HORIZONTAL DIRECTIONAL DRILLING- INSTALLATION PROCEDURE HORIZONTAL DIRECTIONAL DRILLING - PE100 APPLICATIONS This is not a technique to which the ‘lowest price wins the contract’ principle should be applied.

This is a highly specialised technique, and needs an experienced and highly trained operating team, an essential member of which is the drilling mud technician, particularly on the larger diameters. For the larger diameters, the equipment is large, and requires support equipment such as generators and hydraulic power units. Where large parts of the route of the main are not accessible, such as for river crossings, horizontal directional drilling is a much less costly technique than tunnelling, and can be used for large diameters, such as trunk mains. This method is regularly used on distribution systems, which typically use small diameter mains, and on rural distribution systems it often enables mains to be installed alongside the carriageway without impeding traffic flow, as the drilling equipment is compact and self contained. This method has a very small potential damage footprint provided that adjacent buried infrastructure can be accurately located. When new pipe is to be installed or it is not possible to rehabilitate a pipe, so that it needs to be replaced but is in a congested area of buried infrastructure so that conventional methods such as bursting cannot be used safely, then a new or replacement PE100 pipe can often be installed by horizontal directional drilling. HORIZONTAL DIRECTIONAL DRILLING - TECHNIQUE

Directional drilling