Glass Reinforced Polyester (GRP) Pipes / Glass Reinforced Vinylester (GRV) Pipes Amiantit Fiberglass Industries Limited (AFIL) was established in 1977, and it is the largest Glass Reinforced Polyester (GRP) Glass Reinforced Vinylester (GRV) Pipe manufacturing plant in the world. GRP/GRV Pipes are specially designed and manufactured for sanitary sewerage .