Effect of varying pressure/flow at the nozzle – range of jetting machines – configurations & categories (pressure washers / general purpose / medium-heavy duty / UHP / drain & sewer jetters)

Health & Safety at Work Act – WJA Codes of Practice – status, use and recognition by the HSE Management Regulations – RISK Assessment – PPE at Work regulation s- COSH – Employer/employee responsibilities-
Enforcement Powers – other relevant legislation e.g. Environmental Protection Act / Control of Pollution Act.

Jet principles – purpose of nozzles – power of water jet – jet pressure/flow characteristic – jet reaction force.
Types of nozzle – forward facing, fixed & spinning jets, multi-jet fixed & spinning nozzles.

Pump configuration – standard piston / plunger pump, positive displacement action, operating features, effects of blockages, variation of plunger sizes. Other pump configurations – diaphragm and intensifier types. Drive arrangements- engine / electric motor, hazardous area equipment. Water supply/delivery features – filtration requirements, boost feed pumps, pulsation dampers, jump-jet. Pressure safety relief
options – relief valve / bursting disc. Pressure gauge features.

Dump & dry shut controls – fail-safe / selector versions, direct manual operation / remote operation via electric-pneumatic-hydraulic controls, automatic unloader valve for dry shut, pressure regulators, and automatic off-load engine speed control systems.

Hazards arising directly from the water jet – from operational regime – from site environment

Effects of impact by high pressure water jet – nature of internal injuries caused – action in event of ajetting injury – awareness of possible absence of visual injury & use of WJA Medical Card.

General principles regarding use of PPE, as a last resort; Main body protection – limits on effectiveness against direct impact of water jet; Protection of head, hands, feet, hearing, respiration; Particular requirements when using UHP.

Routine care & inspection – site preparations – preparations for operation – team operation.

Safety points during operation – use of manual jetting gun/lance, tube/pipe/drain cleaning nozzle/lance/ hose combinations & techniques. Safe use of non-standard equipment e.g. tee nozzle.

Site shutdown & anti freeze procedures. Use of DO / DO NOT GUIDE.

Review of course content as above, with opportunity for further discussion prior to Questionnaire.