This part of IS0 11922 specifies tolerance grades for the outside diameter, out-of-roundness and wall thickness of metric thermoplastics pipes for the conveyance of fluids and manufactured with nominal outside diameters and nominal pressures in accordance with IS0 161-1[1] and nominal wall thicknesses in accordance with IS0 4065[31 (see annex A). It is applicable to smooth thermoplastics pipes of constant circular cross-section along the whole length of the pipe, whatever the method of manufacture, the pipe material or the intended application. NOTE - It is intended that the tolerance grades specified in product standards be selected from this part of IS0 11922, taking into account the material and the intended application.