McKillican | Green Reference - Terms starting with the letter P

Terms starting with ...

Paint	Any pigmented liquid, liquifiable, or mastic composition designed for application to a substrate in a thin layer that converts to an opaque solid film after application.
Pallet	A low wood or metal platform on which material can be stacked to facilitate mechanical handling, moving, and storage.
Paperboard	The distinction between paper and paperboard is not sharp, but broadly speaking, the thicker (greater than 0.3 mm (0.012 in.)), heavier, and more rigid grades of paper are called paperboard.
Papreg	Any of various paper products made by impregnating sheets of specially manufactured high-strength paper with synthetic resin and laminating the sheets to form a dense, moisture-resistant product.
Parallel Strand Lumber (PSL)	A structural composite lumber made from wood strand elements with the wood fiber oriented primarily along the length of the member.
Parenchyma	Short cells having simple pits and functioning primarily in the metabolism and storage of plant food materials. They remain alive longer than the tracheids, fibers, and vessel elements, sometimes for many years. Two kinds of parenchyma cells are recognized-those in vertical strands, known more specifically as axial parenchyma, and those in horizontal series in the rays, known as ray parenchyma.
Particleboard	A panel products made from sawdust and other residue that comes in different densities and characteristics to suit specific end uses.
Particles	The aggregate component of particleboard manufactured by mechanical means from wood. These include all small subdivisions of wood such as chips, curls, flakes, sawdust, shavings, slivers, strands, wafers, wood flour, and wood wool.
Passive Solar	Non-mechanical methods of using sunlight to heat the home. Conceptually, sunlight is let into the house to heat a thermal mass, such as a slab floor, which then in turn radiates the heat back into the house when needed at night.
Patterned Lumber	Lumber that is shaped to a pattern or to a molded form in addition to being dressed, matched, or shiplapped, or any combination of these workings.
Peck	Pockets or areas of disintegrated wood caused by advanced stages of localized decay in the living tree. It is usually associated with cypress and incense-cedar. There is no further development of peck once the lumber is seasoned.
Peel	To convert a log into veneer by rotary cutting. In an adhesively bonded joint, the progressive separation of a flexible member from either a rigid member or another flexible member.
Perlite	Expanded volcanic glass, very light in weight and useful as insulation although it has a lower R-value than some materials. It can be added to plaster and is fire resistant.
Permaculture	A design system that integrates landscape and building issues, permaculture emphasizes low maintenance, edible landscaping, and single design features (including plants) that fill more than one function.
Pervious Paving	Paving systems that allow surface water to percolate through to the ground below and thereby minimize stormwater run off. Also known as porous pavement or permeable surfaces.
Phenols	Hydrocarbons used to make resins and glues. Very toxic and may off gas.
Phloem	The tissues of the inner bark, characterized by the presence of sieve tubes and serving for the transport of elaborate foodstuffs.
Photovoltaics (PVs)	Photovoltaic cells (or PV cells) are solar panels that have no moving parts, yet they convert sunlight directly into electricity to be used to satisfy all of a building's electricity needs. The energy can be used immediately, stored in batteries, or fed directly into a city's electric power grid via electronic devices called inverters. (See also BIPVs)
Pile	A long, heavy timber, round or square, that is driven deep into the ground to provide a secure foundation for structures built on soft, wet, or submerged sites (for example, landing stages, bridge abutments).
Pin Knot	A knot that is not more than 12 mm (1/2 in.) in diameter.
Pitch Pocket	An opening extending parallel to the annual growth rings and containing, or that has contained, pitch, either solid or liquid.
Pitch Streaks	A well-defined accumulation of pitch in a more or less regular streak in the wood of certain conifers.
Pith	The small, soft core occurring near the center of a tree trunk, branch, twig, or log.
Pith Fleck	A narrow streak, resembling pith on the surface of a piece; usually brownish, up to several centimeters long; results from burrowing of larvae in the growing tissues of the tree.
Plainsawn Lumber Grain	Another term for flat-grained lumber.
Planing Mill Products	Products worked to pattern, such as flooring, ceiling, and siding.
Plank	A broad, thick board laid with its wide dimension horizontal and used as a bearing surface.
Plastic Wood	A substitute wood product made from recycled plastic and wood strands.
Plasticizing Wood	Softening wood by hot water, steam, or chemical treatment to increase its moldability.
Platform-Frame Construction	The type of construction most often used in home building in which the floor joists are completed first and completely covered with a sub-flooring to form a platform upon which exterior walls and interior partitions are erected.
Ply	PLY - A term referring to any layer of veneer in a piece of plywood. A 3-ply panel has three layers of veneer, 5-ply has five layers, etc.
Plywood	A glued wood panel made up of relatively thin layers of veneer with the grain of adjacent layers at right angles or of veneer in combination with a core of lumber or of reconstituted wood. The usual constructions have an odd number of layers.
Pocket Rot	Advanced decay that appears in the form of a hole or pocket, usually surrounded by apparently sound wood.
Polar	Characteristic of a molecule in which the positive and negative electrical charges are permanently separated, as opposed to nonpolar molecules in which the charges coincide. Water, alcohol, and wood are polar in nature; most hydrocarbon liquids are not.
Polyethylene	A semi-transparent plastic used in sheets as vapor barriers or for packaging and containers. Made in high density (HDPE) and low density (LDPE) varieties. Low in toxicity, it produces low risk vapours when burned.
Polyethylene Terephthalate (PET)	Polyester fibers and sheet plastics such as recyclable soft drink bottles are made from this polyester resin.
Polymer	A compound formed by the reaction of simple molecules having functional groups that permit their combination to proceed to high molecular weights under suitable conditions. Polymers may be formed by polymerization (addition polymer) or polycondensation (condensation polymer). When two or more different monomers are involved, the product is called a copolymer.
Polymerization	A chemical reaction in which the molecules of a monomer are linked together to form large molecules whose molecular weight is a multiple of that of the original substance. When two or more different monomers are involved, the process is called copolymerization.
Pore	(See Vessel Elements)
Portland Cement	A type of cement made by burning limestone and clay at extremely high temperatures. It is a basic ingredient in concrete. The production of one tonne of cement produces approximately one tonne CO2 emissions. (See Greenhouse Gases)
Post Cure	(1) A treatment (normally involving heat) applied to an adhesive assembly following the initial cure, to complete cure, or to modify specific properties. (2) To expose an adhesive assembly to an additional cure, following the initial cure; to complete cure; or to modify specific properties.
Post-Consumer Recycled Content	Consumer waste that has become a raw material (feedstock) for another product. It originates from products that have served a useful purpose in the consumer market. Much of this feedstock comes from residential and commercial (office) recycling programs for aluminum, glass, plastic and paper. Other post-consumer feedstock is supplied by businesses that recycle construction and demolition debris.
Postformed Plywood	The product formed when flat plywood is reshaped into a curved configuration by steaming or plasticizing agents.
Postforming Grade	Can be formed around curved edges by application of heat and restraint. Maximum thickness is approximately 0.038” (0.97 mm) and can normally be formed to radii as small as 3/8” (9.5 mm).
Post-Industrial	Term used by some product manufactures in reference to their wood fibers. Per most sustainability programs, this term is not recognized and materials labeled such are to be considered same as "Pre-Consumer".
Pozzolan	A type of silicon/alumina material that occurs naturally and is produced as a byproduct of coal combustion. When powdered and moistened it will react with calcium hydroxide and water. Its most useable form is fly ash.
Pre-Consumer (% recycled content)	(See Post-Industrial Recycled Content)
Pre-Consumer Recycled Content	(Formerly known as post-industrial) Output from a process that has not been used as part of a consumer product, that is sold, traded, or exchanged under commercial terms as feedstock for another industrial process, and that would otherwise be landfilled, incinerated or somehow disposed of as a waste, as defined by the Federal Trade Commission. For instance, a composite board manufacturer may purchase (or haul away for free) sawdust from a lumber mill or waste straw from a wheat farm. Wood chips would not fit this definition.
Precure	Condition of too much cure, set, or solvent loss of the adhesive before pressure is applied, resulting in inadequate flow, transfer, and bonding.
Predicted Air Concentration	Basically, a concentration describes the amount of chemicals or particles contained in a unitized volume of air. When the air in a dynamic chamber is sampled, or an air sample is taken from an indoor environment, the mass collected is what is actually measured. The air concentration (µg/m3) is then derived as the collected mass of the contaminant (in micrograms, µg) divided by the amount of air sampled (m3). The measured air concentration is representative of what the building's occupants will be breathing. To convert a product's known emission characteristics to an approximation of the product's contribution to the actual indoor air, a predicted air concentration modeling calculation must be performed
Prefabricated Housing	(See Manufactured Housing).
Preservative	Any substance that, for a reasonable length of time, is effective in preventing the development and action of wood-rotting fungi, borers of various kinds, and harmful insects that deteriorate wood.
Pressure Process	Any process of treating wood in a closed container whereby the preservative or fire retardant is forced into the wood under pressures greater than one atmosphere. Pressure is generally preceded or followed by vacuum, as in the vacuum- pressure and empty-cell processes respectively; or they may alternate, as in the full-cell and alternating-pressure processes.
Psychrometer	An instrument for measuring the amount of water vapor in the atmosphere. It has both a dry-bulb and wet-bulb thermometer. The bulb of the wet-bulb thermometer is kept moistened and is, therefore, cooled by evaporation to a temperature lower than that shown by the dry-bulb thermometer. Because evaporation is greater in dry air, the difference between the two thermometer readings will be greater when the air is dry than when it is moist.
Purlins	Horizontal roof members that span the trusses or rafters and support the roof cladding.