Construction Safety Dictionary
ABOVE GRADE: A term applied to any part of a structure or site feature that is above the adjacent finished, or intact, ground level.
ADHESIVE: A sticky material or glue that adheres two surfaces. Construction uses include adhering tile to subflooring or sealing joints between trusses and roof decking.
AGGREGATE: A coarse material, such as gravel, broken stone or sand, with which cement and water are mixed to form concrete. Crushed stone is usually designated as coarse aggregate and sand as fine aggregate.
ANCHORING: Tying a wall down to resist racking or lift. Walls can be “anchored” to the ground using foundation bolts, straps, and special brackets.
ANNEALED-GLASS: Standard glass used for most windows. It can be baked to create tempered glass.
ARSON FIRE: A wildfire willfully ignited by anyone to burn, or spread to, vegetation or property without consent of the owner or his/her agent.
ASCE 7-98: The American Society of Civil Engineers design standard for buildings and other structures. The standard addresses wind loads.
BALLOON-FRAMING: A continuously framed gable wall where studs form one continuous piece from the floor to the roof. In the balloon method, the gable and the wall are framed all in one piece. Most houses have a rafter set on top of the wall to form the gable, and this is not a preferred method for wind resistance.
BEARING WALL: A structural wall that provides support for all or major portions of the vertical loads. Shear walls or braced frames provide seismic and high wind resistance.
BOTTOM PLATE: The lower horizontal board that is permanently attached to the foundation and nailed to the bottom of the wall studs. This board should be pressure-treated.
BRUSH: A collective term that refers to stands of vegetation dominated by shrubby, woody plants, or low-growing trees, usually of a type undesirable for livestock or timber management.
BRUSH FIRE: A fire burning in vegetation that is predominantly shrubs, brush, and shrub growth.
BUILDING ENVELOPE: The entire exterior surface of the building, including walls, doors and windows, which encloses or envelops the space within.
CANOPY: The stratum containing the crowns of the tallest vegetation present (living or dead), usually above 20 feet.
CATALYTIC REACTION: A chemical reaction, which employs a catalyst. A catalyst is a substance that aids a reaction but remains unchanged. Examples of catalytic reactions include catalytic converters in automobiles that use platinum to reduce pollution emissions and boat resins, which are hardened (or cured) using a catalyst.
CLADDING: Cladding can mean several different things. Cladding as siding includes vinyl siding, wood siding, cementious (“Hardy Board”) or aluminum siding. Cladding for windows and doors refers to the vinyl or aluminum skin used on the outside in place of paint i.e. “vinyl clad” or “aluminum clad.” Cladding in general can refer to skylights, glazing, glass block, shutters or any other external protection device.
CONNECTOR: A mechanical device for securing two or more pieces, parts, or members together, including anchors, wall ties, and fasteners.
CROWN FIRE: A fire that advances from top to top of trees or shrubs more or less independent of a surface fire.
DEFENSIBLE SPACE: An area, typically a width of 30 feet or more, between an improved property and a potential wildfire where the combustibles have been removed or modified.
DIAPHRAGM: A horizontal or nearly horizontal system designed to transmit lateral forces to shear walls or other vertical resisting elements.
DWELLING: A building occupied exclusively for residential purposes by not more than two families.
FASTENERS: Nails, wood screws, sheet metal screws, self tapping screws, “Tek” screws, bolts & nuts with washers, epoxy (glued) anchors, lag bolts or “J” bolts, etc.
FILLET WELD: A weld where two pieces of metal or other material are welded together at a right angle on the inside of the joint.
FIRE FRONT: That part of a fire within which continuous flaming combustion is taking place. Unless otherwise specified it is assumed to be the leading edge of the fire perimeter.
FIRE-RESISTANT ROOFING: The classification of roofing assemblies A, B or C as defined in the Uniform Building Code (UPC) Standard 32.7.
FIRE-RESISTIVE RATING: The time that the material or construction will withstand fire exposure as determined by a fire test made in conformity with the standard methods of fire tests of building, construction and materials, glowing phases of combustion by direct application to the burning fuel.
FIREBRAND: Any source of heat, natural or human made, capable of igniting wildland fuels. Flaming or glowing fuel particles that can be carried naturally by wind, convection currents, or by gravity into unburned fuels. Examples include: leaves, pine cones, glowing charcoal, and sparks.
FIREBREAK: A natural or construct barrier used to stop or check fires that may occur, or to provide a control line from which to work.
FIREWISE LANDSCAPING: Vegetative Management that removes flammable fuels from around a structure to reduce exposure to radiant heat. The flammable fuels may be replaced with green lawn, gardens, certain individually spaced green, ornamental shrubs, individually spaced and pruned trees, decorative stone or other non-flammable or flame-resistant materials.
FLASHING: A material, such as sheet metal, used in roof and wall construction to shed water.
FOOTING: A masonry section usually made of concrete, in a rectangular form wider than the bottom of the foundation wall or pier it supports.
FUEL BREAK: An area, strategically located for fighting anticipated fires, where the native vegetation has been permanently modified or replaced so that fires burning into it can be more easily controlled.
Fuel breaks divide fire-prone areas into smaller areas for easier fire control and to provide access for fire fighting.
FUEL MODIFICATION: Any manipulation or removal of fuels to reduce the likelihood of ignition or the resistance to fire control.
FUELS: All combustible material within the wildland/ urban interface or intermix, including vegetation and structures.
GABLE: The upper triangular-shaped portion of the end wall of a house above the eave line of a double sloped roof.
GABLE END: The entire end wall of a house having a gable roof.
GROUND FUELS: All combustible materials such as grass, duff, loose surface litter, tree or shrub roots, rotting wood, leaves, peat or sawdust that typically support combustion.
HIGH VELOCITY HURRICANE ZONE (FBC): This zone consists of Broward and Dade counties.
HORIZONTAL SEPARATION: The distance in feet measured from the building face to the closest interior lot line, to the centerline of a street, alley or public way, or to an imaginary line between two buildings on the same property.
HURRICANE STRAPS: Galvanized steel or stainless brackets used to strengthen “wood to wood” and “wood to concrete” connections. Straps may also be referred to as “hurricane clips”.
HYDROSTATIC LOADS: Forces placed on a structure by water.
IGNITION PROBABILITY: Chance that a firebrand will cause an ignition when it lands on receptive fuels.
IMPACT RESISTANT GLASS: Glass formed where two pieces of annealed glass are bonded together with an interlayer that holds the glass in the window frame even when it is broken or shattered. Similar technology is used to make automobile windshields; the difference is that windshields are tempered.
IMPACT-PROTECTION: Shutter systems or impact-resistant glass systems used to protect windows, doors and openings from wind-borne debris.
INSULATED GLASS: A glass unit using more than one piece, i.e. “double pane” or “double glazed”, “triple pane” or “triple glazed”.
LADDER FUELS: Fuels that provide vertical continuity allowing fire to carry from surface fuels into the crowns of trees or shrubs with relative ease.
LAMINATED GLASS: Window systems that combine two panes of glass with a plastic middle insert to create impact-resistant surfaces.
LOAD/LOAD PATH: When wind forces are placed on a house, the force must ultimately make its way into the ground. For example, a wind load path can follow from the roof to the framing through a wall into the foundation and then into the ground. The path that the force takes is called the load path.
MITIGATION: Building or retrofitting an existing building to resist damage caused by natural disasters like hurricane, windstorm, wildfire, floods.
MODIFIED BITUMEN ROOF COVERING: One or more layers of polymer modified asphalt sheets. The sheet materials shall be fully adhered or mechanically attached to the substrate or held in place with an approved ballast layer.
NATURAL BARRIER: Any area where lack of flammable material obstructs the spread of wildfires.
NONCOMBUSTIBLE BUILDING MATERIAL: A material which meets either of the following requirements:
Materials that pass the test procedure set forth in ASTM E 136.
Materials having a structural base of noncombustible materials as defined in 1, with a surfacing not more than 1/8 inch (3.17 mm) thick which has a flamespread rating not greater than 50 when tested in accordance with ASTM E 84.
O.C., ON CENTRE: The measurement of spacing for structural members like studs, rafters and joists in a building, from the center of one member to the center of the next.
ORIENTED STRAND BOARD: Commonly referred to as “OSB” is a siding, or sheathing made from wood chips that are bonded together with glue under pressure and soaked or sprayed with sealants to resist damage caused by moisture.
PERMIT: An official document or certificate issued by the building official authorizing performance of a specified activity such as construction.
PIERS: A column of masonry, usually rectangular in horizontal cross section, used to support other structural members.
PILES: A support made of wood, concrete or other material that is driven or embedded into the ground. Examples include wood pilings used with elevated, coastal homes.
PRESCRIBED BURNING: Controlled application of fire to wildland fuels in either their natural or modified state, under specified environmental conditions, which allows the fire to be confined to a predetermined area, and to produce the fire behavior and fire characteristics required to attain planned fire treatment and resource management objectives.
PURLINS: Purlins are metal tracks used to support metal roofs or siding. Purlins can also mean the members placed at right angles to rafters to break up the roof board span.
RACKING: A misshaping of a frame caused when horizontal loads applied to vertical boards displace the frame from its rectangular position.
RAFTER (ROOF JOIST): The pitched roof board used in conventional framing. This is also referred to as the “top chord” of the truss.
RAKE BEAM: The beam that supports the roof on a gable or the top two sides of the triangle that form the gable.
REINFORCED GLASS: Glass formed by using a wire mesh or other strands inside the glass. This process makes it more burglar or missile-resistant.
REROOFING: The process of recovering or replacing an existing roof covering.
ROOF ASSEMBLY: A system designed to provide weather protection and resistance to design loads. The system consists of a roof covering and roof deck or a single component serving as both the roof covering and the roof deck. A roof assembly includes the roof deck, vapor retarder, substrate or thermal barrier, insulation and roof covering.
ROOF COVERING: The covering applied to the roof deck for weather resistance, fire classification or appearance.
ROOF DECK SHEATHING: The intermediate covering on the roof deck, sometimes referred to as underlayment.
ROOF JOIST/RAFTER: The pitched roof board used in conventional framing. This is also referred to as the “top chord” of the truss.
ROOF MEMBRANE: See underlayment.
ROOF SHEATHING: The boards or sheet material fastened to the roof rafters on which the shingle or other roof covering is laid.
SCREEN ENCLOSURE: A building or part thereof, in whole or in part self-supporting, and having walls of insect screening with or without removable vinyl or acrylic wind break panels and a roof of insect screening, plastic, aluminum or similar lightweight material.
SECONDARY WATER RESISTANCE: A tar (bituminous) backed tape or membrane consisting of items such as self-adhering waterproof strips. This is sometimes referred to as “peel & seal”, or ice and snow shield.
SHEAR WALL: A bearing wall designed to resist lateral forces from other than its own mass, acting in the plane of the wall.
SHEATHING: The material covering the house frame on the exterior.
SILL PLATE: The framing board that the wall rests on or that carries the weight of a wall. A typical sill plate is a 2”x 4” or 2”x 6” treated wood board that is bolted into the slab.
SLAB ON GRADE: A one- piece slab and footer that is poured at the same time on level ground.
SLOPE: The variation of terrain from the horizontal; the number of feet rise or fall per 100 feet measured horizontally, expressed as a percentage.
SOFFIT: The underside of the eave system. Soffits are usually vented to provide airflow to the attic areas.
SPALLING: When poured concrete chips, fragments or breaks apart. This problem is usually caused when the reinforcement bar (rebar) is located too close to surface or edges. It can also result from improper or inconsistent concrete mixture or a combination of excessive moisture and temperature change.
STEMWALLS: A concrete block or brick wall used on top of the footer for “off grade” houses where the ground slopes from one side to the other.
STRUCTURAL FOAM: Commercially available substance used to reinforce roof sheathing to rafters/trusses.
SUPPRESSION: Suppression is the most aggressive fire protection strategy. The goal of suppression is to totally extinguish the fire.
SURFACE FUEL: Fuels lying on or near the surface of the ground, consisting of leaf and needle litter, dead branch material, downed logs, bark, tree cones, and low stature living plants.
TEMPERED GLASS: Annealed glass that is baked or tempered. Tempered glass breaks into small pieces instead of shattering and offers a safety advantage.
TENSION TIE DOWNS: Metal connectors that secure masonry or other material to adjoining frames or the foundation.
TOENAILING: The practice of nailing at an angle to the first member to ensure penetration into a second member.
TOP PLATE: The horizontal board, typically two-ply, nailed to the top of the partition or wall studs in a building.
TREE CROWN: The primary and secondary branches growing out from the main stem, together with twigs and foliage.
TRUSSES: A truss system includes the top chord or rafter (where roof sheathing is nailed), a joist or bottom chord (where the interior ceiling is nailed) and angled pieces that form a web and are used to add strength.
UNDERLAYMENT: One or more layers of felt, sheathing paper, non-bituminous saturated felt, or other approved material over which a steep-slope roof covering is applied.
UPLIFT: Wind moving over a structure causes negative wind pressure (suction) to be placed on a building that creates uplift forces (upward pull). Roofs are designed to resist uplift caused when high winds travel over and across the roof.
URBAN INTERFACE: Any area where wildland fuels threaten to ignite combustible homes and structures.
WALL STUDS: Usually 2”x 4” or 2”x 6” wood or metal these run vertically from the bottom plate (floor) to the top plate (ceiling).
WALL TOP PLATE: Usually consists of 2- 2”x 4” or 2- 2”x 6” nailed on top of each other at the top of your wall. Supports the roof trusses and provides the attachment point for wall to roof.
WALL, BEARING: A wall supporting any vertical load in addition to its own weight.
WALL, EXTERIOR: A wall, bearing or nonbearing, which is used as an enclosing wall for a building, other than a party wall or fire wall.
WALL, FOUNDATION: A wall below the first floor extending below the adjacent ground level and serving as support for a wall, pier, column or other structural part of a building.
WALL, NONBEARING: A wall that supports no vertical load other than its own weight.
WEATHER BARRIER: The outer most assembly of the building envelope, used to protect the inner structure and insulation from the effects of wind and rain. Materials typically used are siding, building paper and flashing.
WILDFIRE: An unplanned and uncontrolled fire spreading through vegetative fuels, at times involving structures.
WILDLAND: An area in which development is essentially nonexistent, except for roads, railroads, power lines, and similar transportation facilities. Structures, if any, are widely scattered.
WILDLAND FIRE: Any fire occurring on the wildlands, regardless of ignition source, damages or benefits.
WILDLAND/URBAN INTERFACE: Any area where wildland fuels threaten to ignite combustible homes and structures.
WIND LOAD: The forces superimposed on a building or structure by the movement of an air mass at a specified velocity.
WIND-BORNE DEBRIS: Missiles or airborne projectiles that cause glass breakage and other damage to buildings during severe wind events.
WIND-BORNE DEBRIS IMPACT RESISTANT PRODUCTS: Products that meet Standards PA 201-94, PA 202-94, SSTD-12 and ASTM E1996 and that have a valid Notice of Approval (NOA).
WIND-BORNE DEBRIS REGION: The American Society of Civil Engineers (ASCE) definition for areas within hurricane prone regions that are located either (1) within one mile of the coastal mean high water line where the basic wind speed is equal to or greater than 110 mph and in Hawaii, or (2) areas where the basic wind speed is equal to or greater than 120 mph.
(Note: Hurricane prone regions are areas in the United States and its territories that are vulnerable to hurricanes. They include the US Atlantic Ocean; the Gulf of Mexico coasts where basic wind speed is great than 90 mph; Hawaii; Puerto Rico; Guam; Virgin Islands and American Samoa.)