Converting pressure units
One bar equals 100,000 Pascals (Pa) or approximately atmospheric pressure at sea level. A pressure of 3,000 bar therefore equals 300 MPa (megapascals) or 30,000 N/cm². This means that a 1 cm² area must withstand a force load of 3 tonnes! For perspective — normal pneumatic brakes on a truck operate at approximately 8–10 bar. A high-pressure pump rated for 3,000 bar is thus a technical marvel requiring special materials and precision manufacturing.
Why pressure alone is insufficient for performance assessment
The effect of a water jet depends on the product of pressure and flow rate. A pump rated 500 bar/20 L/min may clean faster than one rated 1,500 bar/3 L/min on the same surface because the total energy delivered per second is higher. Additionally, pressure does not account for nozzle orifice size — a narrow jet with lower flow but higher pressure cuts deeper than a wide jet with lower pressure and higher flow. The overall system performance is determined by the combination of all parameters.
When you need high pressure
Pressures above 1,000 bar are essential for reinforced-concrete demolition work, removal of very resistant coatings and specific industrial applications. Medium pressures 400–700 bar suffice for most routine cleaning, rust removal and thin coatings. Low pressures under 350 bar serve for gentle rinsing and preparatory work. Customers often assume higher pressure equals better results. In reality it depends on the correct setting for the specific task. Excessively high pressure on a sensitive substrate causes more damage than benefit.
Safety aspects at working pressures
Equipment rated for operation above 300 bar must meet strict safety requirements — piping, hoses, couplings and nozzles must be certified according to EN ISO 16524-1. Operators must use full protective equipment (see article Safety in Hydrodemolition). Before each use, the condition of hoses and fittings must be visually inspected — hose bursts under 3,000 bar can be fatal. Regular audits and hydraulic tests of pressure components are mandatory.