Section 20-10. Cleaning and repair of high pressure jetting systems

Leakages in pipe and hose couplings shall only be repaired after relieving the systems of pressure.
Repair and replacement of couplings shall only be carried out using special equipment and by competent personnel, preferably the hose supplier or system supplier.
When cleaning jetting devices, replacing nozzles etc., the pump shall be stopped and the liquid pressure released from all parts of the system.
Where a pressure reduction valve has been installed, the adjusting screw for setting the working pressure shall be set to fully relieve the pressure.
On centrally controlled systems, the jetting device and pertaining hose shall be relieved of pressure.
Insofar as it is possible, the same shall be done when the person operating the jetting device leaves his/her workplace.