High-pressure jetting is one of the most popular methods for drain clearance, removing hard and soft deposits and clearing blockages.
The method involves using water jet nozzles that are propelled using pressures of over 3000 psi to break up blockages, remove encrustations and loosen hard debris. Using high pressure water with a lance is also a good method of cleaning exteriors to remove graffiti, moss and other surface coverings.
However, High Pressure Jetting, if not handled competently is a potentially hazardous process due to the power of the jet and the proximity of the operator to the jetting equipment.Before jetting commences an area of public exclusion should be created using barriers preferably. Also, if the surface of this area is to be cleaned, then the area needs to be free from debris as this can be propelled at a high velocity and cause injury or damage. Authorised persons wishing to enter this area should wait until the jetting has stopped. If any unauthorised entry is detected the pressure should be shut off safely and immediately. Hoses outside the exclusion zone should be protected.
Water at high pressure with the possible inclusion of hazardous chemicals is capable of inflicting very severe injuries. This must be subject to a suitable and sufficient risk assessment, from which can be developed a safe system of work. In most on site situations, only the use of personal protective equipment (PPE) represents a reasonably practicable means of reducing the risk to an acceptable level. The PPE required for all members of the jetting team will consist of as a minimum:
- Safety Helmet
- Water Proof Gauntlets
- Heavy Duty Water-Proof Overalls
- Hearing Protection
- Face Shield
- Safety Boots with metatarsal protection.
All equipment should be checked daily by users and weekly by supervisors for any damage or corrosion in accordance with the manufacturer’s instructions. These checks should be recorded on a log sheet. Inspection should include:
- Condition of hoses and couplings. Should be suitable for the required pressures and be inspected for kinks, tears or bulges.
- Jetting Lance. Should be a minimum of 1 metre long for standard operations; the trigger mechanism should be free from debris and never locked or wedged in the on position.
- Jetting unit. This should be checked for external damage with special emphasis on connections, junction boxes, switches and supply cables. All electrical systems and their associated components should be protected from the ingress of water.