- Substrate
- Steel
- Material to remove
- Paint, coating or corrosion deposits
- Specification needed
- Required surface condition and next coating system
- Recovery issue
- Removed coating, corrosion products and washwater
Coating and preparation requirements
The existing coating and the finish needed for the next coating system define the cleaning objective. Removing loose material for maintenance is not the same job as preparing steel to a specified standard for recoating.
The coating specification should set the required preparation and how it will be checked. A surface that looks clean is not necessarily ready for every coating system.
What water jetting can and cannot do
Method selection depends on steel condition, coating adhesion, access and the amount of material to remove. Electrical equipment, occupied areas and sensitive plant nearby can also affect containment and working controls.
Water jetting removes material; it does not repair section loss in the steel. The surface left behind also depends on the existing substrate and the jetting process, so any further preparation or steel repair belongs in the coating or engineering specification.
Residues and washwater
If the existing coating is unknown, its composition may need checking before it is disturbed or a waste route is chosen. Removed coating, corrosion products and washwater then need collection and management that reflect what they contain.
High-pressure water and overspray require controls for the actual work area. The Water Jetting Association code sets industry guidance for water-jetting operations, but the site and task still need their own assessment.
Inspection before recoating
The final record should identify the area treated, the specified finish, the inspection or testing completed and any inaccessible sections. The coating specification, not the cleaning method alone, sets the acceptable conditions and timing for recoating.