Hydrocleaning

Hydrocleaning, high pressure cleaning or waterblasting is the use of water propelled at high speeds to clean surfaces and materials. By focusing and pressurizing the water stream, the force generated can remove, for example:
*Paint from walls, metal, and highways
*Rubber from runways (airfield rubber removal)
*Sealants and membranes from concrete
*Gum from side walks

Pressures

In order to standardize cleaning operations and surface preparation specifications the Steel Structures Painting Council (SSPC) has adopted the following four definitions for cleaning operations using water jetting technology:
*Low-pressure water cleaning (LP WC) is the use of water pressure less than 5,000 psi (34 MPa) for cleaning.
*High-pressure water cleaning (HP WC) is the use of water pressure between 5,000 to 10,000 psi (34 to 70 MPa) for cleaning.
*High-pressure water jetting (HP WJ) is the use of water pressure between 10,000 to 25,000 psi (70 to 170 MPa) for cleaning.
*Ultrahigh-pressure water jetting is the use of pressures above 25,000 (170 MPa) for cleaning.

Applications

urface preparation

Any time a hard surface, such as asphalt, concrete or metal, needs to have a coating applied, the surface must first be prepared. The use of high pressure and ultra high pressure water has been used to prepare various surfaces for the purpose of repair and reapplication of such coatings. Coatings are used to protect concrete from the elements, rain, salt, and to create a friendlier surface for human use. Concrete can also be covered with carpet or tiles using a heavy duty glue or mastic. Asphalt and concrete can be painted to communicate acceptable travel patterns, potential hazards, or for aesthetics. High pressure water can be used to clean these materials off when new ones are desired.High pressure water has been used to remove:
*Membranes:
**Elastomeric
**Rubber
**Urethane
**Hot applied
*Paint from:
**Highways
**Runways
**Parking structures
**Metal surfaces

Airfield rubber removal

Commercial and military airports are required to keep certain levels of friction on the landing strips in order to prevent planes from skidding off. Runway design, weather and amount of rubber on the runway all play a role in the level of friction of a landing strip. If too much rubber is present, especially in rainy weather, the friction of the landing strip will be lower requiring more distance for the plane to land. High pressure water can be used to remove rubber left from airplane tires and restore required friction levels. The level of use, number of landings, determines how often each runway needs to be cleaned. This process of removal is sometimes known as Airfield rubber removal.

General surface cleaning

High pressure water can be used to clean a multitude of surfaces dirtied by gum, pollution or graffiti.

References

*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

External links

* [http://www.technicalservicesmidatlantic.com/membranecoating.html More about membrane and Coating Removal]
* [http://www.rampart-hydro.com/rubber_removal.htm Rates of Rubber Removal]
* [http://mac10.umc.pitt.edu/u/FMPro?-db=ustory&-lay=a&-format=d.html&storyid=7446&-Find Surface cleaning of the Cathedral of Learning]