11.0HP and UHP Water Jetting

Content

1.0Purpose

2.0Scope

3.0Definitions

4.0Responsibility

5.0Training

7.0Manual Handling

8.0Risk Assessment

9.0Working at Height

10.0Protective Clothing and Equipment

11.0HP and UHP Water Jetting

12.0HP/UHP Pipe Cleaning

13.0UHP Cold Cutting

14.0Water Jetting Using Entrained Abrasives

15.0Selection, Assembly and Testing Of Equipment

16.0Care and Maintenance of Equipment

17.0Special Conditions

18.0Accidents / Incidents and Near Miss Situations

19.0Audits

20.0Quality Manual

21.0Water Jetting Unit Start Up / Maintenance Procedures

24.0References

Document Control

All printed copies of this document shall be regarded as uncontrolled and all relevant persons shall be informed of revision issue by email. Approved copies can only be found on the Tipa Integrated Management System. All amendments to this document revision shall be recorded in the Amendment Log below, refer to section 4.2.3 of the Tipa BS EN ISO 9001:2008 Quality Manual for detailed document control procedures.

1. Draft

1.0Purpose

The purpose of this procedure is to ensure that all water jetting activities undertaken by Tipa are carried out in a safe and efficient manner and in accordance with the specific requirements of each work site. Water jetting activities undertaken by Tipa include all forms of high pressure (HP) water jetting and all forms of ultra-high pressure (UHP) water jetting including use of entrained abrasives for HP and UHP cold cutting and surface preparation.

2.0Scope

This procedure details the standard methods and safe working systems associated with high pressure (HP) and ultra-high pressure (UHP) water jetting activities including HP / UHP water jetting with entrained abrasives. The principles apply to all forms of water jetting activities carried out by Tipa personnel at both onshore sites and offshore installations. However, job specific procedures will be required for certain applications and work environments to take into consideration local constraints and specific risks. It is imperative that a risk assessment is undertaken prior to commencing operations in order to ensure that all factors are evaluated and incorporated in the final agreed method.

This procedure will detail protective clothing, equipment requirements and the assembly, testing and operating methods that shall be used by personnel during all HP / UHP water jetting operations.

For the purposes of this procedure high pressure (HP) includes all pressures up to 1700 bar. Where the water is mechanically or hydraulically propelled to attain these pressures, with ultra-high pressure (UHP) referring to all pressures over 1700 bar.

3.0Definitions

An Abrasive feed system is a piece of equipment, generally used in conjunction with an entrainment head, which enables the abrasive material to flow from a storage container into the water jet stream. The container may take the form of a hopper with a series of valves that enable the operator to control the flow of abrasive material.

Abrasive material takes the form of a granular substance such as garnet, generally used in conjunction with water jetting for cold cutting or surface preparation. These substances vary in their abrasive properties ranging from fine to course. Manufacturer’s guidelines shall be followed when selecting an abrasive material.

A Burst Diskis a device, which can be fitted instead of or in addition to a Safety Relief Valve, which serves the same purpose, of protecting the system from over-pressurisation, but is designed to fail at a given pressure thus dumping the water. (Burst disks shall be sized to burst at approximately 15% greater than the lowest rated component of any system).

(Tipa’s current policy is that lower range high pressure units (below 350 bar.) are fitted with burst discs, High pressure units from 350 to 1,000 bar. are fitted with relief valves and all units capable of pressures of 1,000 bar and over are fitted with relief valves and burst disks as a secondary protection.)

Cold Cutting is the term used when material such as steel or concrete is cut using no naked flames or potential ignition source. This procedure deals with cold cutting using UHP water with grit entrainment.

Centraliser is a device used during the cleaning of large diameter pipes to hold internal pipe cleaning heads in the centre for more effective cleaning.

Cutting Head, working on the same principle as an entrainment head, is the piece of equipment which draws the abrasive material into a mixing chamber by the venturi principal and focuses the water and abrasive stream to carry out the required cut, when used in conjunction with the UHP cold cutting system.

Dry shut off gun is a device used to direct the flow of water during hand held operations whichhave a two port valve assembly (one inlet and one outlet) the outlet is fitted with a jet to give the required pressure and flow. When the trigger is released the water is blocked from the outlet line, having no dump facility, therefore the equipment stays under pressure until the pump is switched off and equipment depressurised. The trigger mechanism shall be fitted with a safety catch and be protected by a guard adequate to prevent accidental operation.

Dump gunis a device used to direct the flow of water during hand held operations. This system incorporates a three way valve assembly (one inlet and two outlets) and a failsafe trigger mechanism which when released enables the water to be dumped instantaneously from one of the outlet ports. The second outlet incorporates a jet which, when the trigger is pulled, creates a water jet at the required velocity, flow-rate, pressure, shape and distribution for a particular application. The trigger mechanism shall be fitted with a safety catch and be protected by a guard adequate to prevent accidental operation.

This type of gun can be found in use for both HP and UHP water jetting activities; these will be specifically rated for use at each pressure range and will be fitted with the appropriate fitting to prevent these being used for the wrong purpose.

An Entrainment head, working on the same principal as the cutting head is a tool, which can be attached to the end of a jetting gun, which enables a supply of abrasive material to be introduced into the water stream for surface preparation. The entrainment head works on the venturi principle in that the water flowing through the head causes a vacuum effect used to draw the abrasive into the head mixing chamber.

A Fan jetis a nozzle fitted to the gun, lance or other accessory, sized to create the desired pressure at a specific flow; the fanspreads the stream of water in one plane thus giving wide band coverage of the work piece.

Filtration relates to the filtration of all water supplies to HP and UHP water jetting pump units to prevent equipment damage and excessive wear by poor quality water and possible blockage of jets, which would be likely to cause over pressurisation of the system.

Gaiters are (TST or similar) covers capable of being strapped over protective footwear. These afford additional protection to the foot and shin and shall be fitted in all instances where the protective rating of the footwear available is less than the actual operating pressure of the equipment to be used. As with the TST suits these are available in two ratings for use in HP and UHP applications.

High Pressure ispressures up to 1700 bar where the water is mechanically or hydraulically propelled to achieve these pressures.

Hose Shroud or hose protector is a 1.4m or 1.8m protective sheath which fits over the pressure delivery hose at the point of connection to a hand held gun or tool to protect the operator in the unlikely event of a burst or leaking hose. Tipa supply these in two protection ratings for use with HP or UHP equipment.

HP fitting is any connector, fitting or adapter used to join the components of the high pressure jetting system together. As with the hoses they are rated for a certain maximum pressure and are identified accordingly. Tipa use BSP fittings for HP jetting connections. All such fittings shall have compatible threads and have a maximum working pressure greater than or equal to the maximum working pressure of the whole system.

HP Hoses are supplied in many formats and are manufactured to specific standards and ratings for different applications. Each hose shall be checked for suitability prior to use. All Tipa high pressure hoses are uniquely identified and are provided complete with pressure test certificates detailing test pressure and maximum safe working pressure. The maximum working pressure of the hose shall be greater than or equal to the maximum working pressure of the whole system. Typical HP hose assemblies consist of a wire braided core with rubber or polyurethane inner and outer protective sleeves, couplings are swaged in place by the manufacturer and fitted with BSP female swivel ends. All HP hoses are pressure tested by the manufacturer to 1.5 times the maximum working pressure and have a burst pressure rating of 2.5 times the maximum working pressure. All hoses are subject to routine visual inspection and are subject to retest annually or sooner if found to be defective or damaged.

Jetting unit / jetting pump is the main component in any water jetting system, consisting of a prime mover (typically a diesel engine but sometimes an electric motor or air motor) coupled to a positive displacement pump, used to deliver a flow of water to a gun, lance, or nozzle.

Lance is a length of tube carrying high pressure water to the nozzle. Each lance is manufactured from suitable drawn tube of length, diameter and material to suit the application. The lance is used in conjunction with a safety control valve and like all other components of a high pressure jetting system has a recognised maximum working pressure and corresponding identification and test certification.

Manipulator is a powered carriage, which carries the cold cutting head and is operated remotely using a pneumatic control panel.

Manipulator control panel enables the operator to control the start, stop, speed and direction of the cold cutting equipment. The panel is pneumatically powered and shall be positioned within vision of the worksite yet keeping the operator at a safe distance.

Metatarsal Boot is the trade name for the industry standard water jetting protective Wellington. These boots give additional reinforced protection across the bridge of the foot and are available in several protective ratings. The original boot, which carries no printed rating is rated for pressures up to 400bar (5,800psi) while the recently introduced three higher rated boot types are marked Primo 800 rated for pressures up to 800bar (11,400psi), Ultra 12 rated for pressures up to 1200bar (17,000psi) and Ultra 17 rated for pressures up to 1700bar (24,000psi).

Additional protection in the form of Gaiters shall be worn in cases where the Metatarsal boots are rated below the actual operating pressure of the equipment to be used.

Multi Jet Head can relate to a variety of jets which have more than one jet configured for different purposes. These include jet heads used in conjunction with the HP water weevil system, speciality drain jets and jets fitted to UHP rotary guns. (eg. Barracuda head for UHP guns.)

Pencil jet (otherwise referred to as a straight jet) is a nozzle fitted to the gun, lance or other accessory, sized to create the desired pressure at a specific flow; this jet concentrates the stream of water over a small circular area by minimising the spread. Focused jets such as these are typically used in cutting operations or in multi-nozzle rotary heads used in surface preparation. (eg. Barracuda head for UHP guns. Used in conjunction with pencil jet nozzles)

Pneumatic (twin trigger) gun is used primarily in UHP jetting, fitted with a rotary jet (eg. Barracuda head), to direct the flow of water in hand held operations. The two triggers on the gun are used to activate air pressure pilot lines to operate a remote safety station (dump valve also known as a “tumble box”) and can also be set up to control the pump remotely. In this configuration both triggers shall be operated to activate the system but the release of either one of the triggers will deactivate the system. Both triggers shall be fitted with guards to prevent accidental operation.

Pressure regulating valve (otherwise referred to as an unloader or pressure control valve) is used to limit the pressure at which the pump operates by releasing a preset proportion of the generated flow back to the pump header tank or to waste. The purpose is to regulate the water flow from the pump and may be individually set for specific operation.

Pressure Relief Valve This device is fitted on the pump discharge chamber to protect the equipment system from over pressurisation. The relief valve is designed such that it lifts from its seat when over-pressurised thus dumping the water. (Pressure relief valves shall be set to approximately 10% greater than the lowest rated component of any system).

Retro-jet (otherwise referred to as a pipe or drain nozzle) is a nozzle intended for cleaning the internal surfaces of pipes or drains. There are a wide variety of retro-jets for different applications, but generally they can be self-propelled by the rearward directed jets with particular combinations of forward facing, radial and rearward jets used for specific applications.

Rotary Pipe Cleaning Heads are rotating heads used for internal pipe cleaning, which use the water power for the rotation of the head and a viscous fluid to control the rotational speed for improved performance. These head are available in HP and UHP format, in a variety of shapes and sizes for cleaning and descaling of pipework sizes from 30mm to in excess of 1000mm in diameter. (Using extension legs and centralisers for the larger diameters).

Safety foot valve (otherwise known as a foot pedal or dump pedal) is a foot activated control valve using a similar three way valve assembly to the dump gun, which instantaneously diverts flow from the gun, lance or other accessory to the dump line when released by the operator. The dump line shall be of sufficient size to prevent back pressure when the full flow is diverted and shall be firmly secured to prevent the whipping action that would otherwise occur when the flow is diverted. The foot valve shall be fitted with a shield adequate to prevent accidental operation.

Safety Station is a remote pneumatically operated dump valve used in conjunction with UHP equipment, which diverts the water from the jetting tool to dump, controlled by air signals controlled by the operator. The safety station is also fitted with a manual shut off which when activated stops the flow of water to the jetting tool. This is achieved by the shut off, isolating the air supply to the tool and diverting the flow of water to the open dump. The jetting tool cannot then be reactivated unless the safety station is reset.

Stinger or jet extension bar is a rigid extension piece fitted between a pipe or drain cleaning jet (retro jet) and the flexible jetting hose. This is fitted to prevent the jet turning back on itself inside the pipe in instances when the pipe diameter is larger than the bend radius of the flexible hose.

TST Suit is the trade name for the specialist personal protective suit systems supplied by Tipa for use with HP and UHP equipment. These are supplied in two protective ratings, with suits rated for all HP operations, identified as 1000 bar and suits rated for all UHP operations, identified as 2000 bar suits.

Tube Lancing Systemrefers to an air or hydraulically powered mechanical device used to feed and retract a flexible, semi rigid or ridged lance for the internal cleaning of small bore pipework and tube bundles. This system eliminates the requirement for the operator to hold and manually feed or retract the lances.

Ultra High Pressure is all pressures over 1700 bar.

UHP fittingis any connector, fitting or adapter used to join the components of the Ultra High Pressure Jetting System together. As with the hoses they are rated for a certain maximum pressure and are identified accordingly. Tipa use Autoclave fittings for UHP jetting connections. All such fittings shall have compatible threads and have a maximum working pressure, which is greater than or equal to the maximum working pressure of the whole system.

Two different fitting sizes are used for compatibility with the two hose sizes used by Tipa. For use with DN5 hoses (gun to safety station) 3/8” UNF fittings are used, which shall be tightened to a torque setting of 50 lbf.ft (68Nm) as recommended by the manufacturer. For use with DN8 hoses 11/8” UNC are used, which shall be tightened to a torque setting of 110 lbf.ft (150Nm) as recommended by the manufacturer.

UHP hoses Tipa uses two standard UHP hose sizes. Type one (DN5) is 5mm internal diameter hose, used between the safety station and the pneumatic twin trigger gun to reduce weight and allow relative flexibility. This hose is classed as 6005STW wire braided hose with inner and outer extruded plastic protective sleeves, c/w 3/8”-24 UNF left hand thread male stand pipe on each end. Type two (DN8) is used for all other UHP duties. This hose is classed as 6108STW wire braided hose with inner and outer extruded plastic protective sleeves, c/w 9/16”-18 UNF left hand thread male stand pipe on each end. All Tipa UHP hoses are uniquely identified and are provided complete with pressure test certificates detailing test pressure and maximum safe working pressure. The maximum working pressure of the hose shall be greater than or equal to the maximum working pressure of the whole system. All UHP hoses are pressure tested by the manufacturer to 1.5 times the maximum working pressure and shall have a burst pressure rating of 2.5 times the maximum working pressure. All hoses are subject to routine visual inspection and subject to retest annually or sooner if found to be defective or damaged.