Standards are defined as a basis for comparison; a reference point against which others can be evaluated. Trenchless construction works comprises of a chain of several interlinked activities wherein even a partial variation in the expected outcome of a single activity can severely impact the final product or project alignment. Technique, its inputs, outcomes and all related activities & outcome standardization, therefore, is an important part of a successful project development and execution process and are termed as Specifications. This would comprise of a set of directives which can assist designers, engineers, and contractors in developing the precise working schedules and expected outcomes of each operation thereby concluding the complete construction activity successfully. Such set of specifications would form a part of the contract agreement thereby insuring the desired result from the entire project process. It is an important tool as this would assist one to evaluate the complete Techno-economic feasibility of any particular technique application and make a judicious selection. In addition, using these codes of practice would remove the doubts from the minds of project engineers and encourage them to apply the techniques in more projects. IndSTT is engaged in establishing different Codes of Practice (CoP) for various Trenchless Techniques and is honoured to present the Code of Practice for HDD Technique Suiting Indian Conditions.

Horizontal Directional Drilling (HDD) is a steerable technique for the installation of pipes, conduits, and cables in an arc shape using a surface launched drilling rig. This method requires the execution of a pilot bore which is then enlarged with the use of a reamer prior to installation of the product pipe. Depending on the diameter of the product pipe, multiple enlargements may be required. The excavation is performed by the mechanical action of a fluid assisted cutting head.

This Code of Practice therefore addresses the following issues for a successful project:

• Works should conform to general workplace safety

• Works should conform to efficient work practices

• They should stipulate conditions to prepare and set-up the plant and equipment

• They should stipulate conditions to prepare the new pipe-work material

• They should stipulate conditions assisting in drilling holes to desired requirements

• They should be identifying tracking parameters for a successful drilling operations

• They should be stipulating conditions for installing new pipe-work

• They should help in developing as built / as installed drawings

• They should help in managing drilling fluid/mud and related plants

• Help in erecting and dismantling plant (cranes and rigs)

• Assist in operating plant or machinery to lift and transfer loads

• Assist in operating plant or machinery to extract material

• Assist in operating plant or machinery to excavate

• Assist in operating plant or machinery to receive and transport loads

• Detailing slinging and signalling the movement of loads

• Stipulating conditions for equipment de-commissioning.

As HDD provides a cost effective alternative for developing subsurface pipelines in the Trenchless way this code of Practice is expected to provide a useful benchmark for the user. Like all codes this code is also expected to grow with time and the Society invites the readers/users to provide their inputs to include additional issues to make the code more useful.

(Prof. Niranjan Swarup)

Executive Director IndSTT & Secretary Working Group