Fig. 1.

a An operator with a mobile unit working in a drain cleaning setting, across an estimated working pressure up to 206 bar (= 204 atm = 3.000 psi). The unit would be (on average) operating at 12–15 gallons (US) per minute (= 45–55 L/min). b An example of a spinning/rotary nozzle. Generally used for the full circumference cleaning of pipes and drains, particularly effective for removing fats and grease and the de-scaling of pipes and drains. The drain cleaning nozzles tend to use round (pencil jets) which in terms of an accident will definitely cause more damage to the body than a fan jet. c Ultra-high pressure (UHP) operations begin at a level over 1.700 bar (= 1.677,77 atm = 24.656,42 psi). At UHP, the jet velocity is in excess of 2.400 km/h, when a pencil jet is used this jet is the most concentrated and is subsequently capable of creating the most severe operator injuries