TERMS CONCERNING THE HEAD OF THE SCREW

BEARING SURFACE:
The bearing surface is the supporting or locating surface of a fastener with respect to the part which it fastens (mates). The loading of a fastener is usually through the bearing surface, (i.e. the bearing surface of the Hex Washer Head style is under the washer of the head, the part that touches the  top material being fastened.).     

COUNTERSUNK:
Any head style that has the bearing surface flush with the top material being attached, (i.e. a flat head used in wood applications, or bugle head used to attach drywall.).

HEAD:
The head of a fastener is the enlarged shape preformed on one end of a headed fastener to provide a bearing surface. 

NIBS:
Located under the head if the headset has the bearing surface under the head or on the angled sides of a countersunk type of head.  Normally the nibs aid in cutting the top material to allow a flush or countersink connection. 

RECESSED DRIVE:
A drive system indented or recessed in the top surface of the head of the screw. (i.e. Phillips, square, Quadrex®). 

RECESSED HEAD:
A recessed head is a head having a specially formed indentation or recess centered in its top surface.  Common forms of recessed head styles are Phillips or square. 

SERRATIONS:
Reverse locking serrations are normally found under the head of the screw to aid in slowing down the final set of the screw to assist in possible stripping.  The serrations also aid in locking the screw in the material providing protection from vibration.

SLOTTED HEAD:
A slotted head is a head having a slot centered across its top surface.

TERMS CONCERNING THE THREADS OF THE SCREW

COARSE THREAD:
Tapping screws have  separate specifications, one for sharp point screws and one for self-drilling screws.  Examples of the sharp point coarse thread are 6-15, 8-15, 10-12, 12-10, 1/4-10.  The first number is the body diameter and the second shows the number of threads per inch.  Examples of the self-drilling coarse threads are 6-20, 8-18, 10-16, 12-14. 

CREST:
The highest point of the thread. (Maximum diameter) 

EXTERNAL THREAD:
A thread is a portion of a screw encompassed by one pitch.  On a single-start thread it is equal to one turn of the screw. Typically, all fasteners used in construction are externally threaded. 

FINE THREAD:
Tapping screws have  separate specifications, one for sharp point screws and one for self-drilling screws. Examples of the sharp point fine and extra-fine threads are 6-20 and 6-32, 8-18 and 8-32, 10-16, 10-24 and 10-32, 12-14 and 12-24.  The first number is the body diameter and the second shows the number of threads per inch. Examples of the self-drilling fine and extra-fine threads are 6-32, 8-32, 10-24 and 10-32, 12-24.

HIGH & LOW THREAD:
Also called alternating threads.  The threads alternate with one high thread and then one lower thread.   Originally designed for connections in plastic material to prevent cracking, somewhat effective in wood or thin metal.  Normally, the coarse thread would be recommended in wood applications.

ROOT:
The lowest point of the thread. (Minor diameter) 

THREAD - CUTTING:
A thread that cuts its mating threads, which includes some type of chip cavity to collect the material removed by the tapping operation.  A type of tapping screw. 

THREAD - FORMING:
A thread that displaces material to form a mating thread.   A type of tapping screw. 

THREAD PITCH:
Thread pitch is the distance between the threads.

THREAD - TAPPING:
A thread that taps a mating internal thread. 

T.P.I.:
T.P.I. Is the number of threads per inch on any screw. 

TWINFAST:
Also called double lead, twin lead or multi-lead thread.   A screw thread with two or more lead threads.   Lead threads are the starting threads at the tip of the sharp point screw. 

TERMS CONCERNING POINTS OF THE SCREW

1,2,3,4,5 POINTS:
When referencing self-drilling screws, the number of the point determines the drilling capacity of the fastener.  The higher the number the thicker material can be drilled.   Minimum drill capacities for 2 & 3 points are found in SAE J78 specification. 

FORGED POINT (TYPE "SD"):
When referenced to a self-drilling screw it is the method used to form the drill point by a forging process.  Sometimes referred to as a pinch point.

MILLED POINT (TYPE "SD"):
When referenced to a self-drilling screw,  it is the method used to form the drill point by a milling (cutting) process.

PINCH POINT:
See Forged Point. 

REAMER:
See "winged". 

SELF-DRILLING (DARTS® BRAND TYPE "SD"):
Self-drilling tapping screws are externally threaded fasteners with the ability to drill their own hole and form or cut their own internal mating threads into which they are driven without deforming their own thread and without breaking during assembly. 

SELF-PIERCING (MARKER® BRAND TYPE "S"):
Self-piercing tapping screws are externally threaded fasteners with the ability to self-pierce metallic material form a sleeve by extruding metallic material and tap their own mating threads when driven.  Self-piercing screws are high-strength, one-piece, one-side-installation fasteners, with sharp point angles of 25 to 30 degrees.  

TAPPING SCREWS:
Tapping screws are threaded fasteners with the ability to tap their own internal mating threads when driven into preformed or no preformed holes in metallic and nonmetallic materials.  Tapping screws are high-strength, one-piece, one-side-installation fasteners. 

WINGED:
Term normally used when referring to a self-drilling screw with reaming type wings attached after the threads and before the drill point to ream out the top material, eliminating any jacking action.

TERMS CONCERNING BASIC DIMENSIONS OF TAPPING SCREWS

HEAD O.D.:
Outside diameter of a head style. If washer faced head style there will be a second dimension noting the O.D. of the washer.

MAJOR DIAMETER:
Measurement of the outside dimension of the threads (crest to crest). The outside dimension of the cylinder. 

MINOR DIAMETER:
Measurement of the inside dimension between the threads. 

OVERALL LENGTH:
The entire length of the fastener from the top surface of the head to the end of the sharp or drill point. 

RECESS DEPTH:
Measured from the surface of the head to the bottom of the recess.

THREAD LENGTH:
The length of the thread beginning at the point on a sharp point or after the drill point on the SD type to the end of the last fully formed thread. 

TOLERANCE:
The total permissible variation of a size.  The tolerance is the difference between the limits of size.

TERMS CONCERNING PERFORMANCE OF TAPPING SCREWS

BURN-OUT:
Term used when describing what happens to the self-drilling point when it is drilled with a tool using too much speed.  The speed burns out  the drill point and the basic function of the fastener is nullified. 

CAM-OUT:
The drive of a fastener is rounded out or deformed not allowing fastener to completely set. 

CORROSION RESISTANCE:
The amount of time before white or red rust appears on the surface.  Test procedure ASTM B117 is used to measure corrosion in hours of salt fog. 

HEAD 'POPS':
One mode of failure when fastener has pull-over, pull-through failure. 

JACKING ACTION:
Jacking action occurs when the top piece of material pulls away from the base material by engaging threads into the top material forcing it up the body of the screw.  Using the correct fastener will stop this problem. 

PULL-OUT (TENSION):
The amount of force required to pull the fastener out of the base material. 

PULL-OVER  (PULL-THROUGH):
The amount of force required to pull the material over the head of the fastener. Example - 1/2"  plywood is attached to thin metal.  The metal is secured on a bottom fixture and the plywood is pulled upward until the wood pulls over the head (pull over) or the fastener pulls out of the base material (pull-through). 

SHEAR STRENGTH:
Shear strength of a connection is the force required to pull the base material in one direction and the top material in the other direction until failure.  Modes of failure include deformation of the base material to allow the fastener to pull out of the base material and fastener fracture. 

STRIP-OUT (SPIN-OUT):
Fastener spins freely in connection. 

TENSILE STRENGTH:
The amount of force required to pull a fastener apart by securing one end and pulling up on  the other end.  Tensile, or pull value may be different when comparing the tensile strength  of the screw with the tensile strength of a connection.

THREAD ENGAGEMENT:
The point at which the threads of the screw engage the base material.  Proper thread engagement ensures a good connection. Improper thread engagement can cause "Jacking Action" to occur.  

TORSIONAL STRENGTH:
The twisting strength of a fastener, measured in foot pounds. The screw is secured in a fixture and torque (twisting action) is added until screw twists apart. Minimum standards are noted in the Industrial Fastener Standards publication. 

WALKING:
Term used to describe what happens to the screw if the point is not sharp enough, or if the operator does not hold the screw gun perpendicular to the connection.

WOBBLE:
Normally refers to the wobble of the recess drive such as Phillips.  Wobble is the back and forth motion of a bit tip in a recessed drive. A 5 degree wobble is within most tolerances.

TERMS CONCERNING MATERIAL AND HEAT TREATMENT

ALLOY:
A homogeneous mixture or solid solution of two or more metals, the atoms on one replacing or occupying interstitial positions between the atoms of the other. Brass is an alloy of copper and zinc. 

ALLOY STEEL:
Steel containing elements other than carbon which have been added to obtain definite mechanical or physical properties, such as higher strength at elevated temperatures, toughness, etc. 

ANNEALED:
A fastener is considered in the annealed state when it has been heated and cooled to make it soft - that is, free of hardness caused by working or previous heat treatment. To subject glass or metal to a process of heating and slow cooling in order to toughen and reduce brittleness. 

CARBON STEEL:
Carbon steel is a steel which does not contain any substantial amounts of alloying materials other than carbon.  There are three broad categories of carbon steel.  Low carbon steel, medium carbon steel and alloy steel. 

CARBON STEEL - LOW:
Low carbon steels that are used for fasteners, are defined as those with insufficient carbon content to permit a predictable response to a strengthening heat treatment process.  The most commonly used analyses are AISI 1006, 1008, 1016, 1018,1021 and 1022.  These steels have good workability, they can be case hardened and are weldable.  They have good strength properties which can be substantially improved through cold working. 

CARBON STEEL - MEDIUM:
Medium carbon steels are heat treatable, which mean that through metallurgical treatments the tensile strength of the fastener after processing can be significantly higher than that of its original raw material.  Popular analyses are AISI 1030, 1035, 1038 and 1541. 

CASE HARDENED:
A case hardened fastener is a fastener of ferrous material having a surface which has been made harder than the core. All tapping screws are case hardened. 

DECARBURIZED:
A fastener has a decarburized surface when the carbon content of the surface is lower than the carbon content of the core.

SOFT:
Describes the condition of a fastener which can be, and normally is, hardened by heat treatment , is left in the as-fabricated temper. Not case hardened. 

STAINLESS STEEL:
Stainless steel is a corrosion resistant type of alloy steel which contains a minimum of 12 percent chromium.

TERMS CONCERNING FINISH OF FASTENERS 

ANODIZING:
Anodizing is the formation of an oxide film on the surface by means of an anodic treatment.  This is commonly used on aluminum. 

COATING:
Coating is the application of some material such as a metal, organic compound, etc., to the surface of a fastener, e.g., PLUS COAT™ ceramic, LIFECOAT® dip-spin. 

ELECTRO-GALVANIZING:
Is the process of coating metal with zinc by electrode position. 

FINISH:
The term finish is commonly applied to the condition of the surface of a fastener as a result of chemical or organic treatment subsequent to fabrication.

FLASH FINISH:
Flash plating is a very thin deposit of metal, usually on the order of 1-4 mils in thickness as an undercoating.

GALVANIZING:
Galvanizing is the process of coating iron or steel with zinc - originally by using direct current and a zinc anode.  Methods of zinc deposition are: Electro-Galvanizing, Hot Dipped , and Mechanical. 

HOT DIP GALVANIZING:
Is the process of immersing the parts to be coated in a bath of molten zinc. 

MECHANICAL GALVANIZING:
Is a process in which powdered zinc is applied to a base metal using the principles of cold welding and barrel finishing techniques. 

OILED:
Oiled is the term denoting the application of a suitable corrosion retarding oil to a fastener. 

PASSIVATING:
Passivating is the process of dissolving ferrous particles and surface impurities from stainless steel by chemical means (normally a nitric acid dip) and to produce a passive film on the surface.  The purpose is to improve the corrosion resistance of the surface.

PICKLING:
Pickling is the process of removing surface oxides or impurities by chemical or electrochemical means. 

PLAIN:
Plain as applied to finish of fasteners is used to indicate that the fastener has had no supplementary surface treatment, such as plating or coating, other than being oiled. 

SURFACE HEAT TREATMENT:
Surface heat treatment is a process that improves the hardness or other mechanical property of the fastener in any surface area.  One type of surface heat treatment is case hardening. 

SURFACE TREATMENT:
Surface treatment is any treatment which changes the chemical, physical or mechanical properties of a surface.

TERMS CONCERNING TOOLING

ADJUSTABLE TORQUE:
An option on a screw-gun that allows the operator to set the torque (or twisting strength) of a tool in order to assure that a connection will not be stripped. 

BIT TIPS:
Bit tips are the small (normally) 1", Phillips, square, etc., design that are inserted into the bit holder in a tool. 

DEPTH-SENSITIVE:
Term normally refers to a specially designed nosepiece attached to a tool which will allow the operator to set the desired depth of the fastener. 

HEX SOCKETS:
Hex sockets are designed to fit the Hex Washer Head design screw. 

POWER BITS:
Power bits are the bits that have a hex design on one end that are inserted directly into the tool.  Do not require a bit holder. 

RPM:
Rotations per minute.  The top speed of the tool is normally noted on the identity plate.

SCREW-GUN:
Electric or battery operated tool designed for case hardened fasteners.  Available in many RPM's and with a variety of specialized options such as adjustable torque and clutch.

TERMS CONCERNING CONSTRUCTION

ANCHOR:
Metal securing device embedded or driven into masonry, concrete, steel or wood. 

ANCHOR BOLT:
Heavy, threaded bolt embedded in the foundation to secure sill to foundation wall or bottom plate of exterior wall to concrete floor slab. 

BAR JOIST:
Open-web, flat truss structural member used to support floor or roof structure. Web section is made from bar or rod stock, and chords are usually fabricated form "T" or angle sections. 

BATTEN:
Narrow  strip of wood, plastic, metal or gypsum board used to conceal an open joint.

BEAM:
Loadbearing member spanning a distance between supports. 

BRIDGING:
Members attached between floor joists to distribute concentrated loads over more than one joist and to prevent rotation of the joist. Solid bridging consists of joist-depth lumber installed perpendicular to and between the joists. Cross-bridging consists of pairs of braces set in an "X" form between joists. 

CARRYING CHANNEL:
Main supporting member of a suspended ceiling system to which furring members or channels attach.

CASING:
The trim around windows, doors, columns or piers. 

CLADDING:
Gypsum panels, gypsum bases, gypsum sheathing, cement board, etc. applied to framing. 

COLUMN:
Vertical load bearing member. 

CORNER BRACE:
Structural framing member used to resist diagonal loads that cause racking of walls and panels due to wind and seismic forces. May consist of a panel or diaphragm, or diagonal flat strap or rod. Bracing must function in both tension and compression. If brace only performs in tension, two diagonal tension members must be employed in opposing direction as "X" bracing. 

CORNER POST:
Timber or other member forming the corner of a frame. May be solid or built-up as a multi-piece member.

CRIPPLE:
Short stud such as that used between a door or window header and the top plate. 

CURTAIN WALL:
Exterior wall of a building that is supported by the structure and carries no part of the vertical load except its own. Curtain walls must be designed to withstand wind loads and transfer them to the structure. 

DEAD LOAD:
Load on a building element contributed by the weight of the building materials. 

DEFORMATION:
Change  in shape of a body brought about by the application of a force internal or external. Internal forces may result from temperature, humidity or chemical changes. External forces from applied loads can also cause deformation.

DESIGN LOAD:
Combination of weight (dead load) and other applied forces (live loads) for which a building or part of a building is designed. Based on the worst possible combination of loads. 

EXTERIOR INSULATION AND FINISH SYSTEM (EIFS):
Exterior cladding assembly consisting of a polymer finish over a reinforcement adhered to foam plastic insulation that is fastened to masonry, concrete, building sheathing or directly to the structural framing. The sheathing may be cement board or gypsum sheathing. 

FASCIA BOARD:
Board fastened to the ends of the rafters or joists forming part of a cornice. 

FIRE WALL:
Fire-resistant partition extending to or through the roof of a building to retard spread of fire. See Area Separation Wall. 

FLASHING:
Strips of metal or waterproof material used to make joints waterproof, as in the joining of curtain wall panels.

FOOTING:
Lower extremity of a foundation or load bearing member that transmits load to load-bearing substrate. 

FORCE:
Amount of applied energy to cause motion, deformation or displacement and stress in a body.

FOUNDATION:
Component that transfers weight of building and occupants to the earth.

FURRING:
Member or means of supporting a finished surfacing material away from the structural wall or framing. Used to level uneven or damaged surfaces or to provide space between substrates. Also an element for mechanical or adhesive attachment of paneling. 

GABLE:
Uppermost portion of the end wall of a building that comes to a triangular point under a sloping roof. 

GIRDER:
Beam, especially a long, heavy one; the main beam supporting floor joists or other smaller beams. 

GUSSET:
Wood or metal plate riveted, bolted, glued or pressed (wood trusses) over joints to transfer stresses between connected members. 

HEADER:
Horizontal framing member across the ends of the joists. Also the member over a door or window opening in a wall. 

HEEL OF RAFTER:
Seat cut in a rafter that  rests on the wall plate. 

HVAC:
Heating, ventilating and air conditioning. (ASHRAE Guide is the technical reference source.)

INSULATION (THERMAL):
Any material that measurably retards heat transfer. There is wide variation in the insulating value of different materials. A material having a low density (weight/volume) will usually be a good thermal insulator.

JAMB:
One of the finished upright sides of a door or window frame. 

JAMB STUD:
Wood or metal stud adjacent to the door jamb. 

JOIST:
Small beam that supports part of the floor, ceiling or roof of a building. 

JOIST HANGER:
Metal shape formed for hanging on the main beam to provide support for the end of a joist.

LEDGER STRIP:
Strip fastened to the bottom edge of a flush girder to help support the floor joists. 

LINTEL:
Horizontal member spanning an open such as a window or door. Also referred to as a Header.

LIVE LOAD:
Part of the total load on structural members that is not a permanent part of the structure. May be variable, as in the case of loads contributed by the occupancy, and wind and snow loads.

LOAD:
Force provided by weight, external or environmental sources such as wind, water, and temperature, or other sources of energy. 

MITER:
Joint formed by two pieces of material cut to meet at an angle.  

MOULDING (ALSO MOLDING):
Narrow decorative strip applied to a surface.

MULLION:
Vertical bar or division in a window frame separating two or more panes. 

MUNTIN:
Horizontal bar or division in a window frame separating multiple panes or lights.

PARAPET WALL:
Extension of an exterior wall above and/or through the roof surface.

PITCH OF ROOF:
Slope of the surface, generally expressed in inches of vertical rise per 12" horizontal distance, such as "4-in-12 pitch." 

PLATE:
"Top" plate is the horizontal member fastened to the top of the suds or wall on which the rafters, joists or trusses rest; "sole" plate is positioned at bottom of studs or wall. 

PLATFORM:
Floor surface raised above the ground or floor level.

PLATFORM FRAMING:
Technique of framing where walls can be built and tilted-up on a platform floor, and in multistory construction are erected sequentially from one platform to another. Also known as "Western" framing. 

PLENUM:
Chamber in which the pressure of the air is higher (as in a forced-air furnace system) than that of the surrounding air. Frequently a description of the space above a suspended ceiling. 

PURLIN:
Horizontal member in a roof supporting common rafters, such as at the break in a gable roof. Also, horizontal structural member perpendicular to main beams in a flat roof. 

RACKING:
Forcing out of plumb of structural components, usually by wind, seismic stress or thermal expansion or contraction. 

RAFTER:
That member forming the slanting frame of a roof or top chord of a truss. Also known as hip, jack or valley rafter depending on its location and use.

RAFTER TAIL:
That part of a rafter that extends beyond the wall plate -- the overhang.

RIDGE:
Peak of a roof where the roof surfaces meet at an angle. Also may refer to the framing member that runs along the ridge and supports the rafters.  

RISE:
Measurement in height of an object; the amount it rises. The converse is "fall".  

RISER:
Vertical face of a step supporting the tread in the staircase. 

SCAB:
Small piece or block of wood that bridges several members or provides a connection or fastening between them. 

SHEATHING:
Plywood, gypsum, wood fiber, expanded plastic or composition boards encasing walls, ceilings, floors and roofs of framed buildings. May be structural or non-structural, thermal-insulating or non-insulating, fire-resistant or combustible.  

SHEETROCK:
Leading brand of gypsum panel for interior wall and ceiling surfaces, developed and improved by United States Gypsum Company. There is only one SHEETROCK brand Gypsum Panel.

SHORING:
Temporary member placed to support part of a building during construction, repair or alteration; also may support the walls of an excavation. 

SILL:
Horizontal member at the bottom of door or window frames to provide support and closure.  

SILL PLATE:
Horizontal member laid directly on a foundation on which the framework of a building is erected.

SLAB:
Flat (although sometimes ribbed on the underside) reinforced concrete element of a building that provides the base for the floor or roofing materials.

SOFFIT:
Under surface of a projection or opening; bottom of a cornice between the fascia board and the outside of the building; underside of a stair, floor or lintel. 

SPAN:
Distance between supports,  usually a beam or joist.  

SPANDREL BEAM:
Horizontal member, spanning between exterior columns, that supports the floor or roof. 

SPANDREL WALL:
Exterior wall panel, usually between columns, that extends from the window opening on one floor to one on the next floor.  

STILE:
Vertical outside member in a piece of sill work, as a door or sash. 

STIRRUP:
Hanger to support the end of the joist at the beam. 

STOP:
Strip of wood fastened to the jambs and head of a door or window frame against which the door or window closes.  

STRINGER:
Heavy horizontal timber supporting other members of the frame in a wood or brick structure; a support also for steps.  

STRUT:
Slender structural element that resists compressive forces acting lengthwise. 

STUD:
Vertical load-bearing or non-load bearing framing member. 

SUBFLOOR:
Rough or structural floor placed directly on the floor joists or beams to which the finished floor is applied.  As with resilient flooring, an underlayment may be required between subfloor and finished floor.

SUBSTRATE:
Underlying material to which a finish is applied or by which it is supported. 

THRESHOLD:
Raised member at the floor within the door jamb. Its purpose is to provide a divider between dissimilar flooring materials or serve as a thermal, sound or water barrier. 

TOENAIL:
Method of fastening two boards together as in a "T" by driving nails into the board that forms the stem of the "T" at an angle so they enter the other board and cross each other.  

TONGUE-AND-GROOVE JOINT:
Joint where the projection or "tongue" of one member engages the mating groove of the adjacent member to minimize relative deflection and air infiltration; widely used in sheathing, flooring and paneling. Tongues may be in "V", round or square shapes.

TREAD:
Horizontal plane or surface of a stair step.

TRIMMER:
Double joists or rafters framing the opening of a stairway well, dormer opening, etc. 

TRUSS:
Open, lightweight framework of members, usually designed to replace a large beam where spans are great.

WEEP HOLE:
Small aperture at the base of an exterior wall cavity intended to drain out trapped moisture.

TERMS CONCERNING STEEL FRAMING

ACCEPTED ENGINEERING PRACTICE:
That which conforms to accepted principles, tests, or standards of nationally recognized technical or scientific authorities.  

APPROVED:
Refers to approval by the code official or other authority having jurisdiction as the result of investigation and tests conducted by him, or by reason of accepted principles or tests by nationally recognized organizations. 

AXIAL LOAD:
The longitudinal force acting on a member. Examples are the gravity loads carried by columns or studs. 

BUCKLING:
The bending, warping or crumpling of a member (such as a wall stud) subjected to axial, bending, or shear loads.

CEILING JOIST:
A horizontal structural framing member which supports a ceiling and/or attic loads. Refer to Figure 2. 

C-SECTION:
Used for structural framing members (such as studs, joists, headers, beams, girders, and rafters). The name comes from the member's "C" shaped cross-sectional configuration consisting of a web, flange and lip. Figure 1 shows this cross-section and defines the different parts of the C-section. C-section web depth measurements are taken to the outside of the flanges. C-section flange width measurements also use outside dimensions.

CLIP ANGLE:
An L shaped short piece of metal (normally with a 90 degree bend). It is typically used for connections.

COLD-FORMING:
A process where light-gauge steel members are manufactured by (1) press-braking blanks sheared from sheets or cut length of coils or plates, or by (2) roll forming cold- or hot-rolled coils of sheet steel; both forming operations are performed as ambient room temperature, that is, without manifest addition of heat such as would be required for hot forming.

FLANGE:
The part of a C-section or track that is perpendicular to the web.   Refer to Figure 1.

FLAT STRAP:
Sheet steel cut to a specified width without any bends (typically used for bracing and other flat applications). Refer to Figure 2. 

FLOOR JOIST:
A horizontal structural framing member that supports floor loads.   Refer to Figure 2.

GALVANIZED STEEL:
Steel that has a zinc protective coating for resistance against corrosion, The level of protection provided is measured by the weight of the galvanized coating applied to the surface area of the steel (e.g.. G-40 or G-60).

HEADER:
A horizontal built-up structural framing member used over wall or roof openings to carry loads across the opening. Refer to Figure 2.

IN-LINE FRAMING:
Framing method where all vertical and horizontal load carrying members are aligned. Refer to Figure 2.

JACK STUD:
A vertical structural member that does not span the full height of the wall and supports vertical loads and/or transfers lateral loads. Jack studs are used to support headers. Refer to Figure 2.

KING STUD:
A vertical structural member that span the full height of the wall and supports vertical loads and lateral loads. Usually located at both ends of a header adjacent to the jack studs to resist lateral loads. Refer to Figure 2.

LIP:
The part of a C-section which extends from the flange at the open end. The lip increases the strength characteristics of the member and acts as a stiffener to the flange. Refer to Figure 1.

LOADS, LIVE AND DEAD:
Dead loads are the weight of the walls, partitions, framing, floors, ceilings, roofs, and all other permanent stationary construction entering into and becoming a part of a building. Live loads are all loads except dead and lateral loads.

MATERIAL PROPERTIES:
The chemical, mechanical, and physical properties of steel before or after the cold-forming process.

MATERIAL THICKNESS:
The base metal thickness excluding any protective coatings. Thickness is expressed in mils (1/1000 of an inch).

MIL:
A unit of measurement typically used in measuring the thickness of thin elements. One mil equals 1/1000 of an inch.

MULTIPLE SPAN:
The span made by a continuous member having intermediate supports.

NON-LOAD BEARING WALLS (NON-STRUCTURAL WALLS)
Refer to walls.

PUNCHOUT:
A hole in the web of a steel framing member allowing for the installation of plumbing, electrical, and other trade installation.

RAFTER:
A structural framing member (sloped) which supports roof loads.   Refer to Figure 2.

SEISMIC ZONE:
Seismic zones designate areas with varying degrees of seismic risk and associated seismic design parameters (i.e. effective peak ground acceleration). Seismic zones 1, 2, 3, and 4 correspond to effective peak ground acceleration of 0.1g, 0.2g, 0.3g, and 0.4g, respectively (1g is the acceleration of the earth's gravity at sea level). Refer to ASCE 7-93 for more details.

SHEARWALL:
A wall assembly capable of resisting lateral forces to prevent racking from wind or seismic loads acting parallel to the plane of the wall.

SINGLE SPAN:
The span made by one continuous structural member without any intermediate supports.

SPAN:
The clear horizontal distance between bearing supports. 

STRUCTURAL SHEATHING:
The covering (e.g. plywood) used directly over structural members (e.g.  studs or joists) to distribute loads, brace walls, and strengthen the assembly. Refer to Figure 2. 

STUD:
Vertical structural element of a wall assembly which supports vertical loads and/or transfers lateral loads. 

TRACK:
Used for applications such as top and bottom plate for walls and bands joists for flooring systems. The track has a web and flanges, but no lips. Track web depth measurements are taken to the inside of the flanges. Refer to Figure 2.

WALLS:
1. Structural or load bearing: (i.e. transverse and/or axial load bearing). Steel framing systems that exceed the limits for a non-structural system (e.g. wall studs).
2. Non-structural: (i.e. non-load bearing). Steel framing systems that are melted to 10 psf (0.479 kN/m2) maximum lateral (transverse) load and/or limited, exclusive of sheathing materials, to 100 pounds (450 N) per lineal foot (305 mm) or 200 pounds (900 N) maximum superimposed vertical load per member (e.g. partitions).

WEB:
The part of a C-section or track that connects the two flanges.

WEB CRIPPLING:
The bending, warping or crumpling of the web of a member subjected to concentrated load. Refer to Figure 1.

WEB STIFFENER:
Additional material that is attached to the web to strengthen the member against web crippling. Also called bearing stiffener. 

WIND EXPOSURE:
Wind exposure is determined by site conditions that affect the ground level wind speeds experienced at a given site. For the purpose of this document, Exposure B represents a suburban or wooded terrain and Exposure C represents open terrain with scattered obstructions. Refer to ASCE 7-93 for more details. 

WIND SPEED:
Wind speed is the design wind speed related to winds that could be expected to occur once every 50 years at a given site ( i.e. 50-year return period). Wind speeds in this document are given in units of miles per hour by "fastest-mile" measurements. Refer to ASCE 7-93 for more details. 

YIELD STRENGTH:
A characteristic of the basic strength of the steel material. It is the highest unit stress that the material can endure before permanent deformation occurs.

ORGANIZATIONS

ACCA: Air Conditioning Contractors of America
AISI: American Iron and Steel Institute
ASHRAE: American Society of Heating, Refrigeration and Air-Conditioning Engineers
ASTM: American Society for Testing and Materials
AWCI: Association of the Wall and Ceiling Industries
CABO: Council of American Building Officials
CSI: Construction Specifiers Institute
HUD: Housing and Urban Development, federal agency.
ICBO: International Conference of Building Officials
ICC: International Codes Council
IFI: Industrial Fastener Institute
IISI: International Iron and Steel Institute
IRC: International Residential Code
LGSEA: Light Gauge Steel Engineers Association
NAHB: National Association of Home Builders
SAE: Society of Automotive Engineers
UBC: Uniform Building Code