Twiga Glass Pipe Wrap is a thin flexible, uniform felt, composed of glass fibers in an open porous structure, bonded with a phenolic binder that is compatible with hot coal-tar enamel. The mat may be of the reinforced or non-reinforced type.
For water, crude oil and gas pipelines, the anti-corrosive protections mostly utilized are hydrocarbon base systems (oil or pit carbon derivates) mixed with mineral fillers and reinforced with Twiga Glass Mat (normally utilized as “INNERWRAP”) and impregnated Twiga Glass Mat (as “OUTERWRAP”).
Coating with Twiga Pipe Wrap ensures a higher mechanical resistance, uniformity of thickness and permanent adhesion to the pipeline walls.
Twiga Pipe Wrap conforms to International standards (AWWA C 203 latest versions / IS 10221 – 1982) for anti-corrosion coatings of pipe works as well as to the technical specifications provided by the major pipeline engineering groups.
Twiga Glass INNERWRAP shall be mechanically applied by continuous end feed machine or by a lathe-type machine or by other approved application equipment. The application shall be simultaneous with the first coat of coal tar enamel. The roll of inner wrap shall be under tension sufficient to embed the fibre glass tissue in the enamel before the latter sets or cools. The wrapper shall not be pulled through the hot enamel to the metal surface.
The three methods of application of wrapping materials that can be followed are:
(a) Mill wrapping.
(b) Site or yard wrapping.
(c) Line wrapping.
The choice between the three methods of application of pipe wrappings shall depend on a detailed assessment of site conditions and the technical aspects, including corrosion engineering and economic factors involved in the construction work. The conditions which decide the selection of wrapping method are:
(a) Weather conditions.
(b) Site conditions.
(c) Size of pipeline.
(d) Location of site.
Twiga Glass Tissue is saturated with Coal Tar enamel. The resultant Twiga Glass Tissue based OUTERWRAP shall be uniform, flexible and of uniform porosity to facilitate the release of hot gases and achieves better finishing. The outer surface of OUTERWRAP shall be lightly dusted with talc, fine sand, or other approved mineral powder sufficient to prevent sticking in the rolls under condition likely to be met at site. The inside surface shall receive minimum dusting, as excessive amount may impair the bond between outer wrap and enamel.
OUTERWRAP shall be mechanically applied in a continuous end feed machine or in a lathe-type machine or by other suitable outerwrap application equipment. The OUTERWRAP shall be applied to, but not buried in, the outer surface immediately following the final coat of enamel.
Twiga Glass Tissue comes in roll form wrapped on a core and packed in a corrugated box/ corrugated sheet and needs to be handled a as per prescribed methods to prevent tissue and pipe core from getting damaged. The boxes should be kept vertically as shown in the box.