Sealant: (1) A material that has the adhesive and cohesive properties to form a seal; (2) A mixture of polymers, fillers, and pigments used to fill and seal joints where moderate movements is expected; unlike caulking, it cures to a resilient solid.
Sealer: A coating designed to prevent excessive absorption of finish coats into porous surfaces; a coating designed to prevent bleeding.
Seam: A joint formed by mating two separate sections of material. Seams can be made or sealed in a variety of ways, including adhesive bonding, hot air welding, solvent welding, using adhesive tape, sealant.
Series Circuit: The simplest arrangement of an electrical circuit; all the elements of the circuit are connected onto each other.
Series – Parallel Circuit: A combination of the series and the parallel circuits; part of the circuit is in series and part of the circuit is parallel.
Service Temperature Limits: The minimum or maximum temperature at which a coating, SPF or other material will perform satisfactorily.
Short Circuit: A direct electric connection of very low resistance across the power source or a component, usually resulting in fault currents.
Short Haul Inspection: Taking a vessel out of the water to examine the vessel’s wetted surface, underwater running gear, and fittings around penetrations in the hull that allow water intake and discharge. On small craft the short haul lasts for approximately 1-2 hours during which time the bottom of the hull is cleaned with a pressure washer and allowed to air dry. Following the inspection, the vessel is returned to the water. Thermal infrared inspection of the hull’s wetted surface is applicable as the thermal mass attempts to equilibrate with atmospheric temperature. Larger yachts are typically hauled, bottoms cleaned and then moved to an area in the boatyard where they are stored for several days before being returned to the water.
Siding: The finish covering of an exterior wall of a frame building. Siding may be a cladding material such as wood, aluminum or vinyl (but not masonry).
Single-Ply Membranes: Roofing membranes consisting of one layer of membrane material (either homogeneous or composite) rather than multiple layers.
Single-Ply Roofing: A roofing system in which the principal roof covering is a single layer flexible membrane often thermoset or thermoplastic membrane.
Skylight: An opening in a roof that is glazed with a transparent or translucent material, used to admit diffused light to the space below.
Slag: A hard aggregate that is left as a residue from blast furnaces, which may be used as a surfacing material on certain (typically bituminous) roof membrane systems.
Small Craft: The term that identifies vessels up to 79 feet (24 meters) in length.
Snow Guard: (1) A series of devices attached to the roof in a pattern that attempts to hold snow in place, thus preventing sudden snow or ice slides from the roof. (2) Any device intended to prevent snow from sliding off a roof.
Snow Load: The live load due to the weight of snow on a roof. This weight should be included in design calculations.
Soffit: The exposed undersurface of any exterior overhanging section of roof eave.
Soffit Vent: A pre-manufactured or custom-built air inlet source located at the down-slope eave or in the soffit of a roof assembly.
Solar Cell: An electrical device that converts the energy of light directly into electricity by the photovoltaic effect.
Solar Driven Infrared Thermography: Technique employed that utilizes the sun to create a detectable temperature differential across the surface of an object.
Solar Irradiance: A measure of solar power in the form of electromagnetic radiation striking a given area of the Earth’s surface.
Solar Panel: A set of solar cells electrically connected and mounted on a supporting structure. Solvent: Any liquid used to dissolve another material.
Specification: A precise statement of a set of requirements to be satisfied by a material, product, system, or service.
Specular Reflector: A surface that produces a direct image of a reflected source.

Spot Radiometer: An electronic device that converts IR energy emitted by an object surface into a temperature value.
Sprayed Polyurethane Foam (SPF): A foamed plastic material, formed by spraying two components, PMDI (A compound) and a resin (B compound) to form a rigid, fully adhered, water-resistant, and insulating membrane.
Square: A unit used in measuring roof area equivalent to 100 square feet (100 sf) of roof surface.
Standard: (1) A set of specifications established for use as a rule or basis or comparison in measuring or judging capacity, quantity, content, extent, value, quality, etc. (2) A level of excellence, attainment, etc., regarded as a measure of adequacy. (3) Standard applies to some measure, principle, model, etc., with which things of the same class are compared in order to determine their quantity, value, quality, etc. (standards of purity for drugs).
Standing Seam: In metal roofing, a type of seam found between adjacent sheets of material. It is made by turning up the edges of two adjacent metal panels and then folding or interlocking them in a variety of ways.
Step-Down Transformer: A transformer whose secondary voltage is less than the primary voltage.
Step-Up Transformer: A transformer whose secondary voltage is higher than the primary voltage.
Stress: The internal resistance of a material to a force, measured as a force per unit area.
Substrate: The surface upon which the roofing or waterproofing membrane is applied (e.g., in roofing, the structural deck or insulation).
Surface-Modifying Material: Any tape, spray, or paint that is used to change the emittance of an object.
Switch: Device for directing or controlling the current flow in a circuit.
