The standard measure of total dissolved solids. Parts of dissolved material in one million parts of water. (eg. one pound of mineral salts dissolved in a million pounds of water would be on part per million).
PASCAL (pa)
A unit of pressure equal to one newton of force per square meter. One thousand pascals equal one kilopascal (KPa); a kilopascal equals 0.145 pounds per square inch. Alternatively, 1 psi = 6895 Pa = 6.895 kN/sq.m = 0.0703 kg/sq.cm.
PATHOGENS
Micro-organism that can cause disease in other organisms or in humans, animals and plants. They may be bacteria, viruses or parasites and are found in sewage, in runoff from animals and in water used for swimming. Fish and shellfish contaminated by pathogens, or the contaminated water itself, can cause serious illness.
PERMEABLE
Allowing some material to pass through.
pH
A measurement of water acidity or alkalinity using a scale of 0 to 14. 7 = neutrality, numbers less than 7 = acidity, numbers greater than 7 = alkalinity. Relative acidity or alkalinity of a substance, such as water, as indicated by the hydrogen ion concentration.
PHENOLS
Weak aromatic acids, which are indicative of industrial pollution of water supplies. When combined with chlorine, they produce an objectionable taste and odor.
PINCHING HAZARD
Any configuration of components that would pinch or entrap the fingers or toes of a bather.
POLYAMIDE
A synthetic polymer of the nylon family used in the fabrication of reverse osmosis and ultrafiltration membranes.
POLYMERS
A chemical compound with many repeating structural units.
POLYSULFONE
A synthetic polymer used to fabricate reverse osmosis and ultrafiltration membranes, which are characterized by extreme thermal stability and chemical resistance. Popular in dental waterline filtration systems.
POLYVALENT ION
A cation or anion having a multiple electrical charge.
POLYVINYL CHLORIDE
A thermoplastic piping material produced by the polymerization of vinyl chloride.
POOL BOILER
A type of pool heater operating as an Indirect Type, but using steam instead of hot water in the closed system.
POOL DEPTH
The vertical distance between the floor level and or which is inclined 45° or less from horizontal. The normal or operating water level when the pool is in use.
POOL FLOOR
That portion of the pool interior which is horizontal or which is inclined 45° or less from horizontal.
POOL HEATER
A device through which pool water is circulated to increase the temperature of the water. In the Direct Type, the heat is transferred directly to the pool water circulating tubes. The Indirect Type utilizes a separate enclosed system which is directly exposed to heat generator and which heats the pool water by circulating the steam or hot water around the tubes of a heat exchanger through which the water circulates. The heat generator is considered part of every heater.
POOL WALL
The sides of a pool above the floor which are vertical at the top and coved at the bottom, or which are inclined to the pool no more than 45° from the vertical.
POOLS - Above ground/Portable Swimming Pool
A removable pool of any shape that is deeper than forty-two inches (42”) or holds more than 2,500 gallons of water or has a water surface area in excess of 150 square feet. The aboveground pool frame is located entirely above ground and may be readily disassembled for storage and reassembled to its original integrity.
POOLS - In Ground Swimming Pool
Any pool, spa or hot tub whose sides rest in partial or full contact with the earth.
POOLS - Non-Permanently Installed Swimming Pool
One that is so constructed that it may be readily disassembled for storage and reassembled to its original integrity.
POOLS - On-Ground Swimming Pool
Any pool, spa or hot tub whose sides rest fully above the surrounding earth and that has a deep area below the ground level.
POOLS - Public
Any pool, other than a residential pool, which is intended to be used for swimming or bathing and is operated by an owner, lessee, operator, licensee or concessionaire, regardless of whether a fee is charged for use.
POOLS - Public Class A - Competition
Any pool intended for use for accredited competitive aquatic events such as FINA, AAU, NCAA, N.F., etc. The pool may also be used for recreation.
POOLS - Public Class B
Any pool intended for public recreational use.
POOLS - Public Class C
Any pool operated solely for and in conjunction with lodgings such as hotels, motels, apartments, condominiums, etc.
POOLS - Public Class D - Special Purpose
Any pool operated for medical treatment, water therapy or nonrecreational functions.
POOLS - Public Type VI thru Type X
Public Pools suitable for the installation of diving equipment by type. Diving equipment classified at a higher type may not be used on a pool of lesser type (i.e., Type VIII equipment on a Type VI pool).
POOLS - Residential
A residential pool shall be defined as any constructed pool, permanent or nonportable, that is intended for noncommercial use as a swimming pool by not more than three-owner families and their guests and that is over twenty-four inches (24”) in depth, has a surface area exceeding 250 square feet and/or a volume over 3,250 gallons. Residential Pools shall be further classified into types as an indication of the suitability of a pool for use with diving equipment.
POOLS - Residential - Type I thru Type V Diving Equipment
Residential pools suitable for the installation of diving equipment by type. Diving equipment classified at a higher type may not be used on a pool of lesser type (i.e., Type III equipment on a Type II pool).
POOLS - Residential - Type Q
Any residential pool where the installation of diving equipment is prohibited.
POOLS - Wading
A pool that may range in water depth from two feet (2’) to zero feet (0’) for wading.
PORE
An opening in a membrane, which allows certain components to pass through, but not others.
POTABLE WATER
Any water, such as an approved domestic water supply, which is bacteriologically safe and otherwise suitable for drinking.
POTASSIUM PERMANGANATE
An oxidizing agent commonly used for the regeneration of manganese green sand iron filters and occasionally used as a disinfectant.
POWER
The rate at which work is expended.
PPB
Parts per billion (equivalent to micrograms per liter)
PPM
Parts per million (equivalent to milligrams per liter).
PPM (PARTS PER MILLION)
Unit used for the measurement of the concentration of a chemical or other substance in the pool, spa or hot tub water, where this concentration is expressed in terms of “n” molecules of substance per one million molecules of water.
PRECHARGE
The air put into a pressure tank to make it operate within a specific pressure range
PRECHARGED TANK
A water storage tank pre-charged with air at factory featuring a vinyl bag to separate water from air which prevents waterlogging. This tank design provides greater drawdown than standard tanks. Pre-charged tanks do not require air volume control.
PRECOAT
The coating of filter aid on the septum of a diatomite type filter at the beginning of each filter cycle.
PRECOAT FEEDER
A device used to feed a calculated amount of filter aid at the start of a diatomaceous earth filter cycle - following the cleaning operation.
PREMEATE
See product water.
PRESSURE
The effect produced by the application of force over the surface of an area.
PRESSURE DIFFERENTIAL
The difference is pressure between two parts of a hydraulic system (influent and effluent of a filter, suction and discharge of a pump, the up and down-stream sides of a venturi or orifice).
PRESSURE DROP
Sometimes referred to as "delta P", it is the decrease in hydrostatic force (pressure) due to the effects of friction or restrictions on a flowing liquid.
PRESSURE HEAD
The vertical distance (in feet) equal to the pressure (in PSI) at a specific point. The pressure head is equal to the pressure in PSI times 2.31 ft.
PRIORITY POLLUTANTS
Those pollutants that pose the most serious health hazards determined by the EPA (Environmental Protection Agency).
PRODUCT WATER
The purified water stream from equipment, such as distillation, reverse osmosis and ultra filter units.
PSI
An abbreviation for “pounds per square inch” (see “Feet of Head”).
PUMP STRAINER
A device, placed on the suction side of a pump, which contains a removable strainer basket designed to trap debris in the waterflow with a minimum of flow restriction (sometimes referred to in the past as a “Hair and Lint Trap”).
PUMPING LEVEL
The lowest water level reached during pumping operation.
PUNCTURE HAZARD
Any surface or protrusion that would puncture a bather’s skin under casual contact.
PYROLOSIS
A breakdown process which occurs when organic matter is subjected to elevated temperatures.