Spray Lining

Concept of spray lining

Spray lining systems are intended for small-diameter pressure pipes where man entry is not possible.

In water distribution rehabilitation, a common objective is to remove deposits and corrosion and then apply a lining that inhibits future deterioration and seals minor leakage.

Materials and application

The most commonly used materials are cement mortar and epoxy resin.

They are applied by a robotic spraying machine pulled through the pipeline at a predetermined constant speed.

A spray head applies the lining to the inside surface of the pipe, forming an internal protective layer.

Application to sewer networks

Spray lining methods have also been developed for small-diameter sewers without man access, although no process has achieved the same level of commercial prominence.

This may partly reflect different sewer rehabilitation requirements, where the objective is often to increase resistance to external loading and prevent corrosion.

Practical challenges

Another challenge is the need to ensure that inflow into the pipeline is completely stopped during lining application and curing.

A practical spray lining system should also minimize the service-reconnection issues inherent in other rehabilitation techniques.

Use in gas and potable-water networks

Spray lining is rarely used in gas distribution mains, although in some countries it is extensively used for domestic gas service connections.

Worldwide, its most common application is in potable-water distribution networks.