Pressure washing or power washing is the use of high-pressure water spray to remove loose paint, mold, grime, dust, mud, and dirt from surfaces and objects such as buildings, vehicles and concrete surfaces. The volume of a mechanical pressure washer is expressed in gallons or liters per minute, often designed into the pump and not variable. The pressure, expressed in pounds per square inch,
pascals
The pascal (symbol: Pa) is the unit of pressure in the International System of Units (SI), and is also used to quantify internal pressure, stress, Young's modulus, and ultimate tensile strength. The unit, named after Blaise Pascal, is defined ...
, or
bar
Bar or BAR may refer to:
Food and drink
* Bar (establishment), selling alcoholic beverages
* Candy bar
* Chocolate bar
Science and technology
* Bar (river morphology), a deposit of sediment
* Bar (tropical cyclone), a layer of cloud
* Bar (u ...
, is designed into the pump but can be varied by adjusting the unloader valve. Machines that produce pressures from 750 to 30,000
psi
Psi, PSI or Ψ may refer to:
Alphabetic letters
* Psi (Greek) (Ψ, ψ), the 23rd letter of the Greek alphabet
* Psi (Cyrillic) (Ѱ, ѱ), letter of the early Cyrillic alphabet, adopted from Greek
Arts and entertainment
* "Psi" as an abbreviatio ...
(5 to 200 MPa) or more are available.
The terms pressure washing and power washing are used interchangeably in many scenarios, and there is some debate as to whether they are actually different processes.
A pressure washing surface cleaner is a tool consisting of two to four high-pressure jets on a rotating bar that swivels when water is flowing. This action creates a uniformed cleaning pattern that can clean flat surfaces at a rapid rate.
Hydro-jet cleaning is a more powerful form of power washing, employed to remove buildup and debris in tanks and lines.
Areas of use
Pressure washing is employed by businesses and homeowners to reduce allergies, minimize hazards, and improve aesthetics. A pressure washer is used to clean surfaces such as:
* Gutters
* Roofs
* Decks
* Sidewalks
* Patios
* Driveways
* Siding
* Parking lots
*Cladding
Depending upon the surface to be cleaned, higher or lower pressure should be used, as well as the appropriate nozzle.
Nozzles
Pressure washer nozzles alter the direction of flow and velocity of the water. Nozzles allow users to reach a greater distance or apply more pressure to a difficult to clean surface, however, they can be dangerous. Nozzles are color coded for easy identification, with black nozzles covering the widest degree (65°) and red nozzles covering the least (0°). Great care should be taken when using a 0° nozzle as it can cause injury to both the user and passerby, alongside damage to surfaces.
See also
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Washdown
Washdown (also wash down) is the process of cleaning or washing a surface for appearance, sanitation, or removal of contamination. It may involve pressure washing. Sometimes wash down involves rinsing with fresh water; other times it involves use ...
References
Further reading
*
Steel Structures Painting Council (1995), ''Surface Preparation and Cleaning of Steel and Other Hard Materials by High- and Ultrahigh-Pressure Water Jetting Prior to Recoating.'' Pittsburgh, PA. SSPC
*U.S. Water Jet Technology Association, ''Recommended Practices for the Use of Manually Operated High-Pressure Water Jetting Equipment'', St. Louis, MO: US Water Jet Technology Association, 1987
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Cleaning tools
Cleaning methods