Padmount Transformer A transformer designed for mounting on a concrete pad with underground connecting cables.
Palladian window A window arrangement with a half-round window on top of a wider rectangular window.
Panelboard The center for controlling electrical circuits.
Paradichlorobenzene a chemical ingredient in mothballs and certain deodoriser products, currently regarded as a possible carcinogen; p-dichlorobenzene
Parapet Low wall or railing at the edge of a roof; it extends above the roof level.
Parge coat Thin coat of cement mortar applied to a masonry wall for refinement or dampproofing.
Parking Stand Arrester A metal oxide varistor elbow with a parking stand bracket used for overvoltage protection of open point cable runs.
Parquet flooring Flooring, usually wood, laid in an alternating or inlaid pattern to form various designs.
Particles (Particulates) Solids or liquids light enough to be suspended in the air.
Particulates small airborne particles
Partition An interior wall that separates two rooms.
Party wall Wall common to adjoining buildings in which both owners share, such as a wall between row houses or condominiums.
Passive smoking the inhalation of environmental tobacco smoke; also called involuntary smoking
Passive vent an opening in the building exterior that is a planned exit point for exfiltration air
Pathogen any microorganism or substance that causes disease. An obligate pathogen requires a living host for survival. An opportunistic pathogen is an organism normally found in the flora of the human body or the environment that causes disease under unusual circumstances
Peak Demand The maximum integrated demand during a time period.
Peak Line Current Maximum instantaneous current during a cycle.
Pediment A triangular space formed in the middle of a gable; also used as a decoration above a door.
PELs Permissible Exposure Limits (standards set by OSHA).
Penicillium a genera of fungi found in indoor air, plant materials, and wet insulation, which has been associated with hypersensitivity pneumonitis in susceptible individuals
Penny Term used to identify nail size.
Percent IR (%IR) The voltage drop due to conductor resistance at rated current expressed in percent of rated voltage.
Percent IX (%IX) The voltages drop due to reactance at rated current expressed in percent of rated voltage.
Percent IZ (%IZ) The voltage drop due to impedance at rated current expressed in percent of rated voltage.
Pergola Open, structural framework over an outdoor area, usually covered with climbing vines to form an arbor.
Periphery Entire outside edge of an object or surface.
Permanent Threshold Shift (PTS) A permanent decrease of the ability to hear at a specified frequency as compared to a previously established reference level. The amount of permanent threshold shift is usually expressed in decibels._
Permissible Exposure Limit (PEL) 90 dBA TWA. Employees may be exposed to 90 dBA for an 8 hour time weighted average (TWA) exposure without experiencing serious hearing effects. An exposure limit that is published and enforced by OSHA as a legal standard. The PELs refer to levels of exposure and conditions under which it is believed that nearly all healthy workers may be repeatedly exposed, day after day without adverse effects. Currently, the OSHA PEL for noise is 90 dBA as an 8-hour Time-Weighted Average (TWA). Exposures at and above this level are considered hazardous.
Perspective A drawing of an object in a three dimensional form on a plane surface. An object drawn as it would appear to the eye.
Pesticide a chemical used to kill or control living organisms. Pesticides include insecticides, herbicides, fungicides, rodenticides, antimicrobial agents, and plant growth regulators
Ph A chemical symbol expressing the degree of acidity or alkalinity of a solution. The pH scale runs from 0 to 14, with 7 indicating neutrality. The pH number increases as alkalinity increases and decreases as acidity rises.
Phase Classification of an ac circuit usually single-phase, two wire or three wire; two-phase, three wire or four wire; or three-phase, three wire or four wire.
Picocurie a unit of measurement used to describe radon concentration. A curie is the amount of any radionuclide that undergoes exactly 3.7 x 1010 radioactive disintegrations per second. A picocurie is one trillionth (10-12) of a curie, or 0.037 disintegrations per second
PicoCurie (pCi) A unit for measuring radioactivity, often expressed as picocuries per liter (pCi/L) of air.
Pier Support, usually in the crawl space, to support the floor framing.
Pilaster Rectangular pier attached to a wall for the purpose of strengthening the wall; also a decorative column attached to a wall.
Piles Long posts driven into the soil in swampy locations, or whenever it is difficult to secure a firm foundation, upon which the foundation footing is laid.
Pillar A column used for supporting parts of a structure.
Pinnacle Projecting or ornamental cap on the high point of a roof.
Pitch Another term for sound frequency. Higher pitches are higher frequency sounds.
Pitot tube a device used to measure total and static pressures in an air stream
Plan A horizontal, graphic representational section of a building.
Plank Lumber 2" thick or more and more than 4" wide, such as joists, flooring, and the like.
Plaster A mortarlike composition used for covering walls and ceilings. Usually made of portland cement mixed with sand and water.
Plaster ground A nailer strip included in plaster walls to act as a gage for thickness of plaster and to give a nailing support for finish trim around openings and near the base of the wall.
Plasterboard A board made of plastering material covered on both sides with heavy paper.
Plat A map or chart of an area showing boundaries of lots and other parcels of property.
Plate Top or bottom horizontal members of a row of studs in a frame wall; also, the sill member over a foundation wall.
Plate cut The cut in the rafter that rests upon the plate. It is also called the seat cut or birdmounth.
Plate glass A high-quality sheet of glass used in large windows.
Platform Framing in which each story is built upon the other.
Plenum Air compartment connected to a duct or ducts in the HVAC system. Plenum the portions of the air distribution system that makes use of the building structure, and the sheet metal that connects distribution ductwork to an air handling unit. Many buildings use the space above a dropped ceiling as a plenum
Plenum system A system of heating or air-conditioning in which the air is forced through a chamber connected to distributing ducts.
Plot The land on which a building stands.
Plow To cut a groove running the same direction as the grain of the wood.
Plug flow a type of airflow whereby supply air moves in one direction from supply to exhaust, sweeping contaminants from the work space or breathing zone
Plumb Said of a member when it is in true vertical position as determined by a plumb bob or vertical level.
Plywood A piece of wood made of three or more layers of veneer joined with glue and usually laid with the grain of adjoining piles at right angles.
Pollutant Pathways Avenues for distribution of pollutants in a building.HVAC systems are the primary pathways in most buildings; however, all building components interact to affect how air movement distributes pollutants.
Polycyclic aromatic hydrocarbons (PAH) a group of complex organic substances generally associated with certain combustion processes, such as tobacco smoking, wood burning, and cooking. Health effects attributed to PAHs include cardiovascular effects and irritation. The US EPA classifies four PAH compounds as Group B2 probable carcinogens: benz(a)anthracene, benzo(a)pyrene, dibenzo(a,h)anthrancene, and 3-methylcholanthrene
Pontiac fever a form of legionellosis that is much milder than Legionnaire's disease. It has a short incubation period (2-3 days) and attacks 90% of those infected. Reports of Pontiac fever are rare, possibly because of the similarity of the symptoms --- fever, chills, headache, muscle ache
Porch A covered area attached to a house at an entrance.
Porte cochere A covered, drive-through structure that extends from the side of a home, providing shelter for people getting in and out of vehicles.
Portico A roof supported by columns; often used at an entry.
Portland cement A hydraulic cement, extremely hard, formed by burning silica, lime, and alumina together and then grinding up the mixture.
Positive Pressure Air will move from the space to outside the space where the pressure is lower.
Positive pressure differential a condition in which a given room or area is under higher pressure than adjacent areas
Post A perpendicular supporting member.
Post & beam construction Wall construction consisting of large, widely spaced posts to support horizontal beams.
Powder A granule form of soap or detergent. Powders differ in size, density, and form as a result of their method of manufacture.
Power Follow Current Refer to Follow Current.
Power Fuse In accordance with ANSI/IEEE C37.46, a power fuse (expulsion and current-limiting) has high voltage ratings of 2.8-167 kV and x/r ratios of 15-25 (refer to distribution fuse).
Power Outage An interruption of power.
Power-Frequency Sparkover Voltage The rms value of the lowest power-frequency sinusoidal voltage that will cause sparkover when applied across he terminals of an arrester.
Power-Frequency Withstand Voltage A specified rms test voltage at power frequency that will not cause a disruptive discharge.
PPM Parts per million. Measurement of concentration of particles in the air.
Precast Concrete shapes made separately before being used in a structure.
Prefabricated buildings Buildings that are built in sections or component parts in a factory, and then assembled at the site.
Presbycusis The decline in hearing acuity (ability) that is attributed to the aging process.
Prescribed Fire: (also called prescribed or controlled burn) A fire ignited under known conditions of fuel, weather, and topography to achieve specific objectives.
Prescription A statement or plan specifying management objectives to be obtained, and air temperature, humidity, season, wind direction and speed, fuel and soil moisture conditions under which a fire will be started or allowed to burn.
Preservative A substance that protects against the natural effects of aging, such as decay, discoloration, oxidation, and spoilage. In soap products, preservatives are used to prevent or slow down the natural tendency to develop rancidity upon aging. Preservatives also protect colors and fragrances. Butyrate hydroxytoluene, stannic chloride, or EDTA are the most commonly used preservatives in the cleaning chemical industry.
Presoak Product designed to loosen and remove grease and oils. Builder ingredients used in presoaks are sodium tripolyphosphate, sodium silicate and sodium carbonate. In non-phosphate formulations, builders are sodium bicarbonate and sodium citrate.
Pressure differential the difference between air pressures measured at two locations
Pressure, Static In flowing air, the total pressure minus velocity pressure. The portion of the pressure that pushes equally in all directions.
Pressure, Total In flowing air, the sum of the static pressure and the velocity pressure.
Pressure, Velocity. In flowing air, the pressure due to the velocity and density of the air.
Pressurisation a radon mitigation strategy based on adjusting ventilation until the air pressure inside the building is consistently higher than the air pressure in the area below the slab
Preventive maintenance a program of building maintenance implemented to reduce the possibility of IAQ problems, usually through periodic inspection, cleaning, adjustment, calibration, and replacement of functioning parts of the MVAC system, as well as housekeeping practices to reduce the buildup of potential contaminants
Primary Taps Taps added in the primary winding (see Tap).
Primary Voltage Rating Designates the input circuit voltage for which the primary winding is designed.
Primary Winding A winding connected to the voltage source or input.
Prime coat First coat of paint applied to wood or metal to prime the surface for succeeding coats.
process hazard analysis [PHA] A thorough, orderly, and systematic approach used to identify, evaluate, and control hazardous chemical processes. It involves a review of what could go wrong and what steps may be taken to safeguard against highly hazardous chemical releases.
process How diagram A diagram or set of diagrams of a process depicting the equipment, flow of material, control schemes, raw materials, operating conditions including temperature and pressure, process stream characteristics, intermediates, and products.
process safety information Written information on the highly hazardous chemicals, technology, and equipment associated with a process.
product liability The liability of a manufacturer, processor, or nonmanufacturing seller arising from personal injury or property damage caused by a defective or dangerous
product proficiency (Analytical) The ability to satisfy a specified level of analytical performance.
protectioa factor (Respiratory Protection) [PF] The ratio of the concentration of a contaminant in the ambient air to that inside a respirator.
protective clothing Special clothing that is worn to protect a worker from exposure to or contact with hazardous materials. Level A: Provides the highest level of protection from chemical hazards for both contact and respiratory protection. Level B: Provides the highest level of protection for respiration, but decreased skin protection. Level C: Provides minimum respiratory and skin protection and is used where there is no skin absorption hazard. Level D: No specific respiratory or skin protection is needed, and common work clothes are adequate.
protective hand cream A product designed to protect the hands from the harmful effects of some hazardous substances.
Psychogenic originating in the mind or in mental or emotional conflict
Psychogenic Illness This syndrome has been defined as a group of symptoms that develop in an individual, or group of individuals in the same environment, who are under some type of physical or emotional stress. This does not mean that individuals have a psychiatric disorder or that they are imagining symptoms.
Psychosocial Factors Psychological, organizational and personal stressors that could produce symptoms similar to those caused by poor indoor air quality.