High pressure water jetting is vital for the petrochemical industry. High quality training, safe systems and new technology ensure it can be carried out safely, says the Water Jetting Association.

Water jetting is vital to the petrochemical industry. It is used for cleaning and de-fouling a huge range of equipment, including heat exchangers, process vessels, holding tanks, large-diameter pipes and site drainage systems.

It is also used for surface preparation during construction and structural maintenance and intrinsically safe cold-cutting and hydrodemolition.

Water jetting delivers excellent results and is better for the environment than alternative mechanical approaches. Without water jetting, it is fair to say, the petrochemical industry would grind to a halt.

However, water jetting is a risky business. Which is why, 40 years ago this year, the Water Jetting Association (WJA) was established in the UK.

“water jets at pressures as low as 7 bar, or 100 pounds per square inch (PSI), can penetrate skin, causing damage to internal tissue”

It was the first association of its kind in the world. Now its members, which include water jetting contractors, training providers and equipment manufacturers, are at the forefront of efforts to raise water jetting quality standard and skills in the Middle East and Africa.

Hand and arm risks and protection

Hand and arm injury is a major concern in any industrial process. With water jetting, a key issue is the risk of fluid injection injury or major trauma caused by water jets striking the body.

Water jets at pressures as a low as 7 bar, or 100 pounds per square inch (PSI), can penetrate skin, causing damage to internal tissue.

High pressure water jetting (HPWJ) is carried out at pressures up to 1,700 bar (25,000psi). Ultra-high pressure water jetting (UHPWJ) reaches 2,700 bar (40,000psi) and beyond.

At these pressures, fluid injection injuries can be very serious indeed.

Research commissioned by the WJA, published in 2019, [See WJA Medical Guidelines below] highlighted two critical consequences of high pressure fluid injection injuries (HPFII).

Firstly, the trauma can be so severe that people die rapidly from loss of blood. Secondly, less traumatic injury still has the potential to cause life-changing injury or death.

As a result, the WJA has written into its two codes of practice (for HPWJ and UHPWJ and for safe use of water jetting in sewers) measures that must be taken to control these risks. These include:

  1. Safe systems of work (SSoW) to control the risk of hand and arm injury. These include using jetting guns and lances of a specified design and length which prevent a water jet from be directed at the operative’s body.
  2. Where hand-held jetting guns or lances are being used, operatives must wear specialist PPE, including full body suits and additional arm gauntlets, if needed. These suits are made from ultra-tough materials, designed to withstand the forces exerted by water jets.
  3. Moving the operative away from the water jets by using semi-automatic and automatic water jetting equipment, also known as robotic equipment.

Avoiding HAVs

Research carried out by the UK Health and Safety Executive’s (HSE) Health and Safety Laboratory on behalf of the WJA confirmed HPWJ using single-jet equipment does not create a risk of hand-arm vibration (HAV).

Therefore, water jetting can often be safer and more productive than using electro-mechanical and pneumatic tools, such as jackhammers and power chisels, which are well known for their HAV injury risks.

The HSE’s research concluded that there was no need to take measures to reduce exposure to vibration when carrying out HPWJ with single jet equipment. Control measures would have to be considered when using orbital or rotating jetting nozzles.

Training and site control

John Jones, WJA Vice-President and Chairman of its Training and Safety Committee, said safety awareness training for all site workers, backed by effective site controls, is still vital.

“One of the biggest hazards is the failure of other people on a worksite to understand the kinetic power of water jets,” he explained.

“This can result in workers entering a controlled area, disturbing a water jetting operative, or interfering with equipment which will put them and others at risk.”

Water jetting surge

Effective training is at the heart of risk control. Water jetting training has developed significantly in the Middle East over the last 10 years, which is having a significant impact on health and safety standards.

Steve Williams is a UK-based WJAapproved training instructor. Like his instructor colleagues, he has opportunities to train operatives around the world.

He is struck by the growing awareness of the importance of both quality standards and training among contractors and the willingness to learn demonstrated by operatives on his courses.

“We’ve witnessed notable and positive behaviour changes as access to training and knowledge-sharing spreads across the Middle East,” said Williams.

“Contractors are using the right PPE and practicing standard, safe practices for high-pressure jetting applications. They are investing in the latest semiautomated cleaning methods and learning how to better maintain and optimise their high-pressure equipment.”

Another WJA-approved instructor, Roy Dykes, agrees real progress is being made in terms of recognition that training and safety standards are important, with more still to be achieved.

He believes standards are being lifted across the region by big and visible projects such as construction for the FIFA World Cup in Qatar in 2022. But, he says, the oil and gas industry still has the biggest influence.

“large companies like Qatar Gas are setting standards which others are being encouraged to follow”

Large companies like Qatar Gas are setting standards which others are being encouraged to follow,” he said. “Qatar Gas is very active across the region and is taking its approach to water jetting safety with it, which is helping to establish the WJA’s codes of practice as the water jetting ‘gold standard’ in the Middle East.

“The codes of practice have been continuously updated by people who’re at the sharp end of water jetting,” he added. “They’re recognised by all the major petrochemical companies, which is positive because it’s creating a consistent, high quality approach to safety across the region.”

A key challenge for training instructors across the region is language. The technical language in the petrochemical industry is English. But most water jetting operatives are migrant workers from the Indian subcontinent, notably from India.

WJA-approved instructor Richard Walton, said: “Language is a challenge for us, but it can be seen as a benefit for the operatives we train.”

He explained: “The language barrier means we have to work harder to get the learning points across.

“The WJA Safety Awareness course lasts a day in the UK, but I’ve taken up to three days to complete it in the Middle East. Operatives still have to pass the test at the end of the course. Operatives must also successfully complete a practical module to achieve WJA registration and receive a photo-id card. Key safety messages are well embedded by the time we’ve finished.”

WJA instructors make sure they emphasis key issues when water jetting in the Middle East, such as the need to wear PPE even in hot weather. Contractors should provide sunscreens for water jetting teams, and good hydration is crucial.

There are still huge opportunities to expand training. He still sees water jetting practice that gives serious cause for concern. Increasingly, though, contractors understand that skilled water jetting operatives are both safer and more productive.

“The commercial case for high quality water jetting training is made time and again,” he said

“Clients can see the benefits in terms of faster turnaround of maintenance and cleaning programmes. With water jetting, safety and profit definitely go hand in hand.”

Transforming the emergency response to injury

The priority is always to eliminate risk and to prevent untoward incidents. But you must be prepared if the worst does happen.

That is the principle behind the new water jetting injury management guidelines.

The guidelines are supported by an algorithm that details best practice actions at each step of the emergency response from giving first aid to ongoing hospital care.

They are based on research commissioned by the WJA and carried out by a team of UK emergency medicine physicians.

The research found that treatment outcomes for people who suffer high pressure fluid injection injuries (HPFII) are often compromised by poor medical care.

Our new guidelines are now incorporated into our Codes of Practice, given to all WJA members. It represents a step change in our understanding of how to treat these injuries.

For the first time, employers, paramedics and hospital medical teams have clear guidelines on the optimum treatment protocols for patients.

The research paper – Management of industrial high-pressure fluid injection injuries (HPFII): The Water Jetting Association (WJA) experience with water-driven injuries – has been published in the European Journal of Trauma and Emergency Surgery.

The study found that the unique nature of HPFII injuries makes them look less serious than they are. This often leads to delays in patients receiving the appropriate emergency treatment.

Intensive Care Consultant Dr Sancho Rodriguez-Villar, of Kings College Hospital, who led the research team, said: “The evidence shows that, without early and correct intervention, the outcome for those injured is often catastrophic, including death, loss of limbs and long-term disability.

“Following this research, we strongly advise all parties involved to observe the WJA’s updated guidelines for the management of high-pressure injection injuries.”

Recommendations, incorporated in the algorithm, include:

  • As part of their first aid response, operational water jetting teams should have access to trauma kits specifically to prevent blood loss
  • Individuals who experience HPFIIs, and those responsible for their wellbeing, should be trained to alert medical personnel about the serious nature of the injuries and signpost the WJA management guidelines
  • All HPFIIs should always be treated as severe traumas in a tertiary specialist hospital whenever possible
  • Evacuation by air ambulance to a trauma centre with surgical facilities must be considered in the early stages
  • Early access to CT and MRI scans should be obtained to assess internal injuries
  • All wounds should be treated as if they are contaminated – so kept open and surgically cleaned, in stages if necessary
  • Patients should be kept under an appropriate period of medical observation
  • Wound swabs and tissue samples should be taken as soon as possible and sent for microbiological and histological examination


The best way to protect humans from ultra high pressure water jets leaving nozzles at over twice the speed of sound is to move them out of harm’s way.

That is the principle behind robotic water jetting, also known as semi-automated water jetting. It is a technology that can deliver key benefits for contractors in the Middle East.

In water jetting, there is a hierarchy of risk mitigation. If possible, remove the risk by removing the person. If you can’t, protect the person with guarding. If you can’t do that, provide appropriate PPE. If that’s not possible, find a different solution.

Semi-automatic water jetting is the first of those actions and is being used more and more in step with the development of robotic technology.

WJA member Jeremy Twigg argues that this gives Middle East contractors who want to make use of high and ultra high pressure water jetting the opportunity to jump a technology generation and benefit from the advantages of automation.

“There’s nothing wrong with using jetting guns,” he says. “But they require a lot of operator skill to use to their best advantage. It can take an operator years to develop those skills.

“semi-automated water jetting is a technology that can deliver key benefits for contractors in the Middle East”

“It makes sense, then, to use automated systems, where that is possible. In key situations, robotic water jetting can be more productive and, clearly, safer. It can also go where sometimes humans can’t, for example into hazardous environments.”

However, sustainability, especially in terms of access to the right volumes of clean water needed for water jetting in the Middle East, is a potential issue.

Robotic systems can consume twice as much water and energy as handheld jetting gun water jetting due to the control an experienced operator has over the process.

Some tasks, either due to their size or location, for example in confined spaces, are better suited to hand-held water jetting.

However, robotic water jetting is proving itself in an increasing number of projects, including cold-cutting, cleaning and hydrodemolition.

An example is the use, by a WJA member, of ultra-high-pressure abrasive water jet cutting equipment to remove a collapsed 72m-diameter floating roof from inside an oil tank located in Focados, Nigeria.

The solution had to be intrinsically safe. The UK-based water jetting team first cut a 5.75m by 4.5m opening in the tank. Then water jetting was used to dissect the 4,000m2 roof and carry each piece out of the tank.

The project was completed safely in 17 weeks. A new roof could then be fitted, and the tank could be brought back online.

Cleaning challenges in the Middle East’s petrochemical industry are driving important innovations.

Another WJA member that champions robotic water jetting has just launched a remote access water jetting system for cleaning shell side tubes. Called a Shell Side Jet, it automatically removes fouling to a guaranteed standard of thermal efficiency without the need for confined space entry.

It is designed to be fully automated without the need for confined space entry, while removing fouling to guaranteed standards of thermal efficiency.