Glossary – T

Tack: Any equipment used to ride or care for a horse, such as saddles, girths, cinches, bridles or wraps.


Tar: A brown or black bituminous material, liquid or semi-solid in consistency, in which the predominating constituents are bitumen’s obtained as condensates in the processing of coal, petroleum, oil-shale, wood, or other organic materials.


Tear-Off: The removal of all roof system components down to the structural deck, followed by installation of a completely new roof system. (See Reroof.)


Tear Resistance: The load required to tear a material, when the stress is concentrated on a small area of the material by the introduction of a prescribed flaw or notch. Expressed in psi (pounds force) per inch width.


Temperature Rise: Amount of heat a transformer or motor generates above the ambient temperature.


Tensile Strength: The strength of a material under tension as distinct from torsion, compression or shear.


Test Cut: A sample of the roof system or assembly which exposes the roof deck and is used to diagnose the condition of the membrane, evaluate the type and number of plies or number of membranes, or rates of application.


Thermal Anomaly: See Exception.


Thermal Block: A compression-resistant insulation block installed between structural steel roof panels
and their supporting members to help maintain insulation R-values and reduce condensation.


Thermal Conductance (C): (1) The time rate of heat flow through a unit area of a body induced by a unit temperature difference between bodies. (2) The number of BTUs that pass through specified thickness of a one square foot sample of material in one hour with temperature difference between the two surfaces of 1°F. (2) A thermal conductance (C) value applies to a specific thickness of a specific material.


Thermal Conductivity (K): (1) The time rate of heat flow through a unit area of a homogenous material in a direction perpendicular to isothermal planes induced by a unit temperature gradient. (2) The number of BTUs that pass through a 1 inch thickness of a 1 square foot sample of material in one hour with a temperature difference between the two surfaces of 1°F.


Thermalcouple: Two dissimilar metals joined at a common junction point. The junction of two dissimilar metals when heated produces a current flow. As this junction changes in temperature, the thermalcouple will provide different levels of currents.


Thermal Expansion: The increase in the dimension or volume of a body due to temperature variations.


Thermal Imager: Camera-like device capable of detecting, displaying and recording thermal patterns
across the surface of an object.


Thermal Infrared Inspection: The use of infrared imaging equipment to provide specific thermal information and related documentation about a structure, system, or object.


Thermal Insulation: A material applied to reduce the flow of heat.


Thermal Movement: Changes in dimension of a material as a result of temperature changes.


Thermal Resistance (R): (1) Under steady conditions, thermal resistance is the mean temperature difference between two defined surfaces of material or construction that induces unit heat flow through a unit area. (2) A thermal resistance (R) value applies to a specific thickness of a material or construction. (3) The thermal resistance (R) of a material is the reciprocal of the thermal conductance (C) of the same material (R=1/C).


Thermal Sensitivity: See Noise Equivalent Temperature Difference


Thermogram: A recorded visual image that maps the apparent thermal pattern of an object or scene
into a corresponding contrast or color pattern.


Thermographer: The person who performs infrared inspections. (See Infrared Thermographer.)


Thermoplastic Olefin (TPO): Polymer/filler blends usually consisting of some fraction of a thermoplastic, an elastomer or rubber, and a filler. Thermoplastics may include polypropylene (PP), polyethylene (PE), block copolymer polypropylene (BCPP), and others.


Through-Wall Flashing: A water-resistant membrane or material assembly extending totally through a wall and its cavities, positioned to direct water within the wall to the exterior, usually through weep holes.


TPO: See Thermoplastic Olefin.