Sacrificial protection—Reducing the extent of corrosion of a metal in an electrolyte by coupling it to another metal that is electrochemically more active in the environment, i.e., galvanic protection.

Saddle—A small structure that helps to channel surface water to drains. Frequently located in a valley, a saddle is often constructed like a small hip roof or like a pyramid with a diamond-shaped base (Also See Cricket).

Salvage value—The value of an asset, assigned for tax computation purposes, that is expected to remain at the end of the depreciation period.

Sandwich panel—A panel assembly used as covering; consists of an insulating core material with inner and outer skins.

SBA—Systems Builders Association (Formerly MBDA)

SBC—Standard Building Code (See SBCCI) SBCCI—Southern Building Code Congress International, Inc. Sealer—Equivalent name for counter in an electronic circuit.

Scanning line frequency—The number of lines scanned by an infrared scanner per second. The number of lines in a TV picture divided by the number of times per second that the picture is repeated.

Scarf—To scrap or abrade a surface to remove degraded or wet polyurethane foam.

Sealing washer—A metal-backed rubber washer assembled on a screw to prevent water from migrating through the screw hole.

Seam strength—Strength of a seam of material measured either in shear or peel modes. Strength of the seams is reported either in absolute units, e.g., pounds per inch of width, or as a percent of the strength of the sheeting.

Secondary members—Members which carry loads to the primary members. In metal building systems, this term includes purlins, girts, struts, diagonal bracing, wind bents, flange, and knee braces, headers, jambs, sag members, and other miscellaneous framing.

Section modulus—A mathematically obtained physical property of a structural member of a given cross-sectional area. It is used in design and basically describes the bending strength of a member.

Seismic load—Seismic load is the assumed lateral load acting in any horizontal direction on the structural system due to the action of earthquakes.

Self-drilling screw—A fastener which drills and taps its own hole. It is used as a fastener for attaching panels to purlins and girts.

Self-tapping screw—A fastener which forms receiving threads when turned into a previously drilled hole. It is for attaching panels to purlins and girts and for connecting trim and flashing.

Selvage—An edge or edging which differs from the main part of: (1) A fabric, or (2) Granule surfaced roll roofing.

Shark fin—Curled felt projecting upward through the flood coat and aggregate of a BUR membrane.

Shear—The force tending to make two contacting parts slide upon each other in opposite directions parallel to their plane of contact.

Screeding—The process of striking off the excess concrete

Sheeting—A form of plastic or rubber in which the thickness is
bring the top surface of the concrete to proper finish and elevation.

Scrim—A woven, open mesh reinforcing fabric made from continuous filament yarn. Used in the reinforcement of polymeric sheeting.

Scupper—Channel through parapet, designed for peripheral drainage of the roof, usually a safety overflow to limit accumulation of ponded rainwater caused by clogged drains.

Sealant—Any material which is used to close up cracks or joints to protect against leaks. Lap sealant is applied to exposed lap edges in E/P systems.

Shelf-life—Maximum safe time to store a fluid construction material before use.

Shingle—(1) A small unit of prepared roofing designed for installation with similar units on overlapping rows on inclines normally exceeding 25%; (2) To cover with shingles, and (3) To apply any sheet material in overlapping rows like shingles.

Shingling—(1) The procedure of laying parallel felts so that one longitudinal edge of each felt overlaps, and the other longitudinal edge underlaps an adjacent felt. (See also Ply). Normally, felts are shingled on a slope so that the water flows over rather than against each lap; (2) The application of shingles to a sloped roof.

Shoulder bolt—A fastener used to attach wall and roof paneling to the structural frame. It consists of a large diameter shank and a small diameter stud. The shank provides support for the panel rib.

SI—The international symbol for the metric unit (Le Systeme International d'Unites).

Side lap—The continuous overlap of closures along the side of a panel.

Side lap fastener—A fastener used to connect panels together at the side lap.

Sieve—An apparatus with square apertures for separating sizes of material.

Siliconized polyesters—Polyesters modified by the addition of silicon, an inorganic substance. Possess superior exterior durability, non-chalking properties and gloss retention features.

Sill—The bottom horizontal framing member of an opening such as a window or door.

Simple span—The term used in structural analysis to describe a support condition for a beam, girt, purlin, etc., which offers no resistance to rotation at the supports. A span between two supports, each of which is free to rotate.

Single slope—A sloping roof with one surface. The slope is from one wall to the opposite wall of rectangular building.

Single span—A building or structural member without intermediate support.

Siphon break—A small groove to arrest the capillary action of two adjacent surfaces.

Skylight—A roof accessory to admit light, normally mounted on a curbed, framed opening.

Slab—A semi-finished steel product, intermediate between ingot and plate, with the width at least twice the thickness.

Slippage—Relative lateral movement of adjacent felts (or sheets) in a roof membrane. It occurs mainly in roofing membranes on a slope, sometimes exposing the lower plies or even the base sheet to the weather.

Slope—The tangent of the angle between the roof surface and the horizontal plane, expressed as a percentage, or in inches of rise per foot of horizontal distance. (See also Incline)

Smooth surfaced roof—A roof membrane without mineral aggregate surfacing.

Snow load—A load imposed on buildings or other structures due to snowfall.

Soffit—The underside covering of any exterior overhanging section of a roof, gable or sidewall.

Softening point—The temperature at which a bitumen becomes soft enough to flow as determined by an arbitrary, closely defined method.

Softening point drift—Change in softening point during storage or application (See also Fallback).

Solid mopping—See Mopping.

Solubility—The amount of a substance that can be dissolved in a given solvent under specified conditions.

Spacer bar—A standard measuring bar, used to guide the erection of metal panels to maintain uniform modular distance.

Spall—A chip or fragment of concrete which has chipped, weathered, or otherwise broken from the main mass of concrete.

Span—The distance between supports of beams, girders, or trusses.

Spangle—An individual zinc crystal or crystal aggregates present in zinc coating. Formed in regular patterns resembling a frosted windowpane.

Specifications—A statement of particulars of a given job, as to size of building, quality, and performance of men and materials to be used, and the terms of the contract.

Spectral absorptance—The quantity characterizing the ability of a substance to retain radiation which is incident upon it. It is equal to the ratio of the amount of radiation absorbed by a substance to that which would be absorbed by a black body for given wave length.

Spectral range—A region of the electromagnetic spectrum defined by a continuity of wave lengths between two defined wave length limits.

Spectral reflectance—The quantity characterizing the surface of a substance equal to the ratio of the amount of incident radiation which is reflected to that which would be reflected by a black body for a given wave length.

Splice—A connection in a structural member; in E/P systems, the joining of adjacent sheets.

Spot wobbling—A method of display on an IR scanner which broadens the lines of the display thereby filling the spaces between the lines on the screen. Sometimes used to improve the apparent resolution of the picture.

Sprinkle mopping—See Mopping.

Spud—To remove the roofing aggregate and most of the bituminous top coating by scraping and chipping.

Spudder—Heavy steel implement with a dull, bevel-edged blade for removing embedded aggregate from a BUR membrane surface.

Spunbonded—A generic name for nonwoven fabrics formed directly from polymer chips, spun into continuous filaments which are laid down and bonded continuously, without an intermediate step.

Spunlaced—A hydroentangled nonwoven fabric whereby a dry laid staple fabric is mechanically bonded by water jet which entangles the individual fibers.

Square—A roof area of 9.29 m2 (100 ft2), or enough material to cover 9.29m2 of deck.

Stack vent—A vertical outlet designed to relieve pressure exerted by water vapor between a membrane and the vapor retarder or deck.

Stainless steel—An alloy of steel which contains a high percentage of chrominum. Also may contain nickel or copper. Has excellent resistance to corrosion.

Standing seam—Watertight seam type featuring an upturned rib, which may also be structural. It is made by turning up the edges of two adjacent metal panels and then folding them over in one of a variety of ways.

Standing water test—Evaluations in which test panels are submerged in aqueous solutions and alternately dried in air.

Starting platform—A movable platform used to support a seaming machine as it begins to roll-seal a metal seam.

Steep asphalt—A relatively viscous roofing asphalt conforming to the requirements of Specification D 312, Type III.

Strain—A change in length per unit length. It is the deformation of a body that is acted upon by forces.

Strawberry—See Blueberry.

Stress—(1) A measure of the load on a structural member in terms of force per unit area, (kips per sq. in.) (MPa); (2) The force acting across a unit area in solid material in resisting the separation, compacting or sliding that tends to be induced by external forces. Also the ratio of applied load to the initial cross sectional area, or the maximum stress in the outer fibers due to an applied flexural load.

Stress concentration—A condition in which stress is highly localized, usually induced by an abrupt change in the shape of a member or at a substrate joint (e.g., between insulation joints)

Stress relaxation—The time-dependent change in the stress which results from the application of a constant total strain to a specimen at a constant temperature. The stress-relaxation at a
given elapsed time is equal to the maximum stress resulting when the strain is applied minus the stress at the given time.

Strikethrough—A term used in the manufacture of fabric reinforced polymeric sheeting to indicate that two layers of polymer have made bonding contact through the scrim.

Strippable films—Added protection sometimes applied to continuous strip in coil coating process. Applied after prime and top coats to resist damage prior to and during erection.

Stripping—Strip flashing: (1) The technique of sealing a joint between metal and built-up membrane with one or two plies of felt or fabric and hot- or cold-applied bitumen; (2) The technique of taping joints between insulation boards or deck panels.

Strut—A brace fitted into a frame work to resist forces parallel to its length.

Styrene Butadiene Styrene Copolymer (SBS)—High molecular weight polymers that have both thermoset and thermoplastic properties, formed by the block copolymerization ofstyrene and butadiene monomers. These polymers are used as the modifying compound in SBS polymer modified asphalt roofing membranes to impart rubber-like qualities to the asphalt.

Substantial completion—The stage in the progress of the work when it is sufficiently complete for the owner to occupy or utilize the work for its intended use.

Substrate—The surface upon which the roofing or waterproofing membrane is placed (structural deck or insulation).

Suction—A partial vacuum resulting from wind loads on a building which cause a load in the outward direction.

Super-steep asphalt—A high viscosity roofing asphalt conforming to the requirements of Specification D 312, Type IV.

Supported sheeting—See Fabric reinforcement

Surface cure—Curing or vulcanization which occurs in a thin layer on the surface of a manufactured polymeric sheet or other items.

Surface passivation—The changing of the chemically active surface of a metal to a much less reactive state.

Surfactants—Surface active agents that reduce surface tension when dissolved in water or water solutions, or reduce interfacial tension between two liquids, or between a liquid and a solid.

Susceptibility—When not otherwise qualified, the degree of change in viscosity with temperature.