main Frame".
Bermuda Seam
A metal panel featuring a stepped profile. The panel runs perpendicular to the slope of
the roof.
Bill of Materials
A list that enumerates by part number or description each piece of material or assembly
to be shipped. Also called tally sheet or shipping list.

Bird Screen
Wire mesh used to prevent birds from entering the building through ventilators and
louvers.
Blanket (batt) insulation
A layer or sheet of flexible fiberglass thermal insulation.
Blind Rivet
A small headed pin with expandable shank for joining light gage metal. Typically used
to attach flashing, gutter, etc.
BOCA
Building Officials and Code Administrators International, Inc.
Box Girder
Girders, trucks or other members of rectangular cross-section enclosed on four sides.
Bracing
Rods, angles or cables used in the plane of the roof and walls to transfer loads, such as
wind, seismic and crane thrusts to the foundation.
Bracket
A structural support projecting to a structural member. Examples are canopy brackets,
lean-to brackets, and crane runway brackets.
Brake
A machine used to bend, fold or form sheet metal.
Bridge (Crane)
That part of an overhead crane consisting of girders, trucks, end ties, walkway and
drive mechanism which carries the trolley and travels in a direction parallel to the
runway.
Bridge Crane
A load lifting system consisting of a hoist that moves laterally on a beam, girder or
bridge, which in turn moves longitudinally on a runway, made of beams and rails.
Bridging
Bracing or systems of bracing used between structural members.
British Thermal Unit (BTU)
That amount of heat required to raise the temperature of one pound of water by 1°F.
Builder
A party who, as a routine part of his business, buys the Metal Building System from a
manufacturer for the purpose of resale. Also see Section IV, Common Industry
Practices, regarding roles and responsibilities of the Builder.
Building
A structure forming an open, partially enclosed, or enclosed space constructed by a
planned process of combining materials, components, and subsystems to meet specific
conditions of use.
Building Aisle
A space defined by the length of the building and the space between building columns.
Building Code
Regulations established by a recognized agency describing design loads, procedures
and construction details for structures usually applying to a designated political
jurisdiction (city, county, state, etc.).
Building Envelope
The elements of a building that enclose conditioned spaces through which thermal
energy is capable of being transferred.
Built-Up Roofing
A roof covering made up of alternating layers of tar and asphaltic materials or layers
(plies) of organic or synthetic fabric.
Built-Up Section
A structural member, usually an I-shaped section, made from individual flat plates
welded together.
Bumper
An energy-absorbing device for reducing impact when a moving crane or trolley
reaches the end of its permitted travel; or when two moving cranes or trolleys come
into contact.
Butt Plate
The end plate of a structural member usually used to rest against a like plate of another
member in forming a connection. Sometimes called a splice plate or bolted end plate.
Button Punch
A process of indenting two or more sheets of metal that are pressed against each other
to prevent slippage between the metal.
Butyl Tape
A common abbreviation for polyisobutylene-isoprene polymer sealant tape used
between metal roof panel and flashing joints.
Bypass Girt
See "Exterior Framed".