What are the general guidelines for inspections, maintenance and repairs of water jetting equipment?
As a rule, for all the components of a water jetting system, major servicing operations and repairs requiring specialist knowledge should only be carried out by competent workers with knowledge of the equipment.
Operators of water jetting systems only carry out simple adjustments or replacement of parts which are specifically listed in the manufacturer’s instructions for use and periodic service. Other repairs or maintenance should be carried out by the manufacturer or another suitably qualified party.
Maintenance records should be kept for each component of the equipment and after each inspection or service recommended by the manufacturer the person carrying out the work should record the following information:
- The condition of the equipment and hoses
- Repairs performed
- Adjustments performed
- The date when the inspection or work was carried out and the name of the person who carried out the job
Pumps
The pump unit must always be maintained in accordance with the manufacturer’s instructions.
However, its maintenance should include daily pre-operational checks on the following items:
- Engine and drive unit: lubricating oil, water, hydraulic fluid and fuel levels.
- Pump unit: lubricating oil, water filters, drive belts, gauges and gearbox oil levels.
- Hydraulic hose reel: lubricating oil and fluid levels.
- Condition of guards, shields and safety interlocks.
- Electric leads and connectors.
Filters and strainers
Water filters must be checked and inspected regularly, in accordance with the pump manufacturer’s recommendations, and with a frequency that will depend basically on the water supply conditions
Filters must be cleaned regularly, following the pump manufacturer’s recommendations.
Hoses and connections
All the hoses and connections selected before assembly should be suitable for their use with the maximum working pressure of the water jetting unit to be used.
Before starting every operation, they should be visually inspected by a competent person to ensure the following aspects:
- The correct pressure rating and size has been selected.
- There are is no apparent structural damage.
- Hose connections to equipment or to other hoses are restrained with braided stockings, whip checks or are restricted in some other suitable way to stop their movement if the hose end fails.
After the inspection, hoses and connections presenting any damages (broken wires, deep abrasions, kinking, blisters, bubbles in the outer covering, cracks, corrosion, damaged threads, etc.) should be identified and taken out of service, clearly marked and tagged to prevent further use.
Generally, hose assemblies used in water jetting systems should be tested when they are new, have been damaged, have been re-ended, repaired, or have been exposed to adverse operational conditions which may have affected their structural integrity.
They should be tested in accordance with the requirements established by national regulations where the operation is going to take place and records should be kept of all tests. Only those hoses identified as meeting the safe operating performance recommendations should be returned to service.
The service life of a hose assembly is affected by many factors like storage, pressure cycles, temperature, environment, chemical exposure and longitudinal stress.
To maximise their service life, the following measures can be adopted:
- Exposure of hoses to temperatures more than the stated rating should be avoided.
- Hose assemblies should not unnecessarily be exposed to chemicals or corrosive substances. Where hose assemblies are exposed to these such substances, steps should be taken as soon as possible to neutralise their effect.
- Repetitive and prolonged use of hose assemblies in long-line drain cleaning functions and long vertical drops should be avoided.
- Unnecessary exposure to sharp, protruding and abrasive surfaces should be avoided. Where this is not practical, steps should be taken to minimise the damage to hose assemblies.
- Hose assemblies should be stored lying flat in a cool dry area.
Nozzles
Water jetting nozzles are devices with one or more orifices through which the water (or any other fluid used) discharges from the water jetting system. The nozzle restricts the area of flow of the fluid, accelerating the water to the required velocity and shaping it to the required flow pattern.
Nozzles should always be kept clean and stored safely when not in use. And before each use they should be inspected for blocked or damaged orifices, damage to threads, cracks or any other structural damage that could adversely affect their safe operation.
Those nozzles presenting any damages or problems should be removed from service and repaired or destroyed to avoid accidents that can cause serious injuries.
Jetting guns and lances
Jetting pistols/guns and lances should be fitted with at least one fast acting trigger system to control the water jet (or any other fluid used).
This device is under the direct control of the jetter carrying out the work. Safer working methods are available in the form of jetting guns with double-action safety trigger mechanisms.
As is with all the water jetting equipment, it is not permissible to manipulate the equipment in any way which would nullify the safety features.
Both, jetting pistols/guns and lances must be maintained by a competent person in accordance with the manufacturer’s recommendations.
And they should be inspected and tested before each use, checking the following aspects:
- The correct operation of the trigger mechanism and guard
- The hose connections
- The nozzle holders and seals
- The hose is secured to the gun by whip check
- An impervious over hose shroud is fitted
- The handle or shoulder stock is fitted as required by manufacturer’s instructions
Foot control devices
Foot control devices are designed so that the operator can activate the water jet using a foot in place of or in addition to another form of control. It is used to pressurise or depressurise the water jetting tool.
They should always be fitted with a guard or cover to prevent them being operated accidentally.
Foot control devices should be maintained by a competent person in accordance with the manufacturer’s recommendations.
Electrical equipment
Electrical equipment used in water jetting systems should be of an extra low voltage type and should comply with electrical design and use requirements.
Electrical connectors should be waterproof, suitable and rated for the environment they are going to be used in, and they should be protected from unintended closed and open circuit failures. IP certification.
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