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Viewing results 0 - 10 of 112 matches for "L" Back   |   Next
labeled
equipment or materials to which a label, symbol, or other identifying mark of an organization, acceptable to the authority having jurisdiction, has been attached. This organization is concerned with product evaluation and maintains periodic inspection of the production of labeled equipment or materials. By labeling the equipment or materials, the manufacturer indicates compliance with appropriate standards or performance in a specified manner.
laboratory
facility acceptable to the local, national, or international recognized authority having jurisdiction and which provides uniform testing and examination procedures and standards for meeting design, manufacturing, and factory testing requirements.
laboratory fume hood
box-like structure enclosing a source of potential air contamination, with one or more open or partially open sides into which air is moved for the purpose of containing and exhausting air contaminants. A laboratory hood is generally used for bench scale laboratory operations but does not necessarily involve the use of a bench or table.
labyrinth seal
device consisting of a series of grooves, fins, etc., machined into or fitted onto a shaft, piston, packing piece, etc. to prevent leakage of a fluid.
lag
(1) delay attributable to the transport of material or the finite rate of propagation of a signal or condition. Note: also termed transport lag and transportation lag. (2) delay in action of the sensing element of a control device due to the time required for the sensing element to reach equilibrium with the variable being controlled (i.e., temperature lag, flow lag). (3) in thermal insulation, preformed, narrow blocks attached around large pipes or vessels by wires or bands. (4) retardation of an output with respect to the causal input.
Lambert’s law
(1) illumination of a surface by a light ray varies as the cosine of the angle of incidence between the normal to the surface and the incident ray. (2) luminous intensity in a given direction radiated or reflected by a perfectly diffusing plane surface varies as the cosine of the angle between that direction and the normal to the surface.
laminar flow
having airflow nominally in one direction.
lap weld
weld formed by lapping two pieces of metal and then pressing or hammering; applied particularly to the longitudinal joint produced by a welding process for tubes or pipe, in which the edges of the skelp are beveled or scarfed so that when they are overlapped, they can be welded together.
latent cooling capacity
the rate, expressed in Btu/h (W), at which the equipment removes latent heat (reduces the moisture content) of the air passing through it under specified conditions of operation.
latent cooling effect
that portion of the cooling effect that results in water vapor condensation in the air circulating through the equipment.
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About ASHRAE Terminology

ASHRAE Terminology, a free resource, is a comprehensive online glossary of more than 3700 terms and definitions related to the built environment, with a focus on heating, ventilating, and air conditioning (HVAC), as well as refrigeration, building envelope, electrical, lighting, water and energy use, and measurement terms.

This searchable glossary was designed for use by engineering professionals but is also useful for architects, building owners and operators, educators, public officials, and homeowners.

The terms in ASHRAE Terminology have been assembled and defined and are updated on an ongoing basis by ASHRAE Technical Committee (TC) 1.6, Terminology. TC 1.6 is concerned with terminology, nomenclature, definitions, abbreviations, symbols, and the International System (SI) and Inch-Pound (I-P) units used in the fields of heating, ventilating, air conditioning, water heating, and refrigeration.

To request a free electronic file of the complete list of terms and definitions, email ashraetermseditor@ashrae.org.