High pressure cleaning - a high pressure job

16th of December 2019
High pressure cleaning -  a high pressure job
High pressure cleaning -  a high pressure job

What are the risks involved to the operator when carrying out high pressure cleaning? And how much training is needed to ensure that it can be achieved as safely as possible? Ann Laffeaty assesses the role of the operator in any high pressure cleaning task.

High pressure cleaning is a highly effective method of removing hard-to-shift substances from a range of surfaces, often using water alone. It is a versatile, accurate and efficient means of cleaning and one that can greatly facilitate difficult tasks such as removing graffiti from walls and washing away concrete from surfaces.

But high pressure cleaning also poses risks. For example, operators may struggle with the high levels of noise and vibrations that are sometimes associated with this form of cleaning. They could also sustain an injury from an uncontrolled hose striking the body, or suffer from muscular issues from the strain of holding the hose in a fixed position for long periods at a time.

And if the operator’s skin is punctured by a jet of fluid under pressure this could cause a serious hydraulic fluid injection injury. This type of injury is characterised by very small entrance wounds and no exit wounds. This means the water penetrates deep into the tissues, potentially bringing with it debris and bacteria from the cleaning process.

And this could cause serious infections leading to long-term disability and potentially even the loss of limbs or death. So, how do manufacturers ensure that their equipment is as safe as possible?

Specific training needs to be provided for professional operators according to IPC communications manager Gabriella Bianco. “Domestic high pressure washers are so easy to use that the manual included within the package is usually a sufficient means of instruction,” she said. “But professional models on the other hand need to be bigger and more powerful in order to cope with industrial applications. So the user should be given an appropriate introduction to them.”

She says operators need to be informed of the importance of protective clothing when using high pressure cleaning equipment to avoid the risk of injury. “This equipment should include adequate shoes, comfortable clothing and easy-to-use gloves,” says Bianco. “It’s a question of safety first.”
She adds that noise levels emanating from the motor pump plus the sound of the jetting water can often be excessive when a machine is in operation.

“Operators could therefore benefit from some form of hearing protection when using high pressure washers, particularly when carrying out industrial applications,” she said.

IPC offers Multifunction Safety Control technology in some models which automatically shuts down the machine after a period of inactivity. Meanwhile, the company’s Micro Leakage Control system is designed to detect any dangerous leaks in the hydraulic circuit and close the machine down if any such leak occurs.

The fact high pressure cleaners are powerful machines means that there are always risks involved for the operator according to Dibo managing director Arno van den Borne.

Limiting risks

“A safe and ergonomically-designed machine made from high quality materials coupled with proper operator training and protective clothing will all help to limit those risks,” he said.

Dibo carries out a risk analysis for all its machines and provides operator training along with manuals featuring clear safety instructions. “We also advise every user to take responsibility for his or her own personal protection and we indicate in our manuals and courses what the maximum vibration levels should be,” he said.

“However, those maximum levels will rarely be reached. And if there is even the slightest possibility that these values may be exceeded it is clearly stated in our manuals that a recommended number of working hours will be set and respected.”

Easy to operate

According to van den Borne it is important to ensure high pressure cleaning equipment is easy and comfortable to operate. “All our high pressure cleaners are user-friendly and have simple and clear operation,” he said. “And in fact even our most complex machines – high pressure cleaners on a trailer - are equipped with intuitive and self-explanatory instructions.”

Operational errors are almost unprecedented, he claims. “This is because a fully automatic safety and control system is always running constantly in the background,” says van den Borne. “In this way the high pressure cleaner is continuously being monitored while in operation.  And in
the case of any malfunction it will switch itself off and indicate where the malfunction is located.”

Dibo machines feature an emergency switch, an automatic start/stop system and an ergonomic handle, he says. “And our heaviest machines - our high pressure cleaners on a trailer - are equipped with a graphic digital display and can be easily operated by a joystick, even when wearing gloves,” he said.

Kärcher’s high pressure cleaning product manager Benjamin Weiss says it is crucial to have a skilled and committed labour force in place when carrying out high pressure applications. “Cleaning performance will depend on various parameters such as pressure, water flow, temperature and detergents,” he said.

“Carrying out the task correctly requires experience because the operator needs to choose the right nozzle for the task – whether it is a flat or rotary jet nozzle, for example -  and then clean from the correct distance to avoid any damage to the surface.”

He says all training should take the form of practical experience. “Operators can learn the theory and basics of high pressure cleaning virtually, but it is very different when one actually comes to clean,” he said. “There is always a ‘wow effect’ for inexperienced users when working with a high pressure cleaner for the first time.”

One of the most common risks to high pressure cleaning operators is that of muscle stress to the fingers and arm when holding a trigger gun open, says Weiss. Kärcher machines offer an Easy!Force trigger gun to reduce the level of muscle stress.

Vibration levels are a risk factor but are heavily regulated these days, says Weiss. “Vibration levels will depend on the machine’s performance, the type of nozzle used and the intensity of usage but the target is below 2.5 m/s² hand-arm vibrations,” he said. “Over that value there are limitations as to how long the operator should work with the system.”

And he adds that it is important to ensure all high pressure cleaning equipment is easy and comfortable to operate. “Labour protection laws are in place to protect users during physically demanding activities such as high pressure cleaning,” he said. “And in the future, companies must disclose the workload required and offer compensation to employees whether this is in the form of money, breaks or early retirement.”

Kärcher machines are said to be easy to operate and require the use of just one main switch for on/off and temperature adjustment.

Serious accidents

Despite the best efforts of manufacturers, serious accidents do sometimes occur in the high pressure cleaning industry. In August 2017 a drainage operative was killed in Canada when he was struck on the neck by a water jet. The system had not been fitted with an automatic shut-off device and the contractor was fined the equivalent of €99,000.

Some countries promote recommended safety guidelines that are published by professional bodies in an effort to keep high pressure cleaning operators safe. For example, the SIR organisation In Belgium and the Netherlands offers training courses for working with high pressure cleaners of less than 250 bar. And medical research commissioned by the UK’s Water Jetting Association led to the publication in July this year of a comprehensive set of guidelines aimed at avoiding high pressure fluid injection injuries.

The guidance aims to transform the current emergency medical response to water jet injuries and greatly reduce the risk of death, long-term disability or prolonged periods of recovery.

But in order to make high pressure cleaning safer still, could it ever be automated? Some degree of automation already exists according to Dibo’s Arno van den Borne. “However, this is only found in specific production processes where the same cleaning tasks are constantly being repeated,” he said.

“And we do build custom-made cleaning installations for the food and pharmaceutical industries. However, other cleaning applications are too diverse to be automated and they all require their own special approach.”

The nature of the task in hand makes automation a major challenge for the high pressure industry, adds Kärcher’s Benjamin Weiss. “High pressure cleaning applications are more complex than vacuums or scrubber dryers because you are cleaning 3D objects rather than a 2D floor,” he said.

“Having said that, automated high pressure cleaning is already being used in gantry car washes. But for mobile, functional and affordable high pressure cleaning, robots are still a long way off.”


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