Hydrocleaning

Rubber deposits removed from a runway using ultra-high-pressure water

Hydrocleaning, high-pressure cleaning or waterblasting, are terms which describe 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 films and materials such as paint from walls, metal, and highways, rubber from airfield runways, sealants and membranes from concrete and chewing gum from sidewalks.

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) uses water pressure less than 5,000 psi (34 MPa);
• High-pressure water cleaning (HP WC) uses water pressure between 5,000 to 10,000 psi (34 to 70 MPa);
• High-pressure water jetting (HP WJ) uses water pressure between 10,000 to 25,000 psi (70 to 170 MPa);
• Ultrahigh-pressure water jetting uses pressures above 25,000 psi (170 MPa).

Applications

Surface preparation

Any time a rigid surface, such as asphalt, concrete or metal, needs to have a coating applied, the surface must first be prepared. Hydrocleaning has been used to prepare for the application of such coatings. Coatings are used to protect concrete from rain and salt, and to create a smoother 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. Hydrocleaning can be used to remove such materials off.

Partially shredded membrane from a hydrocleaning surface preparation job.

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

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 come to a stop after touching down. Hydrocleaning can be used to remove rubber particles which are peeled off airplane tires as they touch down, and thus restore required friction levels. The level of use (number of landings) determines how often a 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 surfaces that are dirtied by gum, pollution or graffiti.

See also

• Abrasive blasting
• Hydro-jet cleaning
• Pressure washer

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