Surface performance

No post image

Maintaining a runway in the best of order is not only a safety issue – as important as that is – it’s also about efficiency and performance. There is a wide range of equipment available to ensure that runways are kept clear of detritus of all kinds and that apron markings are as clear as they can be

Over any significant period of time and depending on the type of covering, aggregate, and the frequency of traffic on it, rubber marks left by aircraft tyres will gradually deteriorate a runway’s surface, making it far smoother and impairing potential tyre grip. Moreover, as the surface is worn and covered by contaminants like rubber, the covering no longer helps to drain water from the runway and the film of water that then lies on the surface can lead to da  ngerous aquaplaning.

If, as has been estimated, a large aircraft can leave up to 700g of rubber per tyre on a runway when landing, the potential scale of the problem is evident, and a number of companies offer solutions. Blastrac, a long-serving manufacturer of surface preparation equipment dedicated to the airport market, is one such. Its primary focus is shot blasting – a non-destructive method of removing rubber from an apron surface that uses centrifugal force to apply an abrasive material to the runway contaminant, thereby removing the pollutant and re-establishing the previous rough texture of the surface.

Plus, the process will remove old line markings and, according to Netherlands-based Blastrac’s marketing manager Clément Charpentier, improve light reflection and the general optical characteristics of the surface. Shot blasting will also, he says, help to reduce vibration and noise levels during aircraft take-offs and landings.

The company’s vehicle-mounted 2-45DTM system can shot-treat up to 3,600 square metres of runway per hour. The technique is purely mechanical, requiring no chemical substances or water, so there is no waste to dispose of and no possibility of cleaning fluid or water seeping into the surface and doing damage itself.

“It can prolong the runway life by a number of years without the need to invest in a new top coat,” Charpentier points out. Furthermore, shot-blasting can also be used for surface preparation of storage areas, maintenance halls and parking decks, marking removal and as preparation before laying a new surface coat.

As well as the 2-45DTM and many other shot-blasting systems, just last year Blastrac introduced its biggest yet walk-behind shot blaster, which, the company says, is ideal for airport runway maintenance. The company’s product range now stretches from hand-held devices, through walk-behind machines to its big vehicle-mounted systems.

Under pressure

Other rubber removal technologies have been working well for many decades, one of which is the seemingly simply measure of pumping water under high pressure onto a runway surface. One of the supporters of this methodology is Berlin, Germany-based SMETS-Technology, which specialises in rubber and paint marking removal from runways (although it also offers sewer cleaning vehicles and friction-testing equipment, the latter in the role of distributor). While a comparative newcomer to the field – the business was only formed in 2009 – SMETS has quickly developed its portfolio and its client base; according to co-owner and technical manager Stephan Smets, the company already boasts more than 50 customers around the world.

SMETS supplies the complete unit (it offers the ARC 1000® and ARC 2000® airport runway cleaner systems, as well as various other products such as the ARC 2400® surface retexturing and de-marking truck) – the vehicle and the surface treatment unit that is attached to it. It can also supply just the treatment mechanism kit and then install it on a locally available chassis where import prices make importing a complete vehicle very expensive – in Brazil, for example.

With all the essential components hydraulically powered, the SMETS rubber cleaning system operates on the linear model, across the width of the vehicle. The surface cleaner is positioned between the first and second axles of the truck and, once its job is done, the mechanism can be raised from the surface automatically from the cab; the vehicle is then ready for normal driving on public roads (unlike for some of the competition’s models, notes Smets, whose cleaning systems must be dismantled from a vehicle when not required to prepare the truck for regular highway driving).

Another big advantage of the ARC runway cleaners, he considers, is their efficiency of operation. The high-pressure pump of the ARC 1000® handles a flow of between 15 and 29 litres of water per minute and has, Smets insists, proved highly effective at removing all rubber deposits from runway surfaces, whether concrete or asphalt-based. This unit cleans, on average, an area of up to 1,200 square metres an hour, the ARC 2000® system up to 2,400 square metres per hour. Either way, the company guarantees that 95 percent of rubber deposit will be removed; it also guarantees that friction on the runway surface will be improved as a result of treatment. The nozzle configuration and extremely high nozzle speeds (about 450km/h) mean that the system doesn’t cause damage to a treated surface.

An additional unique selling point that Smets highlights is the ease of use of the various ARC systems. While three weeks’ worth of training is provided as part of the sales package, the simplicity of the operating system – which, for the operator, involves manipulation of a simple colour touch-screen display in the cab – means that most of the training can be performed ‘on-the-job’.

The SMETS systems can be delivered with several optional extras, such as laser-line pointer, permanent magnetic device for FOD (foreign object damage) cleaning, a washing-vacuum device and sweeping mechanism.

SMETS-Technology’s own research and development resources developed the software, and it is this R&D capability that, Smets says, has allowed the company to develop quality products so quickly. Highlighting this, he notes the recent sale of four more ARC 1000® units, the deal struck at the end of October last year. Two vehicles are to be deployed into China, one at Erbil in Iraq and one across Nigeria’s airports.

High-powered Jetting

Jetting Systems was incorporated in 2003 with the aim of supplying specialised water jetting cleaning solutions to industry. In its first year of trading, the company secured orders for runway rubber removal equipment for use in the US, the UK and Korea. Since then, says the company’s managing director and owner, Simon Carling, the runway cleaning business has changed significantly, with the volume of water being used falling markedly and the pressure used increasing. Taken together, he notes, these have the advantage of reducing the waste produced and therefore disposal costs and environmental impact. Improvements in technology mean that the working speed of equipment is also increasing.

Jetting Systems has a whole product line of jet cleaning systems available to the airport market that it calls Osprey, the range incorporating full truck-mounted systems and kit units that can be mounted onto customers’ own tractor units.

“The concept is that the vehicle must be completely self-contained and not require any support equipment,” Carling explains. “It must be able to arrive at an airport and deploy for rubber removal operations within minutes. In the event of an emergency landing being required, the Osprey can be ready to evacuate the runway at full road speed in seconds.”

An Osprey unit comes with a water tank sufficient for 4.5 hours operation and a debris tank that has enough capacity to hold all of the water from the clean water tanks plus any rainwater that will also be recovered – as well, of course, as the rubber deposits collected.

Water is taken from the clean water tanks and pressurised to in excess of 2,000 bar. It is then applied to the runway surface through a rotary cleaning head. This has numerous sapphire nozzles fitted, each of which directs a jet of water to the runway surface. According to Carling, the magic comes in generating sufficient impact to remove the rubber whilst leaving the underlying surface intact. The heart of the Osprey concept is precision rubber removal and this is achieved by the use of a robotic motion control system.

Unlike products offered elsewhere on the market, he says, the Osprey’s process of rubber removal is totally automated, using a system that ensures the potentially damaging rubber removal head is constantly moving over the surface and never stationary over any one point. Moreover, the head is always travelling parallel to the front of the truck and there is a controlled and safe overlap of treated areas.

Ray of light?

Denmark-headquartered Beam has a number of different offerings in the runway maintenance space. Founded in 1972 and now a company forming part of Bucher Municipal, Beam initially acted as a contractor providing sweeping services; it then started to make its own sweepers and, when the product was found to be so good that other companies wanted to buy the units, Beam switched from contractor to manufacturer and now has more than 2,000 systems in use with airports and service providers around the world.

According to export sales manager Nigel Mottershead, over half of Beam’s business is now with airports, its clients as wide-ranging as London Heathrow, London Stansted, Leeds Bradford and Jersey in the UK and Paris Charles de Gaulle in France, New York JFK in the US and Palermo airports in Sicily amongst them. Its staple offering to airports is the A9500 (so-called because it has a 9.5 cubic metre hopper) high-speed runway sweeper that has both powerful suction and side-blowing equipment that operate fully effectively even when the unit is moving at a speed of 40 kilometres per hour.

As well as the A950, Beam also offers bespoke products made to order for airports. Built on two- or three-axle chassis with hoppers from 7 cubic metre capacity to 14 cubic metre capacity, the sweepers are built to specification from their various building blocks – chassis, engine, hopper, high water pressure pumps and a host of other options to suit the end user’s needs.

Some of the company’s airport customers are using these sweepers for runway maintenance, some for taxiways and some for stands – or any combination thereof. Others are using the units specifically for glycol recovery, sucking up the expensive but potentially damaging fluid and then moving it on for recycling.

Beam is also offering equipment designed specifically for rubber removal from runways using the jetted water technique described above. It employs ultra-high-pressure water squirted from rotating nozzles at the back of a vehicle, supplemented by a full-width suction unit to collect the removed contaminant. This technology allows a large area to be effectively cleared of rubber in a very short time, Mottershead argues.

Prolonging runway life

Extending the effective life of a runway surface offers obvious benefits. One offering in this area is Rhinophalt©, a preservative for asphalt runway (and road) surfaces. Rhinophalt works with the bituminous binder, the ‘glue’ holding together the stones within an asphalt surface. It forms an impervious seal within the bitumen that not only keeps out water but also delays oxidization, and therefore the deterioration of the binder.

Reducing the need for unplanned repairs, as well as postponing the need for resurfacing, brings major benefits to airport authorities and operators in terms of both lower maintenance cost and reduced disruption. “It is quite unique in what it does,” enthuses Barrie Simpson, sales representative of UK-based ASI, which developed the product.

Applied by any spray tanker with minimal modification, the product takes about an hour to dry. Runway/taxiway lines are then reapplied by one of ASI’s ‘preferred partners’, of which there are three in the UK and a number of others in overseas markets across Europe, the Middle East and Asia.

While ASI only began offering Rhinophalt into the airport market some half-dozen years ago, awareness of the process has spread quickly. In the UK, Rhinophalt has been used at locations such as Manston, Airbus UK and RAF Northolt, as well as in Germany and Italy, at Singapore Changi and at Beijing Capital International Airport (BCIA) in China.

Another important customer is Iceland’s Keflavik International, whose airside surfaces have all been treated over the last five years and which has requested a second treatment to be undertaken on its runways next year.

Equally effective in either the sub-zero temperatures of Iceland or the heat of an Indian or Chinese summer, Rhinophalt has a growing track record as a preventative maintenance tool. Although it should not, Simpson points out, be confused with repair systems designed to fill cracks and potholes or replace the existing wearing course, he concludes: “Rhinophalt is a highly effective and extremely convenient tool for any airport authority looking to prolong the life of its existing asphalt surfaces.”

Keeping up

With many airports becoming ever busier and functioning for longer and longer hours, their operating authorities are requiring runway cleaners that can work faster, coping with the same amount of runway areas in less and less time and, of course, as effectively as possible.

Whatever the method of surface cleaning that the various manufacturers have chosen to concentrate upon, the demands on their equipment are becoming more and more stringent. Happily, it appears that the equipment is keeping pace with the requirements.

 

Share
.