This specification covers the standard of re-enforced Glass Fiber Wrap to be used as part of protective coating of buried pipelines.
This material is required to be incorporated in the Corrosion Protection Coating on the exterior of a buried natural gas pipeline.
The coating is intended to be applied by hot continuous flooding of Coal Tar/Asphalt enamel on steel pipe line by conventional line traveling machine or hand wrapping, together with simultaneous application of the glass fiber inner Wrap and “enamel per-saturated Glass Fiber”. The intended minimum thickness of coating is to be 3/32″ + 1/32″ when machine applied or 5/32″ when hand applied.
The material may also be used for conversion into Outer wrap by impregnation with Coaltar / Asphalt Enamel at the purchaser’s plant and is be suitable, too for the later purpose.
The Glass Fiber Wrap consists of a thin flexible uniform mat, generally as defined by ASTM Definitions C162-80.Chemically resistant Boro-silicate Glass containing not less than 5% of B2O3.
The Glass Fiber Mono-Filaments making up the mat is arranged in random pattern to provide a uniformly porous structure, which is reinforced by parallel longitudinal yarns of continuous filament Glass Fiber embedded in the mat and spaced at regular intervals. The whole is bonded with an inert phenolic type resin, which is compatible with hot Coaltar / Asphalt enamel.
The mat is sufficiently porous so that, it can be drawn into the hot Coaltar / Asphalt enamel coating as it is applied to the exterior of the pipe by a line traveling machine or hand application and does not pull right through the coating on to the pipe under normal tension. In this application the enamel will be to BS:4164-1980 or BS: 4147-87.
The glass mat does not cause bubbling during application to the enameled pipe, nor causes lamination of the Coaltar /Asphalt enamel coating after it is embedded. No disbanding of individual Glass fiber shall occur during or following the embedding process. The mat is free from thin spots , high spots, tufting, lamination, large holes, wrinkles , torn edges, dust oil and grease.
Fiber Glass mat wrap is made in continuous rolls of specified length, which contain no joints. The ends of the rolls are clean rolls, smooth, square out and does not show any sign of telescoping.