Impacted rubber deposits are effectively milled from the runway surface and recovered along with the used water by way of powerful vacuum, so no water or arisings that might constitute Foreign Object Debris (F.O.D.) are left behind. The result is a clean, dry surface, immediately safe for aircraft operations. Where practical and applicable, several machines can operate in echelon much the same as pavers do.

The effect of our proprietary process, which incidentally has numerous other uses, is to rid the runway touch-down zone of rubber deposits and fuel spillages. It makes a significant improvement in the Mu (coefficient of friction) or grip number, thus improving airport safety. The system operates at a minimum working width of 2.3 m and at rates of progress of between 0.5–1.25 km per hour. Outputs of 10,000 m2 per shift are frequently achieved. Porous friction-wearing courses require more care because of the inherently fragile nature of the material, while Pavement-Quality concrete surfaces need greater water pressure as the rubber tends to "burn" into surface voids and removal requires more persuasion.

Pavements suitable for the process

The system is capable of dealing with all types of surfacing materials including grooved Marshall asphalt, porous friction course stone mastic asphalts, concrete block-paved* runways and PQ concrete. Runways surfaced with Slurry Seal may be treatable, but great care would be required as the process is capable of removing micro materials.

*Block paving, unless previously sealed, will suffer a loss of jointing sand. We have a process that can replace the sand and re-seal the runway with an environmentally friendly, hard wearing resin sealant.

Runway touch-down zones paved with grooved Marshall asphalt can be cleaned without damaging the edges of the grooves. As the system uses a rotary cleaning method, it is not necessary to clean parallel to the grooves. It makes no difference which direction you travel in, the effect is the same. However, efficiency dictates working down the runway, beginning at the centre line and working outwards. The process is so controllable that work can proceed between aircraft movements (off-peak). The runway can be vacated within seconds of a command from the ATC. No potential F.O.D. (Foreign Object Debris) is left behind and operational delays to airport operators are virtually nil.

The Operation

Sites are identified and inspected for QA purposes, and limits are agreed upon with the Client's representative.

The machine is fully charged with clean water (6,000 l) at the outset of the working shift and once clearance is received from the ATC, the machine and support plant enters the runway under escort. As described above, work commences at the centre line and proceeds in one direction down the runway to the end of the TDZ or designated working area.

Support vehicles in attendance are a water bowser which provides clean water for the process and a vacuum tanker for used and waste water. Recharging and decanting takes about 10 minutes after each operational hour. The waste is taken to a liquid waste processing plant where the water is fully recycled. Solid waste is collected and taken to a landfill site. Our operations manager remains with the team on a full-time basis. The whole team moves around as a unit.

The process is "all-weather," but it is inadvisable to work in ambient temperatures at or below 0oC or in fog.

Normally, friction testing is carried out by our employee or an independent, testing house. We can, however, offer an inspection, test and treatment package, if required. Tests are valid and accurate only if pre-treatment tests are carried out and post-treatment tests are done as soon as possible after operations have been completed.

Safety