This repair method, used by SINSO - Integrated Welding Solutions, consists of welded gutters around the perimeter of a pipe, applicable to pipes and ducts. The double gutter can be dimensioned for pressurization or not, depending on the type of gutter installed and the damage to the pipe. This repair applies to internal or external damage to the pipe to be reinforced.

Double gutters are welded by means of two longitudinal joints and can be of two types: Type A (without circumferential closing joints) and Type B (with circumferential closing joints).

Type A is not capable of containing internal pressure, but serves as structural reinforcement of the damaged area. It is used for damage to pipes without leaks or where the expectation is that they will not evolve in service, and is usually applied to external damage that can be controlled. It may not be appropriate for pipe defects oriented in the circumferential direction.

Type B corresponds to the double gutter with circumferential welds, which has the capacity to contain the internal pressure of the pipe in the event of a leak. It is used for defects with leaks or with the potential for leaks during operation. It is also used to contain defects that may reduce the axial load capacity of the pipe. When welding this type of gutter on a leaking pipe, temporary sealing work must be carried out to avoid harmful effects on the welding of the double gutter.