— P —

Pack Test
Used to determine the aerobic capacity of fire suppression support personnel and assign physical fitness scores. The test consists of walking a specified distance, with or without a weighted pack, in a predetermined period of time, with altitude corrections.

Packing Ratio
The fraction of a fuel bed occupied by fuels, or the fuel volume divided by bed volume.

Panoramic Photograph
Photographs from a lookout point, bearing azimuth and vertical angle scales, to assist in locating fires with a firefinder.

Panoramic Profile Map
A panoramic sketch drawn around the circumference of a firefinder map to show the profiles of the topography as it appears from the lookout.

Paracargo
Anything intentionally dropped, or intended for dropping, from any aircraft by parachute, by other retarding devices, or by free fall.

Parallel Attack
Method of fire suppression in which fireline is constructed approximately parallel to, and just far enough from the fire edge to enable workers and equipment to work effectively, though the fireline may be shortened by cutting across unburned fingers. The intervening strip of unburned fuel is normally burned out as the control line proceeds but may be allowed to burn out unassisted where this occurs without undue delay or threat to the fireline.

Parallel Pumping
Procedure by which the flow from two fire pumps is combined into one hose line.

Parallel Tandem Pumping
Procedure by which the flow from two fire pumps is combined into a third pump.

Parameter
A variable which can be measured quantitatively; sometimes, an arbitrary constant; associated with populations. One of the unknown values that determine a model.
see also: Statistic

Parking Tender
Person responsible to the deck coordinator for take-offs and landings of helicopters at an assigned touchdown pad. There is one parking tender for each touchdown pad.

Partial Risk Factor
Part of the National Fire Danger Rating System (NFDRS). Contribution to human-caused risk made by a specific risk source; a function of the daily activity level assigned that risk source and the appropriate risk source ratio.

Partial Risk
Part of the National Fire Danger Rating System (NFDRS). Contribution of a specific source to human-caused risk, derived from the daily activity level assigned a risk source and its risk source ratio.

Partial-thickness Burn
A burn where the outer layer of skin is burned through and the second layer of skin (dermis) is damaged and is typically, a painful injury. Burns of this type cause reddening, blistering, and a mottled appearance. (also called Second Degree Burn)
see also: Full-thickness Burn
see also: Superficial Burn

Particle Size
The size of a piece of fuel, often expressed in terms of size classes.

Particulate Matter
Any liquid or solid particles. “Total suspended particulates”, as used in air quality, are those particles suspended in or falling through the atmosphere. They generally range in size (diameter) from 0.1 to 100 micrometers.

Particulates
see: Particulate Matter

Partners
All agencies and organizations that engage in joint decision making with federal agencies in planning and conducting fire management projects and activities.

Parts of a Fire
Different areas of the fire usually determined by the predominant direction of fire spread and delineated from the fastest moving area (head) to the slowest moving area (base or tail). The most rapidly moving portion is designated the head of the fire, the adjoining portions of the perimeter at right angles to the head are known as the flanks, and the slowest moving portion is known as the rear or the base of the fire.

Passive Crown Fire
A fire in the crowns of trees in which trees or groups of trees torch, ignited by the passing front of the fire. The torching trees reinforce the spread rate, but these fires are not basically different from surface fires.

Patch Burning
Burning in patches to prepare sites for group planting or sowing or to form a barrier to subsequent fires.

Patrol Time
Elapsed time from completion of original mopping up until the fire is declared to be extinguished.

Patrol Unit
Any light, mobile unit with limited pumping and water capacity.

Patrol
(1) To travel over a given route to prevent, detect, and suppress fires. Includes interaction with the public for wildland fire prevention and educational purposes.
(2) To go back and forth vigilantly over a length of control line during and/or after construction to prevent breakovers, suppress spot fires, and extinguish overlooked hot spots.
(3) A person or group of persons who carry out patrol actions.

Pattern Clusters
A group of indicators in a close proximity, of the same or different categories, that exhibit consistent directional values.

Pattern
The distribution of an aerially delivered retardant drop on the target area in terms of its length, width, and momentum (velocity x mass) as it approaches the ground. The latter determines the relative coverage level of the fire retardant on fuel within the pattern.
synonym: Drop Pattern

Payload
Weight of passengers and/or cargo being carried by an aircraft.

Peak Fire Season
That period of the fire season during which fires are expected to ignite most readily, to burn with greater than average intensity, and to create damages at an unacceptable level.

Peak Monthly Average
Highest monthly average of human-caused fires calculated for a protection unit.

Peak Wind Direction
Direction at Peak Wind Speed.

Peak Wind Speed
Maximum wind speed during the previous 60 minutes.

Peak Wind
The greatest 5-second average wind speed during the previous hour that exceeded 25 knots.

Percolation
Passage of liquid through a porous body, as movement of water through soil.

Perennial Plant
A plant that lives for more than two growing seasons. For fire danger rating purposes, biennial plants are classed with perennial plants.
see also: Annual
see also: Annual Plant

Performance Chart
A chart, table, or graph provided by the manufacturer for use in determining an aspect of helicopter and fixed-wing aircraft performance.

Performance Oriented Objectives
On-the-job performance enhancement is a result of online training. Performance oriented objectives or learning objectives for this training is developed, agreed to, and tested to ensure skill transfer. The purpose of learning objectives is to define the type of learning or performance outcomes that will occur at the conclusion of instruction and how learning will be assessed. Both objectives and performance outcomes should be written as precisely as possible in order to best determine whether they have been achieved.

Perimeter Access
Any road, trail, or route that will allow firefighting forces to reach the perimeter of a wildland fire.

Period of Alert
Period of time when suppression crews, equipment, and aircraft are kept ready for deployment on short notice; usually employed when fire danger reaches a predetermined severity index.

Permafrost
A short term for “permanently frozen ground”; any part of the earth’s crust, bedrock, or soil mantle that remains below 32° F (0° C) continuously for a number of years.

Personal Protective Equipment (PPE)
That equipment and clothing required to mitigate the risk of injury from or exposure to hazardous conditions encountered during the performance of duty. PPE includes but is not limited to: fire resistant clothing, hard hat, flight helmets, shroud, goggles, gloves, respirators, hearing protection, chainsaw chaps, and shelter.

Personnel Accountability
The ability to account for the location and welfare of personnel, accomplished when supervisors ensure that the ICS principles and processes are functional and personnel are working within these guidelines.

Personnel Pool
Personnel who have reported to the incident without an assignment (i.e., they are not assigned to an increment, strike team, or organizational unit).

Personnel Time Recorder
Person responsible to the time unit leader for daily recording of the time of all personnel at the incident, posting commissary charges to the time reports, closing out all records prior to personnel leaving the incident, and distributing completed time documents according to each agency’s policy.

Piling and Burning
Piling slash resulting from logging or fuel management activities and subsequently burning the individual piles.

Pilot Balloon Operation (PIBAL)
A method of determining winds aloft by periodically reading the elevation and azimuth angles of a theodolite, usually at one-minute intervals, while tracking the ascent of a small free-lift balloon. A PIBAL is commonly used for constructing a wind profile.

Pilotage
Navigation of aircraft by visual reference to landmarks.

Pilot-in-Command
Pilot responsible for the operation and safety of an aircraft during flight time.

Pin Lug Coupling
A hose coupling with one or more cylindrical studs on its outside rim. The studs allow the use of a spanner wrench to tighten the coupling.

Pincer Action
Direct attack around a fire in opposite directions by two or more attack units. Usually conducted from the fire’s tail to head.

Ping-Pong Ball System
Mechanized method of dispensing DAIDs (Delayed Aerial Ignition Devices) at a selected rate. The DAIDs are polystyrene balls, 1.25 inches in diameter, containing potassium permanganate. The balls are fed into a dispenser, generally mounted in a helicopter, where they are injected with a water-glycol solution and then drop through a chute leading out of the helicopter. The chemicals react thermally and ignite in 25-30 seconds. The space between ignition points on the ground is primarily a function of helicopter speed, gear ratio of the dispenser, and the number of chutes used (up to four).
see also: Aerial Ignition Device
see also: Delayed Aerial Ignition Devices
see also: Helitorch
see also: Plastic Sphere Dispenser

Plan of Attack
The selected course of action and organization of personnel and equipment in fire suppression, as applied to a particular fire or to all fires of a specific type.

Planetary Boundary Layer
That part of the earth’s lower atmosphere that is directly influenced by the presence of the earth’s surface and responds to surface forcings such as fronts, friction, evapotranspiration and convective mixing.

Planning Interval
Period of time between scheduled planning meetings.

Planning Meeting
A meeting held regularly throughout the duration of an incident, to select specific strategies and tactics for incident control operations and to plan for needed service and support. On larger incidents, the planning meeting is a major element in the development of the Incident Action Plan.

Planning Section Chief (PSC1 or PSC2)
This ICS position is responsible for supervising the Planning Section. Reports to the Incident Commander and is a member of the General Staff. This position may have one or more deputies assigned.
see also: Planning Section

Planning Section
Responsible for the collection, evaluation, and dissemination of tactical information related to the incident, and for the preparation and documentation of incident action plans. The section also maintains information on the current and forecasted situation, and on the status of resources assigned to the incident. Includes the situation, resource, documentation, and demobilization units, as well as technical specialists.

Plastic Sphere Dispenser (PSD)
Device installed, but jettisonable, in a helicopter, which injects glycol into a plastic sphere containing potassium permanganate, which is then expelled from the machine and aircraft. This produces an exothermic reaction resulting in ignition of fuels on the ground for prescribed or wildland fire applications.
see also: Aerial Ignition Device
see also: Delayed Aerial Ignition Devices
see also: Helitorch
see also: Ping-Pong Ball System

Plow Line
Fireline constructed by a fire plow, usually drawn by a tractor or other motorized equipment.
see also: Dozer
see also: Dozer Line
see also: Tractor
see also: Tractor Plow

Plume Rise
How high above the level of release an emission plume rises.

Plume
A convection column generated by combustion (of wildland fuel).
see also: Convection Column

Plume-dominated Wildland Fire
A wildland fire whose activity is determined by the convection column.

PM10 (PM10)
Particulate matter of mass median aerodynamic diameter (MMAD) less than or equal to 10 micrometers.

PM2.5 (PM2.5)
Particulate matter of mass median aerodynamic diameter (MMAD) less than or equal to 2.5 micrometers.

Pockets of a Fire
Unburned indentations in the fire edge formed by fingers or slow burning areas.

Point of Attack
That part of the fire on which work is started when suppression crews arrive.

Point of Origin
The location where a competent ignition source came into contact with the material first ignited and sustained combustion occurred.

Point Source Fire Predictions
Predictions that apply to an initiating fire burning during a time when conditions have been relatively constant, or where it can be assumed that the fire will maintain a basically elliptical shape.

Point Source
A permanent source of air pollution that can be distinctly identified such as a smokestack.

Poise
Unit of fluid viscosity in fire retardant, defined as tangential force per unit area (dynes/square centimeter) required to maintain unit difference in velocity (1 centimeter/second) between two parallel planes separated by 1 cm of fluid (1 poise=1 dyne-second/cubic centimeter).

Portable Pump
Small gasoline-driven pump that can be carried to a water source by one or two firefighters or other conveyance over difficult terrain.

Portatank
Container, either with rigid frame or self supporting, which can be filled with water or fire chemical mixture from which fire suppression resources can be filled. It can also be a source for charging hose lays from portable pumps or stationary engines.

Position Currency Requirement
The requirement to perform satisfactorily in a specified position within the last five years (three years for aviation and expanded dispatch positions) in order to maintain qualification for the position.

Position Performance Assignment
An assignment in which an individual is being evaluated for tasks found in the position task book.
see also: Position Task Book

Position Task Book (PTB)
A document listing the performance requirements (competencies and behaviors) for a position in a format that allows for the evaluation of individual (trainee) performance to determine if an individual is qualified in the position. Successful performance of PTB tasks, as observed and recorded by a qualified evaluator, will result in a recommendation to the trainee’s home unit that the individual be certified in the position.
see also: Agency Certification
see also: Behavior
see also: Competency
see also: Evaluator
see also: Home Unit
see also: Trainee

Positive Displacement Pump
A pump which moves a specified quantity of water through the pump chamber with each stroke or cycle; it is capable of pumping air, and therefore is self-priming, but must have pressure relief provisions if plumbing or hoses have shut-off nozzles or valves . Gear pumps and piston pumps are common examples of this type.

Potato Roll
Quick method of rolling hose for pick up; hose is rolled as a ball of string.

Pounds per Square Inch (PSI)
Measurement of pressure (e.g., pump pressure, nozzle pressure, friction loss in hose, pressure loss or gain due to elevation).

Preattack Block
Unit of wildland delineated by logical and strategic topographic features for preattack planning.

Preattack Planning
Within designated blocks of land, planning the locations of firelines, fire camps, water sources, and helispots; planning transportation systems, probable rates of travel, and constraints of travel on various types of attack units; and determining what types of attack units likely would be needed to construct particular firelines, their probable rate of fireline construction, and topographic constraints on fireline construction.

Preattack
A planned, systematic procedure for collecting, recording, and evaluating prefire and fire management intelligence data for a given planning unit or preattack block. The planning phase is usually followed by a construction and development program integrated with other resources and activities.

Precautionary Landing
A landing necessitated by apparent impending failure of engines, systems, or components which makes continued flight unadvisable.

Precipitation Amount
The total amount of precipitation that occurred within the preceding 24-hour period.

Precipitation Duration
Time, in hours and fraction of hours, that a precipitation event lasts. More precisely, for fire danger rating purposes, the length of time that fuels are subjected to liquid water.

Precipitation Gauge
Device commonly used to collect and permit measurement of any form of rain and snow sufficiently heavy to have fallen to the earth’s surface. Also called rain gauge.

Precipitation
Any or all forms of water particles, liquid or solid, that fall from the atmosphere and reach the ground.

Precision Approach Procedure
A standard instrument approach procedure for fixed-wing aircraft in which an electronic glide slope is provided, such as ILS and PAR.

Precision Approach Radar (PAR)
Blind landing in which the aircraft is observed from the ground by means of radar and directed along a suitable glide path by instructions radioed to the pilot.

Preconnected
Hard suction hose or discharge hose carried connected to pump, eliminating delay occasioned when hose and nozzles must be connected and attached at fire.

Predictive Services
Those Geographic Area and National-level fire weather or fire danger services and products produced by wildland fire agency meteorologists and intelligence staffs in support of resource allocation and prioritization.

Pre-Green
In the 1978 version of NFDRS, the herbaceous stage approximately 30 days prior to green-up.

Preignition Combustion Phase
Thermal or chemical decomposition of fuel at an elevated temperature. This is the pre-combustion stage of burning during which distillation and pyrolysis predominate. Heat energy is absorbed by the fuel which, in turn, gives off water vapor and flammable tars, pitches, and gases. These ignite when mixed with oxygen to initiate the flaming combustion phase.

Preignition Phase
Preliminary phase of combustion in which fuel elements ahead of the fire are heated, causing fuels to dry. Heat induces decomposition of some components of the wood, causing release of combustible organic gases and vapors.

Preparedness Level
Increments of planning and organization readiness commensurate with increasing fire danger.

Preparedness Plan
A written plan providing for timely recognition of approaching critical fire situations, priority setting, the deployment of forces, and other actions to respond to those situations.

Preparedness
(1) Activities that lead to a safe, efficient, and cost-effective fire management program in support of land and resource management objectives through appropriate planning and coordination.
(2) Mental readiness to recognize changes in fire danger and act promptly when action is appropriate.
(3) The range of deliberate, critical tasks, and activities necessary to build, sustain, and improve the capability to protect against, respond to, and recover from domestic incidents.
see also: Readiness

Prescribed Burning
Application of prescribed fire.

Prescribed Fire Burn Plan
A plan required for each fire application ignited by management. Plans are documents prepared by qualified personnel, approved by the agency administrator, and include criteria for the conditions under which the fire will be conducted (a prescription). Plan content varies among the agencies.
see also: Implementation Plan

Prescribed Fire
Any fire ignited by management actions to meet specific objectives. A written, approved prescribed fire plan must exist, and NEPA requirements (where applicable) must be met, prior to ignition.
see also: Wildland Fire

Prescribed Natural Fire
see: Wildland Fire Use

Prescription
Measurable criteria that define conditions under which a prescribed fire may be ignited, guide selection of appropriate management responses, and indicate other required actions.

Pressure Gradient
The difference in atmospheric pressure between two points on a weather map. That is, the magnitude of pressure difference between two points at sea level, or at constant elevation above sea level. Wind speed is directly related to pressure gradient. If distance between constant pressure lines is reduced by one-half, wind speed will be doubled. Conversely, if distance between lines is doubled, wind speed will be reduced by one-half.

Pressure Loss
Reduction in water pressure between a pump or hydrant and a nozzle due to expenditure of pressure energy required to move water through a hose; includes losses due to back pressure, friction loss, elevation loss, and/or losses in fittings.

Pressure Pattern
The distribution of surface atmospheric pressure features over an area of the earth as shown on a weather map. Surface pressure features include lines of constant pressure (isobars), highs, lows, and pressure gradient. The pressure pattern is directly related to wind speeds and directions at specific locations.

Presuppression
Activities in advance of fire occurrence to ensure effective suppression action. Includes planning the organization, recruiting and training, procuring equipment and supplies, maintaining fire equipment and fire control improvements, and negotiating cooperative and/or mutual aid agreements.

Pretreat
The use of water, foam or retardant along a control line in advance of the fire. Often used where ground cover or terrain is considered best for control action.

Prevention of Significant Deterioration (PSD)
A program identified by the Clean Air Act to prevent air quality and visibility degradation and to remedy existing visibility problems. Areas of the country are grouped into 3 classes which are allowed certain degrees of pollution depending on their uses. National Parks and Wilderness Areas meeting certain criteria are “Class I” or “clean area” in that they have the smallest allowable increment of degradation.

Prevention
(1) Activities directed at reducing the incidence of fires, including public education, law enforcement, personal contact, and reduction of fuel hazards (fuels management).
(2) Actions to avoid an incident, to intervene for the purpose of stopping an incident from occurring, or to mitigate an incident’s effect to protect life and property. Includes measures designed to mitigate damage by reducing or eliminating risks to persons or property, lessening the potential effects or consequences of an incident.
see also: Fire Education

Primary Lookout
A lookout point that must be staffed to meet planned minimum seen area coverage in a given locality. For that reason, continuous service is necessary during the normal fire season and the lookout (person) is not sent to fires.

Priming
Filling pump with water when pump is taking water not under a pressure head. Necessary for centrifugal pumps.

Probability Forecast
A forecast of the probability of occurrence of one or more of a mutually exclusive set of weather contingencies as distinguished from a series of categorical statements.

Probability of Ignition
The chance that a firebrand will cause an ignition when it lands on receptive fuels.

Probability
A number representing the chance that a given event will occur. The range is from 0% for an impossible event, to 100% for an inevitable event.

Procurement Unit Leader (PROC)
The ICS position responsible for supervising the Procurement Unit. Reports to the Finance/Administration Section Chief.
see also: Procurement Unit

Procurement Unit
Functional unit within the Finance/Administration Section responsible for managing all financial matters pertaining to vendor contracts.

Progressive Hose Lay
A hose lay in which double shutoff wye (Y) valves are inserted in the main line at intervals and lateral lines are run from the wyes to the fire edge, thus permitting continuous application of water during extension of the lay.

Progressive Method of Line Construction
A system of organizing workers to build fireline in which they advance without changing relative positions in line.

Project Activity Level (PAL)
An application of fire danger rating to support regulation of contractors involved in land management activities for fire prevention purposes in California.

Project Objectives
The specific results expected from completing a project.

Proportioner
A device that adds a predetermined amount of foam concentrate to water to form foam solution.

Protecting Agency
Agency responsible for providing direct incident management within a specific geographical area pursuant to its jurisdictional responsibility or as specified and provide by contract, cooperative agreement, etc.
see also: Fire Agency
see also: Responsible Fire Agency

Protection Area
That area for which a particular fire protection organization has the primary responsibility for attacking an uncontrolled fire and for directing the suppression action. Such responsibility may develop through law, contract, or personal interest of the firefighting agent (e.g., a lumber operator). Several agencies or entities may have some basic responsibilities (e.g., private owner) without being known as the fire organization having direct protection responsibility.
synonym: Direct Protection Area

Protection Boundary
The exterior perimeter of an area within which a specified fire agency has assumed a degree of responsibility for wildland fire control. It may include land in addition to that for which the agency has jurisdiction or contractual responsibility.

Protection Indicators
Fuels that are unburned or exhibit a less damaged appearance on the non-origin side of the fuel itself or other objects.

Protection Unit
A geographical area which is administratively defined and which is the smallest area for which organized fire suppression activities are formally planned.

Protection
The actions taken to limit the adverse environmental, social, political, and economical effects of fire.

Psychrometer
General name for instruments designed to determine the moisture content of air. A psychrometer consists of dry- and wet-bulb thermometers that give the dry- and wet-bulb temperatures, which in turn are used to determine relative humidity and dew point.

Public Aircraft
Aircraft used only in the service of a government or a political subdivision. It does not include any government-owned aircraft engaged in carrying persons for commercial purposes.

Public Information Officer (PIO1, PIO2, PIOF)
This ICS position is responsible for developing and releasing information about the incident to the news media, incident personnel, and to other appropriate agencies and organizations. Reports to the Incident Commander and is a member of the Command Staff. This position may have one or more assistants assigned.

Pulaski
A combination chopping and trenching tool widely used in fireline construction, which combines a single-bitted axe blade with a narrow adze-like trenching blade fitted to a straight handle.

Punky Material
Partly decayed material, such as old wood, in which fire can smolder unless it is carefully mopped up and extinguished. A good receptor for firebrands when dry.

Pyrolysis
The thermal or chemical decomposition of fuel at an elevated temperature. This is the preignition combustion phase of burning during which heat energy is absorbed by the fuel which, in turn, gives off flammable tars, pitches, and gases.

Pyrotechnic
A mixture of chemicals designed to produce heat, light, gas, smoke or noise.

Source: National Wildfire Coordinating Group