Underground tanks of glass-reinforced plastics (GRP). Horizontal cylindrical tanks for the non-pressure storage of liquid petroleum based fuels. Requirements and test methods for single wall tanks|Joints, Thickness, Life (durability), Bend testing, Chemical-resistance tests, Leak tests, Underground, Reinforcing materials, Manholes, Stability, Dimensions, Design, Plastics, Cylindrical shape, Laminates, Containers, Tanks (containers), Pipe couplings, Cloth, Pipe fittings, Performance, Grades (quality), Marking, Stiffness, Reinforced materials, Impact testing, Petroleum products, Glass fibres, Tensile testing, Horizontal, Thermosetting polymers, Mechanical testing, Bulk storage containers, Glass, Textile glass, Fuel storage, Low-pressure tests, Testing conditions