Label: A label on equipment that contains operational design specifications and data, also referred to as label plate, nameplate, and data plate.

Labeled: Devices, equipment or materials to which have been affixed a label, seal, symbol or other identifying mark of product evaluation.

Ladder Cage: A means of enclosure that completely encompasses a portion of the climbing space of a fixed ladder and is permanently attached to the side rails. It is also referred to as a cage guard or basket guard.

Lap Seam: Two overlapping membranes that meet and are seamed, sealed or bonded in some way.

Latent Heat: Heat that is felt and not measured.

Lavatory: A sink or wash basin.

Ledger: Dimensional lumber attached to the building framing and used for supporting the section of a deck adjacent to the building.

Length of Climb: The total distance between the start and endpoints of a fixed ladder, including any breaks that exist between multiple ladder installations.

Let-In Brace: Nominal 1-inch-thick boards applied diagonally into notched studs.

Level: Term used to describe any horizontal surface whereby all sides are at the same elevation.

Life Expectancy: Average function time, in years, assuming regular maintenance.

Life Expectancy: The average function time, in years, assuming regular maintenance.

Lintel: A horizontal structural member that supports the load over an opening, such as a door or window.

Liquid-Applied: A continuous roof membrane constructed in place using one or more coats to provide fully adhered, waterproof membranes that conform to all contours.

Listed: Equipment, materials or services included in a list published by an organization that is acceptable to the authority having jurisdiction (AHJ), and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials, or periodic evaluation of services, and whose listing states that the equipment, material or service meets appropriate designated standards, or has been tested and found suitable for a specified purpose.

Live Load: A transient, variable load that may be imposed by gravity, by the building’s occupants, or by the environment, such as seismic, hydrostatic (a water source), snow, or wind.

Lock Jam: The vertical side of a door frame where the locking mechanism is installed.

Lock Stile: The vertical side of the door itself where hinges are attached.

Loose-Laid Membrane: A membrane that is loosely laid over the substrate and anchored only at the roof’s perimeter and penetrations.

Low-Slope Roof: A roof having a slope of 1/4:12 up to 3:12.