Definitions D - H

Damper: A baffle used to open or close the throat of ventilators. They can be operated manually or by motors.
Dead Loads: The dead load of a building is the weight of all permanent construction, such as floor, roof, framing, and covering members.
Deflection: The displacement of a structural member or system under load.
Design Loads: Those loads specified in building codes published by Federal, State, County or City agencies, or in owners' specifications to be used in the design of a building.
Design Professional: Any Architect or Engineer
Diagonal Bracing: See " Bracing"
Diaphragm Action: The resistance to racking generally offered by the covering systems, fasteners, and secondary framing.
Door Guide: An angle or channel used to stabilize or keep plumb a sliding or rolling door during its operation.
Downspout: A conduit used to carry water from the gutter of a building.
Drift (sidesway): Horizontal displacement at the top of a vertical element due to lateral loads. Drift should not be confused with "Deflection".
Drift (Snow): The snow accumulation at a height discontinuity.
Drift Pin: A tapered pin used during erection to align holes in steel members to be connected by bolting.
Eave: the line along the sidewall formed by the intersection of the planes of the roof and wall.
Eave Canopy: A projecting roof system on the sidewall that is supported and restrained at one end only.
Eave Gutter: See "Gutter"
Eave Height: The vertical dimension from finished floor to the top of the eave strut.
Eave Strut: A structural member at the eave to support roof panels and wall panels. It may also transmit wind forced from roof bracing to wall bracing.
Edge Strip: The surface area of a building at the edges of a roof and at the wall intersections where the wind loads on components and cladding are greater than at other areas of the building.
Effective Wind Area: The area used to determine the wind coefficient. The effective wind area may be greater than or equal to the tributary area.
Elastic Design: A design concept utilizing the proportional behavior of materials when all stresses are limited to specified allowable values in the elastic range.
Electric operated Crane: A crane in which the bridge, hoist or trolley is operated by electric power.
Electric Overhead Traveling Crane: An electrically operated machine for lifting, lowering and transporting loads, consisting of a movable bridge carrying a fixed or movable hoisting mechanism and traveling on an overhead runway structure.
End Approach: The minimum horizontal distance, parallel to the runway, between the outermost extremities of the crane and the centerline of the hook.
End Bay: The bays adjacent to the endwalls of a building. Usually the distance from the endwall to the first interior main frame measured normal to the endwall.
End Frame: A frame located at the endwall of a building which supports the loads from a portion of the end bay.
End Post: See "Endwall Column"
End Stop: A device attached to a crane runway or rail to provide a safety stop at the end of a runway.
End Truck: The unit consisting of truck frame, wheels, bearings, axles, etc., which supports the bridge girders.
Endwall: An exterior wall which is parallel to the interior main frame of the building.
Endwall Column: A vertical member located at the endwall of a building which supports the girts. In post and beam endwall frames, endwall columns also support rafter.
Endwall Overhang: See "Purlin Extension"
End Zone: The surface area of a building along the roof at the endwall and at the corners of walls.
Engineer/Architect of Record: The Engineer or Architect that is responsible for the overall design of the building project. The manufacturer's engineer is not the Engineer of Record.
Erection: The on-site assembling of fabricated Metal Building System components to form a completed structure.
Erection Bracing: Materials used by erectors to stabilize the building system during erection, also typically referred to as temporary bracing.
Erection Drawings: Roof and Wall erection (framing) drawings that identify individual components and accessories furnished by the manufacturer in sufficient detail to permit proper erection of the Metal Building System.
Erector : A party who assembles or erects a Metal Building System.
Expansion Joint: A break or space in construction to allow for thermal expansion and contraction of the materials used in the structure.
Exterior Framed: A wall framing system where the girts are mounted on the outside of the columns
Fabrication: The manufacturing process performed in a plant to convert raw material into finished Metal Building System components. The main operations are cold forming, cutting, punching, welding, cleaning and painting.
Façade: an architectural treatment, partially covering wall, usually concealing the eave and/or the rake of the building.
Fading: Refers to the paint finish on panels becoming less vibrant of color.
Fascia: A decorative trim or panel projecting from the face of the wall.
Fenestration: Windows or other panels of glass; their numbers and location.
Field: the "job site", "building site" or general marketing area.
Filler Strip: See "Closure Strip"
Film Laminated Coil: coil metal that has a corrosion resistant film laminated to it prior to the forming operation.
Fixed Clip: A standing seam roof system hold down clip which does not allow the roof panel to move independently of the roof substructure.
Fixed Base: A column base that is designed to resist rotation as well as horizontal or vertical movement.
Flange: The projecting edge of a structural member.
Flange Brace: A member used to provide lateral support to the flange of a structural member.
Flashing: The metal used to "trim" or cover the juncture of two planes of material.
Floating Clip: A standing seam roof system hold down clip which allows the roof panel to move independently of the roof substructure. Also known as "Sliding Clip" or "Slip Clip"
Floor Live Load: Those loads induced on the floor system by the use and occupancy of the building.
Flush Girts: A wall framing system where the outside flange of the girts and the columns are flush.
Footing: A pad or mat, usually of concrete, located under a column, wall or other structural member, that is used to distribute the loads from the member into the supporting soil.
Force: The action of one body to another body which changes or tends to change its state of rest or motion. A force may be expressed in pounds (Newtons), kips, or other similar units and may act in any one of the following ways:
      A. Compression Force: A force acting on a body tending to compress the body, (pushing action)
      B. Shear Force: A force acting on a body which tends to slide one portion of the body against the
          other portion of the body. (sliding action)
      C. Tension Force: A force acting on a body tending to elongate the body. (sliding action)
      D. Torsion Force: A force acting on a body which tends to twist the body.
Foundation: The substructure which supports a building or other structure.
Framed Opening: Frame work (headers and jambs) and flashing which surround an opening in the wall or roof of a building; usually for field installed accessories such as overhead doors or powered roof exhausters.
Framing: The primary and secondary structural members (columns, rafters, girts, purlins, brace rods, etc.) which go together to make up the skeleton of a structure to which the covering can be applied.
Framing Drawings: Plans and erection instructions which identify all individual parts in sufficient detail to permit the proper erection and installation of all parts of the metal building system furnished by the seller (also known as erection drawings)
Gable: The triangular portion of the endwall from the level of the eave to the ridge of the roof.
Gable overhang: See "Purlin Extension"
Gable Roof: A roof consisting of two sloping roof planes, that form a ridge and form a gable at each end.
Galvanized: Steel coated with zinc for corrosion resistance.
Gantry Crane: A crane similar to an overhead crane except that the bridge for carrying the trolley or trolleys is rigidly supported on one or more legs running on fixed rails or other runway.
Girder: A main horizontal or near horizontal structural member that supports vertical loads. It may consist of several pieces.
Girt: A horizontal structural member that is attached to sidewall or endwall columns and supports paneling.
Glaze: The process of installing glass in windows and doors.
Glazing: Glass panes or paneling used in windows and doors.
Grade: The term used when referring to the ground elevation around a building.
Grade Beam: A concrete beam around the perimeter of a building.
Ground Snow Load: The probable weight of snow on the ground for a specified recurrence interval exclusive of drifts or sliding snow.
Grout: A mixture of cement, sand and water used to fill cracks and cavities. Sometimes used under base plates or leveling plates to obtain uniform bearing surfaces.
Gusset Plate: A steel plate used to reinforce or connect structural elements.
Gutter: A light gauge metal member at an eave, valley or parapet designed to carry water from the roof to downspouts or drains.
 "H" Section: A steel member with a cross section in the shape of an "H"
Hair Pin: "V" shaped reinforcing steel used to transfer anchor bolt shear to the concrete floor mass.
Hand Geared (Crane): A crane in which the bridge, hoist, or trolley is operated
Haunch: The deepened portion of a column or rafter designed to accommodate the higher bending moments at such points. (Usually occurs at the intersection of the column and the rafter)
Header: The horizontal framing member located at the top of a framed opening.
High Strength Bolts: any bolt made from steel having a tensile strength in excess of 100,000 pounds per square inch.
High Strength Steel: structural steel having a yield stress in excess of 36,000 pounds per square inch.
Hinged Base: see "Pinned Base"
Hip: The line formed at the intersection of two adjacent sloping planes of a roof.
Hip Roof: A roof which rises by inclined planes from all four sides of a building. The line where two adjacent sloping sides of a roof meet is called the hip.
Hood (Door): The metal flashing used over exterior slide door track along the full length of the door header to protect the tracks from weather and to conceal them for aesthetic purposes.
Hoist: A mechanical lifting device usually attached to a trolley, which travels along a bridge, monorail or rib crane. May be chain or electric operated.
Horizontal Guide Rollers: Wheels mounted near the ends of end trucks which roll on the side of the rail to restrict lateral movement of the crane.
Hot-Rolled Shapes: Steel sections (angles, channels, "S" shapes, "W" shapes etc.) which are formed by rolling mills while the steel is in a semi-molten state