GLOSSARY 

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L 

LAC

A natural resin secreted by insects that live on the sap of certain trees in Far Eastern countries. This resin is refined to make shellac. 
 

LACQUER

A coating composition based on synthetic, thermoplastic, film-forming material dissolved in organic solvent that dries primarily by solvent evaporation. 

LADDER HOOK

Steel hook shaped like an inverted U. One end attaches to the ladder and the other end hooks the ladder to a roof, pipe, or similar anchorage. 

LADDER JACK

A metal support that attaches to an extension ladder. When used in pairs, ladder jacks may support a plank or lightweight stage placed across them to form a light-duty scaffold. 

LADDER SHOE

A device mounted on the base of a ladder side rail to give stability and slip resistance to the ladder. 

LADDER, HIGHEST STANDING LEVEL

The rung or step of a ladder above which the user should never climb for safety reasons. 

LADDER, TYPES OF

  • STEPLADDER - A self-supporting ladder of fixed height, which usually has flat, broad, level steps, a movable back frame hinged to the front legs, and a spreading device to hold the ladder open.
  • DOUBLE STEPLADDER - A stepladder with steps on both sides.
  • STRAIGHT LADDER - A non-self-supporting ladder of fixed length, consisting of two parallel sides, or rails, joined by rungs.
  • EXTENSION LADDER - A non-self-supporting ladder of adjustable length; it consists of two or three straight ladder sections that fit together so that the ladder length can be adjusted using a rope and pulley.
  • TRESTLE LADDER - A self-supporting ladder of fixed height with two runged sections joined at the top with hinges and a spreader. A plank can be placed across the top of two trestle ladders to form a work platform.
  • EXTENSION TRESTLE LADDER - Essentially the same as a trestle ladder except for a vertical section that extends up between the angled sections.
  • SECTIONAL LADDER - A ladder made of two or more straight ladder sections that are designed to be locked together to form a single ladder.
  • ARTICULATED LADDER - A ladder with one or more joints that can be locked into position to enable it to be used as a straight ladder, stepladder, scaffold, or work table.
  • PLATFORM LADDER - A self-supporting, non-adjustable ladder with a platform at the highest standing level.
 

LADDER, WORKING LENGTH

The distance along the side rails of a non-self-supporting ladder from the bottom to the upper support points. 

LAITANCE

A thin, weak, brittle layer of cement and aggregate fines on a concrete surface usually caused by an overly wet or overworked mixture, improper or excessive finishing, or a combination of these factors. Laitance can create an egg-shell surface over hidden voids; if not removed before painting, the disintegration of the laitance will leave unfilled holes on the surface. 

LANYARD

A rope attached at one end to a D-ring on a safety belt or body harness and at the other end to a lifeline. Most lanyards have double-locking snap hooks and a shock absorber to reduce the impact of a fall being stopped. 

LAP

The region where one area of a coated surface merges into an adjacent, freshly coated area during application of a single coat. The objective of the painter is to avoid showing the lap. 

LATEX PAINT

A paint containing a stable aqueous dispersion of synthetic resin, produced by emulsion polymerisation, as the principal constituent of the binder. 

LEAD

A metal, previously used as a pigment in paints. Discontinued in the early 1950s by industry consensus standard, and banned by the Consumer Products Safety Commission in 1978 because of its toxicity. 

LEL METER

A device used to measure the concentration of combustible vapours in an air sample and determine whether or not it is explosive. 

LEVELING

A coating’s ability to flow out on a surface so that brush or roller marks or other irregularities produced during application are not apparent. 

LIFELINE

A safety line that is securely fastened above the job sit to a solid anchor on the building or structure and that extends to the ground. The worker’s safety belt or body harness is attached to the lifeline with a lanyard. An individual lifeline is required for each worker who must have fall protection equipment. 

LIFTING

Softening and raising or wrinkling of a previous coat of paint by the application of an additional coat. 

LINING PAPER

Blank stock used as a liner or surface conditioner to obtain a smoother surface and better adhesion before other wallcovering is applied. Lining paper can be used to cover rough surfaces such as cinder block, texture surfaces such as stucco or panelling, or cracked or defective surfaces so that the wallcovering will be flat and smooth. 

LINSEED OIL

Oil obtained from flaxseed. Linseed oil is used in paints in larger quantities than any other oil. It is considered a fine vehicle for exterior paints because of its excellent drying properties and durability. 

LIQUID DRIERS

Solution of soluble driers in organic Solvents. 

LIQUID WOOD FILLER

Varnish of low viscosity, usually containing extending pigment, used as a first coat on open-grain woods. 

LITHOPONE

A white pigment of barium sulphate and zinc sulphide. 

LITMUS TEST

The use of litmus paper or pH paper to measure the acidity or alkalinity (pH) of a water solution. 

LIVERING

The progressive, irreversible increase in consistency of a pigment-vehicle combination. Livering usually results from a chemical reaction of the vehicle with the solid dispersed material, but it also may result from polymerisation of the vehicle. The irreversible character of the changes distinguishes livered material from thixotropic "build-up," which is reversible. 

LONG OIL ALKYD RESIN

An alkyd resin made with a relatively high oil-to-resin ratio. 

LONG OIL VARNISH

An oleo-resinous varnish, other than alkyd, made with a relatively high oil-to-resin ratio.  Generally slower-drying, tougher, and more elastic than short oil varnishes. 

LOW SOLVENT COATING

Generally, a coating that contains a reduced amount of volatile organic compounds (VOC’s) in the paint as applied. 
 

LOWER EXPLOSIVE LIMIT (LEL)

The concentration, at ordinary ambient temperatures, of a compound in air below which an explosion will not occur if the mixture is ignited. 

LUMINOUS PAINT

A coating that emits light rather than just reflect it. There are three classes: fluorescent, which requires ultraviolet light to activate it; daylight fluorescent, which emits additional light from absorbed solar radiation; and phosphorescent, which continues to glow for some time after the external energy is removed.