“Underground service or ‘cable’ strikes are one of the greatest challenge areas for the utility sector, resulting in a significant number of deaths and injuries per year and incurring millions of pounds in associated damages and compensation costs.” – Water Active Magazine, January 2012.

The January issue of Water Active highlighted the considerable problem of the 60,000 annually reported underground service or cable strikes that happen in the UK every year and the time and financial penalties that result to the industry. Indeed the issue is serious enough for specific Health & Safety Executive guidance (HSG47). While training, education and best practice work in line with HSG47 will clearly play an important role in reducing the problem, one new technique for replacing lead and leaking water pipes is providing another, more fundamental solution to the problem.

Digging trenches and moling both carry considerable risk of service and cable strikes as they mechanically create new spaces for pipes, disrupting the ground and disturbing the other services. But Pipe Pulling – exactly replacing the old pipe with the new -avoids the problem because there is no trench involved and the new pipe sits exactly in the space left behind by the old.

The potential benefits of pipe pulling in reducing cable strikes have been clear for many years but all attempts to successfully achieve the technique have failed until the introduction of the Kobus Pipe Puller which went into regular use with water companies and contractors in the winter of 2010/11.

Indeed the technical and innovative achievement of the Kobus Pipe Puller has recently been awarded both the Water Dragons 2011 Innovation Award, and the NJUG 2011 Quality Award (in conjunction with Veolia Water), and won further recognition in the 2011 PIG and UKSTT Innovation awards. The NJUG Award was an acknowledgement by the utilities industry itself as to the benefits that the Pipe Puller brings in this area.

How does the Kobus Pipe Puller work?
The Kobus Pipe Puller takes a new and innovative approach to replacing service pipes of all different materials or leaking water pipes by feeding a calibrated steel cable through the pipe to be removed and filling the pipe with special formula Kobite, which packs the pipe to the cable to create a single ‘composite rope’. The cable is then attached to the new MDPE pipe to be pulled through and as the old pipe is pulled out under a carefully calculated and maintained force, the new pipe simply slides into the space left by the old pipe and replaces it.

The only digging required is a small 1foot square hole at either end, ideally around the service point or in safe areas where the likelihood of other services is reduced.

Already in use by a number of water companies and contractors for water loss reduction and lead replacement programmes as well as emergency repairs, the approach taken by the Kobus Pipe Puller avoids cable strikes by not disturbing any new ground underneath the road, leaving all services untouched. This feature is especially valuable where rapid repairs are required and underground asset data is limited or doubtful.

By removing the old pipe in the replacement process, the system also avoids the ever growing problem of new services being laid beneath our roads and obsolete services being left where they are. Clearly, as more and more services are buried it becomes harder for contractors following on to be able to detect, through surface equipment, and assess which services are live and which ones are not and for asset owners to keep their underground asset GIS mapping up to date.

Using traditional forms of water pipe replacement the old pipes are left in the ground adding to the problem. Removing them will help contractors to meet the revised water quality target for lead by the end of 2013 .

Removing the Pipe for Recycling
In addition, by removing the old lead pipe from the ground and reducing the amount of under-road clutter, the metal can be recycled saving money and reducing the carbon footprint of the contractor.

Recycling brings another revenue stream for water authorities and contractors and not only removes the risk of further ground contamination, but also means less new lead needs to be mined. It is estimated that, over the next two years, one lead replacement programme for one water authority will remove 9000 lead water pipes each around 10m in length. This alone will enable the recycling of 72 metric tonnes of lead, and lead currently stands at around £2,000.00 per tonne.

With increasing importance placed on carbon footprint, the removal and the recycling of the lead brings considerable environmental benefits to the water company. The total carbon footprint for replacing a 10m water pipe with a Kobus Pipe Puller is calculated at 20.3kg. If the 11lb, 10m pipe is recycled the total carbon saved is 153kg, or a saving of 133kg, the equivalent of running a small family car for over 620miles.

Conclusions
By taking a completely different approach to replacing water pipes the Kobus Pipe Puller has brought a whole host of additional benefits to the industry, a fact recognised by the host of awards it received in 2011. By removing and exactly replacing the old pipe, the system has done away with the problem of cable strikes, has created a large amount of lead for recycling, has reduced the carbon footprint of pipe replacement, and is not adding to the unwanted services under our roads and compounding the striking problem for other services and contractors.

While the Kobus Pipe Puller is not the only solution to the problem of cable strikes, it has, at a stroke, removed the bulk of the risk of them when removing water pipes both in emergency repairs and lead replacement programmes.

Water Active, February 2012, p31