A window on the world

by Arian Bahramsari
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Window cleaning is an indispensable part of the periodic maintenance routine, but what frequency and method is best and safest for your high-rise? ARIAN BAHRAMSARI reports.

As more skyscrapers dominate our cities, consider for a moment the window cleaning requirements of a building like Kuala Lumpur’s Petronas Towers. It is fitted with 32,000 windows and, as one of the highest buildings in the world, the challenge of keeping them clean is a daunting one.

It’s not just about aesthetics; debris and dirt on windows can etch the glass and cause irreversible damage. Regular cleaning is imperative to protect the glass from degradation and maximise its longevity.

So, how often should windows be cleaned? Generally, the frequency depends on factors such as the building’s location and nature of activity, pollution from passing traffic, occupancy levels and weather. In residential buildings, the rule of thumb is twice a year.


Modern buildings, especially those with unusual geometry or specific requirements, have led to the design of mechanical platforms to access all floors of high-rise buildings, but there are some other tried and true methods.

Rope access/abseiling

Rope access, also known as abseiling or twin rope access, is one of the most commonly used methods to clean windows. This technique is also a cost-effective solution with minimum public and noise disruption, and environmental impact.

Apart from ensuring the cleaning company has public liability insurance and its operators have WorkCover certification, facility managers may ask if the technicians are licensed by the IRATA (the Industrial Rope Access Trade Association) and ARAA (Australian Rope Access Association).

Elevating work platform (EWP)

EWPs are sometimes known as aerial work platforms (AWPs) and can be applied for window wipers to access at height from the ground up. These platforms are normally easy to set up and can be operated manually or mechanically to raise and lower a mobile platform from a stabilised ground level position.

EWP machines can access almost anywhere, and they include a wide range of machines such as telescoping boom lifts, articulating boom lifts, scissor lifts, cherry or stock pickers, and bucket trucks. These machines can be powered, trailer-mounted or crawler-mounted.

It is worth mentioning that each EWP serves a different purpose. Depending on the nature of the job, facility managers may choose electric, hybrid or propane powered machines for inside windows or gas and diesel powered for the outside works. Noise level, set-up time, public access and surface characteristics are some of factors that should be considered by facility managers in this regard.

BMU window cleaning

Building Maintenance Units (BMUs) are engineered methods to access the façades and windows of high-rises. These systems vary from motorised and relocatable to bespoke designed ones. Swing stages, davit systems, counterweighted beams, parapet clamps and external monorails are some examples of these systems.

A swing stage, or suspended powered platform, is an adjustable metal scaffold that is suspended by cables attached to a secure anchor points. Swing stages are normally about 15 metres long and provide wide access to several windows for window washers. Some buildings have a permanent swing stage built on top of their roof and others may request a temporary modular one.

The boom is a permanent access system built on the roof and it does not require any socket or support points on lower levels. A scaffold or platform is attached to this system that allows multiple window cleaners to work together. There are two different types of boom systems: fixed and rotating. A rotating boom can bring the platform up to the roof and park it when it is not in use.

A carriage system is similar to boom access, but it provides horizontal and lateral movement via its rails mounted on the roof. The roof carriage is normally electric driven.

The portable davit comprises two primary components – a mast (the vertical piece) and boom (the horizontal piece) – secured to the permanent fixture, called base. The mast on the davit arm is tall enough to allow it to pick the platform up and hoist it onto the roof. After use, the davits and the cradle can be stored in dedicated areas so they are out of sight.

The arm is typically portable with the ability to be raised, lowered and removed. These arms will be used in conjunction with other forms of suspended equipment, such as a single cage or a bosun’s chair and the worker’s independent lifeline will be attached to an independent roof anchor. This line and roof anchor will protect the worker in the event of a fall.

The bosun’s chair, also known as a boatswain’s chair or flying seat, is a fairly common and cost-effective approach for window washers. It takes the form of a comfortable, strap-in seat to access very difficult-to-reach areas of a skyscraper.

There is no one general window cleaning method recommended for all buildings and sometimes a custom-made façade access solution will be required.

123RFs sasilsolutions © 123RF.com


Automated cleaning robots will be game-changers in facility maintenance. These can be integrated to the existing BMU systems, and reduce the risks and costs of window cleaning.

A further benefit of a cleaning robot is its rotating brush and ability to filter the water it uses in the cleaning process. Most of these machines do not apply any chemicals, using deionised water during their cleaning. In addition, cleaning robots are wirelessly controlled and can climb free of human intervention.

There are two ways in which robots attach themselves onto the windows: vacuum suction or magnetic connectivity. Vacuum suction robots are powered by a motor; however, there is always a risk of fall for these machines.

For robots with motor-powered suction, it is wise to use safety cords and also choose those with UPS (uninterruptible power supply) units attached. UPS units can save the robots if the battery goes flat or the power is disconnected.

Robots with magnetic suction technology require a second piece on the opposite side of the window. This requirement means these robots leave a lot to be desired when it comes to use in high-rise buildings. ●

Arian Bahramsari is a facility manager at Facility Management Victoria, based in Docklands, Melbourne.

This article also appears in the Apr/May issue of Facility Management magazine.

Lead image: 123RF’s Branislav Ostojic © 123RF.com

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