If you are just getting familiar with industrial fiberglass here are the basics on glass fiber types and when they are used.
Surfacing Veil versus Carbon Veil
Surfacing veils are applied to the process side of the corrosion liner. They are designed to protect surfaces from the effects of corrosion by providing very high resin content, typically 90%. Carbon veils are used on the inner surface of FRP ducting, exhaust stacks, and other gas handling equipment to eliminate the hazards associated with the build-up of static electricity.
Chopped Strand Mat 1-1/2 oz/sqft versus Chopped Strand Mat 3/4 oz/sqft
Chopped strand mat is used as reinforcement in corrosion liners and in structural laminates. The mat contains high amounts of resin to help increase corrosion resistance when used behind surfacing veils. In structural layers mat aids bonding between layers of woven roving and reduces the risk of interlaminar shear. Utilizing various weights of chopped strand mat allows you to control the amount of high strength woven roving while not increasing overall product thickness.
Woven Roving is typically used in alternating layers with chopped strand mat. This provides the primary structural reinforcement in many contact molded parts. Woven Roving is a bi-directional weave, allowing it to provide strength in two directions.
Weft unidirectional is used to provide axial strength to filament-wound laminates. The fabric is unrolled on the surface of the turning mandrel, which aligns the strands axially with the cylinder.
Filament Winding Strands 450 yield versus 250 yield
Filament winding is most often used for producing cylindrical components, such as piping, ducting, and tank shells. Filament winding allows uniformity and repeatability in manufacturing of large quantities. Lower yield filament winding allows for faster production, at the expense of crack resistance and strength.