A pipe made from thermoplastic material of the PVC-O type having an outer surface extending about an axis of symmetry; the pipe has a main longitudinal extension in a direction parallel to the axis of symmetry from a first end to a second end; at the second end, the outer surface of the pipe has a chamfer having an inclination with respect to a direction parallel to the axis of symmetry equal to an acute angle (β); the pipe has an inner chamber passing from the first end to the second end; the pipe comprises a seal, positioned in a respective housing seat, with circumferential extension relative to the axis of symmetry; the seal being positioned in the housing seat in an irremovable fashion; the seal has an inner surface, facing the inner chamber, and an outer surface, facing the housing seat; the outer surface of the seal has a first portion and a second portion arranged contiguous to each other and in such a way as to define a cusp; the first portion and the second portion are inclined relative to a direction parallel to the axis of symmetry by a respective acute angle (θp; θa); the inner chamber has a first section, having a first diameter, and a second section having at least a second diameter greater than the first diameter, and a third section for connecting the first section to the second section having a convergent shape from the second section to the first section; the pipe being characterised in that the inner chamber has a taper, adjacent to the second section and leading towards the outside environment at the first end of the pipe, having a diverging trend starting from the second diameter of the second section towards the outside environment; the taper has an inclination relative to a direction parallel to the axis of symmetry equal to an acute angle (αf) whose value is proportional to the value of the acute angle (θp) of inclination of the first portion of the outer surface of the seal, relative to a direction parallel to the axis of symmetry of the pipe, with a factor "r" of between 0.75 and 2.5, inclusive, that is α f = r * θ p. at the second end, the outer surface of the pipe has a chamfer having an inclination with respect to a direction parallel to the axis of symmetry equal to an acute angle (β); the pipe has an inner chamber passing from the first end to the second end; the pipe comprises a seal, positioned in a respective housing seat, with circumferential extension relative to the axis of symmetry; the seal being positioned in the housing seat in an irremovable fashion; the seal has an inner surface, facing the inner chamber, and an outer surface, facing the housing seat; the outer surface of the seal has a first portion and a second portion arranged contiguous to each other and in such a way as to define a cusp; the first portion and the second portion are inclined relative to a direction parallel to the axis of symmetry by a respective acute angle (θp; θa); the inner chamber has a first section, having a first diameter, and a second section having at least a second diameter greater than the first diameter, and a third section for connecting the first section to the second section having a convergent shape from the second section to the first section; the pipe being characterised in that the inner chamber has a taper, adjacent to the second section and leading towards the outside environment at the first end of the pipe, having a diverging trend starting from the second diameter of the second section towards the outside environment; the taper has an inclination relative to a direction parallel to the axis of symmetry equal to an acute angle (αf) whose value is proportional to the value of the acute angle (θp) of inclination of the first portion of the outer surface of the seal, relative to a direction parallel to the axis of symmetry of the pipe, with a factor "r" of between 0.75 and 2.5, inclusive, that is α f = r * θ p.