Cleaning under pressure

Choose wisely when selecting a pressure washer for your facility.

Is the outside of your facility looking a bit dingy from the effects of months of hard weather? Pressure washing to flush out soils quickly and efficiently might be just what your exterior surfaces need. Pressure washing can replace the need to manually scrub surfaces with a brush and detergent.

“Speed is a main advantage of pressure washing,” said Kärcher senior sales trainer Nate Abrahams. “That equates to money because if you’re hiring someone to clean, it could take them a day to complete the job rather than a week.”

Pressure washing your facility’s exterior surfaces will not only benefit its curb appeal, it will also help keep the interior cleaner. “Most of the soil in your buildings is from walk-in foot traffic,”

Abrahams said. “If you can remove dirt, oils and spills on sidewalks, drive-up areas, entryways and other waiting areas, you lower the amount of dirt brought inside.”

Moreover, if a facility is busy, cleaning more often will deliver better results, according to Spitwater New South Wales director Milo Gajin.

“The facility will be cleaner and more presentable which in turn will ensure that it is easier and less expensive to clean and maintain,” Gajin said. “The old notion of a ‘spring clean’ is no longer valid as hygiene standards as well as public expectations demand better results.”

Abrahams said using the correct nozzle is key to avoiding damage. “The nozzle creates the pressure at different spray angles – 15 degrees, 25 degrees and 40 degrees,” he said, adding that the 15-degree V-shaped angle delivered the most concentrated spray.

Abrahams recommends spraying 10 to 30 centimetres away from the surface you’re cleaning for optimal results. He added that the sound of the water against the surface will be at its loudest when the user is spraying at the most effective distance.

When purchasing a pressure washer, the first decision you’ll need to make is between an electric, diesel or petrol machine – all of which are available in Australia.

Gajin said the type of high-pressure water cleaner used is generally determined by the application rather than the conditions.

“For example, cleaning of large industrial equipment, mining equipment, truck fleets and on-farm, is generally carried out with electrically powered, single phase or three phase, hot/cold water cleaners with diesel fired burners,” he said.

“Large infrastructure projects use portable, combustion engine powered (diesel or petrol) hot/cold water cleaners with diesel fired burners. These are more powerful and able to be relocated for use.

“Electrically powered cold water pressure cleaners are used in motor vehicle maintenance and small business jobs to be done. They are versatile, inexpensive and offer great results.

“Facilities management, such as public space cleaning, house maintenance, roof cleaning and drain clearing, is almost exclusively done with combustion engine-powered [diesel or petrol] cold water cleaners using a wide range of accessories. Portable, combustion engine powered [diesel or petrol] hot/cold water cleaners with diesel fired burners are also used on bigger cleaning projects.”

City streets and large open spaces are typically cleaned using larger and more powerful units. Gajin said pressure washers commonly used in facilities management were powerful and delivered excellent cleaning results but they can be noisy.

Abrahams said electric models typically cost less, did not need regular tune-ups like other engines would, and are quieter to operate.

“They are good for hotels and other areas where you want less noise,” he said. “They are lightweight and easy to move, and if you have multiple places to plug them in, you are good to go.”

However, he said, the cord can result in portability issues.

He said petrol pressure washers can be higher-performance machines, and can clean much quicker than electric machines. On the downside, petrol and fuel-powered pressure washers require regular maintenance.

“Like our cars, they need tune-ups, spark plug changes and new filters,” Abrahams said.

Pressure washers are also available in hot-water and cold-water models. Abrahams said the hot-water models clean surfaces 40 percent to 60 percent quicker than cold. They are also more efficient in removing oils, grease, and other stains.

“Cold-water machines just push grease around; they don’t really remove it without detergent,” he said.

Cold-water pressure washers, which cost less and require less maintenance than hot-water models, are most effective against dirt, dust, and sand, he said.


A common mistake Abrahams sees in relation to pressure washers is operators neglecting to use the proper accessory.

“I see people using a wand to wash sidewalks, walking along, swiping the wand back and forth,” he said, explaining that the result is a streaked surface.

Instead, Abrahams recommends using a surface cleaner, which attaches to the pressure washer hose and spins five centimetres above the surface. This accessory evenly sprays water over the surface, ensuring a uniformly clean sidewalk.

Abrahams recommends determining what surfaces you want to clean with a pressure washer, and then determining which attachment will achieve your desired results.


Gajin advises buying a machine that meets the Australian standards for high pressure water jetting, but is quick to add that standards are not mandatory.

“They are voluntary and as such, difficult to enforce,” he said. The high-pressure water blasting industry covers an extremely wide range of uses and products, Gajin said. A basic, hardware- store domestic cleaner, operating at six litres per minute water flow and a pressure of 100 Bar (1450 psi) is covered by the same standard as an ultra-high pressure blaster operating at as high as 600 litres per minute and 10,000 Bar (145,000 psi).

He said the Australian industry developed AS/NZS 4233.1 – Use and Maintenance, and AS/NZS 4233.2 – Construction and Performance standards for water blasters to segregate products into different categories depending on their level of performance, to define production and safety standards, applicable PPE, training, user certification and other very important factors.

“The standard is currently going through a major review in order to clarify a number of contentious areas and make it better for all – manufacturers, businesses, contractors, other users and the public,” Gajin said.

He also noted that both standards also incorporated a number of other standards, such as electrical equipment standards and hose standards, just to name two.


Facility managers should look beyond the price of a pressure washer unit to work out the best solution for the job to be done.

“Cost pressures often push facility managers to the cheapest brands,” Gajin said.

Abrahams also encouraged facility managers to buy a commercial pressure washer that will stand up to the rigours of frequently cleaning a public building.

“Sometimes people will buy a pressure washer at a big box store that is a residential machine, not a commercial machine,” Abrahams said.

He explained that a residential machine can handle about half an hour of use once a month, but using it two hours every week would wear it out quickly.

“These people will end up buying two or three residential cold-water machines a year. Although a commercial unit is more expensive, you will save a lot of money because it can last for 10 years if you take care of it.”

Originally published on CMM Online.

Photo by Hilary Halliwell on Pexels.

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