Definitions M - O

Main Frame: An assemblage of rafters and columns that support the secondary framing members and transfer loads directly to the foundation.
Main Wind Force Resisting System: A structural assembly, which provides for the overall stability of the building and receives wind loads from more than one surface. Examples include shear walls, diaphragms, rigid frames, and space structures.
Manufacturer: A party who designs and fabricates a Metal Building System.
Manufacturer's Engineer: An engineer employed by a manufacturer who is in responsible charge of the structural design of a Metal Building System fabricated by the manufacturer. The manufacturer's engineer is not the engineer of record.
Masonry: Anything constructed of materials such as bricks, concrete blocks, ceramic blocks, and concrete.
Mastic: Caulking or sealant normally used in sealing roof panel laps.
MBMA: Metal Building Manufacturers Association
Mean Roof Height: Average height of roof above ground.
Metal Building System: A complete integrated set of mutually dependent components and assemblies that form a building including primary and secondary framing, covering and accessories, and are manufactured to permit inspection on site prior to assembly or erection.
Metal Building Fiber Glass Insulation: A grade of fiberglass insulation blanket specifically manufactured for lamination to a vapor retarder.
Moment: The tendency of a force to cause rotation about a point or axis.
Moment Connection: A connection designed to transfer moment as well as axial and shear forces between connection members.
Moment of Inertia: A physical property of a member, which helps define strength and defection characteristics.
Monolithic Construction: A method of placing concrete grade beam and floor slab together to form the building foundation without forming and placing each separately.
Monolithic Pour: The placing of concrete in a monolithic construction.
Monorail Crane: A crane that travels on a single runway beam, usually a "S" or "W" beam.
Multi-Gable Building: Buildings consisting of more than one gable across the width of the building.
Multi-Span Building: Buildings consisting of more than one span across the width of the building. Multiple gable buildings and single gable buildings with interior columns are examples.
Multiple Girder Crane: A crane, which has two or more girders for supporting the lifted load.
Oil Canning: A waviness that occur in flat areas of light gauge, formed metal products. Structural integrity is not normally affected by this inherent characteristic; therefore oil canning is only an aesthetic issue. Oil canning is not a cause for rejection of the material.
Open Web Steel Joists: Light weight truss.
Order Documents: The documents normally required by the Manufacturer in the ordinary course of entering and processing an order.
Outrigger: See "Auxiliary Crane Girder"
Overhanging Beam: A simply supported beam that extends beyond its support.
Overhead Doors: See "Sectional Overhead Doors"